Preferences settings save open read write application Android example

If some memory leak - problem try release of memory used of a big Bitmap what already not to need;

Bitmpap bmp; // not null
bmp.recycle();
bmp = null;

final boolean bmpIsRecycled = bmp.isRecycled()
// Returns true if this bitmap has been recycled.

//developer.android.com/reference/android/graphics/Bitmap.html
Free the native object associated with this bitmap, and clear the reference to the pixel data. This will not free the pixel data synchronously; it simply allows it to be garbage collected if there are no other references. The bitmap is marked as "dead”, meaning it will throw an exception if getPixels() or setPixels() is called, and will draw nothing. This operation cannot be reversed, so it should only be called if you are sure there are no further uses for the bitmap. This is an advanced call, and normally need not be called, since the normal GC process will free up this memory when there are no more references to this bitmap.

If project is in workspace and only not visible in project explorer using this:

Click on some project in project explorer
Menu:
File
Import project
Existing Projects into Workspace

Problem in Android application:

E/AndroidRuntime(416): FATAL EXCEPTION: main
E/AndroidRuntime(416): java.lang.IndexOutOfBoundsException
E/AndroidRuntime(416): 	at java.util.Arrays$ArrayList.get(Arrays.java:75)
E/AndroidRuntime(416): 	at android.widget.ArrayAdapter.getItem(ArrayAdapter.java:298)
E/AndroidRuntime(416): 	at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:351)
E/AndroidRuntime(416): 	at android.widget.ArrayAdapter.getView(ArrayAdapter.java:323)
E/AndroidRuntime(416): 	at android.widget.Spinner.makeAndAddView(Spinner.java:192)
E/AndroidRuntime(416): 	at android.widget.Spinner.layout(Spinner.java:151)
E/AndroidRuntime(416): 	at android.widget.Spinner.onLayout(Spinner.java:115)

Solution: check code for set and get selection

// Spinner _spin1 contain only  49 items 
// you can set max 48 ( range 0 - 48)
// 50 is IndexOutOfBoundsException
_spin1.setSelection(50);

Generate random number Android Java example source code.

		Random rand = new Random();
		int i = rand.nextInt() % 256; // range -255  +255
		System.out.print(i + "

"); // -184
		i = Math.abs(rand.nextInt() % 12); // range 0  +11
		System.out.print(i); // 7

// Math.random() start with 0.  e.g. 0.35981234 
int nRan = (int) (Math.random()*10); // 0 - 10

// nextDouble(), nextFloat(), nextInt(), nextLong() returns 0 - 10
import java.util.Random;´

Random r = new Random();
int nRan = r.nextInt(); // 0 - 10
double dRan = r.nextDouble() * 10; // e.g. 7.496285271597397

nextDouble – return 0 - 1
nextFloat – same as double
nextInt –  -2147483648  +2147483647
nextLong –  -922337203685775808  +9223372036854775807
nextGaussian –  0.0 aberation 1.0.

public class ApokusActivity extends Activity {
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {

		// CONSTRUCTOR
		public SampleView(Context context) {
			super(context);
			setFocusable(true);

		}
		
		@Override
		protected void onDraw(Canvas canvas) {
			Paint paint = new Paint();
			
			canvas.drawColor(Color.YELLOW);
            
	         
	         paint.setFilterBitmap(true);
	         Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),R.drawable.flower_blue);
	         int targetWidth  = bitmapOrg.getWidth() * 2;
	         int targetHeight = bitmapOrg.getHeight() * 2;
	         Bitmap bmp = Bitmap.createBitmap(targetWidth, targetHeight,Bitmap.Config.ARGB_8888);
	         RectF rectf = new RectF(0, 0, targetWidth, targetHeight);
	         Canvas c = new Canvas(bmp);
	         Path path = new Path();
	         path.addRect(rectf, Path.Direction.CW);
	         c.clipPath(path);
	         c.drawBitmap( bitmapOrg, new Rect(0, 0, bitmapOrg.getWidth(), bitmapOrg.getHeight()),
	                         new Rect(0, 0, targetWidth, targetHeight), paint);
	         Matrix matrix = new Matrix();
	         matrix.postScale(1f, 1f);
	         Bitmap resizedBitmap = Bitmap.createBitmap(bmp, 0, 0, targetWidth, targetHeight, matrix, true);
	         int h = bitmapOrg.getHeight();
           canvas.drawBitmap(bitmapOrg, 10,10, paint);
           canvas.drawBitmap(resizedBitmap, 10,10 + h + 10, paint);
           
		}

	}
}