Develop Reference

How to get right coordinates Zoom In on canvas or ImageView android

Basically I would like to draw lines on imageView when that image is zoomed.
The problem is that i dont know how to get right coordinates on touch event when Zoom In
Here is my code:
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
view.setScaleType(ImageView.ScaleType.MATRIX);
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: //first finger down only
savedMatrix.set(matrix);
if (draw) {
if (i == 1) {
startX = event.getX();
startY = event.getY();
i = 2;
} else if (i == 2) {
endX = event.getX();
endY = event.getY();
onDraw();
i = 3;
} else if (i == 3) {
startX = event.getX();
startY = event.getY();
onDraw();
i = 2;
}
} else {
start.set(event.getX(), event.getY());
Log.d(TAG, "mode=DRAG");
mode = DRAG;
}
break;
case MotionEvent.ACTION_UP: //first finger lifted
case MotionEvent.ACTION_POINTER_UP: //second finger lifted
if (!draw) {
mode = NONE;
Log.d(TAG, "mode=NONE");
}
break;
case MotionEvent.ACTION_POINTER_DOWN: //second finger down
if (!draw) {
oldDist = spacing(event);
Log.d(TAG, "oldDist=" + oldDist);
if (oldDist > 10f) {
savedMatrix.set(matrix);
midPoint(mid, event);
}
}
break;
case MotionEvent.ACTION_MOVE:
if (!draw) {
if (mode == DRAG) {
matrix.set(savedMatrix);
matrix.getValues(matrixValues);
matrixX = matrixValues[2];
matrixY = matrixValues[5];
width = matrixValues[0] * (view.getDrawable().getIntrinsicWidth());
height = matrixValues[4] * (view.getDrawable().getIntrinsicHeight());
dx = event.getX() - start.x;
dy = event.getY() - start.y;
//if image will go outside left bound
if (matrixX + dx > 0) {
dx = -matrixX;
}
//if image will go outside right bound
if (matrixX + dx + width < view.getWidth()) {
dx = view.getWidth() - matrixX - width;
}
//if image will go oustside top bound
if (matrixY + dy > 0) {
dy = -matrixY;
}
//if image will go outside bottom bound
if (matrixY + dy + height < view.getHeight()) {
dy = view.getHeight() - matrixY - height;
}
matrix.postTranslate(dx, dy);
}
break;
}
} //perform the transformation.
view.setImageMatrix(matrix);
return true; // indicate event was handled
}
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (float) Math.sqrt(x * x + y * y);
}
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
private void sizeScreen() {
DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
screenHeight = displaymetrics.heightPixels;
screenWidth = displaymetrics.widthPixels;
}
Here is method for zoom
#Override
public void onClick(View v) { // Parameter v stands for the imageView that was clicked.
matrix.set(savedMatrix);
float[] values = new float[9];
matrix.getValues(values);
switch (v.getId()) {
case (R.id.bt_zoom_in):
if (!draw) {
scale = scale + 0.1f;
if (scale > MAX_ZOOM) {
scale = MAX_ZOOM;
} else if (scale < MIN_ZOOM) {
scale = MIN_ZOOM;
}
}
break;
case R.id.bt_zoom_out:
if (!draw) {
scale = scale - 0.1f;
if (scale > MAX_ZOOM) {
scale = MAX_ZOOM;
} else if (scale < MIN_ZOOM) {
scale = MIN_ZOOM;
}
//matrix.setScale(scale, scale, mid.x, mid.y);
//imageView.setImageMatrix(matrix);
}
break;
case R.id.bt_draw:
if (draw) {
draw = false;
bt_draw.setText("Draw");
} else {
draw = true;
bt_draw.setText("Finish");
}
break;
}
matrix.setScale(scale, scale, mid.x, mid.y);
imageView.setImageMatrix(matrix);
}
Here is method for draw
public void onDraw() {
Bitmap lineABmp = ((BitmapDrawable) imageView.getDrawable()).getBitmap();
Bitmap lineAMutBmp = lineABmp.copy(Bitmap.Config.ARGB_8888, true);
Bitmap copy = Bitmap.createBitmap(lineAMutBmp);
Canvas c = new Canvas(copy);
Paint pnt = new Paint();
pnt.setColor(Color.rgb(27, 163, 156));
pnt.setStrokeWidth(7);
c.drawLine(startX, startY, endX, endY, pnt);
imageView.setImageBitmap(copy);
}
}

Finally do it using this link I used the answer by Andres
public boolean onTouch(View v, MotionEvent event) {
...
float []m = new float[9];
matrix.getValues(m);
float transX = m[Matrix.MTRANS_X] * -1;
float transY = m[Matrix.MTRANS_Y] * -1;
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: //first finger down only
savedMatrix.set(matrix);
if (draw) {
if (i == 1) {
startX = Math.abs((event.getX() + transX) / scale);
startY = Math.abs((event.getY() + transY) / scale);
i = 2;
} else if (i == 2) {
endX = Math.abs((event.getX() + transX) / scale);
endY = Math.abs((event.getY() + transY) / scale);
onDraw();
i = 3;
} else if (i == 3) {
startX = Math.abs((event.getX() + transX) / scale);
startY = Math.abs((event.getY() + transY) / scale);
onDraw();
i = 2;
}
} else {
..
}
break;
case MotionEvent.ACTION_UP: //first finger lifted
case MotionEvent.ACTION_POINTER_UP: //second finger lifted
...
break;
case MotionEvent.ACTION_POINTER_DOWN: //second finger down
...
break;
case MotionEvent.ACTION_MOVE:
...
break;
}
} //perform the transformation.
view.setImageMatrix(matrix);
return true; // indicate event was handled
}

Android ImageView Scaling and translating issue

I’m developing an android application (API 19 4.4) and I encounter some issue with ImageViews.
I have a SurfaceView, in which I dynamically add ImageViews which I want to react to touch events.
On so far, I have managed to make the ImageView move and scale smoothly but I have an annoying behavior.
When I scale down the image to a certain limit (I would say half the original size) and I try to move it, the image flicker.
After a short analysis, it seems that it’s switching its position symmetrically around the finger point on the screen, cumulating distance, and finally gets out of sight (all that happens very fast ( < 1s).
I think I am missing something with the relative value of the touch event to the ImageView/SurfaceView, but I’m a quite a noob and I’m stucked…
Here is my code
public class MyImageView extends ImageView {
private ScaleGestureDetector mScaleDetector ;
private static final int MAX_SIZE = 1024;
private static final String TAG = "MyImageView";
PointF DownPT = new PointF(); // Record Mouse Position When Pressed Down
PointF StartPT = new PointF(); // Record Start Position of 'img'
public MyImageView(Context context) {
super(context);
mScaleDetector = new ScaleGestureDetector(context,new MySimpleOnScaleGestureListener());
setBackgroundColor(Color.RED);
setScaleType(ScaleType.MATRIX);
setAdjustViewBounds(true);
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
lp.setMargins(-MAX_SIZE, -MAX_SIZE, -MAX_SIZE, -MAX_SIZE);
this.setLayoutParams(lp);
this.setX(MAX_SIZE);
this.setY(MAX_SIZE);
}
int firstPointerID;
boolean inScaling=false;
#Override
public boolean onTouchEvent(MotionEvent event) {
// get pointer index from the event object
int pointerIndex = event.getActionIndex();
// get pointer ID
int pointerId = event.getPointerId(pointerIndex);
//First send event to scale detector to find out, if it's a scale
boolean res = mScaleDetector.onTouchEvent(event);
if (!mScaleDetector.isInProgress()) {
int eid = event.getAction();
switch (eid & MotionEvent.ACTION_MASK)
{
case MotionEvent.ACTION_MOVE :
if(pointerId == firstPointerID) {
PointF mv = new PointF( (int)(event.getX() - DownPT.x), (int)( event.getY() - DownPT.y));
this.setX((int)(StartPT.x+mv.x));
this.setY((int)(StartPT.y+mv.y));
StartPT = new PointF( this.getX(), this.getY() );
}
break;
case MotionEvent.ACTION_DOWN : {
firstPointerID = pointerId;
DownPT.x = (int) event.getX();
DownPT.y = (int) event.getY();
StartPT = new PointF( this.getX(), this.getY() );
break;
}
case MotionEvent.ACTION_POINTER_DOWN: {
break;
}
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
case MotionEvent.ACTION_CANCEL: {
firstPointerID = -1;
break;
}
default :
break;
}
return true;
}
return true;
}
public boolean onScaling(ScaleGestureDetector detector) {
this.setScaleX(this.getScaleX()*detector.getScaleFactor());
this.setScaleY(this.getScaleY()*detector.getScaleFactor());
invalidate();
return true;
}
private class MySimpleOnScaleGestureListener extends SimpleOnScaleGestureListener {
#Override
public boolean onScale(ScaleGestureDetector detector) {
return onScaling(detector);
}
#Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
Log.d(TAG, "onScaleBegin");
return true;
}
#Override
public void onScaleEnd(ScaleGestureDetector arg0) {
Log.d(TAG, "onScaleEnd");
}
}
}
I have also another questions about rotations. How should I implement this?
Could I use the ScalegestureDetector in some way or have I to make this works in the view touch event? I would like to be able to scale and rotate in the same gesture (and move in another).
Thank for helping me, I would really appreciate!
Sorry for my english

this is a working example of two fingers move/scale/rotate (note: the code is quite short due to smart detector used - see MatrixGestureDetector):
class ViewPort extends View {
List<Layer> layers = new LinkedList<Layer>();
int[] ids = {R.drawable.layer0, R.drawable.layer1, R.drawable.layer2};
public ViewPort(Context context) {
super(context);
Resources res = getResources();
for (int i = 0; i < ids.length; i++) {
Layer l = new Layer(context, this, BitmapFactory.decodeResource(res, ids[i]));
layers.add(l);
}
}
#Override
protected void onDraw(Canvas canvas) {
for (Layer l : layers) {
l.draw(canvas);
}
}
private Layer target;
#Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
target = null;
for (int i = layers.size() - 1; i >= 0; i--) {
Layer l = layers.get(i);
if (l.contains(event)) {
target = l;
layers.remove(l);
layers.add(l);
invalidate();
break;
}
}
}
if (target == null) {
return false;
}
return target.onTouchEvent(event);
}
}
class Layer implements MatrixGestureDetector.OnMatrixChangeListener {
Matrix matrix = new Matrix();
Matrix inverse = new Matrix();
RectF bounds;
View parent;
Bitmap bitmap;
MatrixGestureDetector mgd = new MatrixGestureDetector(matrix, this);
public Layer(Context ctx, View p, Bitmap b) {
parent = p;
bitmap = b;
bounds = new RectF(0, 0, b.getWidth(), b.getHeight());
matrix.postTranslate(50 + (float) Math.random() * 50, 50 + (float) Math.random() * 50);
}
public boolean contains(MotionEvent event) {
matrix.invert(inverse);
float[] pts = {event.getX(), event.getY()};
inverse.mapPoints(pts);
if (!bounds.contains(pts[0], pts[1])) {
return false;
}
return Color.alpha(bitmap.getPixel((int) pts[0], (int) pts[1])) != 0;
}
public boolean onTouchEvent(MotionEvent event) {
mgd.onTouchEvent(event);
return true;
}
#Override
public void onChange(Matrix matrix) {
parent.invalidate();
}
public void draw(Canvas canvas) {
canvas.drawBitmap(bitmap, matrix, null);
}
}
class MatrixGestureDetector {
private static final String TAG = "MatrixGestureDetector";
private int ptpIdx = 0;
private Matrix mTempMatrix = new Matrix();
private Matrix mMatrix;
private OnMatrixChangeListener mListener;
private float[] mSrc = new float[4];
private float[] mDst = new float[4];
private int mCount;
interface OnMatrixChangeListener {
void onChange(Matrix matrix);
}
public MatrixGestureDetector(Matrix matrix, MatrixGestureDetector.OnMatrixChangeListener listener) {
this.mMatrix = matrix;
this.mListener = listener;
}
public void onTouchEvent(MotionEvent event) {
if (event.getPointerCount() > 2) {
return;
}
int action = event.getActionMasked();
int index = event.getActionIndex();
switch (action) {
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_POINTER_DOWN:
int idx = index * 2;
mSrc[idx] = event.getX(index);
mSrc[idx + 1] = event.getY(index);
mCount++;
ptpIdx = 0;
break;
case MotionEvent.ACTION_MOVE:
for (int i = 0; i < mCount; i++) {
idx = ptpIdx + i * 2;
mDst[idx] = event.getX(i);
mDst[idx + 1] = event.getY(i);
}
mTempMatrix.setPolyToPoly(mSrc, ptpIdx, mDst, ptpIdx, mCount);
mMatrix.postConcat(mTempMatrix);
if(mListener != null) {
mListener.onChange(mMatrix);
}
System.arraycopy(mDst, 0, mSrc, 0, mDst.length);
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
if (event.getPointerId(index) == 0) ptpIdx = 2;
mCount--;
break;
}
}
}

I tried to implementation of multiple touch on view not on bitmap using matrix, now i success. Now i think it will helpful to you for individual gesture for multiple image. Try it, it work best for me.
public class MultiTouchImageView extends ImageView implements OnTouchListener{
float[] lastEvent = null;
float d = 0f;
float newRot = 0f;
public static String fileNAME;
public static int framePos = 0;
//private ImageView view;
private boolean isZoomAndRotate;
private boolean isOutSide;
// We can be in one of these 3 states
private static final int NONE = 0;
private static final int DRAG = 1;
private static final int ZOOM = 2;
private int mode = NONE;
private PointF start = new PointF();
private PointF mid = new PointF();
float oldDist = 1f;
public MultiTouchImageView(Context context) {
super(context);
}
public MultiTouchImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public MultiTouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
}
#SuppressWarnings("deprecation")
#Override
public boolean onTouch(View v, MotionEvent event) {
//view = (ImageView) v;
bringToFront();
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
//savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
mode = DRAG;
lastEvent = null;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
if (oldDist > 10f) {
midPoint(mid, event);
mode = ZOOM;
}
lastEvent = new float[4];
lastEvent[0] = event.getX(0);
lastEvent[1] = event.getX(1);
lastEvent[2] = event.getY(0);
lastEvent[3] = event.getY(1);
d = rotation(event);
break;
case MotionEvent.ACTION_UP:
isZoomAndRotate = false;
case MotionEvent.ACTION_OUTSIDE:
isOutSide = true;
mode = NONE;
lastEvent = null;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
lastEvent = null;
break;
case MotionEvent.ACTION_MOVE:
if(!isOutSide){
if (mode == DRAG && !isZoomAndRotate) {
isZoomAndRotate = false;
setTranslationX((event.getX() - start.x) + getTranslationX());
setTranslationY((event.getY() - start.y) + getTranslationY());
} else if (mode == ZOOM && event.getPointerCount() == 2) {
isZoomAndRotate = true;
boolean isZoom = false;
if(!isRotate(event)){
float newDist = spacing(event);
if (newDist > 10f) {
float scale = newDist / oldDist * getScaleX();
setScaleX(scale);
setScaleY(scale);
isZoom = true;
}
}
else if(!isZoom){
newRot = rotation(event);
setRotation((float)(getRotation() + (newRot - d)));
}
}
}
break;
}
new GestureDetector(new MyGestureDectore());
Constants.currentSticker = this;
return true;
}
private class MyGestureDectore extends GestureDetector.SimpleOnGestureListener{
#Override
public boolean onDoubleTap(MotionEvent e) {
bringToFront();
return false;
}
#Override
public boolean onDoubleTapEvent(MotionEvent e) {
return false;
}
}
private float rotation(MotionEvent event) {
double delta_x = (event.getX(0) - event.getX(1));
double delta_y = (event.getY(0) - event.getY(1));
double radians = Math.atan2(delta_y, delta_x);
return (float) Math.toDegrees(radians);
}
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return FloatMath.sqrt(x * x + y * y);
}
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
private boolean isRotate(MotionEvent event){
int dx1 = (int) (event.getX(0) - lastEvent[0]);
int dy1 = (int) (event.getY(0) - lastEvent[2]);
int dx2 = (int) (event.getX(1) - lastEvent[1]);
int dy2 = (int) (event.getY(1) - lastEvent[3]);
Log.d("dx1 ", ""+ dx1);
Log.d("dx2 ", "" + dx2);
Log.d("dy1 ", "" + dy1);
Log.d("dy2 ", "" + dy2);
//pointer 1
if(Math.abs(dx1) > Math.abs(dy1) && Math.abs(dx2) > Math.abs(dy2)) {
if(dx1 >= 2.0 && dx2 <= -2.0){
Log.d("first pointer ", "right");
return true;
}
else if(dx1 <= -2.0 && dx2 >= 2.0){
Log.d("first pointer ", "left");
return true;
}
}
else {
if(dy1 >= 2.0 && dy2 <= -2.0){
Log.d("seccond pointer ", "top");
return true;
}
else if(dy1 <= -2.0 && dy2 >= 2.0){
Log.d("second pointer ", "bottom");
return true;
}
}
return false;
}
}

I finally use this (spacing is used to calculated the distance between two fingers), I offset the imageview after scaling to keep it centered, works fine for now :
float newDist = spacing(event);
float scale = newDist / oldDist;
int oldH =getLayoutParams().height;
int oldW =getLayoutParams().width;
int newH =(int) (getLayoutParams().height*scale);
int newW =(int) (getLayoutParams().width*scale);
if(newH<MAX_SIZE && newW<MAX_SIZE){
//scale the height and width of the view
getLayoutParams().height = newH;
getLayoutParams().width = newW;
//calculate the X and Y offset to apply after scaling to keep the image centered
int xOffset = (int)(getLayoutParams().height - oldH)/2;
int yOffset = (int)(getLayoutParams().width - oldW)/2;
setX(getX()-xOffset);
setY(getY()-yOffset);
requestLayout();
setAdjustViewBounds(true);
oldDist=newDist;

All these examples had a glitchy gesture support because of scaleType was set to matrix. When I tried to zoom, I was not able to keep the image in center and control the amount of zoom. So I did some study and wrote a small, easy but very pleasing code for this: https://stackoverflow.com/a/65697376/13339685

How to draw an arrowhead in a free handed drawn line in Android?

I need to make a arrow head in a line that is defined by a lot of points, that the user will drawn.
I hope that I could be clear about what is my question.
Thanks.
Note: All the questions/answers that I saw here were to resolve the problem of a line that was defined by two points, taken in the ACTION_DOWN and ACTION_UP. It's different in my case, because I need to take the first point while the line is being drawn.
This is my onTouch() method. It just draw a line defined by where the user touches in the screen.
public boolean onTouch(View v, MotionEvent event) {
if(getEditMode()) {
float eventX = event.getX();
float eventY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
path.moveTo(eventX, eventY);
break;
case MotionEvent.ACTION_MOVE:
path.lineTo(eventX, eventY);
break;
case MotionEvent.ACTION_UP:
//Here i have to draw an arrow.
drawCanvas.drawPath(path, paint);
path.reset();
invalidate();
break;
}
invalidate();
return true;
} else {
return false;
}
}

I override draw and rotate the canvas before drawing the arrow.
//NOTE: 0, 0 is the bottom center point
vehicle.draw(canvas);
//draw arrow
if (arrow != null && heading != BusLocation.NO_HEADING)
{
//put the arrow in window
int arrowLeft = -(arrow.getIntrinsicWidth() / 4);
int arrowTop = -vehicle.getIntrinsicHeight() + arrowTopDiff;
//use integer division when possible. This code is frequently executed
int arrowWidth = (arrow.getIntrinsicWidth() * 6) / 10;
int arrowHeight = (arrow.getIntrinsicHeight() * 6) / 10;
int arrowRight = arrowLeft + arrowWidth;
int arrowBottom = arrowTop + arrowHeight;
arrow.setBounds(arrowLeft, arrowTop, arrowRight, arrowBottom);
canvas.save();
//set rotation pivot at the center of the arrow image
canvas.rotate(heading, arrowLeft + arrowWidth/2, arrowTop + arrowHeight / 2);
Rect rect = arrow.getBounds();
arrow.draw(canvas);
arrow.setBounds(rect);
canvas.restore();
}
}

So, I found a solution.
I store all the points that construct the line in an arraylist.
After I took a point of the line that would be in the 0.9 * arraylist.size() as reference to draw an arrowhead that follow the line direction.
Here is my onTouch() method and the funciont that I used to draw the arrow.
public boolean onTouch(View v, MotionEvent event) {
if(getEditMode()) {
float eventX = event.getX();
float eventY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN: {
path.moveTo(eventX, eventY);
pList.clear(); // When I start a line need to clear the previous coorfinates.
break;
}
case MotionEvent.ACTION_MOVE: {
int hSize = event.getHistorySize();
path.lineTo(eventX, eventY);
PointF aux, auxH;
if(darrow) {
if(hSize > 0) { // If movement is too fast.
for(int i = 0; i < hSize; i++) {
auxH = new PointF(event.getHistoricalX(i), event.getHistoricalY(i));
pList.add(auxH);
}
}
aux = new PointF(eventX, eventY);
pList.add(aux);
}
break;
}
case MotionEvent.ACTION_UP: {
pend.x = eventX;
pend.y = eventY;
if(darrow) { // If need to draw an arrow head to the end of the line;
arrowPath = drawArrow(pend); // Store the right arrowhead to a path.
}
drawCanvas.drawPath(path, paint);
drawCanvas.drawPath(arrowPath, paint);
path.reset();
arrowPath.reset();
invalidate();
break;
}
}
invalidate();
return true;
} else {
return false;
}
}
And the drawArrow(PointF) function:
private Path drawArrow(PointF pfinal) {
float dx, dy;
PointF p1, p2;
PointF pstart;
Path auxPath = new Path();
if(pList.size() > 0) {
PointF[] auxArray = pList.toArray(new PointF[pList.size()]);
int index = (int)(auxArray.length * 0.9);
Log.d(msg, "Size: " + auxArray.length + " | index: " + index);
pstart = auxArray[index];
dx = pfinal.x - pstart.x;
dy = pfinal.y - pstart.y;
float length = (float)Math.sqrt(dx * dx + dy * dy);
float unitDx = dx / length;
float unitDy = dy / length;
final int arrowSize = 10;
p1 = new PointF(
(float)(pfinal.x - unitDx * arrowSize - unitDy * arrowSize),
(float)(pfinal.y - unitDy * arrowSize + unitDx * arrowSize));
p2 = new PointF(
(float)(pfinal.x - unitDx * arrowSize + unitDy * arrowSize),
(float)(pfinal.y - unitDy * arrowSize - unitDx * arrowSize));
auxPath.moveTo(pfinal.x, pfinal.y);
auxPath.lineTo(p1.x, p1.y);
auxPath.moveTo(pfinal.x, pfinal.y);
auxPath.lineTo(p2.x, p2.y);
auxPath.close();
}
return auxPath;
}

How to get the item in listview by touch event in android, so I set background color of that item when I move event on it

I want to move the figure on list view item that contains phone number.
When I move figure from right to left, make a call. I'm failing to get that particoular item in list view to get the phone number and make a call.
My code is
#Override
arg1.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View arg0, MotionEvent event) {
float startX = 0;
float startY;
float endX;
float endY;
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
startX = (int) event.getX();
startY = (int) event.getY();
System.out.println("startX" + startX);
System.out.println("startY" + startY);
break;
case MotionEvent.ACTION_MOVE:
endX = event.getX();
endY = (int) event.getY();
System.out.println("endX" + endX);
System.out.println("endY" + endY);
float sub = endX - startX;
System.out.println("sub" + sub);
if ((endX - startX) < 100) {
arg0.setBackgroundColor(Color.GREEN);
}
if ((endX - startX) > 100) {
try {
TextView ph_tv = (TextView) arg0
.findViewById(R.id.textnum);
String Pho_no = ph_tv.getText().toString();
arg0.setBackgroundColor(Color.RED);
Intent intent = new Intent(
Intent.ACTION_CALL, Uri
.parse("tel:" + Pho_no));
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
lv.setBackgroundColor(Color.BLACK);
} catch (ActivityNotFoundException e) {
Toast.makeText(
getApplicationContext(),
"Error in your phone call"
+ e.getMessage(),
Toast.LENGTH_LONG).show();
}
section(path_name, lv1);
}
break;
case MotionEvent.ACTION_UP:
endX = (int) event.getX();
endY = (int) event.getY();
}
return true;
}
});

float hX = Float.NaN, historicY = Float.NaN;
static final TRIGGER_DELTA = 50; // Number of pixels to travel till trigger
#Override public boolean onTouchEvent(MotionEvent e) {
switch (e.getAction()) {
case MotionEvent.ACTION_DOWN:
hX = e.getX();
historicY = e.getY();
break;
case MotionEvent.ACTION_UP:
if (e.getX() - hX > -TRIGGER_DELTA) {
onSlideComplete(Direction.LEFT);
return true;
}
else if (e.getX() - hX > TRIGGER_DELTA) {
onSlideComplete(Direction.RIGHT);
return true;
} break;
default:
return super.onTouchEvent(e);
}
}
enum Direction {
LEFT, RIGHT;
}
interface OnSlideCompleteListener {
void onSlideComplete(Direction dir);
}

Get Canvas coordinates after scaling up/down or dragging in android

I'm developing an application in which I'm pasting images, doing drawing and painting on canvas. This app can also Scale up/down the canvas or drag it to different location.
My problem is: I can't get the correct canvas coordinates after scaling or dragging the canvas. I want to draw finger paint after the canvas is scaled or dragged but unable to retrieve the right place where i've touched..:(
Also I'm new bee. Here is the code.
#Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.save();
//canvas.translate(mPosX, mPosY);
canvas.scale(mScaleFactor, mScaleFactor, super.getWidth() * 0.5f,
super.getHeight() * 0.5f);
mIcon.draw(canvas);
for (Path path : listPath) {
canvas.drawPath(path, paint);
}
canvas.restore();
}
public TouchExampleView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
#Override
public boolean onTouchEvent(MotionEvent ev) {
// Let the ScaleGestureDetector inspect all events.
mScaleDetector.onTouchEvent(ev);
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: {
final float x = ev.getX();
final float y = ev.getY();
mLastTouchX = x;
mLastTouchY = y;
mActivePointerId = ev.getPointerId(0);
break;
}
case MotionEvent.ACTION_MOVE: {
final int pointerIndex = ev.findPointerIndex(mActivePointerId);
final float x = ev.getX(pointerIndex);
final float y = ev.getY(pointerIndex);
// Only move if the ScaleGestureDetector isn't processing a gesture.
if (!mScaleDetector.isInProgress()) {
final float dx = x - mLastTouchX;
final float dy = y - mLastTouchY;
mPosX += dx;
mPosY += dy;
invalidate();
}
mLastTouchX = x;
mLastTouchY = y;
break;
}
case MotionEvent.ACTION_UP: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_CANCEL: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_POINTER_UP: {
final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId) {
// This was our active pointer going up. Choose a new
// active pointer and adjust accordingly.
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mLastTouchX = ev.getX(newPointerIndex);
mLastTouchY = ev.getY(newPointerIndex);
mActivePointerId = ev.getPointerId(newPointerIndex);
}
break;
}
}
float objectNewX,objectNewY;
if (mScaleFactor >= 1) {
objectNewX = ev.getX() + (ev.getX() - super.getWidth() * 0.5f) * (mScaleFactor - 1);
objectNewY = ev.getY() + (ev.getY() - super.getHeight() * 0.5f) * (mScaleFactor - 1);
} else {
objectNewX = ev.getX() - (ev.getX() - super.getWidth() * 0.5f) * (1 - mScaleFactor);
objectNewY = ev.getY() - (ev.getY() - super.getHeight() * 0.5f) * (1 - mScaleFactor);
}
if (ev.getAction() == MotionEvent.ACTION_DOWN) {
path = new Path();
path.moveTo(objectNewX,objectNewY);
path.lineTo(objectNewX,objectNewY);
} else if (ev.getAction() == MotionEvent.ACTION_MOVE) {
path.lineTo(objectNewX,objectNewY);
listPath.add(path);
} else if (ev.getAction() == MotionEvent.ACTION_UP) {
path.lineTo(objectNewX,objectNewY);
listPath.add(path);
}
return true;
}
private class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener {
#Override
public boolean onScale(ScaleGestureDetector detector) {
mScaleFactor *= detector.getScaleFactor();
// Don't let the object get too small or too large.
mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 5.0f));
invalidate();
return true;
}
}

Done it finally by myself.
Draw everything by applying this formula to (px,py) coordinates:
float px = ev.getX() / mScaleFactor + rect.left;
float py = ev.getY() / mScaleFactor + rect.top;
rect = canvas.getClipBounds();
//Get them in on Draw function and apply above formula before drawing

#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
clipBounds_canvas = canvas.getClipBounds();
/////Do whatever you want to do..!!!
};
#Override
public boolean onTouchEvent(MotionEvent ev) {
int x = ev.getX() / zoomFactor + clipBounds_canvas.left;
int y = ev.getY() / zoomFactor + clipBounds_canvas.top;
//Use the above two values insted of ev.getX() and ev.getY();
}
Hope this will help.