创建列表明细应用1－使用fragment

男娘i 2021-11-10 05:26 249阅读 0赞

[创建列表明细应用1－使用fragment][1_fragment]

笔记自《Android编程权威指南第二版》

第七章，创建一个列表明细应用

![20779-20170930123532356-1474283357.jpg][]

fragment是一种控制器对象，activity可委派它完成一些任务，这些任务通常就是管理用户界面。（管理用户界面的fragment又称UI fragment。它自己也产生布局文件）

利用fragment，可轻松实现选择不同的列表项就显示对应的明细视图Activity负责以一个明细fragment替换另一个明细fragment

![20779-20170930123834622-34266874.jpg][]

托管可以这样理解，activity在其视图层级里提供一处位置来放置fragment的视图。fragment本身不具有在屏幕上显示视图的能力。

![20779-20170930124053356-1946005729.jpg][]

添加支持库：

dependencies {
          
        compile fileTree(include: ['*.jar'], dir: 'libs')
        androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
          
            exclude group: 'com.android.support', module: 'support-annotations'
        })
        compile 'com.android.support:appcompat-v7:26.+'
        compile 'com.android.support.constraint:constraint-layout:1.0.0-alpha8'
        testCompile 'junit:junit:4.12'
        compile 'com.android.support:support-v4:26.0.0-alpha1'
        compile 'com.android.support:recyclerview-v7:26.0.0-alpha1'
    }

项目结构：

![20779-20170930124355606-540835978.jpg][]

Crime实体类：

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

package com.homelink.testcriminal;
    
    import java.util.Date;
    import java.util.UUID;
    
    /**
     * Created by ysc on 2017/9/30.
     */
    
    public class Crime {
    
        private UUID mId;
        private String mTitle;
        private Date mDate;
        private boolean mSolved;
        public Crime() {
            mId = UUID.randomUUID();
            mDate = new Date();
        }
    
    
    
        public UUID getId() {
            return mId;
        }
        public String getTitle() {
            return mTitle;
        }
        public void setTitle(String title) {
            mTitle = title;
        }
    
    
        public Date getDate() {
            return mDate;
        }
        public void setDate(Date date) {
            mDate = date;
        }
        public boolean isSolved() {
            return mSolved;
        }
        public void setSolved(boolean solved) {
            mSolved = solved;
        }
    
    }

SingleFragmentActivity抽象基类，用于CrimeActivity , CrimeListActivity。而这两个Activity又分别创建各自的Fragment

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

package com.homelink.testcriminal;
    
    import android.os.Bundle;
    import android.support.v4.app.Fragment;
    import android.support.v4.app.FragmentActivity;
    import android.support.v4.app.FragmentManager;
    
    /**
     * Created by ysc on 2017/9/30.
     */
    
    public abstract class SingleFragmentActivity extends FragmentActivity {
    
        protected abstract Fragment createFragment();
    
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_fragment);
            FragmentManager fm = getSupportFragmentManager();
            Fragment fragment = fm.findFragmentById(R.id.fragment_container);
            if (fragment == null) {
                fragment = createFragment();
                fm.beginTransaction()
                        .add(R.id.fragment_container, fragment)
                        .commit();
            }
        }
    
    
    }

CrimeActitiy.java

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

package com.homelink.testcriminal;
    
    import android.support.v4.app.Fragment;
    import android.support.v4.app.FragmentActivity;
    import android.support.v4.app.FragmentManager;
    import android.os.Bundle;
    
    public class CrimeActivity extends SingleFragmentActivity {
    
        @Override
        protected Fragment createFragment() {
            return new CrimeFragment();
        }
    }

CrimeListActivity.java

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

package com.homelink.testcriminal;
    
    import android.support.v4.app.Fragment;
    
    /**
     * Created by ysc on 2017/9/30.
     */
    
    public class CrimeListActivity extends SingleFragmentActivity {
    
        @Override
        protected Fragment createFragment() {
            return new CrimeListFragment();
        }
    }

activity\_fragment.xml 的layout，用于托管fragment。很简单，就只放了一个FrameLayout，用于承载Fragment

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

<?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="match_parent"
        tools:context="com.homelink.testcriminal.CrimeActivity">
    
        <FrameLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/fragment_container"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            />
    
    </LinearLayout>

fragment\_crime.xml布局：

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        >
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/crime_title_label"
            style="?android:listSeparatorTextViewStyle"
            />
        <EditText android:id="@+id/crime_title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="16dp"
            android:layout_marginRight="16dp"
            android:hint="@string/crime_title_hint"
            />
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/crime_details_label"
            style="?android:listSeparatorTextViewStyle"
            />
        <Button android:id="@+id/crime_date"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="16dp"
            android:layout_marginRight="16dp"
            />
        <CheckBox android:id="@+id/crime_solved"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="16dp"
            android:layout_marginRight="16dp"
            android:text="@string/crime_solved_label"
            />
    </LinearLayout>

![20779-20170930125030137-2014654192.jpg][]![20779-20170930125054497-555718632.jpg][]

横向：

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical" android:layout_width="match_parent"
        android:layout_height="match_parent">
    
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/crime_title_label"
            style="?android:listSeparatorTextViewStyle"
            />
        <EditText android:id="@+id/crime_title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="16dp"
            android:layout_marginRight="16dp"
            android:hint="@string/crime_title_hint"
            />
    
    
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/crime_details_label"
            style="?android:listSeparatorTextViewStyle"
            />
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="16dp"
            android:layout_marginRight="16dp" >
            <Button
                android:id="@+id/crime_date"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1" />
            <CheckBox
                android:id="@+id/crime_solved"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="@string/crime_solved_label" />
        </LinearLayout>
    
    </LinearLayout>

CrimeFragment.java控制器，展示数据

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

package com.homelink.testcriminal;
    
    import android.os.Bundle;
    import android.support.annotation.Nullable;
    import android.support.v4.app.Fragment;
    import android.text.Editable;
    import android.text.TextWatcher;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.Button;
    import android.widget.CheckBox;
    import android.widget.EditText;
    
    /**
     * Created by ysc on 2017/9/30.
     */
    
    public class CrimeFragment extends Fragment {
        private Crime mCrime;
        private EditText mTitleField;
    
        private Button mDateButton;
        private CheckBox mSolvedCheckBox;
    
    
        @Override
        public void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
    
            mCrime = new Crime();
    
        }
    
        @Nullable
        @Override
        public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
            View v = inflater.inflate(R.layout.fragment_crime, container, false);
    
            mTitleField = (EditText)v.findViewById(R.id.crime_title);
            mTitleField.addTextChangedListener(new TextWatcher() {
                @Override
                public void beforeTextChanged(
                        CharSequence s, int start, int count, int after) {
                        // This space intentionally left blank
                }
                @Override
                public void onTextChanged(
                        CharSequence s, int start, int before, int count) {
                    mCrime.setTitle(s.toString());
                }
                @Override
                public void afterTextChanged(Editable s) {
                    // This one too
                }
            });
    
            mDateButton = (Button)v.findViewById(R.id.crime_date);
            mDateButton.setText(mCrime.getDate().toString());
            mDateButton.setEnabled(false);
    
    
    
            return v;
        }
    }

![20779-20170930131300356-123877760.jpg][]

**列表项的控制CrimeListFragment.java:**

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

package com.homelink.testcriminal;
    
    
    import android.os.Bundle;
    import android.support.v4.app.Fragment;
    import android.support.v7.widget.LinearLayoutManager;
    import android.support.v7.widget.RecyclerView;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.CheckBox;
    import android.widget.TextView;
    import android.widget.Toast;
    
    import java.util.List;
    
    /**
     * Created by ysc on 2017/9/30.
     */
    
    public class CrimeListFragment extends Fragment {
    
        private RecyclerView mCrimeRecyclerView;
    
    
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View view = inflater.inflate(R.layout.fragment_crime_list, container, false);
            mCrimeRecyclerView = (RecyclerView) view.findViewById(R.id.crime_recycler_view);
            mCrimeRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
    
            updateUI();
    
            return view;
        }
    
    
    
        private CrimeAdapter mAdapter;
        private void updateUI() {
            CrimeLab crimeLab = CrimeLab.get(getActivity());
            List<Crime> crimes = crimeLab.getCrimes();
    
            mAdapter = new CrimeAdapter(crimes);
            mCrimeRecyclerView.setAdapter(mAdapter);
        }
    
    
        private class CrimeHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
    
            private Crime mCrime;
    
            private TextView mTitleTextView;
            private TextView mDateTextView;
            private CheckBox mSolvedCheckBox;
    
            public CrimeHolder(View itemView) {
                super(itemView);
    
                itemView.setOnClickListener(this);
                mTitleTextView = (TextView) itemView.findViewById(R.id.list_item_crime_title_text_view);
                mDateTextView = (TextView) itemView.findViewById(R.id.list_item_crime_date_text_view);
                mSolvedCheckBox = (CheckBox)itemView.findViewById(R.id.list_item_crime_solved_check_box);
            }
    
    
    
            public void BindCrime(Crime crime){
                mCrime = crime;
                mTitleTextView.setText(mCrime.getTitle());
                mDateTextView.setText(mCrime.getDate().toString());
                mSolvedCheckBox.setChecked(mCrime.isSolved());
            }
    
            @Override
            public void onClick(View view) {
                Toast.makeText(getActivity(), mCrime.getTitle() + " clicked!", Toast.LENGTH_SHORT).show();
            }
        }
        private class CrimeAdapter extends RecyclerView.Adapter<CrimeHolder> {
            private List<Crime> mCrimes;
            public CrimeAdapter(List<Crime> crimes) {
                mCrimes = crimes;
            }
    
            @Override
            public CrimeHolder onCreateViewHolder(ViewGroup parent, int viewType) {
                LayoutInflater layoutInflater = LayoutInflater.from(getActivity());
                View view = layoutInflater.inflate(R.layout.list_item_crime, parent, false);
                return new CrimeHolder(view);
            }
            @Override
            public void onBindViewHolder(CrimeHolder holder, int position) {
                Crime crime = mCrimes.get(position);
                //holder.mTitleTextView.setText(crime.getTitle());
                holder.BindCrime(crime);
            }
            @Override
            public int getItemCount() {
                return mCrimes.size();
            }
        }
    
    
    
    }

数据从哪里来，单例的CrimeLab.java

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

package com.homelink.testcriminal;
    
    import android.content.Context;
    
    import java.util.ArrayList;
    import java.util.List;
    import java.util.UUID;
    
    /**
     * Created by ysc on 2017/9/30.
     */
    
    public class CrimeLab {
    
        private static CrimeLab sCrimeLab;
        public static CrimeLab get(Context context) {
            if (sCrimeLab == null) {
                sCrimeLab = new CrimeLab(context);
            }
            return sCrimeLab;
        }
        private CrimeLab(Context context) {
            initCrimes();
        }
    
    
    
        private List<Crime> mCrimes;
        private void initCrimes(){
            mCrimes = new ArrayList<>();
            for (int i = 0; i < 100; i++) {
                Crime crime = new Crime();
                crime.setTitle("Crime #" + i);
                crime.setSolved(i % 2 == 0); // Every other one
                mCrimes.add(crime);
            }
        }
    
        public List<Crime> getCrimes() {
            return mCrimes;
        }
        public Crime getCrime(UUID id) {
            for (Crime crime : mCrimes) {
                if (crime.getId().equals(id)) {
                    return crime;
                }
            }
            return null;
        }
    
    
    
    
    
    }

如果是显示列表呢，使用recyclerview，fragment\_crime\_list.xml布局：

<?xml version="1.0" encoding="utf-8"?>
    <android.support.v7.widget.RecyclerView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/crime_recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

其中列表项：list\_item\_crime.xml:

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
    
        <CheckBox
            android:id="@+id/list_item_crime_solved_check_box"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:padding="4dp"/>
    
        <TextView
            android:id="@+id/list_item_crime_title_text_view"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_toLeftOf="@id/list_item_crime_solved_check_box"
            android:textStyle="bold"
            android:padding="4dp"
            tools:text="Crime Title"/>
    
        <TextView
            android:id="@+id/list_item_crime_date_text_view"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_toLeftOf="@id/list_item_crime_solved_check_box"
            android:layout_below="@id/list_item_crime_title_text_view"
            android:padding="4dp"
            tools:text="Crime Date"/>
    
    </RelativeLayout>

![20779-20170930130309372-976063114.jpg][]

当然先修改一下AndroidManifest.xml文件：

<?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.homelink.testcriminal">
    
        <application
            android:allowBackup="true"
            android:icon="@mipmap/ic_launcher"
            android:label="@string/app_name"
            android:roundIcon="@mipmap/ic_launcher_round"
            android:supportsRtl="true"
            android:theme="@style/AppTheme">
    
            <activity android:name=".CrimeListActivity">
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />
                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
            <activity android:name=".CrimeActivity">
    
            </activity>
        </application>
    
    </manifest>

运行：

![20779-20170930130506059-398907605.jpg][]

posted on 2017-09-30 13:06 [Anders' Yan][Anders_ Yan] 阅读( ...) 评论( ...) [编辑][Link 1] 收藏

转载于:https://www.cnblogs.com/yansc/p/7614619.html

[1_fragment]: https://www.cnblogs.com/yansc/p/7614619.html
[20779-20170930123532356-1474283357.jpg]: /images/20211109/15b126d76f0c4baea6a0c40b594e6542.png
[20779-20170930123834622-34266874.jpg]: /images/20211109/4ac4ae89e9ad4a8ca4d32409c3cbd4f0.png
[20779-20170930124053356-1946005729.jpg]: /images/20211109/ae3e1e64401c400b8ad0b1612e626c67.png
[20779-20170930124355606-540835978.jpg]: /images/20211109/6dfb54b43ac9437cab12a6e9f460b8d6.png
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[20779-20170930125030137-2014654192.jpg]: https://images2017.cnblogs.com/blog/20779/201709/20779-20170930125030137-2014654192.jpg
[20779-20170930125054497-555718632.jpg]: /images/20211109/c4c829d0195c4ddd88875bff49834048.png
[20779-20170930131300356-123877760.jpg]: /images/20211109/e55a3292773544b7b223b1359b3573a5.png
[20779-20170930130309372-976063114.jpg]: /images/20211109/bb9262327fb44faa9737ef535e8f3a22.png
[20779-20170930130506059-398907605.jpg]: /images/20211109/6365eef3ebf94e8da6c05f04ac676be4.png
[Anders_ Yan]: https://www.cnblogs.com/yansc/
[Link 1]: https://i.cnblogs.com/EditPosts.aspx?postid=7614619