通过手势实现Android ImageView 缩放
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将以下代码写到MulitPointTouchListener.java中，然后对你相应的图片进行OnTouchListener。
例如：imageView.setOnTouchListener(new MulitPointTouchListener ());
在xml中要将ImageView的缩放格式改成Matrix
例如：android:scaleType="matrix"
这样就可以实现图片的缩放了
下面是MulitPointTouchListener.java代码：
public class MulitPointTouchListener implements OnTouchListener {
private static final String TAG = "Touch";
// These matrices will be used to move and zoom image
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView)
// Log.e("view_width",
// view.getImageMatrix()..toString()+"*"+v.getWidth());
// Dump touch event to log
dumpEvent(event);
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
matrix.set(view.getImageMatrix());
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
//Log.d(TAG, "mode=DRAG");
mode = DRAG;
//Log.d(TAG, "mode=NONE");
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
//Log.d(TAG, "oldDist=" + oldDist);
if (oldDist & 10f) {
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
//Log.d(TAG, "mode=ZOOM");
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
//Log.e("view.getWidth", view.getWidth() + "");
//Log.e("view.getHeight", view.getHeight() + "");
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x, event.getY()
- start.y);
} else if (mode == ZOOM) {
float newDist = spacing(event);
//Log.d(TAG, "newDist=" + newDist);
if (newDist & 10f) {
matrix.set(savedMatrix);
float scale = newDist / oldD
matrix.postScale(scale, scale, mid.x, mid.y);
view.setImageMatrix(matrix);
// indicate event was handled
private void dumpEvent(MotionEvent event) {
String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",
"POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };
StringBuilder sb = new StringBuilder();
int action = event.getAction();
int actionCode = action & MotionEvent.ACTION_MASK;
sb.append("event ACTION_").append(names[actionCode]);
if (actionCode == MotionEvent.ACTION_POINTER_DOWN
|| actionCode == MotionEvent.ACTION_POINTER_UP) {
sb.append("(pid ").append(
action && MotionEvent.ACTION_POINTER_ID_SHIFT);
sb.append(")");
sb.append("[");
for (int i = 0; i & event.getPointerCount(); i++) {
sb.append("#").append(i);
sb.append("(pid ").append(event.getPointerId(i));
sb.append(")=").append((int) event.getX(i));
sb.append(",").append((int) event.getY(i));
if (i + 1 & event.getPointerCount())
sb.append(";");
sb.append("]");
//Log.d(TAG, sb.toString());
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);
方法二：自定义一个ImageView，例如TouchImageView：
import android.content.C
import android.graphics.M
import android.graphics.PointF;
import android.graphics.drawable.D
import android.util.AttributeS
import android.util.L
import android.view.MotionE
import android.view.ScaleGestureD
import android.view.V
import android.widget.ImageV
public class TouchImageView extends ImageView {
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
int viewWidth, viewH
static final int CLICK = 3;
float saveScale = 1f;
protected float origWidth, origH
int oldMeasuredWidth, oldMeasuredH
ScaleGestureDetector mScaleD
public TouchImageView(Context context) {
super(context);
sharedConstructing(context);
public TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
sharedConstructing(context);
private void sharedConstructing(Context context) {
super.setClickable(true);
this.context =
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix = new Matrix();
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
mScaleDetector.onTouchEvent(event);
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
last.set(curr);
start.set(last);
mode = DRAG;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float fixTransX = getFixDragTrans(deltaX, viewWidth, origWidth * saveScale);
float fixTransY = getFixDragTrans(deltaY, viewHeight, origHeight * saveScale);
matrix.postTranslate(fixTransX, fixTransY);
fixTrans();
last.set(curr.x, curr.y);
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff & CLICK && yDiff & CLICK)
performClick();
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
setImageMatrix(matrix);
invalidate();
// indicate event was handled
public void setMaxZoom(float x) {
maxScale =
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = detector.getScaleFactor();
float origScale = saveS
saveScale *= mScaleF
if (saveScale & maxScale) {
saveScale = maxS
mScaleFactor = maxScale / origS
} else if (saveScale & minScale) {
saveScale = minS
mScaleFactor = minScale / origS
if (origWidth * saveScale &= viewWidth || origHeight * saveScale &= viewHeight)
matrix.postScale(mScaleFactor, mScaleFactor, viewWidth / 2, viewHeight / 2);
matrix.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY());
fixTrans();
void fixTrans() {
matrix.getValues(m);
float transX = m[Matrix.MTRANS_X];
float transY = m[Matrix.MTRANS_Y];
float fixTransX = getFixTrans(transX, viewWidth, origWidth * saveScale);
float fixTransY = getFixTrans(transY, viewHeight, origHeight * saveScale);
if (fixTransX != 0 || fixTransY != 0)
matrix.postTranslate(fixTransX, fixTransY);
float getFixTrans(float trans, float viewSize, float contentSize) {
float minTrans, maxT
if (contentSize &= viewSize) {
minTrans = 0;
maxTrans = viewSize - contentS
minTrans = viewSize - contentS
maxTrans = 0;
if (trans & minTrans)
return -trans + minT
if (trans & maxTrans)
return -trans + maxT
float getFixDragTrans(float delta, float viewSize, float contentSize) {
if (contentSize &= viewSize) {
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
viewWidth = MeasureSpec.getSize(widthMeasureSpec);
viewHeight = MeasureSpec.getSize(heightMeasureSpec);
// Rescales image on rotation
if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight
|| viewWidth == 0 || viewHeight == 0)
oldMeasuredHeight = viewH
oldMeasuredWidth = viewW
if (saveScale == 1) {
//Fit to screen.
Drawable drawable = getDrawable();
if (drawable == null || drawable.getIntrinsicWidth() == 0 || drawable.getIntrinsicHeight() == 0)
int bmWidth = drawable.getIntrinsicWidth();
int bmHeight = drawable.getIntrinsicHeight();
Log.d("bmSize", "bmWidth: " + bmWidth + " bmHeight : " + bmHeight);
float scaleX = (float) viewWidth / (float) bmW
float scaleY = (float) viewHeight / (float) bmH
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
// Center the image
float redundantYSpace = (float) viewHeight - (scale * (float) bmHeight);
float redundantXSpace = (float) viewWidth - (scale * (float) bmWidth);
redundantYSpace /= (float) 2;
redundantXSpace /= (float) 2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = viewWidth - 2 * redundantXS
origHeight = viewHeight - 2 * redundantYS
setImageMatrix(matrix);
fixTrans();
然后在我们的Activity中就可以直接使用了：
public class TouchImageViewActivity extends Activity {
/** Called when the activity is first created. */
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TouchImageView img = (TouchImageView) findViewById(R.id.snoop);
img.setImageResource(R.drawable.snoopy);
img.setMaxZoom(4f);
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