如何在应用程序中获取SharedPreferences? [英] How to getSharedPreferences in Application?

问题描述

我试图在应用程序中调用 getSharedPreferences...

I tried to call getSharedPreferences in Application...

public class App extends Application{
    public App() {
        SharedPreferences prefs = getSharedPreferences(SHARED_PREFERENCES_NAME, Context.MODE_PRIVATE);
    }
}

...但我得到了一个 NullPointerException:

...but I got a NullPointerException:

java.lang.NullPointerException: Attempt to invoke virtual method
  'android.content.SharedPreferences
  android.content.Context.getSharedPreferences(java.lang.String, int)' 
  on a null object reference

我也试过这个，但得到了同样的异常:

I also tried this and got same exception:

Context con = getApplicationContext();

如何调用 getSharedPreferences?

推荐答案

覆盖 onCreate()，在你的应用中，

Override onCreate(), in your app,

@Override
public void onCreate() {
    super.onCreate();

然后在那里做.不要忘记在 AndroidManifest 中声明你的 Application 子类.例如

and do it there. Don't forget to declare your Application subclass in the AndroidManifest as well. E.g.

  <application
        android:name="App"

这篇关于如何在应用程序中获取SharedPreferences?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！