Monthly Archives: November 2011

How to Override Android’s Back Key When Soft Keyboard is Open

by

There are various scenarios where we need to handle the Android powered handsets’ hardware “back” key to do some important stuff. One scenario that’s very common is to use it on your custom search view where pressing back key only leads to hide the keyboard and user has to tap it again to hide the search view.

Let’s consider this:

Here we have a search view with keyboard open. If user wants to cancel searching and go back, he can press the back key and here is what we get on back key press:

You can see that the keyboard has gone but the search view is still there. User has to press the back key another time to navigate back to original activity.

Apparently, there is no method in your activity which listens to hardware key events when software keyboard is open. onKeyDown() and onKeyUp() methods work only when keyboard is hidden and this happen because Android considers on-screen keyboard as a separate activity and behaves accordingly.

So what should one do to override it?

Answer is simple and the easiest way to do is to override onKeyPreIme() method which is inherited from View class. To override it, you need to create a custom view. we’ll do it With minimum of the effort. For the example above, we have an EditText which we have using for searching.

Now create a new class which extends from EditText class. Override all the constructors to avoid any possible app crash. Now we’ll override the onKeyPreIme() method and check for Back key:

@Override
public boolean onKeyPreIme(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        // User has pressed Back key. So hide the keyboard
        InputMethodManager mgr = (InputMethodManager) mContext.getSystemService(Context.INPUT_METHOD_SERVICE);
        mgr.hideSoftInputFromWindow(this.getWindowToken(), 0);
        // TODO: Hide your view as you do it in your activity
    }
    return false;
}

Replace your EditText with this brand new class and that’s all. Now whenever the soft keyboard is hidden through back key, you’ll be notified and you can do the required code to get things work your way.

Bonus Trick:

Here’s a bonus trick for you. If you have implemented menus in your activity, you might face a problem like this:

If you press menu key when the keyboard is opened, you ‘ll have your menus over the keyboard. Now isn’t that funny? But don’t worry, we don’t have to worry about this. What do we want here is that menus should not become visible when keyboard is opened. Piece of cake!! Update your above code to this:

@Override
public boolean onKeyPreIme(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        // User has pressed Back key. So hide the keyboard
        InputMethodManager mgr = (InputMethodManager) mContext.getSystemService(Context.INPUT_METHOD_SERVICE);
        mgr.hideSoftInputFromWindow(this.getWindowToken(), 0);
        // TODO: Hide your view as you do it in your activity
    } else if (keyCode == KeyEvent.KEYCODE_MENU) {
        // Eat the event
        return true;
    }
    return false;
}

And here you go!! Menus won’t show up on pressing menu key when the keyboard is visible.
Please share the post if you liked.