Develop Reference

How to determine correct device orientation in Android N multi-window mode?

From Multi-Window documentation:
Disabled features in multi-window mode
Certain features are disabled or ignored when a device is in multi-window mode, because they don’t make sense for an activity which may be sharing the device screen with other activities or apps. Such features include:
Some System UI customization options are disabled; for example, apps cannot hide the status bar if they are not running in full-screen mode.
The system ignores changes to the android:screenOrientation attribute.
I get that for most apps it doesn't make sense to distinct between portrait and landscape modes, however I am working on SDK which contains camera view which user can put on any activity they wish - including activity that supports multi-window mode. The problem is that camera view contains SurfaceView/TextureView which displays the camera preview and in order to display preview correctly in all activity orientations, knowledge about correct activity orientation is required so that camera preview can be correctly rotated.
The problem is that my code which calculates correct activity orientation by examining current configuration orientation (portrait or landscape) and current screen rotation. The problem is that in multi-window mode current configuration orientation does not reflect the real activity orientation. This then results with camera preview being rotated by 90 degrees because Android reports different configuration than orientation.
My current workaround is to check for requested activity orientation and use that as a basis, but there are two problems with that:
the requested activity orientation does not have to reflect actual activity orientation (i.e. request may still not be fulfilled)
the requested activity orientation can be 'behind', 'sensor', 'user', etc. which does not reveal any information about current activity orientation.
According to documentation, screen orientation is actually ignored in multi-window mode, so 1. and 2. just won't work
Is there any way to robustly calculate correct activity orientation even in multi-window configuration?
Here is my code that I currently use (see comments for problematic parts):
protected int calculateHostScreenOrientation() {
int hostScreenOrientation = ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED;
WindowManager wm = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
int rotation = getDisplayOrientation(wm);
boolean activityInPortrait;
if ( !isInMultiWindowMode() ) {
activityInPortrait = (mConfigurationOrientation == Configuration.ORIENTATION_PORTRAIT);
} else {
// in multi-window mode configuration orientation can be landscape even if activity is actually in portrait and vice versa
// Try determining from requested orientation (not entirely correct, because the requested orientation does not have to
// be the same as actual orientation (when they differ, this means that OS will soon rotate activity into requested orientation)
// Also not correct because, according to https://developer.android.com/guide/topics/ui/multi-window.html#running this orientation
// is actually ignored.
int requestedOrientation = getHostActivity().getRequestedOrientation();
if ( requestedOrientation == ActivityInfo.SCREEN_ORIENTATION_PORTRAIT ||
requestedOrientation == ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT ||
requestedOrientation == ActivityInfo.SCREEN_ORIENTATION_SENSOR_PORTRAIT ||
requestedOrientation == ActivityInfo.SCREEN_ORIENTATION_USER_PORTRAIT ) {
activityInPortrait = true;
} else if ( requestedOrientation == ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE ||
requestedOrientation == ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE ||
requestedOrientation == ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE ||
requestedOrientation == ActivityInfo.SCREEN_ORIENTATION_USER_LANDSCAPE ) {
activityInPortrait = false;
} else {
// what to do when requested orientation is 'behind', 'sensor', 'user', etc. ?!?
activityInPortrait = true; // just guess
}
}
if ( activityInPortrait ) {
Log.d(this, "Activity is in portrait");
if (rotation == Surface.ROTATION_0) {
Log.d(this, "Screen orientation is 0");
hostScreenOrientation = ActivityInfo.SCREEN_ORIENTATION_PORTRAIT;
} else if (rotation == Surface.ROTATION_180) {
Log.d(this, "Screen orientation is 180");
hostScreenOrientation = ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT;
} else if (rotation == Surface.ROTATION_270) {
Log.d(this, "Screen orientation is 270");
// natural display rotation is landscape (tablet)
hostScreenOrientation = ActivityInfo.SCREEN_ORIENTATION_PORTRAIT;
} else {
Log.d(this, "Screen orientation is 90");
// natural display rotation is landscape (tablet)
hostScreenOrientation = ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT;
}
} else {
Log.d(this, "Activity is in landscape");
if (rotation == Surface.ROTATION_90) {
Log.d(this, "Screen orientation is 90");
hostScreenOrientation = ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE;
} else if (rotation == Surface.ROTATION_270) {
Log.d(this, "Screen orientation is 270");
hostScreenOrientation = ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE;
} else if (rotation == Surface.ROTATION_0) {
Log.d(this, "Screen orientation is 0");
// natural display rotation is landscape (tablet)
hostScreenOrientation = ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE;
} else {
Log.d(this, "Screen orientation is 180");
// natural display rotation is landscape (tablet)
hostScreenOrientation = ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE;
}
}
return hostScreenOrientation;
}
private int getDisplayOrientation(WindowManager wm) {
if (DeviceManager.getSdkVersion() < 8) {
return wm.getDefaultDisplay().getOrientation();
}
return wm.getDefaultDisplay().getRotation();
}
private boolean isInMultiWindowMode() {
return Build.VERSION.SDK_INT >= 24 && getHostActivity().isInMultiWindowMode();
}
protected Activity getHostActivity() {
Context context = getContext();
while (context instanceof ContextWrapper) {
if (context instanceof Activity) {
return (Activity) context;
}
context = ((ContextWrapper) context).getBaseContext();
}
return null;
}
EDIT: I've reported this also to Android issue tracker.

I don’t know if this should be considered a solution or just a workaround.
As you say, your problems come with Android N and its multi-window mode. When the app is in multi window, your Activity is not tied to the full display dimensions. This redefines the concept of Activity orientation. Quoting Ian Lake:
Turns out: “portrait” really just means the height is greater than the
width and “landscape” means the width is greater than the height. So
it certainly makes sense, with that definition in mind, that your app
could transition from one to the other while being resized.
So there is no link anymore between Activity orientation changing and device physically being rotated. (I think the only reasonable use of Activity orientation changes now is to update your resources.)
Since you are interested in device dimensions, just get its DisplayMetrics. Quoting docs,
If requested from non-Activity context
metrics will report the size of the entire display based on current
rotation and with subtracted system decoration areas.
So the solution is:
final Context app = context.getApplicationContext();
WindowManager manager = (WindowManager) app.getSystemService(Context.WINDOW_SERVICE);
Display display = manager.getDefaultDisplay();
DisplayMetrics metrics = new DisplayMetrics();
display.getMetrics(metrics);
int width = metrics.widthPixels;
int height = metrics.heightPixels;
boolean portrait = height >= width;
Width and height values will be swapped (more or less) when the device is tilted.
If this works, I would personally run it every time, deleting the isInMultiWindowMode() branch, because
it’s not expensive
our assumptions stand also in the non-multi-window mode
it will presumably work well with any other future kinds of modes
you avoid the race condition of isInMultiWindowMode() described by CommonsWare

I thought you could utilise the accelerometer to detect where's "down" - and thus the orientation of the phone. The Engineer Guy explains that that's the way the phone itself does it.
I searched here on SO for a way to do that and found this answer. Basically you need to check which of the 3 accelerometers detect the most significant component of the gravitational pull, which you know is roughly 9.8m/s² near the ground of the earth. Here's the code snippet from it:
private boolean isLandscape;
mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
mSensorManager.registerListener(mSensorListener, mSensorManager.getDefaultSensor(
Sensor.TYPE_ACCELEROMETER),1000000);
private final SensorEventListener mSensorListener = new SensorEventListener() {
#Override
public void onSensorChanged(SensorEvent mSensorEvent) {
float X_Axis = mSensorEvent.values[0];
float Y_Axis = mSensorEvent.values[1];
if((X_Axis <= 6 && X_Axis >= -6) && Y_Axis > 5){
isLandscape = false;
}
else if(X_Axis >= 6 || X_Axis <= -6){
isLandscape = true;
}
}
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
};
Be careful as this code might not work in every situation, as you need to take into account scenarios like being on a stopping/accelerating train or moving the phone fast in a game - here's the orders of magnitude page on wiki to get you started. It looks like you're safe with the values Khalil put in his code (in his answer), but I would take extra caution and research into what values might be generated in the different scenarios.
It's not a flawless idea, but I think as long as the API is built the way it is - whithout allowing you to get their calculated orientation - I think it's a beneficial workaround.

Different screen orientation on different devices when landscape mode

I am using
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
for my Activity and I am trying to use OrientationEventListener to find the orientation of the device. On some devices my landscape orientation is showing values around 270 and other devices shows values around 0. On every device where the Home button is placed the orientation value shows 0. I want to have same values when holding the all devices in landscape mode. Is there a flag that can show me which device is showing 270 or 0 for landscape mode as default orientation.
This is my OrientationEventListener
mOrientationListener = new OrientationEventListener(this,
SensorManager.SENSOR_DELAY_NORMAL) {
#Override
public void onOrientationChanged(int orientation) {
Log.v("Orientation changed to ", String.valueOf(orientation));
}
};
Is there a trick that can help to resolve the issue?

I have found the solution.
With this code I am getting the default display rotation:
int rotation = getWindowManager().getDefaultDisplay().getRotation();
in the body of my onOrientationChanged method I can make this:
if (rotation == 0) {
if (orientation >= 90 && orientation <= 270) {
}
} else if (rotation == 1) {
if (orientation < 180 && orientation > 0 ) {
}
}
This will enter the if only if my device is not in the correct landscape position. If my device is on 90+ angle I can give the user a message.

How to rotate views on orientation change without recreating layout?

This question has been asked before here but its answer is incorrect. I would like to rotate some views on screen orientation change, but I want to keep the layout unchanged. They should be rotated 90, 180, 270 or 360 degrees according to the current orientation (SCREEN_ORIENTATION_LANDSCAPE, SCREEN_ORIENTATION_PORTRAIT, SCREEN_ORIENTATION_REVERSE_LANDSCAPE, SCREEN_ORIENTATION_REVERSE_PORTRAIT).
This is what I want to achieve:
The answer in the link I mentioned stated that I should create a new different layout in layout-land. Clearly, this is not what I want. I don't want to recreate the activity or change layout orientation. I only want to rotate some views, and keep other views unchanged on orientation change.
There is a huge difference between rotating specific views and changing or recreating the whole layout (both on orientation change).
Using the answer in this link, I will be able to get the current screen orientation with this method:
public static int getScreenOrientation(Context context) {
WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
int rotation = windowManager.getDefaultDisplay().getRotation();
DisplayMetrics dm = new DisplayMetrics();
windowManager.getDefaultDisplay().getMetrics(dm);
int width = dm.widthPixels;
int height = dm.heightPixels;
int orientation;
// if the device's natural orientation is portrait:
if ((rotation == Surface.ROTATION_0
|| rotation == Surface.ROTATION_180) && height > width ||
(rotation == Surface.ROTATION_90
|| rotation == Surface.ROTATION_270) && width > height) {
switch (rotation) {
case Surface.ROTATION_0:
orientation = ActivityInfo.SCREEN_ORIENTATION_PORTRAIT;
break;
case Surface.ROTATION_90:
orientation = ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE;
break;
case Surface.ROTATION_180:
orientation = ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT;
break;
case Surface.ROTATION_270:
orientation = ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE;
break;
default:
Log.e("ScreenOrientation", "Unknown screen orientation. Defaulting to " + "portrait.");
orientation = ActivityInfo.SCREEN_ORIENTATION_PORTRAIT;
break;
}
}
// if the device's natural orientation is landscape or if the device
// is square:
else {
switch (rotation) {
case Surface.ROTATION_0:
orientation = ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE;
break;
case Surface.ROTATION_90:
orientation = ActivityInfo.SCREEN_ORIENTATION_PORTRAIT;
break;
case Surface.ROTATION_180:
orientation = ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE;
break;
case Surface.ROTATION_270:
orientation = ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT;
break;
default:
Log.e("ScreenOrientation", "Unknown screen orientation. Defaulting to " + "landscape.");
orientation = ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE;
break;
}
}
return orientation;
}
On orientation change, I would like to do something simple like this:
RotateAnimation rotateAnimation = new RotateAnimation(0, getScreenOrientation(getContext()));
rotateAnimation.setDuration(2000);
for (int i = 0; i < 63; i++) {
Button button = (Button) rootView.findViewById(i);
button.startAnimation(rotateAnimation);
}
Another way to rephrase my question would be "Is there any way to detect orientation change in onConfigurationChanged() method without changing the layout?". The problem is that it will not be able to detect any orientation change if I already disable layout orientation change.
Anyone knows how it is done? I might have totally gone through wrong steps, and I think I will have to use Accelerometer Sensor or something similar to that to achieve what I want, so please guide me through.

Try to use OrientationEventListener. You don't need to use onConfigurationChanged and android:configChanges="orientation|keyboardHidden|screenSize". You need set android:screenOrientation="portrait" for the activity in AndroidManifest.xml. Here is my solution with OrientationEventListener:
public class MyActivity extends Activity{
private ImageButton menuButton;
private Animation toLandAnim, toPortAnim;
private OrientationListener orientationListener;
#Override protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_image_ruler);
menuButton=(ImageButton)findViewById(R.id.menu_button);
toLandAnim= AnimationUtils.loadAnimation(this, R.anim.menubutton_to_landscape);
toPortAnim= AnimationUtils.loadAnimation(this, R.anim.menubutton_to_portrait);
orientationListener = new OrientationListener(this);
}
#Override protected void onStart() {
orientationListener.enable();
super.onStart();
}
#Override protected void onStop() {
orientationListener.disable();
super.onStop();
}
private class OrientationListener extends OrientationEventListener{
final int ROTATION_O = 1;
final int ROTATION_90 = 2;
final int ROTATION_180 = 3;
final int ROTATION_270 = 4;
private int rotation = 0;
public OrientationListener(Context context) { super(context); }
#Override public void onOrientationChanged(int orientation) {
if( (orientation < 35 || orientation > 325) && rotation!= ROTATION_O){ // PORTRAIT
rotation = ROTATION_O;
menuButton.startAnimation(toPortAnim);
}
else if( orientation > 145 && orientation < 215 && rotation!=ROTATION_180){ // REVERSE PORTRAIT
rotation = ROTATION_180;
menuButton.startAnimation(toPortAnim);
}
else if(orientation > 55 && orientation < 125 && rotation!=ROTATION_270){ // REVERSE LANDSCAPE
rotation = ROTATION_270;
menuButton.startAnimation(toLandAnim);
}
else if(orientation > 235 && orientation < 305 && rotation!=ROTATION_90){ //LANDSCAPE
rotation = ROTATION_90;
menuButton.startAnimation(toLandAnim);
}
}
}
}
This also prevents from too frequent rotations when orientation is about 45, 135... etc.
Hope it helps.

The basics are actually a lot easier. Have a look at Handling Runtime Changes.
First things first, by setting
android:configChanges="orientation|keyboardHidden|screenSize"
in your Manifest on your activity tag you can handle the orientation change yourself. (orientation should be enough, but there are sometimes issues where the event does not fire with that alone.)
You then skip onCreate and instead onConfigurationChanged gets called. Overwrite this method and apply your layout changes here. Whether you change your linearLayouts orientation here or have a custom view handling layout for different screens itself is up to you and depends on your implementation.
Animating will be a bit trickier, if it is even possilbe. A quick search says it is not.
Update for comment "I only want to rotate some views themselves rather than rotating the layout"
In theory it is possible to create your own layout and handle the drawing of your child views. I just tried it but could not produce any results in an appropriate time, but what you would need to do:
keep your last measured values use tags on the view or similar approaches to keep the last measurements and layouts, so that after the orientation change you can diff
await orientation change: trigger rotated drawing - rotate the canvas, layout the views with the previous dimensions, and draw the child views where they would have been before, and
start an animation interpolate from the last to the new values, rotating the canvas from the last to the new layout
This is how I would do it.

Android determine screen orientation at runtime

Here's a pseudo code to detect screen rotate event, and decide to retain or changes the screen orientation.
public boolean onOrientationChanges(orientation) {
if(orientation == landscape)
if(settings.get("lock_orientation"))
return false; // Retain portrait mode
else
return true; // change to landscape mode
return true;
}
How do I make similar things in Android?
EDIT:
I'm actually looking answer on Where to handle orientation changes. I do not want to fix the orientation by adding screenOrientation="portrait".
I need something, similar to onConfigurationChanges(), where I can handle the orientation, but do no need me to manually redraw the view.

You need a Display instance firstly:
Display display = ((WindowManager) getSystemService(WINDOW_SERVICE)).getDefaultDisplay();
Then orientation may be called like this:
int orientation = display.getOrientation();
Check orientation as your way and use this to change orientation:
setRequestedOrientation (ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
I hope it helps.
Update:
Okay, let's say you've an oAllow var which is Boolean and default value is False.
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
Display display = ((WindowManager) getSystemService(WINDOW_SERVICE)).getDefaultDisplay();
int orientation = display.getOrientation();
switch(orientation) {
case Configuration.ORIENTATION_PORTRAIT:
if(!oAllow) {
setRequestedOrientation (ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
}
break;
case Configuration.ORIENTATION_LANDSCAPE:
if(!oAllow) {
setRequestedOrientation (ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}
break;
}
}
You can add more choices.
I didn't try this sample, but at least tells you some clues about how to solve. Tell me if you got any error.
UPDATE
getOrientation() is already deprecated see here. Instead Use getRotation(). To check if the device is in landscape mode you can do something like this:
Display display = ((WindowManager) getSystemService(WINDOW_SERVICE))
.getDefaultDisplay();
int orientation = display.getRotation();
if (orientation == Surface.ROTATION_90
|| orientation == Surface.ROTATION_270) {
// TODO: add logic for landscape mode here
}

Try running
getResources().getConfiguration().orientation
From your context object to figure out what is the screen orientation at runtime, the possible values are documented here
In order to catch the orientation change event you can find the answer in the Android Dev Guide: Handling the Configuration Change Yourself
From the guide :
For example, the following manifest code declares an activity that
handles both the screen orientation change and keyboard availability
change:
<activity android:name=".MyActivity"
android:configChanges="orientation|keyboardHidden"
android:label="#string/app_name">
Now, when one of these configurations change, MyActivity does not restart. Instead, the MyActivity receives a call to onConfigurationChanged(). This method is passed a Configuration object that specifies the new device configuration. By reading fields in the Configuration, you can determine the new configuration and make appropriate changes by updating the resources used in your interface. At the time this method is called, your activity's Resources object is updated to return resources based on the new configuration, so you can easily reset elements of your UI without the system restarting your activity.
...

if (this.getWindow().getWindowManager().getDefaultDisplay()
.getOrientation() == ActivityInfo.SCREEN_ORIENTATION_PORTRAIT) {
// portrait mode
} else if (this.getWindow().getWindowManager().getDefaultDisplay()
.getOrientation() == ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE) {
// landscape
}

You don't need to intercept the event and then override it. Just use:
// Allow rotation
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_USER);
// Lock rotation (to Landscape)
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_USER_LANDSCAPE);
Points to note here are, if on Jellybean and above this will allow a 180 degree rotation when locked. Also when unlocked this only allows rotation if the user's master settings is to allow rotation. You can forbid 180 degree rotations and override the master settings and allow rotation, and much much more, so check out the options in ActivityInfo
In addition, if you have pre-set that there is to be no rotation, then your activity will not be destroyed and then restarted, just for you to set the orientation back which will again cause the activity to be restarted; Thus setting what you want in advance can be much more efficient.
Pre Jellybean use ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE -- no 180 degree rotation with this.

Check your android screen orientation at Runtime:
ListView listView = (ListView) findViewById(R.id.listView1);
if (getResources().getConfiguration().orientation == ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE) {
//do work for landscape screen mode.
listView.setPadding(0, 5, 0, 1);
} else if (getResources().getConfiguration().orientation == ActivityInfo.SCREEN_ORIENTATION_PORTRAIT) {
//Do work for portrait screen mode.
listView.setPadding(1, 10, 1, 10);
}

Another solution to determine screen orientation:
public boolean isLandscape() {
return Resources.getSystem().getDisplayMetrics().widthPixels - Resources.getSystem().getDisplayMetrics().heightPixels > 0;
}

scrolling and swiping problem in android

In my project i am rendering pdf, in landscape mode i am fitting to pagewidth and in portrait mode i am fitting to pageheight mode. can anybody suggest me how to do scrolling in landscape mode only and swiping in both orientations.
thank you in advance..

I would say the easiest way of doing this, assuming the scrolling is defines in your XML, is to create different layouts for each. somename_land.xml in the layout-land folder would have scrolling defined while somename_port.xml in layout-port would not. Both would have swiping. You then select the context in your code with something like this:
WindowManager winMan = (WindowManager) getBaseContext().getSystemService(Context.WINDOW_SERVICE);
if (winMan != null) {
int orientation = winMan.getDefaultDisplay().getOrientation();
if (orientation == 0) {
// Portrait
setContentView(R.layout.somename_port.xml);
} else if (orientation == 1) {
// Landscape
setContentView(R.layout.somename_land.xml);
}
}