Develop Reference

Black screen on Activity.setRequestedOrientation(...) call in Android

Does anybody know how to cope the problem?
Using the android.app.Activity#setRequestedOrientation(SCREEN_ORIENTATION_LANDSCAPE) method almost always causes the showing a black screen for a split second during the rotation.
But if I rotate the smartphone itself, then the black screen never appears.
How to get rid of the black screen? Is it the Android issue of the setRequestedOrientation() method, or I do something wrong?
EDIT: AFAIK the black screen with setRequestedOrientation() call could happen if we have quite heavy layout, when it takes some more time to initialize it in the UI thread. If you try to call setRequestedOrientation() for instance in a "Hello World!" app with a light layout, you won't see the black screen. So, the loading on the UI thread can be the cause of the black screen when you rotate with setRequestedOrientation(). But, in other hand why it never appears when I rotate the screen changing the phone orientation?

The only solution I've found.
Consider I want to turn screen to landscape and what do I do:
I remove the root Fragment with heavy stuff from the Activity I want to rotate.
Inside the Activity I want to rotate I open an empty white Activity for a moment to cover the black screen. The Activity is calling setRequestedOrientation(SCREEN_ORIENTATION_LANDSCAPE) in its onCreate callback and closes itself after the timeout = 500 ms. I open/close the Activity with fade-in/fade-out animation.
Inside the Activity I want to rotate I call setRequestedOrientation(SCREEN_ORIENTATION_LANDSCAPE) post delayed with 100 ms. This starts the rotation.
After the rotation complete, in the onCreate I add the removed Fragment back.
That's it. Rotation to landscape is finished and the black screen was completely covered.

Edited:
I had the same problem. In older versions of android, if the content of the layout is heavy (if it contains high resolution image, etc.), the running activity is trying to re-create the layout to change the orientation but can't achieve this.
As a solution, we can create 2 different layout resources as portrait and landscape, specifying which one we will use and making it easier for the android.

Content going out of desired div in an Android app

I am working on an Android app. When I slide the screen right I get a blank grey screen and when I slide the screen left I again get a blank screen with some of my content on it. I have attached pictures of the problem to better understand it.
I want to solve this problem via CSS if possible.
Second:
First:

Odd Scaling Behavior in Android ICS WebView

I have an application that displays html pages from resource assets in a WebView. The WebView was chosen in order to permit navigation links on the page, and all navigation action is handled in a WebView Client class by interrupting new page requests and returning the required local asset. The activity that contains the WebView supports both portrait and landscape orientations, and the WebView is configured ("setInitialScale" and "WebSettings") in "onCreate". Pages are displayed to fit inside the width and vertically scrollable. This has worked fine until the ICS update.
Under ICS the initial page selected still displays as before, but further page links that are displayed are wider than the screen width (and include a horizontal scroll bar). This occurs if the device is in portrait or landscape orientation when the initial page is loaded. Rotating the device to landscape and back to portrait solves the problem (causing a re-load of the activity as if the displayed page were the first one), but navigating back to previous pages while in portrait orientation causes them to again have widths that exceed the device display, even when returning to the primary page which was displaying correctly.
This is mostly an annoyance - but the inconsistent behavior is worrying. Unfortunately, there are several other "tweaks" associated with this code (mostly to re-size images within the html to fit the screen and retain the WebView scroll position when the orientation changes). While these could be a source of the current problems, a quick log output of their results shows they are working as expected, suggesting it is the ICS WebView behavior has changed.
I have searched for any similar postings of the problem without finding any direct reference, so my question is really open. Has anyone else seen anything like this in the ICS WebView class, or should I be looking for another source for the changed behavior?
Update:
After eliminating one line of code after another for hours (grrrr), I have identified the problem.
When running under android api 14 or higher, the WebView has unpredictable behavior after setting the view scale with "setInitialScale" to values larger than 100% when the viewport is fixed at the device width (using the meta tag name="viewport" content="width=device-width" in the html css). The initial page load seems to respect the device width, but subsequent page loads may or may not render with the viewport wider than requested, almost randomly.
This may be the expected behavior, although the unpredictability suggests that it is not (and if it is, then it is a fix from the behavior under previous versions).
The code used was setting the scale to allow the user to adjust the text display size in preferences, with the size of page images being "fixed" to a value in code before the page is loaded. This has been replaced by maintaining the page scale at 100%, and setting the text size from the user's preferences using "WebSettings.setDefaultFontSize", which has removed the rendering problems.

Android: correct way to get screen dimensions for target orientation?

My application is bitmap intensive, with pixel-exact layout (it's a sort of game, actually, and it's pretty hard to avoid this pixel-based coordinates).
What I wanted to do is to perform some layout calculations and bitmap pre-scaling in my onCrete - I use well known API - getWindowManager().getDefaultDisplay().getSize() - to retrieve the screen size and do my calculations.
However, I've just hit an unexpected problem. My activity is configured as landscape only, but if I start my application on emulator and onCreate() is called while the emulator is locked, the screen size returned by getSize() indicates portrait orientation. Once I unlock the screen, onCreate() is called again, this time correctly in line with expected landscape mode dimensions.
I'm not sure how to handle this situation. I see the following options:
for each onCreate() call perform full layout calculation and resource scaling again. This is the logically correct solution, but I don't want to the same work twice, just to throw away the first result.
if onCreate() is called for portrait mode, just do nothing, and set black background (I can see there's a silly rotate animation when I unlock the screen, so this would become pretty much a fade-in animation)
Actually I'd prefer second option, but I'm slightly afraid of any side-effects. Anyone faced this problem?
Update (2012-07-08):
I've probably assigned a slightly misleading title to this question (sorry!), as the problem is not in retrieving the dimensions itself, nor calculating the layout. It's more about the activity being first created in portrait mode, and then recreated in landscape mode again, despite being declared as landscape-only. I initially expected (reasonably, huh?) the activity to be created in landscape orientation only.
I eventually decided to fill the activity with black color when it's created in portrait mode, no side effects observed. On Android 4.0 I can see actual rotation animation when I unlock the screen - a bit strange, but well, I guess it is supposed to inform the user that she should rotate the phone. Given that in portrait mode I just fill the screen with black color, this animation looks sort of like a fade-in and rotation combined - perfectly acceptable.

Use that
DisplayMetrics dm=new DisplayMetrics();
this.getWindowManager().getDefaultDisplay().getMetrics(dm);
Using this(Look code at down) only gives you screen size and if your views has static size they will be seen in different size on every different screen.
Display screen=getWindowManager().getDefaultDisplay().getSize();
How to use:
every screen has diffrent density. So use:
float density=dm.density;
with this density, you can set your views size like that:
(YOUR_ITEM_SIZE)*density;
also look here for additional information:
http://developer.android.com/reference/android/util/DisplayMetrics.html

if the emulator is locked , can't you assume that the user can't run anything anyway , so the app doesn't need to handle this end case ?
anyway , as bmavus wrote , use getMetrics for getting the screen size . also , if you need to change the screen orientation of the app , you can do so either in the manifest or in code.
for games , i would advice using opengl solutions , and if you don't have much time digging for it , you can use third party engines that can help you , such as andengine and libgdx.

Android - Views overlaid on the last frame of a fullscreen video don't redraw properly when turning the screen on and off

I have a video that plays in portrait mode. At the end of the video, I need to display some views over it. This works fine so far.
I am however, having a problem where views that are over the last frame of a video don't redraw properly when coming back to the activity after turning the screen off, then on again, then unlocking the screen.
What i'm observing is that when the screen comes back on and I unlock. My video and images are first rendered outside of fullscreen mode (with the status bar still showing) then the screen will go into fullscreen mode shifting all of the views up and causing artifacting.
It seems like the views are being shifted out of their view bounds by the transition to fullscreen after they are rendered.
I'm really stumped as to how to prevent this from happening.
Here is the sandbox project on github to avoid making this a post full of code.
The basic setup for the project is this:
Fragment activity has a video view and a button view on it's layout.
It then adds a fragment into a contentView container. The contentView fades in 1 second prior to the end of video playback.
Everything works smoothly and the problem is with returning back to the app after powering the screen on and off.
Also, sometimes the video will just drop out entirely, leaving the views sitting atop a black background.
Thanks in advance for any help you can provide.
Here's the artifacting that happens when you turn the screen off, back on, and unlock.
Note that I had to take a picture of it. On DDMS the screenshot tool sees the images properly.

rather than prevent the screen from turning off, you can opt in to receive an event when the user unlocks the keyguard after waking the phone.
At this point, it might be a good idea to call View.invalidate on both of your views, this should cause a redraw. The draw chain is very flaky while the lock screen is up, because your app is technically visible, just under the lock screen.
registerReceiver(new BroadcastReceiver() {
#Override
public void onReceive(Context ctx, Intent intent) {
if(intent.getAction().equals(Intent.ACTION_USER_PRESENT))
}
}, new IntentFilter(Intent.ACTION_USER_PRESENT));

It looks like the overlay layout was shifted by controller bar.
Don't you think it was affected by controller (play/pause/ff/rew + progress) area?

there may be a way to prevent the screen going off in 1st place as this would be good resolving your re draw issues, hope this helps.