I have a game board with 5x5 squares made of canvas drawrect:
protected void onDraw(Canvas canvas) {
for (int rowNo = 0; rowNo < nSquares; rowNo++) {
paint.setColor(((rowNo & 1) == 0) ? colorA : colorB);
for (int colNo = 0; colNo < nSquares; colNo++) {
int left = colNo * squareWidth;
int top = rowNo * squareWidth;
Rect areaRect = new Rect(left, top, left + squareWidth, top + squareWidth);
canvas.drawRect(areaRect, paint);
paint.setColor((paint.getColor() == colorA) ? colorB : colorA);
paint.setTextSize((float)(squareWidth*0.8));
RectF bounds = new RectF(areaRect);
String letter = "A";
bounds.right = paint.measureText(letter, 0, letter.length());
bounds.bottom = paint.descent() - paint.ascent();
bounds.left += (areaRect.width() - bounds.right) / 2.0f;
bounds.top += (areaRect.height() - bounds.bottom) / 2.0f;
canvas.drawText(letter, bounds.left, bounds.top - paint.ascent(), paint);
}
}
I want to track touch input to get the squares the user are touching..
My attempt was
public boolean onTouchEvent(MotionEvent event){
int action = MotionEventCompat.getActionMasked(event);
int x = (int)event.getX();
int y = (int)event.getY();
Log.i(DEBUG_TAG, "Position: (" + x + ", " + y + ")");
int squareTouched = gameBoard.getSquare(x,y);
}
where getSquare is
public int getSquare(int x, int y) {
int row = 0;
int col = 0;
for(int rowNo = 1; rowNo <= nSquares; rowNo++) {
Log.i("Row", "Width: " + squareWidth + " rowNo: " + rowNo + " rowNo*squareW: " + rowNo*squareWidth + " y: " + y);
if(rowNo*squareWidth > y)
{
row = rowNo;
break;
}
}
for (int colNo = 1; colNo <= nSquares; colNo++) {
if(colNo*squareWidth > x)
{
col = colNo;
break;
}
}
Log.i(DEBUG_TAG, "Row: " + row + " Col: " + col);
return (row-1)*nSquares + col;
}
The problem is that the onTouchEvent getX and getY are referring to the screen 0,0, but when I draw the squares 0,0,0,0 is referring to the view origin? Am I right?
How can I get the input position relative to the game board view?
Could it be a solution to get the view position in the screen and add/subtract this to the tochEvent x- and y position?
I assume that the onDraw() and getSquare() belong to GameBoardView and onTouchEvent() to its immediate parent. If so then the onTouchEvent() should be like this
public boolean onTouchEvent(MotionEvent event){
int action = MotionEventCompat.getActionMasked(event);
int x = (int)event.getX() - gameBoard.getX();
int y = (int)event.getY() - gameBoard.getY();
Log.i(DEBUG_TAG, "Position: (" + x + ", " + y + ")");
int squareTouched = gameBoard.getSquare(x, y);
}
In a View x and y in both onDraw() and onTouchEvent() is relative to the View itself (Except when the View is scrolled). Since in your case onTouchEvent() belongs to parent and onDraw() to child, I used View.getX() and getY() to translate the coordinates. View.getX() returns the x position plus translationX of the View relative to its parent.
I could not get the gameBoard().getX/Y() to return the correct values. My guess is that the action bar is excluded?
I now use getLocationOnScreen
#Override
public boolean onTouchEvent(MotionEvent event){
int action = MotionEventCompat.getActionMasked(event);
int boardLocation[] = new int[2];
gameBoard.getLocationOnScreen(boardLocation);
int touchX = (int)event.getX();
int touchY = (int)event.getY();
int x = touchX - boardLocation[0];
int y = touchY - boardLocation[1];
int squareTouched = gameBoard.getSquare(x,y);
}
Which solved my issue..
Related
I am working on a Frame multiple layout selection feature of an Android App.
My requirement is to get the top and left coordinate of Bitmap after zoom and pinch the image.
I am using TouchImageView for Zoom and Move feature.
I have tried so many SO solutions, but didn't get the solution of my requirement.
1st try -
public static int[] getBitmapOffset(ImageView img, boolean includeLayout) {
int[] offset = new int[2];
float[] values = new float[9];
Matrix m = img.getImageMatrix();
m.getValues(values);
offset[0] = (int) values[5];
offset[1] = (int) values[2];
if (includeLayout) {
ViewGroup.MarginLayoutParams lp = (ViewGroup.MarginLayoutParams) img.getLayoutParams();
int paddingTop = (int) (img.getPaddingTop() );
int paddingLeft = (int) (img.getPaddingLeft() );
offset[0] += paddingTop + lp.topMargin;
offset[1] += paddingLeft + lp.leftMargin;
}
return offset;
}
2nd try -
Rect r = img.getDrawable().getBounds();
int drawLeft = r.left;
int drawTop = r.top;
int drawRight = r.right;
int drawBottom = r.bottom;
Logger.logsInfo(TAG, "Focus drawLeft : " + i + " : " +drawLeft);
Logger.logsInfo(TAG, "Focus drawTop : " + i + " : " +drawTop);
Logger.logsInfo(TAG, "Focus drawRight : " + i + " : " +drawRight);
Logger.logsInfo(TAG, "Focus drawBottom : " + i + " : " +drawBottom);
Please let me know what i am doing wrong, because i am working on this from last 3 days and still not done.
Thanks in Advance.
Suggestions really appreciated.
Check out getZoomedRect of TouchImageView
Add function and return PointF topLeft = transformCoordTouchToBitmap(0, 0, true);
Method signature
private PointF transformCoordTouchToBitmap(float x, float y, boolean clipToBitmap)
Passing clipToBitmap true mean visible rect
/**
* Return a Rect representing the zoomed image.
* #return rect representing zoomed image
*/
public RectF getZoomedRect() {
if (mScaleType == ScaleType.FIT_XY) {
throw new UnsupportedOperationException("getZoomedRect() not supported with FIT_XY");
}
PointF topLeft = transformCoordTouchToBitmap(0, 0, true);
PointF bottomRight = transformCoordTouchToBitmap(viewWidth, viewHeight, true);
float w = getDrawable().getIntrinsicWidth();
float h = getDrawable().getIntrinsicHeight();
return new RectF(topLeft.x / w, topLeft.y / h, bottomRight.x / w, bottomRight.y / h);
}
I am able to plot bar graph using canvas and drawing rectangle in the view. But the onTouch interaction works for the whole view and hence I am not able to interact with each bar separately.I am not looking for using any library for plotting graphs. Any suggestions would be helpful. Thanks!
protected void onDraw(Canvas canvas) {
float border = 20;
float horstart = border * 2;
float height = getHeight();
float width = getWidth() - 1;
float max = getMax();
float min = getMin();
float diff = max - min;
float graphheight = height - (2 * border);
float graphwidth = width - (2 * border);
paint.setTextAlign(Align.LEFT);
int vers = verlabels.length - 1;
for (int i = 0; i < verlabels.length; i++) {
paint.setColor(Color.BLUE);
float y = ((graphheight / vers) * i) + border;
//canvas.drawLine(horstart, y, width, y, paint);
paint.setColor(Color.BLUE);
canvas.drawText(verlabels[i], 0, y, paint);
}
int hors = horlabels.length - 1;
for (int i = 0; i < horlabels.length; i++) {
paint.setColor(Color.BLUE);
float x = ((graphwidth / hors) * i) + horstart;
//canvas.drawLine(x, height - border, x, border, paint);
paint.setTextAlign(Align.CENTER);
if (i == horlabels.length - 1)
paint.setTextAlign(Align.RIGHT);
if (i == 0)
paint.setTextAlign(Align.LEFT);
paint.setColor(Color.BLUE);
canvas.drawText(horlabels[i], x, height - 4, paint);
}
paint.setTextAlign(Align.CENTER);
canvas.drawText(title, (graphwidth / 2) + horstart, border - 4, paint);
if (max != min) {
paint.setColor(Color.BLUE);
if (type == BAR) {
float datalength = values.length;
float colwidth = (graphwidth / hors);
for (int i = 0; i < values.length; i++) {
float val = values[i] - min;
float rat = val / diff;
float h = graphheight * rat;
canvas.drawRect((i * colwidth) + horstart, (border - h)
+ graphheight+curY, ((i * colwidth) + horstart)
+ (colwidth - 1), height - (border - 1), paint);
}
} else {
float datalength = values.length;
float colwidth = (width - (2 * border)) / datalength;
float halfcol = colwidth / 2;
float lasth = 0;
float h = 0;
for (int i = 0;i<values.length;i++)
canvas.drawLine(((i - 1) * colwidth) + (horstart + 1)
+ halfcol, (border - lasth) + graphheight+curY,
(i * colwidth) + (horstart + 1) + halfcol,
(border - h) + graphheight, paint);
lasth = h;
}
}
}
onTouch method for the view :
public boolean onTouch(View v, MotionEvent event)
{
boolean result=false;
switch (event.getAction())
{
case MotionEvent.ACTION_DOWN:
curX= (int)event.getX();
curY= (int)event.getY();
result=true;
break;
case MotionEvent.ACTION_MOVE:
curX= (int)event.getX();
curY= (int)event.getY();
result=true;
break;
case MotionEvent.ACTION_UP:
curX= (int)event.getX();
curY= (int)event.getY();
result=true;
break;
}
if (result) invalidate();
return result;
}
Whenever an user touches that view, it causes the onTouch method gets called. Once it's getting called, you're given two float numbers: x and y indicating where user's finger touches your view relative to the view coordination system.
As you might grasped the idea, you should get those numbers and internally in your custom view (i.e. bar chart) calculate which bar is affected. Then, you can for example apply a hover effect or do something else.
Note: For updating appearance of your view, you should store changes in data models of your chart view and then issue invalidate(). Subsequently, as a result, your onDraw is invoked and in which you can re-draw your chart. (i.e. You should each time, re-draw your whole chart again)
I am trying to get rgb value at a point on image where user taps. I am using following code to achieve that.
imageView.setOnTouchListener(new ImageView.OnTouchListener(){
#Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
int x=0;
int y=0;
ImageView imageView = ((ImageView)v);
Bitmap bitmap = ((BitmapDrawable)imageView.getDrawable()).getBitmap();
int pixel = bitmap.getPixel(x,y);
int redValue = Color.red(pixel);
int blueValue = Color.blue(pixel);
int greenValue = Color.green(pixel);
if(pixel == Color.RED){
}
Log.v("RGB",pixel+ " :R: "+redValue+ " G: "+blueValue+ " B:"+greenValue);
return true; }
});
But it returns same value of RGB for every point on the image that is "-10197916 :R: 100 G: 100 B:100".
I have even used int x=(int)event.getIntX();
int y=(int)event.getIntY();
But result is always same. What did I miss?
You have used:
int x=0;
int y=0;
You need to use:
int x = (int)event.getX();
int y = (int)event.getY();
This one worked,problem was to get right x,y as:
imageView.setOnTouchListener(imgSourceOnTouchListener);
OnTouchListener imgSourceOnTouchListener
= new OnTouchListener(){
#Override
public boolean onTouch(View view, MotionEvent event) {
float eventX = event.getX();
float eventY = event.getY();
float[] eventXY = new float[] {eventX, eventY};
Matrix invertMatrix = new Matrix();
((ImageView)view).getImageMatrix().invert(invertMatrix);
invertMatrix.mapPoints(eventXY);
int x = Integer.valueOf((int)eventXY[0]);
int y = Integer.valueOf((int)eventXY[1]);
System.out.println(
"touched position: "
+ String.valueOf(eventX) + " / "
+ String.valueOf(eventY));
System.out.println(
"touched position: "
+ String.valueOf(x) + " / "
+ String.valueOf(y));
Drawable imgDrawable = ((ImageView)view).getDrawable();
Bitmap bitmap = ((BitmapDrawable)imgDrawable).getBitmap();
System.out.println(
"drawable size: "
+ String.valueOf(bitmap.getWidth()) + " / "
+ String.valueOf(bitmap.getHeight()));
//Limit x, y range within bitmap
if(x < 0){
x = 0;
}else if(x > bitmap.getWidth()-1){
x = bitmap.getWidth()-1;
}
if(y < 0){
y = 0;
}else if(y > bitmap.getHeight()-1){
y = bitmap.getHeight()-1;
}
int touchedRGB = bitmap.getPixel(x, y);
System.out.println("touched color: " + "#" + Integer.toHexString(touchedRGB));
return true;
}};
iView_image1.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
Bitmap bmp = Bitmap.createBitmap(v.getDrawingCache());
int color = 0;
try {
color = bmp.getPixel((int) event.getX(), (int) event.getY());
int r = Color.red(color);
int g = Color.green(color);
int b = Color.blue(color);
} catch (Exception e) {
}
return false;
}
});
I have been developing a board game using hexagon boards in android, but when I move the board, the whole 'map' or dozens of entities starts to lag. I believe that it is the cause of using a for-loop, but I have no idea how to fix it. Im using the method of threaded drawing, dont know if it affects though.
I can clearly see lags on my cell phone when moving through the board.
My Game class:
public class Game extends SurfaceView implements SurfaceHolder.Callback {
// Game Vars
int mapWidth = 150, mapHeight = 150;
public static double hexagonSideLength = 80;
public static double cellWidth = 2 * hexagonSideLength, cellHeight = Math
.sqrt(3) * hexagonSideLength;
public static double downwardShift = (0.5) * (cellHeight);
public static double rightShift = hexagonSideLength / 2;
public static int boundaryWidth = 0, boundaryHeight = 0;
public static int error = (int) ((hexagonSideLength) * (0.06));
public static int buffer = 2;
public static int draws = 0;
// Touch Handle
// Offset to the upper left corner of the map
private int xOffset = 0;
private int yOffset = 0;
// last touch point
private int _xTouch = 0;
private int _yTouch = 0;
// scrolling active?
private boolean _isMoving = false;
public Cell[][] map;
private GameThread thread;
static String TAG = Game.class.getSimpleName();
Bitmap image[] = new Bitmap[100];
Paint paint;
public Game(Context context) {
super(context);
Log.i(TAG, "Loaded Game");
// adding the callback (this) to the surface holder to intercept events
getHolder().addCallback(this);
// make the GamePanel focusable so it can handle events
thread = new GameThread(getHolder(), this);
map = new Cell[mapWidth][mapHeight]; // Create new Map
boolean isShiftedDownwards = false;
for (int i = 0; i < mapWidth; i++) {
for (int j = 0; j < mapHeight; j++) {
map[i][j] = new Cell(j, i, isShiftedDownwards);
}
if (isShiftedDownwards == true)
isShiftedDownwards = false;
else
isShiftedDownwards = true;
}
if (mapWidth % 2 != 0) {
boundaryWidth = (int) ((((mapWidth - 1) / 2) * hexagonSideLength)
+ ((mapWidth / 2) * cellWidth) + (2) * hexagonSideLength);
} else {
boundaryWidth = (int) (((((mapWidth - 1) / 2) * hexagonSideLength) + ((mapWidth / 2) * cellWidth)) + (1.5) * hexagonSideLength);
}
boundaryHeight = (int) (mapHeight * cellHeight + 0.5 * cellHeight);
setFocusable(true);
image[0] = Bitmap.createBitmap(BitmapFactory.decodeResource(
this.getResources(), R.drawable.hexagonrgb));
image[1] = Bitmap.createScaledBitmap(image[0], (int) cellWidth + error,
(int) cellHeight + error, false);
Log.i(TAG, "Got Resources");
paint = new Paint();
Log.i(TAG, "Prepared paint");
}
// called every Frame
#Override
protected void onDraw(Canvas canvas) {
Log.i(TAG, "onDraw Called");
// BG
canvas.drawColor(Color.BLACK);
// Resize
// Redraw Map
draws = 0;
for (int column = updateArea(0); column < updateArea(1); column++) {
for (int row = updateArea(2); row < updateArea(3); row++) {
canvas.drawBitmap(image[1], map[column][row].x - xOffset,
map[column][row].y - yOffset, paint);
paint.setColor(Color.WHITE);
canvas.drawText(row + "," + column, map[column][row].x
- xOffset + 80, map[column][row].y - yOffset + 80,
paint);
draws++;
}
}
/** Log */
paint.setColor(Color.WHITE);
paint.setTextSize(20);
canvas.drawText("xOffset: " + xOffset, 0, 30, paint);
canvas.drawText("yOffset: " + yOffset, 0, 50, paint);
canvas.drawText("activeTitlesX: " + updateArea(0) + " - "
+ updateArea(1), 0, 70, paint);
canvas.drawText("activeTitlesY: " + updateArea(2) + " - "
+ updateArea(3), 0, 90, paint);
canvas.drawText("DimX: " + MainActivity.DimX, 0, 110, paint);
canvas.drawText("DimY: " + MainActivity.DimY, 0, 130, paint);
canvas.drawText("Draws: " + draws, 0, 150, paint);
Log.i(TAG, "Cleared canvas");
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
}
// called by thread
public static void update() {
Log.i(TAG, "Updated Game");
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
thread.setRunning(true);
thread.start();
Log.i(TAG, "Thread Started");
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
boolean retry = true;
while (retry) {
try {
thread.join();
retry = false;
} catch (InterruptedException e) {
// try again shutting down the thread
}
}
Log.i(TAG, "Thread Destroyed");
}
#Override
public boolean onTouchEvent(MotionEvent event) {
// touch down
if (event.getAction() == MotionEvent.ACTION_DOWN) {
// start of a new event, reset the flag
_isMoving = false;
// store the current touch coordinates for scroll calculation
_xTouch = (int) event.getX();
_yTouch = (int) event.getY();
} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
// touch starts moving, set the flag
_isMoving = true;
// get the new offset
xOffset += _xTouch - (int) event.getX();
yOffset += _yTouch - (int) event.getY();
// secure, that the offset is never out of view bounds
if (xOffset < 0) {
xOffset = 0;
} else if (xOffset > boundaryWidth - getWidth()) {
xOffset = boundaryWidth - getWidth();
}
if (yOffset < 0) {
yOffset = 0;
} else if (yOffset > boundaryHeight - getHeight()) {
yOffset = boundaryHeight - getHeight();
}
// store the last position
_xTouch = (int) event.getX();
_yTouch = (int) event.getY();
} else if (event.getAction() == MotionEvent.ACTION_UP) {
/*
* // touch released if (!_isMoving) { // calculate the touched cell
* int column = (int) Math.ceil((_xOffset + event.getX()) /
* _cellSize) - 1; int row = (int) Math.ceil((_yOffset +
* event.getY()) / _cellSize) - 1; Cell cell =
* _mapCells.get(row).get(column); // show the id of the touched
* cell Toast.makeText(getContext(), "Cell id #" + cell._id,
* Toast.LENGTH_SHORT).show(); }
*/
}
return true;
}
public int updateArea(int i) {
switch (i) {
case 0: // Left
return Math.max(
(int) (xOffset / (cellWidth - rightShift)) - buffer, 0);
case 1: // Right
return Math
.min((int) (xOffset / (cellWidth - rightShift) + (int) (MainActivity.DimX / (cellWidth - rightShift)))
+ buffer, mapWidth);
case 2: // Up
return Math.max((int) (yOffset / cellHeight) - buffer, 0);
case 3: // Down
return Math.min(((int) (yOffset / cellHeight))
+ (int) (MainActivity.DimY / cellHeight) + buffer,
mapHeight);
}
return 0;
}
/* CELL CLASS */
class Cell {
int x, y;
boolean isShiftedDown;
public Cell(int row, int col, boolean isShifted) {
if (col % 2 != 0) {
isShiftedDown = true;
y = (int) (row * Game.cellHeight + Game.downwardShift);
x = (int) (col * Game.cellWidth - col * Game.rightShift);
Log.i("Shift", "Shifted" + Game.downwardShift);
} else {
isShiftedDown = false;
y = (int) (row * Game.cellHeight);
x = (int) (col * Game.cellWidth - col * Game.rightShift);
Log.i("Shift", "Not Shifted");
}
}
}
}
Thanks in Advance :)
Basic algorithmic analysis shows you are doing this operation:
map[i][j] = new Cell(j, i, isShiftedDownwards);
22500 times. Do you really need to create a new object each time, or can you just change a variable in an existing object?
Update:
for (int column = updateArea(0); column < updateArea(1); column++) {
for (int row = updateArea(2); row < updateArea(3); row++) {
canvas.drawBitmap(image[1], map[column][row].x - xOffset,
map[column][row].y - yOffset, paint);
paint.setColor(Color.WHITE);
canvas.drawText(row + "," + column, map[column][row].x
- xOffset + 80, map[column][row].y - yOffset + 80,
paint);
draws++;
}
}
So this is the double for-loop in question. I'm going to run with the assumption that this needs to be run as many times as it runs. Can the function calls in the loop statements be reduced to variables prior to the loop (they are evaluated with each loop)? This paint.setColor(Color.WHITE); should not be called on each iteration. If you need to change to white after the very first draw, just make a second paint object on startup and and change it before you enter the loop.
If this doesn't help, you need to determine if you can iterate over a smaller area.
Update 2
Rewrite your for loops like so
int minCol = updateArea(0);
int maxCol = updateArea(1);
int minRow = updateArea(2);
int maxRow = updateArea(3);
for(int column = minCol; column < maxCol; column++)
for (int row = minRow; column < maxRow; row++)
....
This will represent a significant reduction in the operations in each iteration.
So I'm attempting to make a "magnetic poetry" type application. Users will move various Button widgets on the screen. I am using a Button widget since it is the closest to the look of the magnet, though I am open to other options!
The objects are not properly moving with my finger. They're close but they're not exactly in line with my finger. The X coordinate on my phone seems to be fine, but the Y corrdinate is off. Is this perhaps due to the title bar?
private final static int DRAGGING_OFF = 0;
private final static int DRAGGING_ON = 1;
private int dragStatus;
private GestureDetector mGestureDetector;
private int mOffsetX;
private int mOffsetY;
private LayoutParams mOldParams;
private RelativeLayout.LayoutParams lp;
#Override
public boolean onTouchEvent(MotionEvent event) {
if(!mGestureDetector.onTouchEvent(event)) {
if(event.getAction() == MotionEvent.ACTION_MOVE) {
if(dragStatus == DRAGGING_ON) {
Log.e(VIEW_LOG_TAG, "Dragging! RAW -- " + event.getRawX() + " : " + event.getRawY() + " NOT RAW -- " + event.getX() + " : " + event.getY());
int rawX, rawY;
int finalX, finalY;
rawX = (int) event.getRawX();
rawY = (int) event.getRawY();
finalX = rawX - mOffsetX;
finalY = rawY - mOffsetY;
lp.setMargins(finalX, finalY, 0, 0);
this.setLayoutParams(lp);
}
return true;
} else if(event.getAction() == MotionEvent.ACTION_UP) {
if(dragStatus == DRAGGING_ON) {
dragStatus = DRAGGING_OFF;
Log.e(VIEW_LOG_TAG, "Stopped dragging!");
}
return true;
} else {
return super.onTouchEvent(event);
}
} else {
return true;
}
}
private final GestureDetector.SimpleOnGestureListener mListener = new GestureDetector.SimpleOnGestureListener() {
#Override
public boolean onDown(MotionEvent e) {
int[] location = new int[2];
Log.e(VIEW_LOG_TAG, "Down! RAW -- " + e.getRawX() + " : " + e.getRawY() + " NOT RAW -- " + e.getX() + " : " + e.getY());
dragStatus = DRAGGING_ON;
// Sets the current location of the View in the int[] passed to it; x then y.
getLocationInWindow(location);
Log.e(VIEW_LOG_TAG, "Down location: " + location[0] + " " + location[1]);
mOffsetX = (int) e.getRawX() - location[0];
mOffsetY = (int) e.getRawY() - location[1];
mOldParams = getLayoutParams();
return true;
}
};
I think the issue is that you're not getting the DELTA of the current touch point Y and the cached, last touch point y. You need something like this:
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final TextView textView = (TextView) findViewById(R.id.text);
final ImageView image = (ImageView) findViewById(R.id.image);
matrix.setTranslate(1f, 1f);
image.setImageMatrix(matrix);
image.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
matrix.getValues(m); //copy matrix values into array
PointF currentXYTouchPoint = new PointF(event.getX(), event.getY());
switch(event.getAction()) {
case MotionEvent.ACTION_DOWN: //start of pressed gesture
lastXYTouchPoint.set(event.getX(), event.getY()); //save the last touchpoint
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
//calculate the change in finger position
float deltaX = currentXYTouchPoint.x - lastXYTouchPoint.x;
float deltaY = currentXYTouchPoint.y - lastXYTouchPoint.y;
matrix.postTranslate(deltaX, deltaY); //move the entire image by the deltas
image.setImageMatrix(matrix);
// save this last starting touchpoint
lastXYTouchPoint.set(currentXYTouchPoint.x, currentXYTouchPoint.y);
break;
}
textView.setText("TouchPoint started at " + currentXYTouchPoint.x + ", " + currentXYTouchPoint.y + " & the matrix is now " + Arrays.toString(m));
return true;
}
});
}
Adapt it to your own purposes, but the basic idea is there.