從活動到Java類的共享首選方法調用

Question

因此，我目前遇到了SharedPreferences內部的上下文問題，它說LoginActivity.this。這是我的device.java類和LoginActivity是我想從中調用此方法的活動。那麼它會像Device.This還是這些線？

方法：

public void validateLogin(String username, String password, String ipAddress) { 

    SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(LoginActivity.this); 

    if (sharedPreferences.contains("ip") && sharedPreferences.contains("username") && sharedPreferences.contains("password")) { 
     String strUsername = sharedPreferences.getString("username", username); 
     String strPassword = sharedPreferences.getString("password", password); 
     String strIpAddress = sharedPreferences.getString("ip", ipAddress); 
     //performLogin(strUsername, strPassword, strIpAddress); 
    } 
} 

public void saveSP(String username, String password, String ipAddress) { 

    SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(LoginActivity.this); 

    sharedPreferences.edit() 
      .putString("ip", ipAddress) 
      .putString("username", username) 
      .putString("password", password) 
      .commit(); 
} 

Answer 1

試試這個：

public class MyActivity extends Activity{ 

    private static MyActivity activity; 

    @Override 
    protected void onCreate(Bundle savedInstanceState){ 
     super.onCreate(savedInstanceState); 

     activity = this; 

     //... 
    } 

    public static MyActivity getActivity(){ 
     return activity; 
    } 

} 

然後當你需要的上下文對象：

PreferenceManager.getDefaultSharedPreferences(MyActivity.getActivity()); 

這是我一貫的做法，當我需要之外的上下文對象Activity類。希望能幫助到你！