I've followed the example pattern for handling the android back button in the react-native docs and it works well. I can use the hardware back button to pop my navigation stack.
At the point that there's only 1 view in the stack though I don't pop it (just like the example), and I return false from my hardwareBackPress event listener. At this point it I see the componentWillUnmount method being called in my final view, at which point my app shuts down.
If I return true then nothing happens at all obviously.
What I want to happen is that the app merely gets "backgrounded" instead of exiting completely.
Answered my own question. The trick is to override the default back button behaviour in the MainActiviy:
public class MainActivity extends ReactActivity {
#Override
protected String getMainComponentName() {
return "foo";
}
#Override
public void invokeDefaultOnBackPressed() {
// do not call super. invokeDefaultOnBackPressed() as it will close the app. Instead lets just put it in the background.
moveTaskToBack(true);
}
}
Though I may be very late in giving the answer it may help other facing the issue.
Recently I came across the same requirement where I have to move the app to the background. I tried the solution provided by #pomo. Though it worked I faced problems. Sometimes on multiple clicking of the back button, the app misbehaves in android though it worked perfectly fine in iOS.
And then I came across the following issues in GitHub where it mentions the reason for the misbehaviour.
The following solution works perfectly fine now.
// android/app/.../MainActivity.java
#Override
public void invokeDefaultOnBackPressed() {
moveTaskToBack(true);
}
<!-- AndroidManifest.xml -->
<activity
...
android:launchMode="singleTop">
Link from where I get the solution
I hope I'm able to help guys with the same requirement.
Related
I am trying to work out how to show the "up" arrow in Xamarin.Forms without a pushing a page onto the stack. I.E. I just want to perform an action when the back button is pressed. I am completely stuck on this so any help would be appreciated.
I have tried creating a custom renderer which handles a view property called DisplayHomeAsBack. Which in the renderer calls the following:
FormsAppCompatActivity context = ((FormsAppCompatActivity)Forms.Context);
Android.Support.V7.App.ActionBar actionBar = context.SupportActionBar;
if (actionBar != null)
{
actionBar.SetDisplayHomeAsUpEnabled(element.DisplayHomeAsBack);
}
Unfortunately it seems this does absolutely nothing, even though all online tutorials and stackoverflow question for android suggest this method.
The plan is that I can then use the "OnBackButtonPressed" override in MasterDetailPage, which should allow me to perform this action. Unfortunately displaying the back button has been the larger hurdle so far!
Any idea of a better way to do this or how I can get the current mechanism to work?
EDIT
I have created a project and uploaded it to this question on the Xamarin support forums, if it helps.
http://forums.xamarin.com/discussion/comment/186330#Comment_186330
Sorry to keep you waiting so long!
Warning that I did not actually run this code and changed it from my own so I would be surprised if it worked perfectly without some changes.
So below should add a back button where there was not one before (so like when there is not really a page to go back to) and then we will add a custom action to perform when it gets pressed.
I would suggest you push a new page onto the stack without using animation so it is transparent to the user and also makes all of this much simpler, but if you absolutely do not want to do that, the below method should work.
MainActivity:
//Use this to subscribe to the event which will create the back button
public override bool OnCreateOptionsMenu(IMenu menu) {
if(menu != null && App.AppMasterPage != null) { //You will need this to make sure you are on your MasterDetailPage, just store a global reference to it in the App class or where ever
Xamarin.Forms.MessagingCenter.Unsubscribe<string>(this, "CreateBackButton");
Xamarin.Forms.MessagingCenter.Subscribe<string>(this, "CreateBackButton", stringWeWillNotUse => { //Use this to subscribe to the event that creates the back button, then when you want the back button to show you just run Xamarin.Forms.MessagingCenter.Send<string>(this, "CreateBackButton")
ActionBar.DisplayOptions = ActionBarDisplayOptions.ShowTitle | ActionBarDisplayOptions.ShowHome | ActionBarDisplayOptions.UseLogo | ActionBarDisplayOptions.HomeAsUp; //You may need to play with these options to get it working but the important one is 'HomeAsUp' which should add the back button
});
} else {
Xamarin.Forms.MessagingCenter.Unsubscribe<string>(this, "CreateBackButton");
}
return base.OnCreateOptionsMenu(menu);
}
Now the next step is do do a custom action when it is pressed. I think you can either override OnBackPressed() or OnOptionsItemSelected() in MainActivity or maybe you can override the MasterDetailPage method. I am not sure.
Which ever one works for you, inside of that override, I would simply check to see if you are on your App.AppMasterPage like we did above, and if so, send a MessagingCenter message which your App.AppMasterPage has already subscribed to in order for it to handle the custom action.
If you get stuck let me know!
I know it sounds like a bit of a hack, but the best "solution" I have found so far is to add a page behind the current page (behind the root) so it is not visible. Then when the user presses the back button, handle it by removing that page.
If my activity implements a 2D Picker, the ambient mode is not entered at all and the activity just stays active the hole time.
My other activities implementing a WearableListView don't have that problem, so i assume my code is correct. I am calling setAmbientEnabled at onCreate and have implemented onEnterAmbient/onExitAmbient.
Does someone have/had the same experience? Is there a workaround?
#Override
public void onEnterAmbient(Bundle ambientDetails) {
super.onEnterAmbient(ambientDetails);
Log.d("Ambient", "active");
ambientView.setVisibility(View.VISIBLE);
}
#Override
public void onExitAmbient() {
super.onExitAmbient();
Log.d("Ambient", "not active");
ambientView.setVisibility(View.GONE);
}
I presume you are using GridViewPager from the Wearable Support Library. Since I don't have your code, I can't be sure how you are setting things up but I did modify our GridViewPager sample project on GitHub and added Always-on required code and it did work. One thing for you to check is that you do not have android:keepScreenOn="true" in your GridViewPager or somewhere else in your activity layout (the GridViewPager sample has that) and also make sure you are not doing the same (i.e. keeping the screen on) from your Activity.
I am learning app development from a book, and have run into a problem with the avd. I have my code set up to change some text when the right arrow key is pressed:
public boolean onKeyDown(int keyCode, KeyEvent event){
if(keyCode==KeyEvent.KEYCODE_DPAD_RIGHT){
textUpdate();
return true;
}
return false;
}
When I run the virtual device and press the arrow keys nothing happens. When I press the arrow keys on my physical keyboard, still nothing. I have done a lot of research and can't find the solution. I have tried editing the avd settings and editing the device(Nexus One) itself to accept keyboard and dpad input. What should I try now?
Have you overriden the method?
There should be an #Override above that function.
Override calls that function whenever its triggered so you can modify it to your specific implementation.
Hope this helps
the "arrow key" means the back key on android device?
if it is then you should override the onBackPressed
#Override
public void onBackPressed() {
// do something
}
Alright, what happened was my onKeyDown() function was inside a Fragment. I don't know why, but when I moved this code into the mainActivity it worked fine. If anyone has an answer as to why this worked and how I could get it to work in the fragment please comment.
Thanks
I noticed that my app was receiving few clicks on the InterstitialAd, and I saw that the Ad could be instantly closed by pressing the Back button. Usually the ad takes a few seconds to appear, so the user can close it even before seeing it (when only a black screen appears).
I don't think that it's fair, is almost useless to show it. Is there anyway to prevent this from happening?
I did this, but nothing happened...
// When creating the InterstitialAd, I set the following listener
mInterstitial.setAdListener(new AdListener() {
#Override
public void onAdLoaded() {
isShowingInterstitialAd = true;
mInterstitial.show();
}
#Override
public void onAdClosed() {
isShowingInterstitialAd = false;
mAdView.setVisibility(View.VISIBLE);
mAdViewClose.setVisibility(View.VISIBLE);
}
});
// On the Activity's class
#Override
public void onBackPressed() {
if (isShowingInterstitialAd) {
return;
}
// ...
}
My understanding is that AdMob draws its own Activity on top of yours, so it has its own implementation of onBackPressed(), which means that you don't have control of anything that happens once you call mInterstitial.show(); until AdMob gives control back to your activity.
Don't sweat the little things like this.
You are much better off spending energy making your app better.
Some people will never click on ads. But if you provide an inapp purchase that removes the ads they may well buy that. That is a better return on investment for your dev effort.
IMHO
Depending on your OS, there are a few ways to override that back button. Search for back button override to find them.
I would like handle back button in my application i have used fragment class in whole application .So when i would like to come back to base activity,it throw out application,Please give me any suggestion.
You just need to override the onBackPressed method on your activity.
#Override
public void onBackPressed() {
//Put your logic here :)
}
I dont understand what you want to do, but if you want to implement your own code in the back button this is how you do it.
#Override
public void onBackPressed() {
// your code
}
If you do nothing, then nothing will happen on a back press.
Edit: perhaps the above is not at all what you want, I've some difficulties understanding you. However, if you properly want to understand activities and how they are managed / created this is a must read. http://developer.android.com/guide/components/tasks-and-back-stack.html