Start Activity when a key is hit

Question

I want to start an activity when the user presses the space bar. My code is not detecting when the space bar is clicked.

@Override
public boolean dispatchKeyEvent(KeyEvent e) {
    if (e.getKeyCode() == KeyEvent.KEYCODE_SPACE) {
        Toast.makeText(MainActivity.this, "YOU CLICKED SPACE KEY",
                Toast.LENGTH_LONG).show();
        return true;
    }
    Toast.makeText(MainActivity.this, "Didnt work", Toast.LENGTH_SHORT)
            .show();
    return super.dispatchKeyEvent(e);
};

}

score 8 · Accepted Answer · edited May 23 '17 at 12:30

8

You can either set the listener to a View that has current focus, or use dispatchKeyEvent in your Activity, as seen in this answer.

Both will work.

Answer for your comments: If you've followed my link, you've probably implemented Activity.dispatchKeyEvent(KeyEvent) by now. :-)

The code doesnt register anykey i press, but when i push the back key it toasts for me "didnt work"

Do you happen to be using the emulator? I ask that because the latest SDK seems to have some problems with the emulator keyboard. The special keys (DPAD, HOME, BACK etc.) work, but the onscreen, QWERTY keyboard does not register any presses. The physical keyboard in my laptop won't register any presses either.

Don't ask me why.

And I say that because this week I posted the answer in the link, and it was working fine. The change is that I updated the Android SDK to R20/JB this morning, so I guess it could be a factor.

However, it will just work on a real device. I've just connected a physical keyboard to my tablet (P7510 / Honeycomb 3.2), and it listens to space presses just fine.

In case you're still doubting, here is proof: :-)

enter image description here

edited May 23 '17 at 12:30

Community

1
1

answered Jul 01 '12 at 04:50

davidcesarino

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So yes, either you didn't set that listener to a View, or the View for which you set the listener is not under focus when you press space bar. – davidcesarino Jul 01 '12 at 04:52
I re edited my code using dispatchkeyevent. I'm going to try it the other way but meanwhile my updated code is posted. – The Tokenizer Jul 01 '12 at 05:25
So, did it work? Does the Toast appear not when you press the ENTER key? – davidcesarino Jul 01 '12 at 13:37
The code doesnt register anykey i press, but when i push the back key it toasts for me "didnt work" – The Tokenizer Jul 01 '12 at 15:14
I updated the answer to address your concerns. PLEASE take a look. – davidcesarino Jul 01 '12 at 22:30
I'm still on this problem. I've tried it on my HTC Inspire and im still not getting a response from space key. – The Tokenizer Jul 29 '12 at 18:29
lol, someone thought I had wrote "yo" (as in street language)... it was a typo ("*to*" your answer). But anyway, thanks for fixing it! – davidcesarino Aug 05 '12 at 14:01

score 2 · Answer 2 · edited Aug 05 '12 at 17:50

2

public abstract boolean onKey (View v, int keyCode, KeyEvent event)

This function can be used to check that which key is pressed.

edited Aug 05 '12 at 17:50

davidcesarino

16,160
16
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answered Aug 05 '12 at 11:01

Rishi

330
2
13

score 1 · Answer 3 · answered Jul 31 '12 at 10:40

For this case, what I have done is , I have used the overridden function 'onKey'

@Override
public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event)
{
    if (keyCode == nNeededKeyCode)
    {
        //do something
    }
    return true;
}

p.s. firstly you need to make use of 'OnKeyListener()' to get the key press event

score 1 · Answer 4 · answered Aug 02 '12 at 12:51

Sorry for the copy/paste answer, but this should accomplish what you're attempting.

This will take place when the user presses the "spacebar" and then lets the spacebar go. If you don't want to wait for them to let it go, you can remove my boolean values, and execute your code in the onKeyDown function. Hope this helps.

boolean spacePressed = false;
@Override
public boolean onKeyDown(View arg0, Editable arg1, int arg2, KeyEvent arg3) {
    // TODO Auto-generated method stub
       switch (keyCode) {
               case KeyEvent.KEYCODE_SPACE:
               {
                  spacePressed = true;
                  return true;
                }
               // other cases can go here
    }

    return true;
}// End of onKeyDown



@Override
public boolean onKeyUp(View arg0, Editable arg1, int arg2, KeyEvent arg3) {
   if (spacePressed){
       // start intent

       // make this false again, so other keys won't trigger it
       spacePressed = false;
   }

    return true;
}// End of onKeyUp

Start Activity when a key is hit

4 Answers4