If you press the home button on an Android device and then you call startActivity() it will silently fail and there doesn't seem to be a way to check when it fails. For example:
#Override
protected void onStop() {
super.onStop();
Handler hndlr = new Handler();
Runnable t = new Runnable() {
public void run() {
startActivity(new Intent(getApplicationContext(), SomeOtherActivity.class)); //this silently fails, no error, nothing
}
};
hndlr.postDelayed(t, 1000);
}
Is there a way to check if it fails to start the activity? I don't intend to start any activity in the background, I just need to know when it fails. Please note that this only happens when you press the home button, I'm actually not sure if this is just an Android bug (I'm testing on Android 11). Thanks!
You could just check that your app is in the foreground like this:
if (getLifecycle().getCurrentState().isAtLeast(Lifecycle.State.RESUMED)){
startActivity(new Intent(getApplicationContext(), SomeOtherActivity.class));
}
I have startActivity and HomeScreen activity. HomeScreen activity appears after startActivity. I want to implement double click back to close the application. I tried this code, but after the app is closed, it immediately reopens again or just returns to startActivity.
#Override
public void onBackPressed() {
if (doubleBackToExitPressedOnce) {
super.onBackPressed();
return;
}
this.doubleBackToExitPressedOnce = true;
Toast.makeText(this, "Нажмите ещё раз что бы закрыть приложение", Toast.LENGTH_SHORT).show();
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
doubleBackToExitPressedOnce = false;
}
}, 2000);
}
If this code is in some child activity (not in the main activity), then try replacing:
super.onBackPressed()
with:
finishAffinity()
Since according to the docs:
The default implementation simply finishes the current activity, but you can override this to do whatever you want.
calling super.onBackPressed() will finish current activity - not the whole application. And probably this is the source of Your bugs, but I cannot know for sure, since You haven't provided us with broader context - more code.
So, on the other hand finishAffinity() might be the solution for You. Docs say:
Finish this activity as well as all activities immediately below it in the current task that have the same affinity.
This should finish all the activities.
I am making an android app in java in which I need to trigger some database requests whenever an activity is completely destroyed which would probably happen if the user presses the back button or leaves the app itself... But the onDestroy() function in my app is randomly getting triggered even when the user is still on the activity... I guess the probable reason for this is configuration changes but I am not able to figure out a proper solution for this.
Is there a way we could exactly detect when an activity is left by a user avoiding any in-page configuration changes??
The onDestroy() that I am using is this:
#Override
protected void onDestroy() {
/// do smthng
super.onDestroy();
}
Any help would be appreciated!!
Solved:
Thank you for the answer guys... For me onStop() worked out perfectly and it is working in every case whether it might be pressing the back button or exiting the activity or the app itself!!
If you want to check if the user ended the activity, meaning pressed back, do this:
#override
public void onBackPressed(){
//do something before we finish the activity
super.onBackPressed();
}
If you want to check when user, goes to next activity, then resturns to the same activity:
#override
public void onResume(){
//do something when return back to this activity
super.onResume();
}
#override
public void onPause(){
//do something before going to another activity
super.onPause();
}
onDestroy is called when the activity is destroyed or finished and not guaranteed to be called always, don't depend on it
We can check on whether our application is foreground or background based on the activity entering and exiting the foreground by implementing ActivityLifecycleCallbacks.
Good reference : https://medium.com/#iamsadesh/android-how-to-detect-when-app-goes-background-foreground-fd5a4d331f8a
Quoting from the above article,
#Override
public void onActivityStarted(Activity activity) {
if (++activityReferences == 1 && !isActivityChangingConfigurations) {
// App enters foreground
}
}
and,
#Override
public void onActivityStopped(Activity activity) {
isActivityChangingConfigurations = activity.isChangingConfigurations();
if (--activityReferences == 0 && !isActivityChangingConfigurations) {
// App enters background
}
}
by which we can make sure that our app is in foreground or not. Here you always have the control of what activity is in foreground based on which you can check and execute the logic.
Hey guys I'm trying to make a function that quit my application when onClick on a Button but it doesn't work.
Would you take a look and let me now what's wrong with the code please ?
Here is the code :
public void addListenerOnButtonLeave()
{
quitButton = (ImageView) findViewById(R.id.quitButton);
quitButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
moveTaskToBack(true);
}
});
}
I put this function into the overrided onCreate().
Thanks for your help guys.
You may also use finishActivity (int requestCode)
Force finish another activity that you had previously started with
startActivityForResult(Intent, int).
Probably some of your activities are running in background. When you have switched between activities, you have not finished them.
First finish those activities by adding
ActivityName.this.finish()
just before you sail to another activity, and then use
getActivity().finish();
System.exit(0);
to quit the app triggered where needed.
When a user presses the back button on an intent, the application should quit. How can I ensure the application quits when the back button is pressed?
In my Home Activity I override the "onBackPressed" to:
#Override
public void onBackPressed() {
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
so if the user is in the home activity and press back, he goes to the home screen.
I took the code from Going to home screen Programmatically
Immediately after you start a new activity, using startActivity, make sure you call finish() so that the current activity is not stacked behind the new one.
EDIT
With regards to your comment:
What you're suggesting is not particularly how the android app flow usually works, and how the users expect it to work. What you can do if you really want to, is to make sure that every startActivity leading up to that activity, is a startActivityForResult and has an onActivityResult listener that checks for an exit code, and bubbles that back. You can read more about that here. Basically, use setResult before finishing an activity, to set an exit code of your choice, and if your parent activity receives that exit code, you set it in that activity, and finish that one, etc...
A better user experience:
/**
* Back button listener.
* Will close the application if the back button pressed twice.
*/
#Override
public void onBackPressed()
{
if(backButtonCount >= 1)
{
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
else
{
Toast.makeText(this, "Press the back button once again to close the application.", Toast.LENGTH_SHORT).show();
backButtonCount++;
}
}
The app will only exit if there are no activities in the back stack. SO add this line in your manifest android:noHistory="true" to all the activities that you dont want to be back stacked.And then to close the app call the finish() in the OnBackPressed
<activity android:name=".activities.DemoActivity"
android:screenOrientation="portrait"
**android:noHistory="true"**
/>
Why wouldn't the user just hit the home button? Then they can exit your app from any of your activities, not just a specific one.
If you are worried about your application continuing to do something in the background. Make sure to stop it in the relevant onPause and onStop commands (which will get triggered when the user presses Home).
If your issue is that you want the next time the user clicks on your app for it to start back at the beginning, I recommend putting some kind of menu item or UI button on the screen that takes the user back to the starting activity of your app. Like the twitter bird in the official twitter app, etc.
Use onBackPressedmethod
#Override
public void onBackPressed() {
finish();
super.onBackPressed();
}
This will solve your issue.
First of all, Android does not recommend you to do that within the back button, but rather using the lifecycle methods provided. The back button should not destroy the Activity.
Activities are being added to the stack, accessible from the Overview (square button since they introduced the Material design in 5.0) when the back button is pressed on the last remaining Activity from the UI stack. If the user wants to close down your app, they should swipe it off (close it) from the Overview menu.
Your app is responsible to stop any background tasks and jobs you don't want to run, on onPause(), onStop() and onDestroy() lifecycle methods. Please read more about the lifecycles and their proper implementation here: http://developer.android.com/training/basics/activity-lifecycle/stopping.html
But to answer your question, you can do hacks to implement the exact behaviour you want, but as I said, it is not recommended:
#Override
public void onBackPressed() {
// make sure you have this outcommented
// super.onBackPressed();
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
To exit from an Android app, just simply use.
in your Main Activity, or you can use Android manifest file to set
android:noHistory="true"
finish your current_activity using method finish() onBack method of your current_activity
and then add below lines in onDestroy of the current_activity for Removing Force close
#Override
public void onDestroy()
{
android.os.Process.killProcess(android.os.Process.myPid());
super.onDestroy();
}
I modified #Vlad_Spays answer so that the back button acts normally unless it's the last item in the stack, then it prompts the user before exiting the app.
#Override
public void onBackPressed(){
if (isTaskRoot()){
if (backButtonCount >= 1){
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}else{
Toast.makeText(this, "Press the back button once again to close the application.", Toast.LENGTH_SHORT).show();
backButtonCount++;
}
}else{
super.onBackPressed();
}
}
you can simply use this
startActivity(new Intent(this, Splash.class));
moveTaskToBack(true);
The startActivity(new Intent(this, Splash.class)); is the first class that will be lauched when the application starts
moveTaskToBack(true); will minimize your application
Add this code in the activity from where you want to exit from the app on pressing back button:
#Override
public void onBackPressed() {
super.onBackPressed();
exitFromApp();
}
private void exitFromApp() {
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
startActivity(intent);
}