I call
getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_HIDE_NAVIGATION)
when my app starts to make my app able to display the full screen.
I want my app's UI to pop up when screen is touched, but Activity.onTouchEvent()
is not triggered until the screen is touched a second time. At first touch, only the Virtual Keys are shown.
So, I have to trigger my app's UI to pop up on
public void onSystemUiVisibilityChange(int visibility) {
if (visibility == View.SYSTEM_UI_FLAG_VISIBLE) {
// show my APP UI
}
}
but onSystemUiVisibilityChange
with View.SYSTEM_UI_FLAG_VISIBLE
will be invoked NOT once per touch (3 times on my Galaxy Nexus) by system, especially if the user touches the screen very fast/often.
project lib 4.0 or 4.03. Samsung galaxy(9250) with 4.03.
Android 4.4 (API Level 19) introduces a new SYSTEM_UI_FLAG_IMMERSIVE
flag for setSystemUiVisibility()
that lets your app go truly "full screen." This flag, when combined with the SYSTEM_UI_FLAG_HIDE_NAVIGATION
and SYSTEM_UI_FLAG_FULLSCREEN
flags, hides the navigation and status bars and lets your app capture all touch events on the screen.
This did work for me:
setOnSystemUiVisibilityChangeListener(new OnSystemUiVisibilityChangeListener() {
@Override
public void onSystemUiVisibilityChange(int visibility) {
if ((visibility & SYSTEM_UI_FLAG_HIDE_NAVIGATION) == 0) {
// show my app UI
}
}
});
What I've done is first imported android.view.GestureDetector
so I can use it to detect gestures. Android has a number of default gestures that are automatically detected in the GestureDector class. Most of this info is found here, but below is code in a form that I've used in an actual project that works.
First I've made an anonymous class in my Activity (this can be nested wherever, but I tend to make my anonymous classes at the bottom, right before the closing bracket). NOTE: You can also implement OnGestureListener
as part of your class, also.
The code below is for using gesture detection to give a simple hide/show.
I've declared and defined my action bar (my UI, which is initially hidden) as an instance variable, so I can access it here, and wherever else, but you can substitute it for a getActionBar().show()
and getActionBar().hide()
in the case you don't want to declare it as an instance variable. Substitute your UI in the place of the actionBar
here:
public class Example extends ActionBarActivity {
// declared in onCreate() method
private android.support.v7.app.ActionBar actionBar;
private GestureDetectorCompat mDetector;
private YourView view1;
private YourView view2;
private YourView view3;
private YourView view4;
// some other code
class GestureListener extends GestureDetector.SimpleOnGestureListener {
private static final String DEBUG_TAG = "Gestures in Example Class";
@Override
public boolean onDoubleTap(MotionEvent event) {
Log.d(DEBUG_TAG, "onDoubleTap: " + event.toString());
// if there is a double tap, show the action bar
actionBar.show();
return true;
}
@Override
public boolean onSingleTapConfirmed(MotionEvent event) {
Log.d(DEBUG_TAG, "onSingleTapConfirmed: " + event.toString());
// if the tap is below the action bar, hide the action bar
if (event.getRawY() > getResources().getDimension(R.dimen.abc_action_bar_default_height)) {
actionBar.hide();
return true;
}
return false;
}
@Override
public boolean onDown(MotionEvent event) {
return true;
}
} // end-of-Example Class
Then in my onCreate()
I've declared my GestureDetector
and also (optionally) set my GestureListeners
:
private GestureDetectorCompat mDetector;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// some code here
mDetector = new GestureDetectorCompat(this, new GestureListener());
// this code is for more advanced view logic not needed for a basic set-up
//setGestureListeners();
} // end-of-method onCreate()
Then in order to actually send gestures to be processed we provide the instructions for doing that, there are two ways I know about, first the simplest:
/**
* This method recognizes a touchEvent and passes it to your custom GestureListener
* class.
*/
@Override
public boolean onTouchEvent(MotionEvent event){
this.mDetector.onTouchEvent(event);
return super.onTouchEvent(event);
}
The second way is more complex, but if you want to only recognize touch events on certain View
s in your layout as in the case where you have overlapping views and can only access the top View
, you can create a custom class to pass the event around or up:
class MyOnTouchListener implements View.OnTouchListener {
public boolean onTouch(View v, MotionEvent event) {
if (v.equals(view4)) {
return mDetector.onTouchEvent(event);
} else return false;
}
} // end-of-class MyOnTouchListener
and then use it here:
public void setGestureListeners() {
/* when we return false for any of these onTouch methods
* it means that the the touchEvent is passed onto the next View.
* The order in which touchEvents are sent to are in the order they
* are declared.
*/
view1.setOnTouchListener(new MyOnTouchListener());
view2.setOnTouchListener(new MyOnTouchListener());
view3.setOnTouchListener(new MyOnTouchListener());
view4.setOnTouchListener(new MyOnTouchListener());
} // end-of-method setGestureListeners()
In my setGestureListeners
method, I gave them all the same set of commands, that essentially only recognizes touchEvents on view4
. Otherwise, it just passes the touchEvent to the next view.
This is code using AppCompat
, but if you are not building for older versions, you can use the regular GestureDetector
and ActionBar
.
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