我正在创建一个 android 应用程序，我正在缩放 ImageView [捏缩放(带有图像转换)]，而且我还必须用两个手指移动来旋转 ImageView只要。因为我想通过单指移动来翻译图像 [滚动]。当我没有添加旋转代码时，捏缩放和平移工作得很好，但是在添加旋转编码图像后，单指移动时图像会旋转并且不会平移。我想检查一下，每当用户在 ImageView 上移动两根手指时，Image 应该旋转，否则不会旋转，这样 Image 翻译就不会受到干扰.如何实现？
这是我的代码。任何帮助将不胜感激
public class CustomizedImageView extends ImageView {
Matrix 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 last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;
int viewWidth, viewHeight;
static final int CLICK = 3;
float saveScale = 1f;
protected float origWidth, origHeight;
int oldMeasuredWidth, oldMeasuredHeight;
ScaleGestureDetector mScaleDetector;
Context context;
float viewRotation;
double fingerRotation;
double newFingerRotation;
public CustomizedImageView(Context context) {
super(context);
sharedConstructing(context);
}
public CustomizedImageView(Context context, AttributeSet attrs) {
super(context, attrs);
sharedConstructing(context);
}
private void sharedConstructing(Context context) {
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix = new Matrix();
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
mScaleDetector.onTouchEvent(event);
PointF curr = new PointF(event.getX(), event.getY());
final float x = event.getX();
final float y = event.getY();
final float new_x = getWidth() / 2;
final float new_y = getHeight() / 2;
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
//Follwing Statements are to TRANSLATE(SCROLL) IMAGE
//*************************************************************************
last.set(curr);
start.set(last);
mode = DRAG;
//*************************************************************************
//Follwing Statements are to ROTATE IMAGE With Finger Movement
viewRotation = getRotation();
fingerRotation = Math.toDegrees(Math.atan2(x - new_x, new_y - y));
//*************************************************************************
break;
case MotionEvent.ACTION_MOVE:
//Follwing Statements are to TRANSLATE(SCROLL) IMAGE
//*************************************************************************
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);
//**********************************************************************
//Follwing Statements are to ROTATE IMAGE With Finger Movement
newFingerRotation = Math.toDegrees(Math.atan2(x - new_x, new_y - y));
setRotation((float) (viewRotation + newFingerRotation - fingerRotation));
//*************************************************************************
}
break;
case MotionEvent.ACTION_UP:
//Follwing Statements are to TRANSLATE(SCROLL) IMAGE
//*************************************************************************
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();
//*************************************************************************
//Follwing Statements are to ROTATE IMAGE With Finger Movement
fingerRotation = newFingerRotation = 0.0f;
//*************************************************************************
break;
case MotionEvent.ACTION_POINTER_UP:
//Follwing Statements are to TRANSLATE(SCROLL) IMAGE
//*************************************************************************
mode = NONE;
//*************************************************************************
break;
}
setImageMatrix(matrix);
invalidate();
return true; // indicate event was handled
}
});
}
public void setMaxZoom(float x) {
maxScale = x;
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = detector.getScaleFactor();
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale) {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
} else if (saveScale < minScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
if (origWidth * saveScale <= viewWidth || origHeight * saveScale <= viewHeight)
matrix.postScale(mScaleFactor, mScaleFactor, viewWidth / 2, viewHeight / 2);
else
matrix.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY());
fixTrans();
return true;
}
}
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, maxTrans;
if (contentSize <= viewSize) {
minTrans = 0;
maxTrans = viewSize - contentSize;
} else {
minTrans = viewSize - contentSize;
maxTrans = 0;
}
if (trans < minTrans)
return -trans + minTrans;
if (trans > maxTrans)
return -trans + maxTrans;
return 0;
}
float getFixDragTrans(float delta, float viewSize, float contentSize) {
if (contentSize <= viewSize) {
return 0;
}
return delta;
}
@Override
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)
return;
oldMeasuredHeight = viewHeight;
oldMeasuredWidth = viewWidth;
if (saveScale == 1) {
//Fit to screen.
float scale;
Drawable drawable = getDrawable();
if (drawable == null || drawable.getIntrinsicWidth() == 0 || drawable.getIntrinsicHeight() == 0)
return;
int bmWidth = drawable.getIntrinsicWidth();
int bmHeight = drawable.getIntrinsicHeight();
Log.d("bmSize", "bmWidth: " + bmWidth + " bmHeight : " + bmHeight);
float scaleX = (float) viewWidth / (float) bmWidth;
float scaleY = (float) viewHeight / (float) bmHeight;
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 * redundantXSpace;
origHeight = viewHeight - 2 * redundantYSpace;
setImageMatrix(matrix);
}
fixTrans();
}
最佳答案
MotionEvent 参数具有每个事件的“指针”(即手指)的数量。
所以 MotionEvent.getPointerCount() 是你的 friend 。
https://developer.android.com/reference/android/view/MotionEvent.html#getPointerCount
关于android - 如何在android中检测单指触摸和两指触摸？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/40122856/