Develop Reference

Android: how to quit an activity without closing it when click on back button?

I have a subActivity that can be open from my mainActivity.
For some reasons, when the user clicks on the back button go back to my mainActivity, I want my subActivity to remain open in background in order to be able to come back for later.
Questions:
how to avoid to close the subActivity when the user clicks back ?
how to come back to the mainActivity without restarting it ?
how to come back later to my opened activity without re-creating it completely ? (just want to bring it to front)
Thanks !

On you subActivity onBackPressed() add this
#Override
public void onBackPressed() {
Intent i = new Intent(SubActivity.this, MainActivity.class);
i.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(i);
}
on mainActivity :
private void openSubActivity() {
Intent intent = new Intent(MainActivity.this,SubActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(intent);
}

override onBackPressed() and remove super from it then try opening the activity which you want to open from there for ex-
#Override
public void onBackPressed() {
// your code
}
and with the help of different activity launch modes you can achieve it

How to exit an app when Back Button is pressed

This is a small question but I'm finding very hard to solve this. I have multiple activities. For example A B and C. When app is launched A is opened and on click of button will redirect me to activity B and then from B on click of another button will take me to C. On Back pressed will now bring me back to B and again on Back button is pressed will take me to A which is main Activity.
Now if I press back button, instead the app should exit...it creates loop between B and A and never exit the app.
I already used the following method
Method 1:
use of this.finishonBackPressed which didn't help
Method 2:
use android:nohistory = true in manifest
But If I do so then from C activity it will directly take me to A which I don't want.
Method 2.
Use of
Intent intent = new Intent(Intent.ACTION_MAIN);
//to clear all old opened activities
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
finish();
when I use this then everytime this opens up in my device
Please anyone help.
This is my code in Mainactivity now
#Override
public void onBackPressed() {
finish();
super.onBackPressed();
}
But also it don't work and it creates loop between A and B Activity.

Your code (in MainActivity) is incorrect , put finish() after super.onBackPressed()
it must be :
#Override
public void onBackPressed() {
super.onBackPressed();
finishAffinity(); // or finish();
}

Have to press the back button twice to get to previous activity?

I am simply trying to click back and navigate to my previous activity. My flow is this: I go to news_feed activity -> Comments activity -> User Profile activity -> click back (Go to Comments activity) -> click back (This does nothing for some reason) -> Click back (Go back to news_feed activity). I'm not sure why I have to click back twice when I try to go from Comments activity back to news_feed activity. If I go from news_feed activity -> Comments -> press back (Go to news_feed activity) this works perfectly. Here is my code:
news_feed.java:
#Override
public void onBackPressed() {
super.onBackPressed();
Intent startMain = new Intent(Intent.ACTION_MAIN);
startMain.addCategory(Intent.CATEGORY_HOME);
startMain.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(startMain);
}
Comments.java:
#Override
public void onBackPressed() {
super.onBackPressed();
this.finish();
}
UserProfile.java:
#Override
public void onBackPressed() {
super.onBackPressed();
Intent intent = new Intent(UserProfile.this, Comments.class);
Bundle bundle = new Bundle();
bundle.putString("postId", postId);
bundle.putString("posterUserId", posterUserId);
bundle.putString("posterName", posterName);
bundle.putString("postStatus", postStatus);
bundle.putString("postTimeStamp", postTimeStamp);
bundle.putString("postTitle", postTitle);
intent.putExtras(bundle);
startActivity(intent);
finish();
}
I don't think navigating to these activities would change anything, but I can include the intents that I used to navigate to these activities also if necessary. Otherwise I just included the onBackPressed code that I had for these activities. Any ideas why this might cause a problem? Any help would be appreciated. Thanks.

In your UserProfile class, in onBackPressed() method, you are starting the Comments class again. Why do you have to do this?
What is happening is, you are starting a new Comments activity onBackPressed() of the USerProfile class, so there are two instances of Comments Activity. So you feel you are pressing back btn twice.
If you have to pass data back to Comments from UserProfile class, then make use of setResult() method.
This will be of help
How to pass data from 2nd activity to 1st activity when pressed back? - android
Sending data back to the Main Activity in android

I you want to send back the result to previous activity the start activity by using
startActivityForResult()
insead of
startActivity()
and don't override
onBackPressed()

You can try something like this:
private boolean clicked;
#Override
public void onBackPressed() {
if (!clicked) { // if it was not clicked before, change the value of clicked to true and do nothing directly return, if clicked again, then it will be finish the activity.
clicked=true;
return;
}
super.onBackPressed();
}
And if you are going to use the time, then you can do like this:
private long lastClicked;
#Override
public void onBackPressed() {
if (System.currentTimeMillis() - lastClicked < 1000) { // within one second
super.onBackPressed();
}
lastClicked = System.currentTimeMillis();
}

You don't need to override onBackPressed() if all you're going to do is call startActivity() and finish() in the current activity. The Android backstack will handle both of those for you. Moreover, in your UserProfile.java you are passing data to previous activity. For this, you should use startActvityForResult() in the Comments activity (i.e the previous activity) instead of startActivity().
To learn more about startActvityForResult() visit: https://developer.android.com/training/basics/intents/result.html

public void onBackPressed() {
if (this.lastBackPressTime < System.currentTimeMillis() - 2000) {
this.lastBackPressTime = System.currentTimeMillis();
} else {
//super.onBackPressed(); for exit
//INTENT HERE TO YOUR SECOND ACTIVITY like below
Intent intent=new Intent(A.this,B.class);
startActivirty(intent);
}
}
Create a global variable
private long lastBackPressTime = 0;
Hope this will help you,Let me know..

On physical back button pressed how to go to device's home screen? [duplicate]

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);
}

Activities Stack Issue

I have two sets of Activities suppose 3 Activities each set, (A1,B1,C1 || A2,B2,C2) I start my App from A1 then -> B1 -> C1 here I want to jump from C1 to -> A2 and at A2 if I press back it should exist the App and not put me back for C1, then from A2 I navigate to -> B2 -> C2.
So it is basically I want to change the starting Activity, it is like I have two Apps in one App and when I flip to the second App I have to clear the Activity Stack. Is that possible? Any Ideas?

Seems to me you've answered your own question. You wrote:
So it is basically I want to change the starting Activity, it is like
I have two Apps in one App and when I flip to the second App I have to
clear the Activity Stack.
I would do it this way:
Create a DispatcherActivity which is the activity that gets launched when the application is started. This Activity is the root activity of your task and is responsible for launching either A1 or A2 depending... and NOT call finish() on itself (ie: it will be covered by A1 or A2 but still be at the root of the activity stack).
In A1, trap the "back" key and tell the DispatcherActivity to quit like this:
#Override
public void onBackPressed() {
Intent intent = new Intent(this, DispatcherActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.addExtra("exit", "true");
startActivity(intent);
}
This will clear the task stack down to the root activity (DispatcherActivity) and then start the DispatcherActivity again with this intent.
In C1, to launch A2, do the following:
Intent intent = new Intent(this, DispatcherActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.addExtra("A2", "true");
startActivity(intent);
This will clear the task stack down to the root activity (DispatcherActivity) and then start the DispatcherActivity again with this intent.
In DispatcherActivity, in onCreate() you need to determine what to do based on the extras in the intent, like this:
Intent intent = getIntent();
if (intent.hasExtra("exit")) {
// User wants to exit
finish();
} else if (intent.hasExtra("A2")) {
// User wants to launch A2
Intent a2Intent = new Intent(this, A2.class);
startActivity(a2Intent);
} else {
// Default behaviour is to launch A1
Intent a1Intent = new Intent(this, A1.class);
startActivity(a1Intent);
}
In A2, trap the "back" key and tell the DispatcherActivity to quit using the same override of onBackPressed() as in A1.
Note: I just typed this code in, so I've not compiled it and it may not be perfect. Your mileage may vary ;-)

You can check when the button that is pressed in Activity A2 and then if its a Back button you can close the app. You can use the following method in A2
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
this.finish();
}
return super.onKeyDown(keyCode, event);
}

try launching the activity A2 with this intent - intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

Handle this using onBackPressed and finish methods.
Before launching other activity, better you close the current activity using finish() method.
If you want to go to previous activity on back press, override onBackPressed method and call the particular intent.
In A2 activity, add finish method in onBackPressed method (dont call previous activity here). This is one of the way.

while passing Intent from Activity C1 to A2 use as
Intent intent=new Intent(C1.this,A2.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
and in Your Activity A2 Override Back Button by
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
A2.this.finish();
}
return super.onKeyDown(keyCode, event);
}

if you want to close your app when press the back button instead of go back last activity, you should overwrite the back button. in the overwrite method call finish() method after close the activity. i hope this may help you.
edited:
check the below link : this is for close all activities in your view stack. before closing your app close all activities.
http://www.coderzheaven.com/2011/08/27/how-to-close-all-activities-in-your-view-stack-in-android/

FLAG_ACTIVITY_CLEAR_TOP is not what you are looking for.
i think you are looking for:
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);