Iterate HashMap getKey getValue Java Example

Bitmap size calculation:
bmpHeight * bmpWidth
For example:
Resolution of image 1024x860 = 880 640 pixels
If every pixel get 4 byte of memory:
880 640x4= 3 522 560 (3.5MB)

Get bitmap size without allocation of memory:

   	BitmapFactory.Options options = new BitmapFactory.Options();
        // If set to true, the decoder will return null (no bitmap), but the out... fields will still
        // be set, allowing the caller to query the bitmap without having to allocate the memory for its pixels. 
    	options.inJustDecodeBounds = true; 
    	BitmapFactory.decodeResource(getResources(), R.drawable.my_image, options);
    	int imageHeight = options.outHeight; // 1024
    	int imageWidth = options.outWidth; // 860
    	String imageType = options.outMimeType; // .jpg .png .gif
 

Get Memory size:
Make your bitmap not bigger as maxMemory size
final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);

    float density = getResources().getDisplayMetrics().density;

    Debug.MemoryInfo memoryInfo = new Debug.MemoryInfo();
    Debug.getMemoryInfo(memoryInfo);
    final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
    final int freeMemory = (int) (Runtime.getRuntime().freeMemory() / 1024);
    String memMessage = String.format(
        "Free=%d kB,

MaxMem=%d kB,

 Memory: Pss=%.2f MB, Private=%.2f MB, Shared=%.2f MB",
        freeMemory,
        maxMemory,
        memoryInfo.getTotalPss() / 1024.0,
        memoryInfo.getTotalPrivateDirty() / 1024.0,
        memoryInfo.getTotalSharedDirty() / 1024.0);
    ((TextView)findViewById(R.id.textViewInfo)).setText(memMessage );

getContext() getApplicationContext() method Java Android example source

Context myContext_1 = ThisClassName.this; // to open a Dialog

Context myContext_2 = getContext();

Context myContext_3 = this.getContext();

Context myContext_4 = this;

Context myContext_5 = this.getApplicationContext ();





	OnClickListener getImageBtnOnClick = new OnClickListener() {

		public void onClick(View view) {

			Context context = view.getContext();



		}

	};

// Toast 

Toast.makeText(getApplicationContext(), "Context == getApplicationContext "

   , Toast.LENGTH_SHORT).show();







// store Context in public class

public class MyActivity extends Activity { 

    public static Context myCnt = null; 

    ... 

    protected void onCreate(Bundle icicle) { 

         ... 

        myCnt = this; 

        MyStorage.setContext(myCnt); 

        // or

        // MyStorage.setContext(this);        

        

        // cntxFromStorage == this

        Context cntxFromStorage = MyStorage.getContext();

        ... 

        }; 

    }; 

    

public class MyStorage

{

    private static Context cntStorageContext = null;

 	  

     

    public static Context getContext() { 

        return cntStorageContext;

     }

        

    public static void setContext(Context context) {

	 MyStorage.cntStorageContext = context;

	  }





    }; 



class DataBaseHelper extends SQLiteOpenHelper {

// get MyActivity context 

Context cnt = MyStorage.getContext();



}

Try this code with CursorLoader:

Uri uri = getIntent().getData();

// DEPRECATED
Cursor cursor = managedQuery(uri, null, null, null, null);

// WORKING - loadInBackground() preventing freezing of app
 Cursor cursor  = new CursorLoader(getApplicationContext(),uri, null, null, null, null).loadInBackground();
        

public class MainActivity 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);

			 Bitmap b = Bitmap.createBitmap(200, 200,
			 Bitmap.Config.ARGB_8888);

			// you need to insert a image flower_blue into res/drawable folder

			paint.setFilterBitmap(true);
			Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
					R.drawable.flower_blue);
			canvas.drawBitmap(bitmapOrg, 10, 10, paint);
			int width, height;

		    Canvas c = new Canvas(b);
		    paint.setAlpha(255); //0x80
		    c.translate(0, 30);
		    c.drawBitmap(bitmapOrg, new Matrix(), paint);
		    paint.setColor(Color.BLUE);
        Path mPath = new Path();
		    mPath.addCircle(50, 50, 50, Path.Direction.CCW);
            //c.clipPath(mPath, Region.Op.UNION);
            //c.clipPath(mPath, Region.Op.DIFFERENCE);
            c.clipPath(mPath, Region.Op.INTERSECT);
            //c.clipPath(mPath, Region.Op.REPLACE);
            //c.clipPath(mPath, Region.Op.XOR);
           paint.setColor(Color.GREEN);
           paint.setAntiAlias(true);
           c.drawCircle(30, 20, 30, paint);

		    int h = bitmapOrg.getHeight();
			//canvas.drawBitmap(bitmapOrg, 10, 10, paint);
			canvas.drawBitmap(b, 0, 10 + h + 10, paint);

		}

	}
}

Try this trick.
In AndroidManifest - activity tag write this code
android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize"
App hold data of a views if will to rotation of device.

       <activity
 android:name=".Tests_Activity"
 android:label="@string/app_name"
 android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize" />