转载自：Android 开发之ActivityLifecycleCallback
一. 简介
ActivityLifecycleCallbacks是Application里的一个接口，在Android4.0（API level 14）中新加。用于监听应用中所有Activity的生命周期的调用情况，callback中的方法会在Activity回调方法之前调用，可以通过实现这个接口来完成一些特殊需求，比如检测APP是否处于前台。
二. 使用
以检测APP是否处于前台为例介绍使用。
1. 实现ActivityLifecycleCallbacks接口
public class ActivityLifecycleCallbackWrapper implements Application.ActivityLifecycleCallbacks {
private static final String TAG = "LifecycleCallback";
private int count;
private boolean isForeground;
public boolean isForeground() {
return isForeground;
}
@Override
public void onActivityCreated(Activity activity, Bundle bundle) {
//to do
}
@Override
public void onActivityStarted(Activity activity) {
count ++;
}
@Override
public void onActivityResumed(Activity activity) {
//to do
}
@Override
public void onActivityPaused(Activity activity) {
//to do
}
@Override
public void onActivityStopped(Activity activity) {
count --;
if(count == 0) {
isForeground = true;
}
}
@Override
public void onActivitySaveInstanceState(Activity activity, Bundle bundle) {
//to do
}
@Override
public void onActivityDestroyed(Activity activity) {
//to do
}
}
2. 创建自定义Application，并在Application中注册callback。
public class MyApplication extends Application {
ActivityLifecycleCallbacks callbacks;
@Override
public void onCreate() {
super.onCreate();
callbacks = new ActivityLifecycleCallbackWrapper();
registerActivityLifecycleCallbacks(callbacks); // 注册Callback
}
}
