全局的Context实现

public class MyApplication extends Application{
    private static Context context;

    @Override
    public void onCreate() {
        super.onCreate();
        context = getApplicationContext();
    }
    public static Context getContext(){
        return context;
    }
}

记得还要在AndroidManifest.xml文件里加入如下,让程序已启动就去实例化该类，包名加类名