Develop Reference

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);
}

Redirection to home after clicking on back button

I am creating an app, which will ask for password before opening any other app.
To start my activity i have created an intent which is having flags as ,
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
The locking/unlocking function is working properly,
but when i press back button it is not redirecting to home screen.

Make sure you have not finished your home screen activity.. or you can try the onBackPressed() method
#Override
public void onBackPressed() {
// INTENT FOR YOUR HOME ACTIVITY
}

how to close android app when back button pressed

I am building a simple login application on android platform.
The 1st Activity is a Login Activity and the 2nd one is a welcome screen.
When a user presses the login button, I start the 2nd Activity by using an Intent.
But in the 2nd Activity, when the user presses the back button, it opens the 1st Activity.
But at this point I want to close my app.
Can I use Fragments?
Any other alternative?

you have to just finish your activity when you switching another activity,
Intent i = new Intent(Login.this, Welcome.class);
startActivity(i);
finish();

you call the finish() in LoginActivity when you start the your SecondActivity
Intent i = new Intent(Login.this, Welcome.class);
startActivity(i);
finish();
OR
you set the android:noHistory = "true" in LoginActivity in AndroidManifest.xml.

you need to create your second activity with FLAG_ACTIVITY_CLEAR_TOP from your first activity.
and then in your second activity you need to call finish() in onbackpressed()
#Override
public void onBackPressed() {
finish();
}

Hide login activity

I have LoginActivity which checks SharedPreferences for login details then it redirects to HomeActivity and other activities after that. I have put Menu item Sign Out on each of this activities and used this code on sign out button.
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
How to hide the Login activity, so that when user press back button from home screen it'll close the app.
Like when I open app it shows Home screen and when I press back button normally it should close the app. But in my case it takes me to the Login screen which is the first screen checking user credentials.
I cannot end the Login activity, otherwise that solution doesn't work.
I'm a new to Android. Please suggest something to solve this problem.

you should try this on your home Activity's back key function:
onBackpress(){
Intent intent = new Intent(mContext, LoginActivity.class);
intent.putExtra("FLAG", 0);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(intent);
}
and on your LoginActivity just do:
onNewIntent(Intent intent){
int i = intent.getIntExtra("FLAG", 0);
if(i == 0)
finish();
}
remember launchMode for activity in menifest should be singleTop.

Override the Activity.onBackPressed() method and then send the application home via an Intent.
From the SDK:
An intent with the following categories will allow you to go home.
ACTION_MAIN with category CATEGORY_HOME -- Launch the home screen.

You can override the back button keypress event and have it close the app when pressed.

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);
}