Android——SharedPreferences

Introducing SharedPreferences

SharedPreferences is a lightweight storage solution provided by Android. It stores data through key-value pairs. The underlying layer uses XML files to store key-value pair data. SharedPreferences will become unreliable during concurrent read/write. , Data may be lost when high concurrency.

SharedPreferences information writing

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button Get = (Button) findViewById(R.id.Get);
        /*
        * SharedPreferences的四种模式：
        * 1：Context.MODE_PRIVATE：默认模式，只能在此应用使用，不能在其他应用使用
        * 2：Context.MODE_APPEND:如果存在就在后面追加
        * 3:Context.MODE_WORLD_READABLE
        * 4:Context.MODE_WORLD_WRITEABLE
        **/
        Get.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //实例化SharedPreferences
                SharedPreferences preferences = getSharedPreferences("SharedPreferences", Context.MODE_PRIVATE);//参数;名称，模式
                //使SharedPreferences为可编辑状态
                SharedPreferences.Editor editor = preferences.edit();
                editor.putString("name","FranzLiszt");
                editor.putInt("age",19);
                editor.commit();//提交
                Intent intent = new Intent(MainActivity.this,SecondActivity.class);
                startActivity(intent);
            }
        });
    }
}

SharedPreferences information read

SharedPreferences preferences = getSharedPreferences("SharedPreferences", Context.MODE_PRIVATE);
        String name = preferences.getString("name","");//后面是默认值
        int age = preferences.getInt("age",1);
        Log.d(TAG,name);
        Log.d(TAG,age+"");

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