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How to detect area click into Image in Android

I have a problem with detect area click into an image.
I have the images below:
https://i.stack.imgur.com/fZmq0.jpg
https://i.stack.imgur.com/sb6Va.jpg
https://i.stack.imgur.com/YMwpy.jpg
How can I detect when touching into the yellow area?

It can be easy. You don't need to slice it.
The thing you have to do is
Click event.
Get the position where you clicked.
Get the colour of the position.
Check if the colour is yellow or not.
Do what you want when it is yellow.
It seems like the yellow is not just one yellow colour. So, What you can do is have a range of the yellow colour and compare all the possible yellow colours.
#Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
float x = event.getX();
float y = event.getY();
if(getColourOfThePixel(x, y)){
// DO SOMETHING
}
}
return super.onTouchEvent(event);
}
public boolean getColourOfThePixel(float x, float y){
int colorXY = mBitmap.getPixel(rangeX, rangeY);
int r = Color.red(colorXY);
int g = Color.green(colorXY);
int b = Color.blue(colorXY);
if (isYellow(r, g, b)) {
return true;
}
return false;
}
public boolean isYellow(int r, int g, int b){
// CHECK THE RANGE OF YELLOW COLOUR
}
To make it sure, you'd better have +-x, y ranges(like a square, maybe +-20pixel) because checking only one pixel may not work sometimes. So, if the square has a yellow colour, the event you wanna implement would work out.
I hope this is helpful.

Android Getting Co ordinates

A little problem for you but Break point for me during the development of an application.
I have a background image of Layout in which I have a Zip(Cloth zip) in the middle and at the top of image.
I want to do the following some things:
get coordinates of center-point(that is the starting point of Touch) of that image where that zip exists.
On moving the finger down, getting the changed coordinates.
X coordinate should be constant after getting the mid point, means the user can only drag on the middle of the screen vertically.
So badly waiting for an expert response.

DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
int height = displaymetrics.heightPixels;
int width = displaymetrics.widthPixels;
int center1 = (width/2) - (aspected touchable area you need);
int center2 = (width/2) + (aspected touchable area you need);
#Override
public boolean onTouchEvent(MotionEvent event) {
int x = (int)event.getX();
int y = (int)event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
//Logic for Zip motion
case MotionEvent.ACTION_UP:
//Logic for Zip motion
}
return false;
}

how do i change specific rect color on a canvas in android?

ive been trying to change the color of specific rects in an array of rects when i touch the screen but it doesnt seem to be working, heres my code:
public Paint blue = new Paint();
RandomColorGen rc;
ArrayList<Integer> colors = RandomColorGen.ColorList(5);
Random rand = new Random();
int columns = 50;
int rows = 50;
Rect square[][] = new Rect[rows][columns];
public boolean isTouched;
public Canvas canvas;
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
this.canvas = canvas;
for (int x = 0; x < rows; x++) {
for (int y = 0; y < columns; y++) {
square[x][y] = new Rect();
blue.setColor(colors.get(rand.nextInt(colors.size())));
blue.setStyle(Paint.Style.FILL);
square[x][y].set(0, 0, (canvas.getWidth() - 10) / rows,
((canvas.getHeight() - 100) / columns));
square[x][y].offsetTo(x * ((canvas.getWidth() - 10) / rows), y
* ((canvas.getHeight() - 100) / columns));
canvas.drawRect(square[x][y], blue);
}
}
if(isTouched){
blue.setColor(colors.get(rand.nextInt(colors.size())));
blue.setStyle(Paint.Style.FILL);
canvas.save();
canvas.clipRect(square[1][1]);
canvas.drawRect(square[1][1], blue);
canvas.restore();
}
}
#Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
isTouched = true;
break;
}
return true;
}
the colors.get() thingy is an arraylist of colors. am i taking the wrong approach?

How you are calling the paint function after the onTouch action performed...
OnTouch action is the first action so how do you call Paint() function??

I just tested your code, it works but there are couple of notes worth mentioning:
Allocating objects during drawing is a very bad behavior ( specially when allocating 50*50 ) ! consider moving the allocation code to the constructor and change position of the rectangles at the onDraw() method if you want to achieve the same behavior you have now.
Your usage for onTouchEvent() is not complete, you need to have the isTouched true as long as the user didn't raise his hand, which can be done as the following :
#Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
isTouched = true;
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
isTouched = false;
break;
}
invalidate();
return true;
}
Also request a layout every time you receive a TouchEvent by using invalidate()

Touch within view only- android

I am trying to do this but it gave me headache
I have a view that draw a color bar. And I want to allow user to move it around (drag and drop)
this is on draw method:
int r,g,b;
for(int i = 0; i < 64; i++)
{
r = Math.round((float)colorBuffer[i][0]*MAX_SCALING);
g = Math.round((float)colorBuffer[i][1]*MAX_SCALING);
b = Math.round((float)colorBuffer[i][2]*MAX_SCALING);
paint.setColor(Color.argb(MAX_SCALING, r, g, b));
canvas.drawLine(x1, y1, x2, y1, paint);
y1+=3;
}
rgb is just the color.
this is my ontouch implementation.
public boolean onTouchEvent(MotionEvent e)
{
float x = e.getX();
float y = e.getY();
switch (e.getAction())
{
case MotionEvent.ACTION_DOWN:
{
Toast t = Toast.makeText(getContext(), "Touch", Toast.LENGTH_SHORT);
t.show();
break;
}
case MotionEvent.ACTION_MOVE:
{
x1=(int) x;
x2=(int) (x+30);
y1=(int) y;
break;
}
case MotionEvent.ACTION_UP:
{
Toast t = Toast.makeText(getContext(), "Release", Toast.LENGTH_SHORT);
t.show();
x1=(int) x;
x2=(int) (x+30);
y1=(int) y;
break;
}
}
invalidate();
return true;
}
this works perfectly fine, but the problem is that it works even outside the view.
so if i touch outsite the view my bar move over there too
even when i click a button my bar try to move too
I want to drag and drop the component only if the user touch within the view
any help would be appreciate
thanks

On touch get the x, y, width, and height of your view. Then every time when you are moving the bar, as I understand in MotionEvent.ACTION_MOVE, check if current coordinates are whithin the views's bounds, if this is true, then allow to move the bar.

Functionality changes after Activity is restarted

I have a puzzle game where pieces are dragged around the screen but can not overlap. If they attempt to overlap, their position is changed back to where they were not overlapping and the UI is redrawn with invalidate(). This is working well except when the activity is destroyed and rebuilt like when closing the app and restarting it or when the orientation is changed.
What seems to happen is that the position variables that I use for collisions (x,y,right,bottom, etc.) are not reset to how they were initialized in the constructor. Pieces collide with invisible objects, snap to seemingly random positions, or move erratically.
The only ways to fix it are to manually kill the app (like with a task killer) or re-install it. Then it will work fine until the game activity is created a second time. What am I doing wrong? Any ideas? Here's how the piece are added in the onCreate() inside my GameView class:
Pieces redtiki = new Pieces(this,0,0,R.drawable.tikired);
...
board.addView(redtiki);
And this is a portion of my Pieces class:
public class Pieces extends View{
private int x;
private int y;
private int width;
private int height;
private int right;
private int bottom;
private int initialX;
private int initialY;
private Bitmap sizedBitmap;
private Bitmap sourceBitmap;
private int boardSize = 6;
public static ArrayList<Pieces> aPieces = new ArrayList<Pieces>();
//private final Paint mPaint = new Paint();
public Pieces(Context context, int x, int y, int img){
super(context);
this.x = x;
this.y = y;
sourceBitmap = BitmapFactory.decodeResource(getResources(), img);
aPieces.add(this);
initialX=x;
initialY=y;
}
private void sizePiece(){
int scaledWidth;
int scaledHeight;
int h = sourceBitmap.getHeight();
int w = sourceBitmap.getWidth();
if (h>w){
scaledWidth = 1;
}else if (w>h){
scaledWidth = w/h;
}else{
scaledWidth = 0;
}
if (h>w){
scaledHeight = h/w;
}else if (w>h){
scaledHeight = 1;
}else{
scaledHeight = 0;
}
int dstWidth = (((((View) getParent()).getWidth())*scaledWidth)/boardSize)-1;//TODO make sure that -1 is necessary for
int dstHeight = (((((View) getParent()).getHeight())*scaledHeight)/boardSize)-1;//fitting all pieces on the board
sizedBitmap = Bitmap.createScaledBitmap(sourceBitmap, dstWidth, dstHeight, true);
width = sizedBitmap.getWidth();
height = sizedBitmap.getHeight();
right = x+width;
bottom = y+height;
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
sizePiece();
canvas.drawBitmap(sizedBitmap, x, y, null);
}
#Override
public boolean onTouchEvent(MotionEvent event){
float eventX = event.getX();
float eventY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
//check if touch is on piece
if (eventX > x && eventX < (x+width) && eventY > y && eventY < (y+height)){
initialX=x;
initialY=y;
break;
}else{
return false;
}
case MotionEvent.ACTION_MOVE:
//determine if piece should move horizontally or vertically
if(width>height){
for (Pieces piece : aPieces) {
//if object equals itself in array, skip to next object
if(piece==this){
continue;
}
//check if there the possibility for a horizontal collision
if(this.isAllignedHorizontallyWith(piece)){
//check for and handle collisions while moving left
if(this.isRightOf(piece)){
if(eventX>piece.right+(width/2)){
x = (int)(eventX-(width/2)); //move normally
/*for(Pieces piece2 : aPieces){
if(this.isAllignedHorizontallyWith(piece2)){
if(this.isLeftOf(piece2)){
if(eventX<piece2.x-(width/2)){
x = (int)(eventX-(width/2));
continue;
}else{
x = piece2.x-width-1;
}
}
}
}*/
continue;
}else{
x = piece.right+1;
}
}
//check for and handle collisions while moving right
if(this.isLeftOf(piece)){
if(eventX<piece.x-(width/2)){
x = (int)(eventX-(width/2));
continue;
}else{
x = piece.x-width-1;
}
}
break;
}else{
x = (int)(eventX-(width/2));
}
}
}
if(height>width){
for (Pieces piece : aPieces) {
//if object equals itself in array, skip to next object
if(piece==this){
continue;
}
//check if there the possibility for a vertical collision
if(this.isAllignedVerticallyWith(piece)){
//check for and handle collisions while moving up
if(this.isBelow(piece)){
if(eventY>piece.bottom+(height/2)){
y = (int)(eventY-(height/2)); //move normally
continue;
}else{
y = piece.bottom+1;
}
}
//check for and handle collisions while moving down
if(this.isAbove(piece)){
if(eventY<piece.y-(height/2)){
y = (int)(eventY-(height/2));
continue;
}else{
y = piece.y-height-1;
}
}
break;
}else{
y = (int)(eventY-(height/2));
}
}
}
invalidate();
break;
case MotionEvent.ACTION_UP:
// end move
if(this.moves()){
GameView.counter++;
}
initialX=x;
initialY=y;
break;
}
// parse puzzle
invalidate();
return true;
}

In your Activity class, implement the methods OnPause(), OnResume().
Use log statements within the above mentioned methods to see whether the positions/coordinates are changed during the closing/opening of the app.
You can save the state of the various components when "OnPause()" is called. When "OnResume()" is invoked (i.e application comes to the foreground) read the saved state and draw the View with the coordinates you read recently.
Please not that "OnCreate()" will only be called once when the Activity is being created. Switching orientations will not invoked "OnCreate()"
You will find a flowchart explaining the Android API documentation.
http://developer.android.com/reference/android/app/Activity.html

I just realized what was wrong. Each time that I create a new Pieces object, it is added to my ArrayList, aPieces. So every time that the orientation changed, or I loaded a new level, it would load all my new pieces and display them, but my old pieces were still in the ArrayList and, therefore, still being checked for collisions. to solve this, before I load each new level (and all the pieces that make up the level), I clear the list with Pieces.aPieces.clear();. Now, it works perfectly.