铸造设备朝向LANDSCAPE，PORTRAIT，LANDSCAPE_REVERTED和PORTRAIT_REVERTED

Question

I have a task where I have to cast (not activity) orientation to 4 values (LANDSCAPE, PORTRAIT, LANDSCAPE_REVERTED and PORTRAIT_REVERTED). I came up with a solution but it uses fixed values, and does not represent the android functionality of how and when it changes the activities orientations.

I was unable to find an api that could easily notify a listener of when the has changed it's orientation to the specified 4 values.

It would be grate if someone could share the function of how the android computes the orientation and informs WindowManager to change the orientation of the activities.

To does who might end up in the same situation as me.

this listener contains all the magic that informs the activity to change it's orientation.

Answer 1

In onConfigChanges()you 'll always be notified whenever ur screen orientation changes and you can always get orientation of ur screen like this :

Display getOrient = getWindowManager().getDefaultDisplay();
switch(orientation){
case Configuration.ORIENTATION_LANDSCAPE:
Log.e();
break;
case Configuration.ORIENTATION_PORTRAIT:
Log.e();
break;
}

Answer 2

Use the screenOrientation in your project manifest and set the orientation.

<activity
            android:name=".SplashScreen"
            android:screenOrientation="portrait"
</activity>

Answer 3

If u want the activity to show and align in landscape mode then add a folder in drawable namely layout-landscape and if u want the app to run only in portrait mode then declare in the manifest as the following

android:screenOrientation="portrait"

or u want in the landscape mode:

 android:screenOrientation="landscape"

Answer 4

I am pretty sure the OS calculate the rotation of the device and change orientation when the rotation angle change by 60 degrees. Thus if the device is in Portrait orientation with rotation angle equal to 0, then when the device is rotated say counterclockwise, the rotation angle will increase and when the rotation angle is about 60 degree, the OS will change to Landscape. Now suppose the device is in Landscape orientation when you rotate the device clockwise, the angle will decrease and at about 30 degree the OS will change to Portrait orientation.

Orientation change state
Left side is the current orientation.
Right side is the new orientation when the device is rotated.
Portrait ---> Landscape rotation counterclockwise rotation angle > 60
Portrait ---> Landscape_Reverse rotation clockwise rotation angle < -60
Landscape ---> Portrait rotation clockwise rotation angle < 30
Landscape ---> Portrait_Reverse rotation counterclockwise rotation angle > 150
Landscape_Reverse ---> Portrait rotation counterclockwise rotation angle > -30
Landscape_Reverse ---> Portrait_Reverse rotation clockwise rotation angle < -150

The rotation angle can not be calculated when the device is laying flat. This is why if you start an app when the device is laying flat and rotate the device no orientation change occurs.
You can see how the rotation angle is calculated at my answer at How to measure the tilt of the phone in XY plane using accelerometer in Android

Answer 5

Use getRotation()

Display display = ((WindowManager) context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
int rotation = display.getRotation();

from the docs

Returns the rotation of the screen from its "natural" orientation. The returned value may be Surface.ROTATION_0 (no rotation), Surface.ROTATION_90, Surface.ROTATION_180, or Surface.ROTATION_270. For example, if a device has a naturally tall screen, and the user has turned it on its side to go into a landscape orientation, the value returned here may be either Surface.ROTATION_90 or Surface.ROTATION_270 depending on the direction it was turned. The angle is the rotation of the drawn graphics on the screen, which is the opposite direction of the physical rotation of the device. For example, if the device is rotated 90 degrees counter-clockwise, to compensate rendering will be rotated by 90 degrees clockwise and thus the returned value here will be Surface.ROTATION_90.