SharedPreferences返回一個空字符串

Question

爲什麼吐司只顯示一個空字符串或任何我輸入作爲上的getString線的「默認」值

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

    SharedPreferences sharedPreferences = this.getSharedPreferences("com.example.stefan.dijeljenepreference", Context.MODE_PRIVATE); 
    sharedPreferences.edit().putString("username", "stefan"); 

    String username = sharedPreferences.getString("username",""); 
    Toast.makeText(this,"username:" + username, Toast.LENGTH_SHORT).show(); 
} 

Answer 1

您應該保存使用適用（）所做的編輯方法這樣

sharedPreferences.edit().putString("username", "stefan").apply();