Android实战演练（kotlin版），词汇记录APP

蔚落 2024-04-03 09:46 55阅读 0赞

效果图

![0e026b532f26428d8bbfdab8a0aeca01.png][]![0fcb3d985355478aac3886ca155091a9.png][]

![97c5d231269e4967b1ddaabe429478a1.png][]

以下是源代码

build.gradle文件

plugins {
        id 'com.android.application'
        id 'org.jetbrains.kotlin.android'
        id 'kotlin-kapt'
    }
    
    android {
        compileSdk 32
    
        defaultConfig {
            applicationId "com.example.word3"
            minSdk 27
            targetSdk 32
            versionCode 1
            versionName "1.0"
    
            testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        }
    
        buildTypes {
            release {
                minifyEnabled false
                proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
            }
        }
        compileOptions {
            sourceCompatibility JavaVersion.VERSION_1_8
            targetCompatibility JavaVersion.VERSION_1_8
        }
        kotlinOptions {
            jvmTarget = '1.8'
        }
    }
    
    dependencies {
    
        implementation 'androidx.core:core-ktx:1.7.0'
        implementation 'androidx.appcompat:appcompat:1.3.0'
        implementation 'com.google.android.material:material:1.4.0'
        implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
        testImplementation 'junit:junit:4.13.2'
        androidTestImplementation 'androidx.test.ext:junit:1.1.3'
        androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
    
        implementation 'androidx.room:room-runtime:2.1.0'
        kapt "androidx.room:room-compiler:2.1.0"
    
        implementation "androidx.lifecycle:lifecycle-livedata-ktx:2.5.1"
    
        implementation "androidx.lifecycle:lifecycle-extensions:2.2.0"
    
        implementation "androidx.navigation:navigation-fragment-ktx:2.5.2"
        implementation "androidx.navigation:navigation-ui-ktx:2.5.2"
        implementation 'androidx.recyclerview:recyclerview:1.2.1'
    
    }

layout

activity\_main.xml

cell\_card.xml

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:clickable="true"
        android:orientation="vertical">
        <androidx.cardview.widget.CardView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            tools:ignore="MissingConstraints">
    
            <androidx.constraintlayout.widget.ConstraintLayout
                android:id="@+id/constraintLayout"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toStartOf="@+id/guideline2"
                app:layout_constraintHorizontal_bias="0.0"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintVertical_bias="1.0"
                android:background="?selectableItemBackground">
                <androidx.constraintlayout.widget.Guideline
                    android:id="@+id/guideline2"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:orientation="vertical"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintGuide_percent="0.8"
                    app:layout_constraintHorizontal_bias="1.0"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toTopOf="parent" />
    
                <androidx.constraintlayout.widget.Guideline
                    android:id="@+id/guideline4"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:orientation="vertical"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintGuide_percent="0.15"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toTopOf="parent" />
    
                <TextView
                    android:id="@+id/textViewNumber"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="1"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintEnd_toStartOf="@+id/guideline4"
                    app:layout_constraintHorizontal_bias="0.38"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toTopOf="parent"
                    app:layout_constraintVertical_bias="0.412" />
    
                <TextView
                    android:id="@+id/textViewEnglish"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginEnd="200dp"
                    android:paddingTop="20dp"
                    android:text="TextView"
                    android:textSize="24dp"
                    app:layout_constraintBottom_toTopOf="@+id/textViewChinese"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintHorizontal_bias="0.0"
                    app:layout_constraintStart_toStartOf="@+id/guideline4"
                    app:layout_constraintTop_toTopOf="parent"
                    app:layout_constraintVertical_bias="0.333"
                    app:layout_goneMarginStart="16dp" />
    
                <TextView
                    android:id="@+id/textViewChinese"
                    android:layout_width="wrap_content"
                    android:layout_height="60dp"
                    android:layout_marginEnd="204dp"
                    android:paddingLeft="0dp"
                    android:paddingTop="40dp"
                    android:text="TextView"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintHorizontal_bias="0.072"
                    app:layout_constraintStart_toStartOf="@id/textViewEnglish"
                    app:layout_constraintTop_toTopOf="parent"
                    app:layout_constraintVertical_bias="0.878" />
    
                <androidx.constraintlayout.widget.ConstraintLayout
                    android:id="@+id/constraintLayout2"
                    android:layout_width="83dp"
                    android:layout_height="80dp"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintHorizontal_bias="0.0"
                    app:layout_constraintStart_toStartOf="@+id/guideline2"
                    app:layout_constraintTop_toTopOf="parent"
                    app:layout_constraintVertical_bias="1.0">
                    <Switch
                        android:id="@+id/aSwitchChineseInvisible"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:paddingStart="30dp"
                        android:paddingEnd="15dp"
                        app:layout_constraintBottom_toBottomOf="parent"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintHorizontal_bias="0.444"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toTopOf="parent"
                        app:layout_constraintVertical_bias="0.484"
                        tools:ignore="TouchTargetSizeCheck,UseSwitchCompatOrMaterialXml" />
                </androidx.constraintlayout.widget.ConstraintLayout>
            </androidx.constraintlayout.widget.ConstraintLayout>
    
        </androidx.cardview.widget.CardView>
    
    </LinearLayout>

cell\_normal.xml

<?xml version="1.0" encoding="utf-8"?>
    <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="60dp"
    
        android:background="#F9F9F9"
        android:clickable="true">
    
        <View
            android:id="@+id/divider"
            android:layout_width="2dp"
            android:layout_height="match_parent"
            android:background="?android:attr/listDivider"
            android:paddingTop="5dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="@+id/constraintLayout"
            app:layout_constraintStart_toEndOf="@+id/constraintLayout"
            app:layout_constraintTop_toTopOf="parent" />
    
        <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/constraintLayout"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:background="@android:drawable/list_selector_background"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toStartOf="@+id/guideline2"
            app:layout_constraintHorizontal_bias="0.0"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="1.0">
    
    
            <androidx.constraintlayout.widget.Guideline
                android:id="@+id/guideline4"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="vertical"
                app:layout_constraintGuide_percent="0.15" />
    
            <TextView
                android:id="@+id/textViewNumber"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="1"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toStartOf="@+id/guideline4"
                app:layout_constraintHorizontal_bias="0.38"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintVertical_bias="0.412" />
    
            <TextView
                android:id="@+id/textViewEnglish"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="200dp"
                android:text="TextView"
                android:textSize="24dp"
                app:layout_constraintBottom_toTopOf="@+id/textViewChinese"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintHorizontal_bias="0.0"
                app:layout_constraintStart_toStartOf="@+id/guideline4"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintVertical_bias="0.333"
                app:layout_goneMarginStart="16dp" />
    
            <TextView
                android:id="@+id/textViewChinese"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="204dp"
                android:text="TextView"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintHorizontal_bias="0.072"
                app:layout_constraintStart_toStartOf="@id/textViewEnglish"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintVertical_bias="0.878" />
        </androidx.constraintlayout.widget.ConstraintLayout>
    
        <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/constraintLayout2"
            android:layout_width="wrap_content"
            android:layout_height="0dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="@+id/guideline2"
            app:layout_constraintTop_toTopOf="parent">
    
            <Switch
                android:id="@+id/aSwitchChineseInvisible"
                android:layout_width="wrap_content"
                android:layout_height="0dp"
                android:paddingStart="20dp"
                android:paddingEnd="15dp"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintHorizontal_bias="0.444"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintVertical_bias="0.484"
                tools:ignore="TouchTargetSizeCheck,UseSwitchCompatOrMaterialXml" />
        </androidx.constraintlayout.widget.ConstraintLayout>
    
        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline2"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            app:layout_constraintGuide_percent="0.8" />
    
    </androidx.constraintlayout.widget.ConstraintLayout>

fragment\_add.xml

fragment\_words.xml

<?xml version="1.0" encoding="utf-8"?>
    <androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/wordsFragmentView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".WordsFragment">
    
    
        <com.google.android.material.floatingactionbutton.FloatingActionButton
            android:id="@+id/floatingActionButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|center_horizontal"
            android:layout_margin="16dp"
            android:clickable="true"
            android:elevation="8dp"
            android:src="@drawable/ic_baseline_add_24"
            tools:ignore="SpeakableTextPresentCheck" />
    
        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    </androidx.coordinatorlayout.widget.CoordinatorLayout>

menu：

main\_menu.xml

<?xml version="1.0" encoding="utf-8"?>
    <menu xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:android="http://schemas.android.com/apk/res/android">
    
        <item
            android:id="@+id/clearData"
            android:title="清空数据" />
        <item
            android:id="@+id/switchViewType"
            android:title="切换视图" />
        <item
            android:id="@+id/app_bar_search"
            android:icon="@android:drawable/ic_menu_search"
            android:title="Search"
            app:actionViewClass="androidx.appcompat.widget.SearchView"
            app:showAsAction="always" />
    </menu>

navigation:

navigation.xml

<?xml version="1.0" encoding="utf-8"?>
    <navigation xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/navigation"
        app:startDestination="@id/wordsFragment">
        <fragment
            android:id="@+id/addFragment"
            android:name="com.example.word3.AddFragment"
            android:label="Add"
            tools:layout="@layout/fragment_add" />
        <fragment
            android:id="@+id/wordsFragment"
            android:name="com.example.word3.WordsFragment"
            android:label="Words"
            tools:layout="@layout/fragment_words">
            <action
                android:id="@+id/action_wordsFragment_to_addFragment"
                app:destination="@id/addFragment"
                app:enterAnim="@anim/nav_default_enter_anim" />
        </fragment>
    </navigation>

values

ids.xml

<?xml version="1.0" encoding="utf-8"?>
    <resources>
        <item name="word_for_view_holder" type="id"/>
    </resources>

####    AddFragment ####

import android.content.Context
    import android.os.Bundle
    import android.text.Editable
    import android.text.TextWatcher
    import androidx.fragment.app.Fragment
    import android.view.LayoutInflater
    import android.view.View
    import android.view.ViewGroup
    import android.view.inputmethod.InputMethodManager
    import android.widget.Button
    import android.widget.EditText
    import androidx.lifecycle.ViewModelProvider
    import androidx.navigation.NavController
    import androidx.navigation.Navigation
    class AddFragment : Fragment() {
        private lateinit var buttonSubmit: Button
        private lateinit var editTextEnglish: EditText
        private lateinit var editTextChinese: EditText
        private lateinit var wordViewModel: WordViewModel
        override fun onCreateView(
            inflater: LayoutInflater, container: ViewGroup?,
            savedInstanceState: Bundle?
        ): View? {
            var view: View = inflater.inflate(R.layout.fragment_add, container, false)
            buttonSubmit = view.findViewById(R.id.buttonSubmit)
            editTextChinese = view.findViewById(R.id.editTextChinese)
            editTextEnglish = view.findViewById(R.id.editTextEnglish)
            return view
        }
    
        override fun onActivityCreated(savedInstanceState: Bundle?) {
            super.onActivityCreated(savedInstanceState)
            buttonSubmit.isEnabled = false
            editTextEnglish.requestFocus()
            wordViewModel= ViewModelProvider(requireActivity()).get(WordViewModel::class.java)
            val imm: InputMethodManager =
                requireActivity().getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
            imm.showSoftInput(editTextEnglish, 0)
            editTextChinese.addTextChangedListener(mydetextWatcher())
            editTextEnglish.addTextChangedListener(mydetextWatcher())
            buttonSubmit.setOnClickListener {
                val english:String=editTextEnglish.text.toString().trim()
                val chinese:String=editTextChinese.text.toString().trim()
                val word:Word= Word(english,chinese,false)
                wordViewModel.insertWords(word)
                val navController: NavController = Navigation.findNavController(it)
                navController.navigateUp()
                val imm:InputMethodManager= requireActivity().getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
                imm.hideSoftInputFromWindow(it.windowToken,0)
            }
        }
    
        inner class mydetextWatcher : TextWatcher {
            override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
            }
            override fun onTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
                val english: String = editTextEnglish.text.toString().trim()
                val chinese: String = editTextChinese.text.toString().trim()
                buttonSubmit.isEnabled = english.isNotEmpty() && chinese.isNotEmpty()
    
            }
            override fun afterTextChanged(p0: Editable?) {
    
            }
        }
    }

#### MainActivity ####

import androidx.appcompat.app.AppCompatActivity
    import android.os.Bundle
    import androidx.navigation.NavController
    import androidx.navigation.findNavController
    import androidx.navigation.fragment.findNavController
    import androidx.navigation.ui.NavigationUI
    
    class MainActivity : AppCompatActivity() {
        private lateinit var navController:NavController
        override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            setContentView(R.layout.activity_main)
          navController=supportFragmentManager.findFragmentById(R.id.fragment)?.findNavController() as NavController
           NavigationUI.setupActionBarWithNavController(this,navController)
        }
        override fun onSupportNavigateUp(): Boolean {
            navController.navigateUp()
            return super.onSupportNavigateUp()||findNavController(R.id.fragment).navigateUp()
        }
    
    }

#### MyAdapter ####

import android.content.Intent
    import android.net.Uri
    import android.view.LayoutInflater
    import android.view.View
    import android.view.ViewGroup
    import android.widget.Switch
    import android.widget.TextView
    import androidx.recyclerview.widget.DiffUtil
    import androidx.recyclerview.widget.RecyclerView
    
    class MyAdapter(var useCardView:Boolean,var wordViewModel: WordViewModel) :androidx.recyclerview.widget.ListAdapter<Word,MyAdapter.ViewHolder>(diffCallback) {
        companion object{
            val diffCallback=object :DiffUtil.ItemCallback<Word>(){
                override fun areItemsTheSame(oldItem: Word, newItem: Word): Boolean {
                    return oldItem.id==newItem.id
                }
    
                override fun areContentsTheSame(oldItem: Word, newItem: Word): Boolean {
                    return (oldItem.word == newItem.word &&
                            oldItem.chineseMeaning == newItem.chineseMeaning &&
                            oldItem.isChineseInvisible == newItem.isChineseInvisible)
                }
            }
        }
    
        override fun onViewAttachedToWindow(holder: ViewHolder) {
            super.onViewAttachedToWindow(holder)
            holder.textViewNumber.text=(holder.absoluteAdapterPosition +1).toString()
        }
        inner class ViewHolder(view:View):RecyclerView.ViewHolder(view){
            val aSwitchChineseInvisible:Switch=view.findViewById(R.id.aSwitchChineseInvisible)
            var textViewNumber:TextView=view.findViewById(R.id.textViewNumber)
            var textViewEnglish:TextView=view.findViewById(R.id.textViewEnglish)
            var textViewChinese:TextView=view.findViewById(R.id.textViewChinese)
    
    
        }
        override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
            var layoutInflater:LayoutInflater=LayoutInflater.from(parent.context)
            var itemView:View = if(useCardView){
                layoutInflater.inflate(R.layout.cell_card,parent,false)
            }else{
                layoutInflater.inflate(R.layout.cell_normal,parent,false)
            }
            val holder: ViewHolder =ViewHolder(itemView)
            holder.itemView.setOnClickListener {
                var uri:Uri= Uri.parse("https://m.youdao.com/dict?le=eng&q="+holder.textViewEnglish.text)
                var intent:Intent= Intent(Intent.ACTION_VIEW)
                intent.setData(uri)
                holder.itemView.context.startActivities(arrayOf(intent))
            }
            holder.aSwitchChineseInvisible.setOnCheckedChangeListener { compoundButton, b ->
                var word:Word=holder.itemView.getTag(R.id.word_for_view_holder) as Word
                if (b){
                    word.isChineseInvisible=true
                    holder.textViewChinese.visibility=View.GONE
                    wordViewModel.updateWords(word)
                }else{
                    word.isChineseInvisible=false
                    holder.textViewChinese.visibility=View.VISIBLE
                    wordViewModel.updateWords(word)
                }
            }
            return holder
        }
        override fun onBindViewHolder(holder: ViewHolder, position: Int) {
            var word:Word=getItem(position)
            holder.itemView.setTag(R.id.word_for_view_holder,word)
            holder.textViewNumber.text= (position+1).toString()
            holder.textViewEnglish.text=word.word
            holder.textViewChinese.text=word.chineseMeaning
    
            if (word.isChineseInvisible){
                holder.textViewChinese.visibility=View.GONE
                holder.aSwitchChineseInvisible.isChecked=true
            }else{
                holder.textViewChinese.visibility=View.VISIBLE
                holder.aSwitchChineseInvisible.isChecked=false
            }
        }
    }

#### MyApplication ####

import android.annotation.SuppressLint
    import android.app.Application
    import android.content.Context
    
    class MyApplication:Application() {
        companion object{
            @SuppressLint("StaticFieldLeak")
            lateinit var context: Context
        }
        override fun onCreate() {
            super.onCreate()
            context=applicationContext
        }
    }

#### Word ####

@Entity
    data class Word (var word: String,var chineseMeaning:String,var isChineseInvisible:Boolean){
        @PrimaryKey(autoGenerate = true)
        var id:Int=0
    }

#### WordDao ####

import androidx.lifecycle.LiveData
    import androidx.room.*
    @Dao
    interface WordDao {
        @Insert
        fun insertWords( vararg word: Word)
        @Update
        fun updateWords(vararg word: Word)
        @Delete
        fun deleteWords(vararg word: Word)
        @Query("DELETE FROM WORD")
        fun deleteAllWords()
        @Query("SELECT * FROM WORD ORDER BY ID DESC")
        fun getAllWordsLive():LiveData<List<Word>>
        @Query("SELECT * FROM WORD WHERE word LIKE:patten ORDER BY ID DESC")
        fun findWordsWithPatten(patten:String):LiveData<List<Word>>
    }

#### WordDatabase ####

import android.content.Context
    import androidx.room.Database
    import androidx.room.Room
    import androidx.room.RoomDatabase
    
    @Database( version = 3, entities = [Word::class],exportSchema = false)
    abstract class WordDatabase: RoomDatabase() {
        companion object {
            private var instance: WordDatabase? = null
            @Synchronized
            fun getWordDatabase(context: Context): WordDatabase {
                instance?.let {
                    return it
                }
                return Room.databaseBuilder(
                    context.applicationContext,
                    WordDatabase::class.java, "word_database"
                ).allowMainThreadQueries().fallbackToDestructiveMigration()
                    .build()
                    .apply {
                        instance = this
                    }
            }
        }
        abstract fun getWordDao():WordDao
    }

#### WordRepository ####

import android.os.AsyncTask
    import androidx.lifecycle.LiveData
    
    class WordRepository {
       lateinit var wordDao: WordDao
        lateinit var allWordsLive: LiveData<List<Word>>
        init {
            val wordDatabase:WordDatabase=WordDatabase.getWordDatabase(MyApplication.context)
            wordDao=wordDatabase.getWordDao()
            allWordsLive=wordDao.getAllWordsLive()
        }
        fun findWordsWithPatten(patten:String): LiveData<List<Word>>{
            return wordDao.findWordsWithPatten("%"+patten+"%")
        }
        fun insertWords(vararg p0: Word?){
            InsertAsyncTask(wordDao).execute(*p0)
        }
        fun updateWords(vararg p0: Word?){
            UpdateAsyncTask(wordDao).execute(*p0)
        }
        fun deleteWords(vararg p0: Word?){
            DeleteAsyncTask(wordDao).execute(*p0)
        }
        fun deleteAllWords(vararg p0: Word?){
            DeleteAllAsyncTask(wordDao).execute()
        }
        companion object {
            class InsertAsyncTask internal constructor(var wordDao: WordDao) :
                AsyncTask<Word, Void, Void?>() {
                override fun doInBackground(vararg p0: Word?): Void? {
                    wordDao.insertWords(*p0 as Array<out Word>)
                    return null
                }
            }
    
            class UpdateAsyncTask internal constructor(var wordDao: WordDao) :
                AsyncTask<Word, Void, Void?>() {
                override fun doInBackground(vararg p0: Word?): Void? {
                    wordDao.updateWords(*p0 as Array<out Word>)
                    return null
                }
            }
            class DeleteAsyncTask internal constructor(var wordDao: WordDao) :
                AsyncTask<Word, Void, Void?>() {
                override fun doInBackground(vararg p0: Word?): Void? {
                    wordDao.deleteWords(*p0 as Array<out Word>)
                    return null
                }
            }
            class DeleteAllAsyncTask internal constructor(var wordDao: WordDao) :
                AsyncTask<Void, Void, Void?>() {
    
                override fun doInBackground(vararg p0: Void?): Void? {
                    wordDao.deleteAllWords()
                    return null
                }
            }
        }
    }

#### WordsFragment ####

import android.content.Context
    import android.content.SharedPreferences
    import android.os.Bundle
    import android.view.*
    import androidx.fragment.app.Fragment
    import android.widget.Toast
    import androidx.appcompat.app.AlertDialog
    import androidx.appcompat.widget.SearchView
    import androidx.lifecycle.LiveData
    import androidx.lifecycle.Observer
    import androidx.lifecycle.ViewModelProvider
    import androidx.navigation.NavController
    import androidx.navigation.Navigation
    import androidx.recyclerview.widget.*
    import com.google.android.material.floatingactionbutton.FloatingActionButton
    import com.google.android.material.snackbar.Snackbar
    
    class WordsFragment : Fragment() {
        private lateinit var wordViewModel: WordViewModel
        private lateinit var recyclerView: RecyclerView
        private lateinit var myAdapter1: MyAdapter
        private lateinit var myAdapter2: MyAdapter
        private lateinit var floatingActionButton: FloatingActionButton
        private lateinit var filteredWords: LiveData<List<Word>>
        val VIEW_TYPE_SHP:String="view_type_shp"
        val IS_USING_CARD_VIEW:String="is_using_card_view"
        private lateinit var allWords:List<Word>
        lateinit var dividerItemDecoration: DividerItemDecoration
        override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            wordViewModel = ViewModelProvider(this).get(WordViewModel::class.java)
            myAdapter1 = MyAdapter(false, wordViewModel)
            myAdapter2 = MyAdapter(true, wordViewModel)
    
        }
       inner class defaultItemAnimator:DefaultItemAnimator(){
            override fun onAnimationFinished(viewHolder: RecyclerView.ViewHolder) {
                super.onAnimationFinished(viewHolder)
                var linearLayoutManager:LinearLayoutManager=recyclerView.layoutManager as LinearLayoutManager
                if (linearLayoutManager!=null){
                    var firstPosition:Int=linearLayoutManager.findFirstVisibleItemPosition()
                    var lastPosition:Int=linearLayoutManager.findLastVisibleItemPosition()
                    for (i in firstPosition until lastPosition+1){
                       var holder: MyAdapter.ViewHolder=recyclerView.findViewHolderForAdapterPosition(i) as MyAdapter.ViewHolder
                        if (holder!=null){
                            holder.textViewNumber.text= (i+1).toString()
                        }
                    }
                }
            }
        }
        override fun onActivityCreated(savedInstanceState: Bundle?) {
            super.onActivityCreated(savedInstanceState)
            recyclerView.itemAnimator=defaultItemAnimator()
            var shp=requireActivity().getSharedPreferences(VIEW_TYPE_SHP,Context.MODE_PRIVATE)
            var viewType:Boolean=shp.getBoolean(IS_USING_CARD_VIEW,false)
            dividerItemDecoration= DividerItemDecoration(requireActivity(),DividerItemDecoration.VERTICAL)
    
            if (viewType){
                recyclerView.adapter=myAdapter2
            }else{
                recyclerView.adapter=myAdapter1
                recyclerView.addItemDecoration(dividerItemDecoration)
            }
            filteredWords=wordViewModel.allWordsLive
            filteredWords.observe(requireActivity(), Observer { count ->
                var temp:Int=myAdapter1.itemCount
                allWords=count
                if (temp!=count.size){
                    if (temp<count.size)
                        recyclerView.smoothScrollBy(0,-200)
                    myAdapter1.submitList(count)
                    myAdapter2.submitList(count)
                }
            })
            ItemTouchHelper(object :ItemTouchHelper.Callback(){
                override fun getMovementFlags(
                    recyclerView: RecyclerView,
                    viewHolder: RecyclerView.ViewHolder
                ): Int {
                    return makeMovementFlags(ItemTouchHelper.UP or ItemTouchHelper.DOWN,ItemTouchHelper.START or ItemTouchHelper.END)
                }
    
                override fun onMove(
                    recyclerView: RecyclerView,
                    viewHolder: RecyclerView.ViewHolder,
                    target: RecyclerView.ViewHolder
                ): Boolean {
                    Toast.makeText(requireActivity(),"慢一点",Toast.LENGTH_SHORT).show()
                    var wordFrom:Word=allWords.get(viewHolder.adapterPosition)
                    var wordTo:Word=allWords.get(target.adapterPosition)
                    var idTemp:Int=wordFrom.id
                    wordFrom.id=wordTo.id
                    wordTo.id=idTemp
                    wordViewModel.updateWords(wordFrom,wordTo)
                    myAdapter1.notifyItemMoved(viewHolder.adapterPosition,target.adapterPosition)
                    myAdapter2.notifyItemMoved(viewHolder.adapterPosition,target.adapterPosition)
                    return false
                }
    
                override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
                    var wordToDelete:Word=allWords.get(viewHolder.adapterPosition)
                    wordViewModel.deleteWords(wordToDelete)
                    Snackbar.make(requireActivity().findViewById(R.id.wordsFragmentView),"删除了一个词汇",Snackbar.LENGTH_SHORT)
                        .setAction("撤销",View.OnClickListener {
                            wordViewModel.insertWords(wordToDelete)
                        })
                        .show()
                }
    
            }).attachToRecyclerView(recyclerView)
            floatingActionButton.setOnClickListener {
                var navController: NavController = Navigation.findNavController(it)
                navController.navigate(R.id.action_wordsFragment_to_addFragment)
            }
    
        }
        override fun onCreateView(
            inflater: LayoutInflater, container: ViewGroup?,
            savedInstanceState: Bundle?
        ): View? {
            // Inflate the layout for this fragment
            var view:View=inflater.inflate(R.layout.fragment_words, container, false)
            recyclerView = view.findViewById(R.id.recyclerView)
            floatingActionButton=view.findViewById(R.id.floatingActionButton)
            recyclerView.layoutManager = LinearLayoutManager(activity)
            recyclerView.adapter = myAdapter1
            setHasOptionsMenu(true)
            return view
        }
        override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
           super.onCreateOptionsMenu(menu,inflater)
            inflater?.inflate(R.menu.main_menu,menu)
           var searchView:SearchView= menu.findItem(R.id.app_bar_search).actionView as SearchView
            searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener {
                override fun onQueryTextSubmit(query: String?): Boolean {
                    return false
                }
                override fun onQueryTextChange(newText: String): Boolean {
                        var patten: String = newText.trim()
                        filteredWords.removeObservers(requireActivity())
                        filteredWords = wordViewModel.findWordsWithPatten(patten)
                        filteredWords.observe(requireActivity(), Observer { count ->
                            var temp = myAdapter1.itemCount
                            allWords=count
                            if (temp != count.size) {
                                myAdapter1.submitList(count)
                                myAdapter2.submitList(count)
                            }
                        })
                    return false
                }
            })
        }
        override fun onOptionsItemSelected(item: MenuItem): Boolean {
            when(item.itemId){
                R.id.clearData->AlertDialog.Builder(requireActivity()).apply {
                    setTitle("清空数据")
                    setPositiveButton("确定"){dialog,which->wordViewModel.deleteAllWords()}
                    setNegativeButton("取消"){dialog,which->}
                    show()
                }
                R.id.switchViewType->{ var shp=requireActivity().getSharedPreferences(VIEW_TYPE_SHP,Context.MODE_PRIVATE)
                    var viewType:Boolean=shp.getBoolean(IS_USING_CARD_VIEW,false)
                    var editor:SharedPreferences.Editor=shp.edit()
                    if (viewType){
                        recyclerView.adapter=myAdapter1
                        recyclerView.addItemDecoration(dividerItemDecoration)
                        editor.putBoolean(IS_USING_CARD_VIEW,false)
                    }else{
                        recyclerView.adapter=myAdapter2
                        recyclerView.removeItemDecoration(dividerItemDecoration)
                        editor.putBoolean(IS_USING_CARD_VIEW,true)
                    }
                    editor.apply()
                }
            }
            return super.onOptionsItemSelected(item)
        }
    }

#### WordViewModel ####

import androidx.lifecycle.LiveData
    import androidx.lifecycle.ViewModel
    
    class WordViewModel: ViewModel() {
        lateinit var wordRepository: WordRepository
        lateinit var allWordsLive: LiveData<List<Word>>
        init {
            wordRepository= WordRepository()
            allWordsLive=wordRepository.allWordsLive
        }
        fun findWordsWithPatten(patten:String): LiveData<List<Word>>{
            return wordRepository.findWordsWithPatten("%"+patten+"%")
        }
        fun insertWords(vararg p0: Word?){
            wordRepository.insertWords(*p0)
        }
        fun updateWords(vararg p0: Word?){
            wordRepository.updateWords(*p0)
        }
        fun deleteWords(vararg p0: Word?){
            wordRepository.deleteWords(*p0)
        }
        fun deleteAllWords(vararg p0: Word?){
            wordRepository.deleteAllWords()
        }
    }

[0e026b532f26428d8bbfdab8a0aeca01.png]: https://img-blog.csdnimg.cn/0e026b532f26428d8bbfdab8a0aeca01.png
[0fcb3d985355478aac3886ca155091a9.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/2622f924f4804521a8742510ae185b96.png
[97c5d231269e4967b1ddaabe429478a1.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/397ac375295847dca8f4624d86ff922c.png