android中判断应用是否在前台

文章转（内容也是从下面出来）
https://blog.csdn.net/zhufuing/article/details/53007705

1、编写MyLifecycleHandler.java文件

public class MyLifecycleHandler implements Application.ActivityLifecycleCallbacks {
private static int resumed;
private static int paused;
private static int started;
private static int stopped;
@Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
}
@Override
public void onActivityStarted(Activity activity) {
++started;
}
@Override
public void onActivityResumed(Activity activity) {
++resumed;
}
@Override
public void onActivityPaused(Activity activity) {
++paused;
android.util.Log.w("test", "application is in foreground: " + (resumed > paused));
}
@Override
public void onActivityStopped(Activity activity) {
++stopped;
android.util.Log.w("test", "application is visible: " + (started > stopped));
}
@Override
public void onActivityDestroyed(Activity activity) {
}
@Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
}
public static boolean isApplicationVisible() {
return started > stopped;
}
public static boolean isApplicationInForeground() {
// 当所有 Activity 的状态中处于 resumed 的大于 paused 状态的，即可认为有Activity处于前台状态中
return resumed > paused;
}
}


2、自己定义的Application中注册

registerActivityLifecycleCallbacks(new MyLifecycleHandler());


3、调用方法判断

boolean inForeground = MyLifecycleHandler.isApplicationInForeground();