Android 初识数据库存储

悠悠 2022-09-25 04:16 195阅读 0赞

**1.点击自动登录或者记住密码，点击登录跳转到另一个页面，另一个页面的switch的状态同主界面checkbox的状态相同。**

**2.设置一个简单的登录页面，输入用户名和密码，点击登录跳转到另一个页面，在另一个页面中点击保存出现输入的用户名和密码。**

**第一个主界面布局及代码：**

**布局：**

**布局效果：**

**![Center][]**

**代码：**

package com.example.administrator.jreduch09;
    
    import android.content.Intent;
    import android.content.SharedPreferences;
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.view.View;
    import android.widget.Button;
    import android.widget.CheckBox;
    import android.widget.EditText;
    
    public class SharedPreferencesActivity extends AppCompatActivity {
        private Button save;
        private CheckBox cb1;
        private CheckBox cb2;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            save=(Button)findViewById(R.id.save);
            cb1= (CheckBox) findViewById(R.id.cb1);
            cb2= (CheckBox) findViewById(R.id.cb2);
    
            final SharedPreferences sp=getSharedPreferences("userInfo",MODE_PRIVATE);
            save.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                   SharedPreferences.Editor editor =sp.edit();
                    editor.putBoolean("1",cb1.isChecked());
                    editor.putBoolean("2",cb2.isChecked());
                    editor.commit();
                    Intent intent=new Intent(SharedPreferencesActivity.this,SettingsActivity.class);
                    startActivity(intent);
                }
            });
        }
    
        @Override
        protected void onStart() {
            super.onStart();
            SharedPreferences sp=getSharedPreferences("switch",MODE_PRIVATE);
            boolean bb1=sp.getBoolean("3",false);
            boolean bb2=sp.getBoolean("4",false);
            cb1.setChecked(bb1);
            cb2.setChecked(bb2);
        }
    }

**第一个跳转界面布局及代码：**

**布局：**

package com.example.administrator.jreduch09;
    
    import android.content.SharedPreferences;
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.view.View;
    import android.widget.Button;
    import android.widget.Switch;
    
    public class SettingsActivity extends AppCompatActivity {
        private Button save;
        private Switch switch1;
        private Switch switch2;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_settings);
            save= (Button) findViewById(R.id.save);
            switch1= (Switch) findViewById(R.id.switch1);
            switch2= (Switch) findViewById(R.id.switch2);
           final SharedPreferences sp=getSharedPreferences("switch",MODE_PRIVATE);
    
            save.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    SharedPreferences.Editor editor =sp.edit();
                    editor.putBoolean("3",switch1.isChecked());
                    editor.putBoolean("4",switch2.isChecked());
                    editor.commit();
                }
            });
        }
        @Override
        protected void onStart() {
            super.onStart();
            SharedPreferences sp=getSharedPreferences("userInfo",MODE_PRIVATE);
            boolean b1=sp.getBoolean("1",true);
            boolean b2=sp.getBoolean("2", true);
            switch1.setChecked(b1);
            switch2.setChecked(b2);
        }
    } 完成效果：

第二个主界面布局及代码：

布局：

<?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="match_parent"
        tools:context=".SharedPreferencesActivity">
    
        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入用户名"
            android:id="@+id/user"
            />
        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入密码 "
            android:id="@+id/pwd"
            android:layout_below="@+id/user"
            />
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="登录"
            android:id="@+id/save"
            android:layout_below="@+id/pwd"
            />
    </RelativeLayout> 代码： package com.example.administrator.jreduch09;
    
    import android.content.Intent;
    import android.content.SharedPreferences;
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.view.View;
    import android.widget.Button;
    import android.widget.CheckBox;
    import android.widget.EditText;
    
    public class SharedPreferencesActivity extends AppCompatActivity {
        private EditText user;
        private EditText pwd;
        private Button save;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            user= (EditText) findViewById(R.id.user);
            pwd= (EditText) findViewById(R.id.pwd);
            save=(Button)findViewById(R.id.save);
    
            final SharedPreferences sp=getSharedPreferences("userInfo",MODE_PRIVATE);
            save.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                   SharedPreferences.Editor editor =sp.edit();
                    editor.putString("userName", user.getText().toString());
                    editor.putInt("userPwd", Integer.parseInt(pwd.getText().toString()));
                    editor.commit();              
                    Intent intent=new Intent(SharedPreferencesActivity.this,SettingsActivity.class);
                    startActivity(intent);
                }
            });
        } 第二个跳转界面布局及代码： 布局： <?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="match_parent"
    
        tools:context="com.example.administrator.jreduch09.Sp2Activity">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:id="@+id/showUser"
        />
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/getUser"
            android:text="获取数据"
            android:layout_below="@+id/showUser"
            />
    </RelativeLayout> 代码： package com.example.administrator.jreduch09;
    
    import android.content.SharedPreferences;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.TextView;
    
    public class Sp2Activity extends AppCompatActivity {
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_sp2);
            Button getUser = (Button) findViewById(R.id.getUser);
            final TextView showUser= (TextView) findViewById(R.id.showUser);
            final SharedPreferences sp=getSharedPreferences("userInfo",MODE_PRIVATE);
            getUser.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    String name= sp.getString("userName","NULL");
                    String pwd= String.valueOf(sp.getInt("userPwd", 8888));
                    showUser.setText("用户名"+name+"\n"+"密码"+pwd);
                }
            });
        }
    } 完成效果：

[Center]: /images/20220718/345c4cebc45546eb8f18f4a3f56ab5b8.png