我正在尝试一个 Android 应用程序，在其中标记用户长按的点。对于触敏图像视图，我使用了这里的大部分代码： http ://android-developers.blogspot.in/2010/06/making-sense-of-multitouch.html http://developer.android .com/training/gestures/scale.html 以及来自 stackoverflow 中各种帖子的一些建议。这是触摸图像视图的代码：
public class SimpleImageView extends ImageView implements OnTouchListener,OnGestureListener {
public HashMap<meeCoordinates, Integer> plotPointsMap = new HashMap<meeCoordinates, Integer>();
private float mPosX = 0f;
private float mPosY = 0f;
private boolean didLongPress = false;
private float mLastTouchX;
private float mLastTouchY;
private float magicX;
private float magicY;
private static final int INVALID_POINTER_ID = -1;
Context context;
Canvas canvas;
private GestureDetector gestureScanner;
int deviceWidth, deviceHeight;
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;
String savedItemClicked;
private int mActivePointerId = INVALID_POINTER_ID;
public SimpleTouchImageView(Context ctx) {
// The ‘active pointer’ is the one currently moving our object.
this(ctx, null, 0);
this.context = ctx;
}
public SimpleTouchImageView(Context ctx, AttributeSet attrs) {
this(ctx, attrs, 0);
this.context = ctx;
}
private ScaleGestureDetector mScaleDetector;
private float mScaleFactor = 1.f;
public SimpleTouchImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// Create our ScaleGestureDetector
if (!this.isInEditMode()) {
mScaleDetector = new ScaleGestureDetector(context,new ScaleListener());
}
gestureScanner = new GestureDetector(context, this);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if (mScaleDetector != null) {
mScaleDetector.onTouchEvent(ev);
}
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: {
Log.d(TAG, "onTouchEvent MotionEvent.ACTION_DOWN");
final float x = ev.getX();
final float y = ev.getY();
// Set them to the X, Y at the beginning of the touch event
mLastTouchX = x;
mLastTouchY = y;
mActivePointerId = ev.getPointerId(0);
// _handler.postDelayed(_longPressed, LONG_PRESS_TIME);
break;
}
case MotionEvent.ACTION_MOVE: {
// _handler.removeCallbacks(_longPressed);
final int pointerIndex = ev.findPointerIndex(mActivePointerId);
final float x = ev.getX(pointerIndex);
final float y = ev.getY(pointerIndex);
if (mScaleDetector != null) {
if (!mScaleDetector.isInProgress()) {
// Calculate the distance moved
final float dx = x - mLastTouchX;
final float dy = y - mLastTouchY;
// Move the object
mPosX += dx;
mPosY += dy;
// Remember this touch position for the next move event
mLastTouchX = x;
mLastTouchY = y;
invalidate();
}
}
mLastTouchX = x;
mLastTouchY = y;
break;
}
case MotionEvent.ACTION_UP: {
// _handler.removeCallbacks(_longPressed);
mActivePointerId = INVALID_POINTER_ID;
// Calculate the Actual X & Y
Drawable drawable = this.getDrawable();
Rect imageBounds = drawable.getBounds();
int intrinsicHeight = this.getDrawable().getIntrinsicHeight();
int intrinsicWidth = this.getDrawable().getIntrinsicWidth();
int imageOffsetX = (int) (ev.getX() - imageBounds.left);
int imageOffsetY = (int) (ev.getY() - imageBounds.top);
float[] f = newfloat[9];
this.getImageMatrix().getValues(f);
final float scaleX = f[Matrix.MSCALE_X];
final float scaleY = f[Matrix.MSCALE_Y];
final int actualWd = Math.round(intrinsicWidth * mScaleFactor);
final int actualHt = Math.round(intrinsicHeight * mScaleFactor);
// CALCULATE THE X,Y COORDINATES CORRESPONDING TO THE POINT OF TOUCH
// IN THE ACTUAL IMAGE,
magicX = ((ev.getX() + (-1 * mPosX)) / mScaleFactor);
magicY = ((ev.getY() + (-1 * mPosY)) / mScaleFactor);
mLastTouchX = ev.getX();
mLastTouchY = ev.getY();
if (didLongPress == true) {
// STORE THE Point where user did long press IN AN ARRAY
plotPointsMap.put ( coordinates, marker );
invalidate();
didLongPress = false;
}
break;
}
case MotionEvent.ACTION_CANCEL: {
// _handler.removeCallbacks(_longPressed);
Log.d(TAG, "onTouchEvent MotionEvent.ACTION_CANCEL");
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_POINTER_UP: {
// _handler.removeCallbacks(_longPressed);
Log.d(TAG, "onTouchEvent MotionEvent.ACTION_POINTER_UP");
break;
}
}
// return true;
return gestureScanner.onTouchEvent(ev);
}
/** Determine the space between the first two fingers */
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);
}
/** Calculate the mid point of the first 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);
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
}
@Override
public void onDraw(Canvas canvas) {
WindowManager wm = (WindowManager) this.context.getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
DisplayMetrics metrics = new DisplayMetrics();
wm.getDefaultDisplay().getMetrics(metrics);
deviceWidth = metrics.widthPixels;
deviceHeight = metrics.heightPixels;
canvas.drawRect(0, 0, getWidth(), getHeight(), backgroundPaint);
if (this.getDrawable() != null) {
canvas.save();
canvas.translate(mPosX, mPosY);
Matrix matrix = new Matrix();
matrix.postScale(mScaleFactor, mScaleFactor, pivotPointX,pivotPointY);
canvas.drawBitmap(((BitmapDrawable) this.getDrawable()).getBitmap(), matrix,null);
// ---add the marker---
if ((plotPointsMap != null) && (plotPointsMap.size() > 0)) {
for (int index = 0; index < plotPointsMap.size(); index++) {
Set<MyCoordinates> setCoordinates = plotPointsMap.keySet();
if ((setCoordinates != null) && (setCoordinates.size() > 0)) {
Iterator<MyCoordinates> setIterator =setCoordinates.iterator();
if (setIterator != null) {
while (setIterator.hasNext()) {
MyCoordinates coordinates = setIterator.next();
int resource = plotPointsMap.get(coordinates).intValue();
int resourceId = R.drawable.location_marker;
Bitmap marker = BitmapFactory.decodeResource(getResources(), resourceId);
float xCoordinate = coordinates.getCoordinateX();
float yCoordinate = coordinates.getCoordinateY();
canvas.drawBitmap(marker, xCoordinate * mScaleFactor, yCoordinate * mScaleFactor, null);
}
}
}
}
}
canvas.restore();
}
}
@Override
public void setImageDrawable(Drawable drawable) {
// Constrain to given size but keep aspect ratio
int width = drawable.getIntrinsicWidth();
int height = drawable.getIntrinsicHeight();
mLastTouchX = mPosX = 0;
mLastTouchY = mPosY = 0;
mScaleFactor = Math.min((float) getLayoutParams().width/ width, (float) getLayoutParams().height/ height);
pivotPointX = ((float) getLayoutParams().width - (int) (width * mScaleFactor)) / 2;
pivotPointY = ((float) getLayoutParams().height - (int) (height * mScaleFactor)) / 2;
super.setImageDrawable(drawable);
}
float pivotPointX = 0f;
float pivotPointY = 0f;
...
...
}
问题 让我们暂时搁置缩放。比如说，图像以其实际大小加载。用户触摸的点被正确记录。比如说，如果用户在 x=120 和 y=50 的情况下触摸 (120, 50)，那么它会正确检测为 (120, 50)。我将点存储在一个数组中并在每个点重新绘制一个标记
public void onDraw(Canvas canvas)
问题是当标记被绘制在该点时（我在 onDraw(canvas) 中打印它），标记被绘制在离实际点大约 30px 的地方。即如果实际 (x,y) 为 (120,50)，则标记图像将绘制在大约 (150,80) 处。总是有这个 30px 的差异。为什么是这样？自从过去两周徒劳无功以来，我一直在这件事上头破血流。有人可以帮忙吗？
这是一张以蓝色显示触摸点的图像（在“US”中的字母“S”上方），您可以看到黑色标记正在从触摸点上移开：
编辑 当我平移图像时， inverse.mapPoints() 不考虑图像远离屏幕的偏移量。比如这里是App启动时的图片，这是加载的图片
当用户平移时，图像可能会移到屏幕边缘的左侧，如下所示：
在这种情况下， inverse.mapPoints() 只返回屏幕边缘的值，但我想要原始图像边缘的值。我该怎么做？我尝试了谷歌搜索并尝试了stackoverflow中给出的一些东西（如getTop（）和getLocationOnscreen（））但徒劳无功。
你能帮我吗？