Date Calendar Java Android Example

FLAG_KEEP_SCREEN_ON saving energy. Protects the battery if a user closing applications using the Return button on device. The device will returned to user screen mode settings.

@Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        //..........
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    }

1. File->Project Structure Ctrl + Alt + Shift + S



2. Select module and Dependencies Tab



3. Click on + PLUS button (right upper corner)



4. Select library


Click OK, OK

Error for example:
webcoreglue(2075): The real object has been deleted

Solution:
If this error message shows if orientation the screen is changed
try insert into AndroidManifest.xml this code:
android:configChanges="keyboard|keyboardHidden|orientation"

      <activity
            android:label="@string/app_name"
            android:name=".MyActivity" 
            android:screenOrientation="portrait"
            android:configChanges="keyboard|keyboardHidden|orientation"
            >

Copy file to another

        File path = Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES);
        File file = new File(path, "MyPicture.jpg");
           // the Pictures directory exists? 
            path.mkdirs();
            InputStream is = getResources().openRawResource(R.drawable.flower_blue);
            OutputStream os = new FileOutputStream(file);
            byte[] data = new byte[is.available()];
            is.read(data);
            os.write(data);
            is.close();
            os.close();

Copy and compress file

Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
					R.drawable.flower_blue);

try {
	 FileOutputStream out = new FileOutputStream("new_bitmap.jpg");
		bitmapOrg.compress(Bitmap.CompressFormat.JPEG, 90, out);
} catch (Exception e) {
	e.printStackTrace();
	Log.e("saveBitmap", e.getMessage());
} 

If You have old PC (Android in emulator with high screen resolution uses a lot of memory) or your testing phone have small screen, You can try this trick.
Rename layout folder for small device screen f.g. from layout into layout-swXXXdp and a large layout-sw600dp into layout.
Your phone with small screnn will do select xml file from renamed layout folder (for small screen).
You can to testing rotation with device en stability of fragments if an application changed orientation.
If you have old pc, you can try to make a new virtual device running on older version of Android, which uses less memory of computer.
For testing of rotation stability - application orientation changed - use on emulator Ctrl+F11, Ctrl+F12 key (Windows).

Important
Before the release of application, you have to rename layout folder to older name layout-sw600dp and layout-swXXXdp to layout.