Develop Reference

Android - backbutton - restarting app

I designed a app with WebView.
Now I am facing issue, while clicking back-button of WebView of Android app. It is
restarting app instead of Homepage/Menu.
Any idea why this is happening?

I think you use the Intent to webview from Home activity.
if you use Intent, dont use finish() after start the Intent like below.
Intent i=new intent(this,WebviewActivity);
startActivity(i);
HomeActivity.this.finish(); // dont use this line, it destroys homeactivity.
if you doesn't use the Intent, post your code clearly.
Hope this Helps.
Happy Coding :)

remove activity from stack

I am developing an application in android. I am new in android.
In my application I have a category selection activity from that user have to check a check-box, based on that he will get view on another screen. I have a menu button in 3rd screen in that I have a button for selecting category, when I click on that button its also works fine but when I click back button it will redirect me 2 times at same activity... How to remove this problem? I have used finish() method but its also creates problem its get's me out from the application directly...
I want redirect to selection activity and it should not show me 2 times when I click back button ....
Is there any way please redirect me thank you.

a call to finish() should work so you schould check your code for multiple calling the wrong method or something like this.
Intent intent = new Intent(activity, activityClass.class);
activity.startActivity(intent);
finish();
you should also take a look at the Intent flags:
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.addFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);
intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);

Your question isn't clear enough for me to know if this will solve your problem, but if you include the following attributes on your Activity in AndroidManifest.xml, the so-attributed Activity will never appear in your history list.
android:excludeFromRecents="true"
android:noHistory="true"
As for removing something from the history, I'm not sure how to do that, but I'm interested in the answer!

You should call finish before you call Intent and go to next activity. so the current task is finished and will not be saved in stack and then you intent activity will come on top of stack. If you directly want to go to Selection activity, override onBackPressed() and intent to the activity you want to go to.

There are different flags that you can use to control how your activity interacts with the activity history stack. Two that might be of interest to you are FLAG_ACTIVITY_CLEAR_TOP and FLAG_ACTIVITY_NO_HISTORY.

How to force stop the application

Is there any possibilities to force stop the android application through program. previously i used finish(); method, but by doing this i can only quit the current activity and place back into existing or previous activity. i want to kill or force close the application, is this possible to do in android application. pls guide me to do this..Thanks in advance.

Using System.exit(0); is not recommanded but works.
In fact it's better to do something like :
System.gc();
finish();
This will ask the system garbage to start cleaning clean, then finishing properly the apps.

May be this can be helpful in getting your answer
How to close Android application?
I got some code..may be this is helpful to you
Intent startMain = new Intent(Intent.ACTION_MAIN);
startMain.addCategory(Intent.CATEGORY_HOME);
startMain.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(startMain);
call this on your button's click event,It'll exit the application
and yes..before you exit.just call System.gc()..I know it's just a warning.but it may be helpful in releasing some memory

How to navigate to another page in android?

I'm new to android. Please tell me how to navigate to a new page in android.
Thanks in advance.
Edit:How to start a new activity from an existing activity

In android to navigate to another page means you have to start another activity. for starting a new activity use this
Intent intent = new Intent(currentActivity.this, nextActivity.class);
startActivity(intent);
You should mention the next activity in the AndroidManifest file.

To change your page (i think you're refering to "Activities" in android you need to issue a so called "intent").
You cann do that by:
startActivity(new Intent(nextactivity,NextActivity.class));
or
startActivityForResult(new Intent(nextactivity,NextActivity.class),1);
if you want the new Activity to return any result to the activity who started the new one.
But what i recommend is, that you read this documentation here:
http://developer.android.com/guide/topics/intents/intents-filters.html
and come back to this question if you have need additional assistance on concrete problems on that topics.
i hope that helps.

Exit an android app

How to close an android app if more than one activity is in active state?

A blog post entitled Exiting Android Application will show how to exit an Android app:
When the user wishes to exit all open activities, they should press a button which loads the first Activity that runs when your app starts, in my case "LoginActivity".
Intent intent = new Intent(getApplicationContext(), LoginActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.putExtra("EXIT", true);
startActivity(intent);
The above code clears all the activities except for LoginActivity. LoginActivity is the first activity that is brought up when the user runs the program. Then put this code inside the LoginActivity's onCreate, to signal when it should self destruct when the 'Exit' message is passed.
if (getIntent().getBooleanExtra("EXIT", false)) {
finish();
}

I got an easy solution for this problem
From the activity you press the exit button go to the first activity using the following source code. Please read the documentation for FLAG_ACTIVITY_CLEAR_TOP also.
Intent intent = new Intent(ExitConfirmationActivity.this, FirstActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
Now overide onResume() of the first activity using finish()

The answer is simple: You really do not need to 'close' an Android application. If no activity is shown any more, the system will kill the process after some time. The users can close activities by pressing the 'back' button. Reto Meier explains it pretty well here:
http://blog.radioactiveyak.com/2010/05/when-to-include-exit-button-in-android.html

You might also want to read this thread; it is very helpful to say the least: Quitting an Android application - Is it frowned upon?

Well, you shouldn't close your applications, as the system manages that. Refer to the posts/topics in the other answers for more information.
However, if you really, really want to, you can still call System.exit (0); like in any other Java application.
EDIT
ActivityManager actmgr = (ActivityManager) this.getSystemService (Context.ACTIVITY_SERVICE);
actmgr.restartPackage ("com.android.your.package.name");
I remembered something. I was trying to use this code to restart my application, but it only managed to kill my app. You can try it and see if it works for you.

I asked a similar question a couple of weeks back. Do go through the answers and comments for more perspective and possible solutions.
IMO quitting an application depends on what your application does and the user expectations. While I understand the rationale on not having a quit button I also do believe that it's a choice that the application designer has to make based on the situation.

Once your last Activity looses focus, Android will unload your process according to the current system needs / free resources.
You shouldn't really care about that - just use the lifecycle onStart, OnStop etc... to manage your state.

If you want to exit from one Android activity, this will bring you back to the previous activity or another activity from a specific place in current activity.
finish();
System.exit(0);