我复制了这种代码以使ImageView可滚动。
example.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
view.setScaleType(ImageView.ScaleType.MATRIX);
float scale;
dumpEvent(event);
//Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: //first finger down only
savedMatrix.set(matrix);
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
mode = NONE;
Log.d(TAG, "mode=NONE");
break;
case MotionEvent.ACTION_POINTER_DOWN: //first and second finger 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");
}
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); //create the transformation in the matrix of points
} else if (mode == ZOOM) {
//pinch zooming
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 10f) {
matrix.set(savedMatrix);
scale = newDist / oldDist; //setting the scaling of the matrix...
//if scale > 1 means zoom in
// if scale < 1 means zoom out
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
}
view.setImageMatrix(matrix); //display the transformation on screen
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 FloatMath.sqrt(x * x + y * y);
}
/*
* --------------------------------------------------------------------------
* Method: midPoint Parameters: PointF object, MotionEvent Returns: void
* Description: calculates the midpoint between the two fingers
* ------------------------------------------------------------
*/
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);
}
我必须在哪里设置变量来设置最大和最小缩放。
在片刻，我可以无限放大或缩小。
亲切的问候！
答案 0 :(得分：2)
您必须创建一个MIN_ZOOM，MAX_ZOOM，然后按如下方式缩放它：
private static final float MIN_ZOOM = 1.0f;
private static final float MAX_ZOOM = WHAT_YOU_WANT;
float scale = Math.max(MIN_ZOOM, Math.min(scale, MAX_ZOOM));
有关详细信息，请查看此answer
答案 1 :(得分：0)
您应该为总比例设置变量，因为您的比例只是当前比例和之前比例之间的差异。如果你完全超出范围，则规范你的本地规模。
// normalize scale
if (scale * scaleAll > MAX_ZOOM) {
scale = MAX_ZOOM / scaleAll;
}
if (scale * scaleAll < MIN_ZOOM) {
scale = MIN_ZOOM / scaleAll;
}
所有代码都是：
private static final float MIN_ZOOM = 0.1f;
private static final float MAX_ZOOM = 4f;
private float scaleAll = 1;
boolean someMethod() {
// Some code
example.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
view.setScaleType(ImageView.ScaleType.MATRIX);
float scale;
dumpEvent(event);
//Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: //first finger down only
savedMatrix.set(matrix);
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
mode = NONE;
Log.d(TAG, "mode=NONE");
break;
case MotionEvent.ACTION_POINTER_DOWN: //first and second finger 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");
}
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); //create the transformation in the matrix of points
} else if (mode == ZOOM) {
//pinch zooming
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 10f) {
scale = newDist / oldDist; //setting the scaling of the matrix...
// normalize scale
if (scale * scaleAll > MAX_ZOOM) {
scale = MAX_ZOOM / scaleAll;
}
if (scale * scaleAll < MIN_ZOOM) {
scale = MIN_ZOOM / scaleAll;
}
scaleAll*=scale;
matrix.set(savedMatrix);
//if scale > 1 means zoom in
// if scale < 1 means zoom out
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
}
view.setImageMatrix(matrix); //display the transformation on screen
return true; //indicate event was handled
}
}
}
答案 2 :(得分：0)
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); //create the transformation in the matrix of points
} else if (mode == ZOOM) {
//pinch zooming
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 10f) {
matrix.set(savedMatrix);
scale = newDist / oldDist; //setting the scaling of the matrix...
//if scale > 1 means zoom in
// if scale < 1 means zoom out
/ *在这里你可以添加像* /
这样的东西 if(scale >= 1 && scale < maxZoom || scale <1 && scale >= minZoom){
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
}
maxZoom = 5或您想要的任何值
minZoom = 0.25或您想要的任何值