Android 首选项键存储在哪里

Android首选项键是一种用于存储和管理应用程序设置的机制。它允许开发者在应用程序中存储和检索用户首选项，例如用户界面设置、用户登录信息等。首选项键通常用于存储简单的键值对数据，如字符串、整数或布尔值。在Android中，首选项键存储在一个特殊的XML文件中，以确保数据的持久性和安全性。

java
SharedPreferences preferences = getSharedPreferences("my_preferences", MODE_PRIVATE);

java
// 读取首选项键的值
String username = preferences.getString("username", "default");
int age = preferences.getInt("age", 0);
boolean isLogged = preferences.getBoolean("isLogged", false);
// 写入首选项键的值
SharedPreferences.Editor editor = preferences.edit();
editor.putString("username", "John");
editor.putInt("age", 25);
editor.putBoolean("isLogged", true);
editor.apply();

java
public class MainActivity extends AppCompatActivity {
    private SharedPreferences preferences;
    private TextView languageTextView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        preferences = getSharedPreferences("my_preferences", MODE_PRIVATE);
        languageTextView = findViewById(R.id.languageTextView);
        String language = preferences.getString("language", "");
        languageTextView.setText(language);
    }
    public void onLanguageButtonClick(View view) {
        String language = ((Button) view).getText().toString();
        SharedPreferences.Editor editor = preferences.edit();
        editor.putString("language", language);
        editor.apply();
        languageTextView.setText(language);
    }
}