全局获取Context

public class MyApplication extends Application {
    public static Context context;
    @Override
    public void onCreate() {
        super.onCreate();
        context = getApplicationContext();
    }

    public static Context getContext() {
        return context;
    }
}

继承Application获得一个应用程序级别的Context,之后在任何的类中需要context调用MyApplication.getContext即可，需要在<application 标签下配置name 告诉程序启动初始化MyApplication