startActivity in onPause() not working after opening new app - android

I Start a second activity when my first activity is paused.
FirstActivity.java
#Override
public void onPause(){
super.onPause();
startActivity(new Intent(this, SecondActivity.class));
}
When I press on the homescreen button, SecondActivity will start but with a delay. In this delay, there is enough time to open a new app (like messenger for instance). However, when I open a new app, SecondActivity will not start anymore (it won't even call the onCreate method of SecondActivity).
How can i still start SecondActivity even when I open a new app?

Override the onBackPressed() method and start new activity from there, instead of adding your code into onPause().
#Override
public void onBackPressed()
{
startActivity(new Intent(this, SecondActivity.class));
super.onBackPressed();
}

I think I have a solution, if you would like to launch the new activity I would go with onStop, instead of onPause.
Start the new activity with the flag of: singleInstance
<activity ..
android:launchMode= "singleInstance" />
Please use onStop() in the second activity and call finish() there. so you killing the 2nd activity instance, when leaving the app. You can restart it easily.

Related

how to exit from all the activities(including resuming activities)

I have 4 activities. First one is splash activity and second is main menu activity and third activity is specific option from main activity and fourth one is result of third activity. I am using the noHistory="true" for second activity in manifest file. I have exit option in option menu for all activity. Once I exit from first three activity in app again I open app means it going launching application (there no resuming activities) but when I was exit from fourth activity then again I will open app means it show third activity instead of launch the app.
Exit code in option menu is
flag_activity_clear_top
flag_activity_no_history
but the previous activity is not close. How can we exit from all activities (including resuming activity)?
If I use the noHistory="true" attribute for third activity means it working properly, but when I press the home screen then again I reopen app it show splash activity instead of resuming activity. So I avoid to use the noHistory attribute in third activity.
Kindly please give solution for exit from all activities.
using Intent
Intent intent = new Intent(getApplicationContext(), FirstActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.putExtra("FLAG_ACTIVITY_CLEAR_TOP", true);
startActivity(intent);
added in OnCreate your All Activity
if (getIntent().getBooleanExtra("FLAG_ACTIVITY_CLEAR_TOP", false)) {
finish();
}
Use sharePreference and check the value inside shared preference (inside onResume or OnStart()) every time you launch the application and navigate accordingly.
To close all Activities you can try call
finishAffinity();
This method finish current activity as well as all activities immediately below it in the current task that have the same affinity.
finishAffinity() can be called from Context i.e (Activity, Service etc)
If every time you close the application you want to close all Activities you just have to call finishAffinity in your OnDestroy() method or in onClick like
#Override
protected void onDestroy() {
super.onDestroy();
finishAffinity();
}
or
finishButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finishAffinity();
}
});
Also example for menu
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.exit_item) {
finishAffinity();
}
return super.onOptionsItemSelected(item);
}
And you should NOT use any Flags for start or close an Activity, just call finishAffinity() where you wanna exit from application and finish all activities.
In this video you can see how it works https://youtu.be/L5w8mhB9aNk

Back button from activity 2 closes down the app instead of going to activity 1 in Android 7

Pressing back button from the second activity returned to the first activity before without problems. I then updated to Android 7.
Then the whole app closed when pressing back button from the second activity.
I know that there are threads about this here and I have checked them all. Basically, they say that finish() should be avoided from the first activity.
I don't call finish(), so that is the problem here. It is difficult to solve, because it works like it should when I launch the app from Android studio.
It returns to the first activity from second. The problem occurs when the app is started by pressing its icon (not from Android studio).
Pressing back from the second activity closes down the whole app. How can I solve this? Here is some of my code:
Activity 1:
Intent glIntent = new Intent("astral.worldstriall.GLActivity");
glIntent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
The below code should be used in 2nd activity so that when u press back button it terminates the current activity(2nd activity) and goes back to previous activity
#Override
public void onBackPressed() {
super.onBackPressed();
finish();
}
I think you just misused the Intent constructor. According to the documentation, you used this constructor Intent(String action). The one that you atually want should be this one Intent(Context packageContext, Class<?> cls).
In the first activity (therefore this being the instance of your first activity), you should write:
Intent glIntent = new Intent(this, astral.worldstriall.GLActivity.class);
glIntent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(glIntent);
For going first to second activity...
Intent i=new Intent(FirstActivity.this,SecondActivity.class);
startActivity(i);
Use below code for going in previous activity...
#Override
public void onBackPressed() {
super.onBackPressed();
Intent i=new Intent(SecondActivity.this, FirstActivity.class);
startActivity(i);
}

Application restart and activity hiding

I have application with two activities: SplashActivity and MainActivity. SplashActivity is the launch activity, it start for few seconds, close and launch MainActivity. MainActivity contains all application logic.
When user minimize application by Home button, then doesn't using application some time and maximize it again, data in my application is expired and I need to restart application. I make it with onStart in MainActivity:
#Override
public void onStart() {
super.onStart();
if (dataIsExpired()) {
finish();
Intent intent = getBaseContext().getPackageManager().getLaunchIntentForPackage(getBaseContext().getPackageName());
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
}
}
It working well, but before SplashActivity launched I see MainActivity with old data for few moments. Is there way to restart without previous activity showing?
I don't need to clear it manually, I just need to restart whole app.
You can call finish() your activity in onPause() or onStop() of MainActivity so that it will be removed when minimising the app and will launch fresh.

startActivity(intent) and onStop

I have a problem concerning startActivity(intent) and onStop. The Android API suggests to save data in onStop, which is what I am doing here:
public void onStop(){
super.onStop();
if(tosave)
{
Editor editor = sp.edit();
editor.putInt(getString(R.string.index_of_text_color), text_color_index);
editor.putInt(getString(R.string.index_of_background_color), background_color_index);
editor.commit();
}
}
However, I would like to start the next activity once it is saved- so I need to use an intent and startActivity(intent).
public void click(View v){
Intent intent = new Intent(this, MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
My question is, does startActivity(intent) with the two flags call the onStop() method as it is finishing the application, or do I need to call finish()? Is it allowed for me to call finish() after I start a new activity? Or, is it because the new activity will be at the top, Android automatically calls onStop as it is in the background now?
There are so many questions about how startActivity(intent) works with the app cycle that I do not understand. It will be helpful if someone points me to a link.
Thank you!
EDIT: the intent is not in onStop. It is in another method which corresponds to a button. As soon as the button is clicked, I will need to save the data-- go to onstop-- and then go to the next activity. How can I do that?
You should save state in onPause(), not onStop(), because under certain conditions onStop() will never be called. You are guaranteed that onPause() will be called.
onPause() will always be called on your activity when another activity is shown in front of it.
That should solve your problem.

How to exit when back button is pressed?

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);
}

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