ondestroy
When exactly is component destroyed?
When Angular runs change detection and the binding to the ngIf input of the NgIf directive is updated, NgIf removes the component from the DOM. After the component is removed from the DOM ngDestroy() is called and then the component is free to get garbage collected. If the parent component is removed while the *ngIf … Read more
android is there any view callback when it’s destroyed?
View does not have a callback (except finalize(), but I don’t think that’s what you’re asking for). View has onDetachedFromWindow() when it is removed from the screen, but this is not related to it being destroyed — it could be attached again, which will call onAttachedToWindow(). Fragment has onDestroyView(), which may be more useful to … Read more
Activity OnDestroy never called?
onDestroy() is called only when the system is low on resources (memory, cpu time, etc) and makes a decision to kill your activity/application or when somebody calls finish() on your activity. So, to test your code you can make a test button, that will call finish() on your activity. Read more here. Also, I believe … Read more
Android save state on orientation change
Add android:configChanges in the Manifest file <activity name= “.MainActivity” android:configChanges=”orientation|screenSize”/> By default, this does not work because changing the orientation causes the onCreate method to be called again and redraws the view. However, if this parameter is included, the framework will handle preserving the state of the screen or layout if the orientation is changed. … Read more
Activity’s onDestroy / Fragment’s onDestroyView set Null practices
So the reason it’s different between Fragments and Activities is because their lifecycles are different. When an Activity is destroyed, it’s going away for good. However, Fragments may create and destroy their views multiple times before they’re actually destroyed. For clarification, in an Activity: onDestroy() onCreate() will never happen in sequence for the same Activity … Read more
What is Activity.finish() method doing exactly?
When calling finish() on an activity, the method onDestroy() is executed. This method can do things like: Dismiss any dialogs the activity was managing. Close any cursors the activity was managing. Close any open search dialog Also, onDestroy() isn’t a destructor. It doesn’t actually destroy the object. It’s just a method that’s called based on … Read more
Android activity life cycle – what are all these methods for?
See it in Activity Lifecycle (at Android Developers). onCreate(): Called when the activity is first created. This is where you should do all of your normal static set up: create views, bind data to lists, etc. This method also provides you with a Bundle containing the activity’s previously frozen state, if there was one. Always … Read more