Develop Reference

Android scrolling makes whole screen blue

I have not been able to replicate this, but is anyone aware of what might cause the entire screen on an Android device to go light blue? It seems related to selecting a radio buttons and then scrolling. It happens on Nexus 5x with Android 8.
Here is what it looks like:
I have only heard of one other instance of this occurring. Could it be device specific? Strangely enough, once it happens it seem to stay this way, though the user says it is somewhat intermittent.
Update:
This only seems to happen on Android 8, if that helps anyone...

So, I eventually found the offending code. I verified this is only happening on Android 8 devices, maybe only Samsung? The offending code was:
mFormScrollView.setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS);
mFormScrollView.setFocusable(true);
mFormScrollView.setFocusableInTouchMode(true);
// Hide the keyboard when moving the screen up or down. This should only
// be an issue when
// on a text edit field. Also disable focus jump using
// "requestFocusFromTouch"
mFormScrollView.setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View view, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_UP || event.getAction() == MotionEvent.ACTION_DOWN) {
Utilities.hideKeyBoard(FormActivity.this, view);
}
// Keeps screen from jumping to nearest EditText
// view.requestFocusFromTouch();
return false;
}
});
The offending line is commented out - the view.requestFocusFromTouch() method, which was meant to keep the screen from auto jumping to the next text field when the keyboard was hidden and focus lost. On Android 8 this is not happening, but I need to verify with older versions.

Prevent application with SYSTEM_ALERT_WINDOW from obscuring my application

Is there any way to assure that my application's window is not obscured by any other application's view using with SYSTEM_ALERT_WINDOW permission?
If not, then is there any better way to assure that my app is not obscured by such window apart from obtaining the same permission and refreshing/showing/whatever my own view (of course shown in alert window) every 100ms or so to keep it visible?
Eventual flickering, in case my application is obscured, is actually a good thing and an indicator to the user that something is wrong.
EDIT: It seems that there is no way to do it except from going through KNOX on Samsung or some other proprietary solution for Trusted UI. Accepted answer is enough for my purpose, but it is not an answer for the question asked.

Even if it's not exactly what you're asking, the closest replacement I know of is:
Either setting android:filterTouchesWhenObscured="true" in your layout (touch events will be filtered and not reach your View if they are going through an overlay, regardless is transparent or opaque). See View#setFilterTouchesWhenObscured(boolean),
Or overriding View#onFilterTouchEventForSecurity(android.view.MotionEvent) and checking for FLAG_WINDOW_IS_OBSCURED. See View#onFilterTouchEventForSecurity(android.view.MotionEvent).
Later can be implemented like so:
override fun onFilterTouchEventForSecurity(event: MotionEvent): Boolean {
if ((event.flags and MotionEvent.FLAG_WINDOW_IS_OBSCURED) == MotionEvent.FLAG_WINDOW_IS_OBSCURED) {
Toast.makeText(context, "Screen overlay detected!", Toast.LENGTH_LONG).show()
return false // touch event is cancelled
}
return super.onFilterTouchEventForSecurity(event)
}
See also the Security section of View class documentation.
Notice that this functionality is available from API 9+. A workaround for older APIs can be found in this SO Question: Analogue of android:filterTouchesWhenObscured for API level below 9.

Trigger(Touch) not working anymore on Android Unity3D VR App

My Cardboard-like VR-Viewer has a button that works by touching the screen. I created an app in Unity3D and this trigger mechanic first worked like a charm. Now all of a sudden, I think I only added an explosion particle effect, the touch function stopped working completely. I have tried things like removing the explosion from my scene again, but nothing seems to work. Another curious thing is, that I can't close the app in a normal way anymore (normally in VR Apps you have an X-Button in the top left of your screen, but clicking it doesn't do anything anymore too (It used to work!)). App still runs, doesn't crash, but no interaction is possible. I looked at the debug logs via adb - no errors there... App works like it used to when I start it inside the Unity Editor.
Did someone encounter a similar error or may have an idea about what the problem is? I'm using Unity Daydream Preview 5.4.2f2.
Edit: I forgot to mention I was using GvrViewer.Instance.Triggered to check if the screen was touched.

For all having the same problem, I worked around it by also checking if a touch just happened. In my Player : Monobehaviour I used:
void Update()
{
if (GvrViewer.Instance.Triggered ||
Input.touchCount > 0 && Input.touches[0].phase == TouchPhase.Ended)
{
//Do stuff.
}
}

Simulate Touch Controls Through Code

I'm trying to make it possible to navigate through my Google Glass application by using head gestures. I'm able to recognize head gestures like looking to the right left and up. They each have their own method for what to do when this gesture is recognized
Now I need to simulate the corresponding touch gestures inside each method. So it will think I'm swiping to the left or right which will allow me to navigate through the cards with the head gestures.
Does anyone have any idea on how to actually achieve this?
Edit
I created a quick hello world application to play with. I added my headgesture code and started trying to get the keys working.
I added the following to my onCreate()
Instrumentation instr = new Instrumentation();
Then I added the following lines to each respective headgesture method.
Headgesture upwards should correspond with tapping the touchpadinst.sendKeyDownUpSync(KeyEvent.KEYCODE_DPAD_CENTER)
Headgesture to the left should correspond with swiping left on the touchpad inst.sendKeyDownUpSync(KeyEvent.KEYCODE_DPAD_LEFT);
Headgesture to the right should correspond with swiping right on the touchpadinst.sendKeyDownUpSync(KeyEvent.KEYCODE_DPAD_RIGHT);
They are responding accordingly now, however I'm getting an exception saying:
java.lang.RuntimeException: This method can not be called from the main application thread

The Solution
In the end I went a different direction then the one I mentioned in my edit above.
I found out that it is possible to call touch controls in the shell by using
adb shell input keyevent <keycode here>
I then found a way to use this in android, I have the following class named issueKey
public class issueKey {
public void issueKey(int keyCode)
{
try {
java.lang.Process p = java.lang.Runtime.getRuntime().exec("input keyevent " + Integer.toString(keyCode) + "\n");
} catch (Exception e) {
Log.wtf("IssueKeyError", e.getMessage());
}
}
}
Then I simply call the class and pass the keycode for the corresponding gesture
mIssueKey.issueKey(4);//functions as swipe down
Here is the list of keycodes that I tested for anyone that is interested.
Keys for each respective button/gesture
4: Swipe Down
21: Swipe Left
22: Swipe Right
23: Tap
24: Volume Up
25: Volume Down
26: Lock/Unlock Screen
27: Camera Button
However, what I'm wondering now is. What would be best practice, getting the solution I metioned in my edit to work by using a asyncTask or is the solution I'm currently using better.

Using the Instrumentation class would work if you use a separate thread to call the sendKeyDownUpSync method from.
This can be done using the following steps:
Create and start a thread from your activity
In the run method, use the Looper class and create a Handler as explained here
Every time you want to call sendKeyDownUpSync, post a Runnable instance to the Handler, which calls sendKeyDownUpSync in its run method.
A similar code sample (not from me) is available here

What DOM events are available to WebKit on Android?

I'm building a mobile web app targeting Android users. I need to know what DOM events are available to me. I have been able to make the following work, but not terribly reliably:
click
mouseover
mousedown
mouseup
change
I have not been able to get the following to work:
keypress
keydown
keyup
Does anyone know the full list of what is supported and in what contexts (e.g., is onchange only available to form inputs?)? I can't find a reference for this on The Googles.
Thanks!
Update: I asked the same question on the Android developers list. I will be doing some more testing and will post my results both here and there.

OK, this is interesting. My use case is that I have a series of links (A tags) on a screen in a WebKit view. To test what events area available, using jQuery 1.3.1, I attached every event listed on this page (even ones that don't make sense) to the links then used the up, down, and enter controls on the Android emulator and noted which events fired in which circumstances.
Here is the code I used to attach the events, with results to follow. Note, I'm using "live" event binding because for my application, the A tags are inserted dynamically.
$.each([
'blur',
'change',
'click',
'contextmenu',
'copy',
'cut',
'dblclick',
'error',
'focus',
'keydown',
'keypress',
'keyup',
'mousedown',
'mousemove',
'mouseout',
'mouseover',
'mouseup',
'mousewheel',
'paste',
'reset',
'resize',
'scroll',
'select',
'submit',
// W3C events
'DOMActivate',
'DOMAttrModified',
'DOMCharacterDataModified',
'DOMFocusIn',
'DOMFocusOut',
'DOMMouseScroll',
'DOMNodeInserted',
'DOMNodeRemoved',
'DOMSubtreeModified',
'textInput',
// Microsoft events
'activate',
'beforecopy',
'beforecut',
'beforepaste',
'deactivate',
'focusin',
'focusout',
'hashchange',
'mouseenter',
'mouseleave'
], function () {
$('a').live(this, function (evt) {
alert(evt.type);
});
});
Here's how it shook out:
On first page load with nothing highlighted (no ugly orange selection box around any item), using down button to select the first item, the following events fired (in order): mouseover, mouseenter, mousemove, DOMFocusIn
With an item selected, moving to the next item using the down button, the following events fired (in order): mouseout, mouseover, mousemove, DOMFocusOut, DOMFocusIn
With an item selected, clicking the "enter" button, the following events fired (in order): mousemove, mousedown, DOMFocusOut, mouseup, click, DOMActivate
This strikes me as a bunch of random garbage. And, who's that cheeky IE-only event (mouseenter) making a cameo, then taking the rest of the day off? Oh well, at least now I know what events to watch for.
It would be great if others want to take my test code and do a more thorough run through, perhaps using form elements, images, etc.

Since this is the second most popular Android + JavaScript post on SO (which is just a sad commentary on the state of web development targeting the Android platform), I thought it may be worthwhile including a link to pkk's touch event test results at http://www.quirksmode.org/mobile/tableTouch.html and also http://www.quirksmode.org/mobile/ in general.

As of Android 1.5, the same touch(start|move|end|cancel) events that the iPhone supports work in Android as well.
One problem I found was that touchmove ends get queued up. No workaround yet.