Map TreeMap get key by value Java Android example

int mCurrentPhotoIndex = 0;
   @Override
    protected void onSaveInstanceState(Bundle outState) {
        outState.putInt("photo_index", mCurrentPhotoIndex);
        super.onSaveInstanceState(outState);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        mCurrentPhotoIndex = savedInstanceState.getInt("photo_index");
        super.onRestoreInstanceState(savedInstanceState);
    }

// or save preferences for new start of Activity in onStop
//onCreate or onResume or onStart etc.
public void loadPreferences() {
		SharedPreferences settings = getSharedPreferences(F.PREFERENCES_NAME, 0);
		mCurrentPhotoIndex = settings.getInt("mCurrentPhotoIndex",mCurrentPhotoIndex);
	// String_sOtazka = settings.getString("_sOtazka", _sOtazka);


}
// onStop
public void savePreferences() {
		SharedPreferences settings = getSharedPreferences(PREFERENCES_NAME, 0);
		SharedPreferences.Editor editor = settings.edit();
		editor.putInt("mCurrentPhotoIndex", mCurrentPhotoIndex);
                // String, boolean, float ...
		// editor.putString("mButton1", mButton1.getText().toString());

		editor.commit();

}

// Context instead Activity as a parameter
@Override
public void onAttach(Context context) {
    super.onAttach(context);

    Activity a;

    if (context instanceof Activity){
        a=(Activity) context;
    }

}

OnNoteClickedListener listener;
/* old emxample of usage
	@Override
	public void onAttach(Activity activity) {
		super.onAttach(activity);
		try {
			listener = (OnNoteClickedListener) activity;
		} catch (ClassCastException e) {
			throw new ClassCastException(activity.toString()
					+ " must implement OnNoteClickedListener");
		}
	}
*/
// new version of code
	@Override
	public void onAttach(Context context) {
		super.onAttach(context);

		Activity a;

		if (context instanceof Activity){
			a=(Activity) context;
			try {
				listener = (OnNoteClickedListener) a;
			} catch (ClassCastException e) {
				throw new ClassCastException(a.toString()
						+ " must implement OnNoteClickedListener");
			}
		}

	}

public class MainActivity extends Activity {
//  //www.apache.org/licenses/LICENSE-2.0
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	   private static class SampleView extends View {
	        private Rect    mRect;
	        private GradientDrawable mDrawable;

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

	            mRect = new Rect(0, 0, 220, 120);
	      
/*	            GradientDrawable.Orientation  BL_TR  draw the gradient from the bottom-left to the top-right   
	              BOTTOM_TOP  draw the gradient from the bottom to the top   
	              BR_TL  draw the gradient from the bottom-right to the top-left   
	              LEFT_RIGHT  draw the gradient from the left to the right   
	              RIGHT_LEFT  draw the gradient from the right to the left   
	              TL_BR  draw the gradient from the top-left to the bottom-right   
	              TOP_BOTTOM  draw the gradient from the top to the bottom   
	              TR_BL  draw the gradient from the top-right to the bottom-left   
*/
	            
	            mDrawable = new GradientDrawable(GradientDrawable.Orientation.LEFT_RIGHT,
	                                             new int[] { 0xFFFF0000, 0xFF00FF00,
	                                                 0xFF0000FF });
	            mDrawable.setShape(GradientDrawable.RECTANGLE);
	            mDrawable.setGradientRadius((float)(Math.sqrt(2) * 60));
	        }
	        
	        static void setCornerRadius(GradientDrawable drawable, float r0,
	                                   float r1, float r2, float r3) {
/*	        	setCornerRadii
	        	Specify radii for each of the 4 corners. For each corner, 
	        	the array contains 2 values, [X_radius, Y_radius]. 
	        	The corners are ordered top-left, top-right, bottom-right, 
	        	bottom-left 
*/
	            drawable.setCornerRadii(new float[] { r0, r0, r1, r1,
	                                                  r2, r2, r3, r3 });
	        }
	        
	        @Override protected void onDraw(Canvas canvas) {
	            
	            mDrawable.setBounds(mRect);

	            float r = 35;
	            
	            canvas.save();
	            canvas.translate(10, 10);
	            mDrawable.setGradientType(GradientDrawable.LINEAR_GRADIENT);
	            setCornerRadius(mDrawable, r, r, 0, 0);
	            mDrawable.draw(canvas);
	            canvas.restore();
	            
	            canvas.translate(0, mRect.height() + 10);
	            canvas.save();
	            canvas.translate(10, 10);
	            mDrawable.setGradientType(GradientDrawable.RADIAL_GRADIENT);
	            setCornerRadius(mDrawable, 0, 0, r, r);
	            mDrawable.draw(canvas);
	            canvas.restore();
	            
	            canvas.translate(0, mRect.height() + 10);
	            canvas.save();
	            canvas.translate(10, 10);
	            mDrawable.setGradientType(GradientDrawable.SWEEP_GRADIENT);
	            setCornerRadius(mDrawable, 0, r, r, 0);
	            mDrawable.draw(canvas);
	            canvas.restore();
	            
	            
	        }
	    }
	}

    protected void showAbout() {
        // Inflate the about message contents
        View messageView = getLayoutInflater().inflate(R.layout.about, null, false);

        // When linking text, force to always use default color. This works
        // around a pressed color state bug.
        TextView textView = (TextView) messageView.findViewById(R.id.about_credits);
        int defaultColor = textView.getTextColors().getDefaultColor();
        textView.setTextColor(defaultColor);

        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setIcon(R.drawable.app_icon);
        builder.setTitle(R.string.app_name);
        builder.setView(messageView);
        builder.create();
        builder.show();
    }

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2009 The Android Open Source Project
          //www.apache.org/licenses/LICENSE-2.0
-->

<LinearLayout xmlns:android="//schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="20dip">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="16sp"
        android:text="@string/app_descrip"
        android:textColor="?android:attr/textColorPrimaryInverse" />

    <TextView
        android:id="@+id/about_credits"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingTop="20dip"
        android:textSize="16sp"
        android:text="@string/app_credits"
        android:autoLink="web"
        android:textColor="?android:attr/textColorPrimaryInverse" />

</LinearLayout>