android – Overriding the Home button – how do I get rid of the choice?-ThrowExceptions

Exception or error:

When creating one Intent so that MyActivity reacts to a User pressing the Home-button is easy using the XML markup:

    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
            <category android:name="android.intent.category.HOME" />
            <category android:name="android.intent.category.DEFAULT" />
    </intent-filter>

I want to know how to avoid getting the choice of “what activity do you want to use” for the Home screen? HTC has made its “Touch Flo” (Sense) override the default “start” Activity and I never get the question if I want to use “Start” or “TouchFlo” usually. However, when I added my own Activity I always get the question.

Yes, I know that I can check the “Use this as standard”-checkbox, but that’s not what I want right now. So, question is: can I make the system override everything else and always use MyActivity as default?

Next, I really only want to override the normal Home Screen when my app is running. If its not running, everything should work as normal, ie MyActivity should NOT be associated with the Home button.

How to solve:

You can’t permanently override the Home button without the user confirming it.

One argument for why this is the case is a security one. The Home button is the one way a user can be guaranteed to exit any application. If you could make the Home button launch your application instead of the Home screen without the user confirming this change, it would then be very easy to write a malicious application that hijacked a user’s phone.

Alternatively, your application could contain a replicate Home Screen that harvested a user’s Google account details; not that hard since the source is available. If your application could silently replace the default Home Screen, it would be hard for the user to tell this had happened.

Also, do you really want to override Home? Home is like an emergency escape button. Pressing Home twice will always take a user back to the center panel of the Home Screen, so whatever application they’re running, it’s easy for a user to get back to somewhere they know. You shouldn’t really be overriding this unless you’re producing a full Home replacement.

###

@Override
public void onAttachedToWindow()
{  
    Log.i("TESTE", "onAttachedToWindow");
    this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
    super.onAttachedToWindow();  
}

With this method, the HOME Button stops working in this activity (only this activity). Then you just reimplement as it was a normal button event (the back button for instance).

public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_HOME) {
    Log.i("TESTE", "BOTAO HOME");
    return true;
}
return super.onKeyDown(keyCode, event);    
}

###

The overridable onUserLeaveHint() lifecycle hook can be used when the user presses the home button.

This hook has been present since API level 3.

@Override
protected void onUserLeaveHint() {
    super.onUserLeaveHint();
    // Your code here
}

More info about the method:

Called as part of the activity lifecycle when an activity is about to go into the background as the result of user choice.

For example, when the user presses the Home key, onUserLeaveHint() will be called, but when an incoming phone call causes the in-call Activity to be automatically brought to the foreground, onUserLeaveHint() will not be called on the activity being interrupted.

In cases when it is invoked, this method is called right before the activity’s onPause() callback.

Source: https://developer.android.com/reference/android/app/Activity.html#onUserLeaveHint()

###

Well, the user would still have to choose the regular home as their home with use as default checked to stop the prompt from coming back. However, I believe it is possible for you to then modify the system settings in some way to incidentally have your particular activity be considered the default home, such that press of home would then do nothing or appear locked to the user at the main activity, and I understand you wish to launch your user into other activities from there, giving them a fast home press return to this root Launcher. I can see the benefit of this completely, and it may even benefit what I’m developing if I choose to implement multiple widget screens that the user can flip left or right between.

There is at least 1 app out there that I’ve downloaded which appears to be doing exactly this. When the user exits the app, it restores the user’s regular default home preference. The app instructs the users very explicitly to choose Launcher as their default home and never do that with the app itself. It has a few different “exit” methods which give the user the choice of which home to return to if they have multiple, and one that just exits to their regular default.

I am researching this as well and will report back with progress & source.

###

Use onUserLeaveHint().

onUserLeaveHint() is a protected method as other lifecycle methods of the activity and if you are handling onUserLeaveHint this will take care of the following case

  1. When User hits home key
  2. When User hits back key
  3. When User hits annunciator bar

Here you can catch Homeb button click.

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