SharedPreferences

一、XML代码界面布局

<LinearLayout
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:text="姓名:"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textSize="25sp"
        android:gravity="center"/>
    <EditText
        android:id="@+id/name"
        android:layout_width="0dp"
        android:textSize="25sp"
        android:layout_height="wrap_content"
        android:layout_weight="4"/>
</LinearLayout>

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:text="密码:"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:textSize="25sp"
            android:gravity="center"/>
        <EditText
            android:id="@+id/password"
            android:layout_width="0dp"
            android:textSize="25sp"
            android:layout_height="wrap_content"
            android:layout_weight="4"/>
    </LinearLayout>

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <Button
            android:id="@+id/write"
            android:text="写入"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:textSize="25sp"
            
            android:onClick="onClick"/>

        <Button
            android:id="@+id/read"
             android:text="读取"
             android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:textSize="25sp"
           
            android:onClick="onClick"/>
    </LinearLayout>
    

二、JAVA代码及功能实现

  public class MainActivity extends AppCompatActivity {

    private EditText name;
    private EditText password;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        name = (EditText) findViewById(R.id.name);
        password = (EditText) findViewById(R.id.password);
    }

    public void onClick(View view) {
        switch (view.getId()){
            case R.id.write:
                String name = name.getText().toString();
                String password = password.getText().toString();
                if(saveToPrefs(password,name)){
                    Toast.makeText(MainActivity.this,"写入完毕",Toast.LENGTH_SHORT).show();
                }
                break;
            case R.id.read:
                readFromPrefs();
                break;
        }
    }
    
    private void readFromPrefs() {
        SharedPreferences preferences = getSharedPreferences("customer.txt",MODE_PRIVATE);
        String name=preferences.getString("name","");
        String password=preferences.getString("password","");
        password.setText(password);
        name.setText(name);
    }
    
    private boolean saveToPrefs(String password, String name) {
        SharedPreferences preferences = MainActivity.this.getSharedPreferences("customer.txt",MODE_PRIVATE);
        SharedPreferences.Editor editor =preferences.edit();
        editor.putString("name",name);
        editor.putString("password",password);
        editor.commit();
        return true;
    }
}