该方法支持需要api14或以上。
1.重写Application，并使用registerActivityLifecycleCallbacks方法接收activity的回调。
public class MyApplication extends Application {
@Override public void onCreate() {
super.onCreate();
registerActivityLifecycleCallbacks(new ActivityLifecycleCallbacks() {
@Override public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
}
@Override public void onActivityStarted(Activity activity) {
}
@Override public void onActivityResumed(Activity activity) {
MyActivityManager.getInstance().setCurrentActivity(activity);
}
@Override public void onActivityPaused(Activity activity) {
}
@Override public void onActivityStopped(Activity activity) {
}
@Override public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
}
@Override public void onActivityDestroyed(Activity activity) {
}
});
}
}
2.MyActivityManager使用weakReference,以防内存泄漏。
public class MyActivityManager {
private static MyActivityManager sInstance = new MyActivityManager();
private WeakReference<Activity> sCurrentActivityWeakRef;
private MyActivityManager() {
}
public static MyActivityManager getInstance() {
return sInstance;
}
public Activity getCurrentActivity() {
Activity currentActivity = null;
if (sCurrentActivityWeakRef != null) {
currentActivity = sCurrentActivityWeakRef.get();
}
return currentActivity;
}
public void setCurrentActivity(Activity activity) {
sCurrentActivityWeakRef = new WeakReference<Activity>(activity);
}
}
3.在需要获取的地方使用：
Activity activity = MyActivityManager.getInstance().getCurrentActivity();
