Java 如何在android画布中使用双击事件保存当前图像
我有一个扩展视图的类,我可以将一个图像移动到另一个图像上。为此,我使用了两个位图图像,一个一个。现在我想使用双击事件保存图像,但我不知道如何执行此操作。有人对此有什么想法或代码吗? `公共类ShowCanvas扩展视图{Java 如何在android画布中使用双击事件保存当前图像,java,android,Java,Android,我有一个扩展视图的类,我可以将一个图像移动到另一个图像上。为此,我使用了两个位图图像,一个一个。现在我想使用双击事件保存图像,但我不知道如何执行此操作。有人对此有什么想法或代码吗? `公共类ShowCanvas扩展视图{ Bitmap CanvasBitmap; Bitmap ScaledBitmap; Bitmap smallbitmap; private static final int INVALID_POINTER_ID = -1; private Drawable mImage; p
Bitmap CanvasBitmap;
Bitmap ScaledBitmap;
Bitmap smallbitmap;
private static final int INVALID_POINTER_ID = -1;
private Drawable mImage;
private float mPosX;
private float mPosY;
private float mLastTouchX;
private float mLastTouchY;
private int mActivePointerId = INVALID_POINTER_ID;
private ScaleGestureDetector mScaleDetector;
private float mScaleFactor = 1.f;
public ShowCanvas(Context context) {
这个(上下文,null,0);
//TODO自动生成的构造函数存根
ScaledBitmap = DrawView.scaled;
mImage = new BitmapDrawable(getResources(), Dress.bitmap);
System.out.println("MImage" +mImage);
mImage.setBounds(0, 0, mImage.getIntrinsicWidth(),
mImage.getIntrinsicHeight());
}
public ShowCanvas(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public ShowCanvas(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
}
public void setBitmap(Bitmap bitmap) {
// TODO Auto-generated method stub
CanvasBitmap = bitmap;
System.out.println("CanvasBitmap" + CanvasBitmap);
int X = CanvasBitmap.getHeight();
int Y = CanvasBitmap.getWidth();
System.out.println("CanvasBitmap " + X + "\t" + Y);
}
@Override
public boolean isLongClickable() {
// TODO Auto-generated method stub
System.out.println("ISLongClickable");
return super.isLongClickable();
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
// Let the ScaleGestureDetector inspect all events.
mScaleDetector.onTouchEvent(ev);
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: {
final float x = ev.getX();
final float y = ev.getY();
mLastTouchX = x;
mLastTouchY = y;
mActivePointerId = ev.getPointerId(0);
break;
}
case MotionEvent.ACTION_MOVE: {
final int pointerIndex = ev.findPointerIndex(mActivePointerId);
final float x = ev.getX(pointerIndex);
final float y = ev.getY(pointerIndex);
// Only move if the ScaleGestureDetector isn't processing a
// gesture.
if (!mScaleDetector.isInProgress()) {
final float dx = x - mLastTouchX;
final float dy = y - mLastTouchY;
mPosX += dx;
mPosY += dy;
invalidate();
}
mLastTouchX = x;
mLastTouchY = y;
break;
}
case MotionEvent.ACTION_UP: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_CANCEL: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_POINTER_UP: {
final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId) {
// This was our active pointer going up. Choose a new
// active pointer and adjust accordingly.
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mLastTouchX = ev.getX(newPointerIndex);
mLastTouchY = ev.getY(newPointerIndex);
mActivePointerId = ev.getPointerId(newPointerIndex);
}
break;
}
}
return true;
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
Paint mpaint = new Paint();
canvas.save();
canvas.drawBitmap(ScaledBitmap, 0, 0, mpaint);
Log.d("DEBUG", "X: " + mPosX + " Y: " + mPosY);
canvas.translate(mPosX, mPosY);
canvas.scale(mScaleFactor, mScaleFactor);
mImage.draw(canvas);
canvas.restore();
}
private class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScale(ScaleGestureDetector detector) {
mScaleFactor *= detector.getScaleFactor();
// Don't let the object get too small or too large.
mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 10.0f));
invalidate();
return true;
}
}
}`如果您是指双击,则必须使用GestureDetector.OnDoubleTapListener。检查这个 试试这个
public class MyView extends View {
GestureDetector gestureDetector;
public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
// creating new gesture detector
gestureDetector = new GestureDetector(context, new GestureListener());
}
// skipping measure calculation and drawing
// delegate the event to the gesture detector
@Override
public boolean onTouchEvent(MotionEvent e) {
return gestureDetector.onTouchEvent(e);
}
private class GestureListener extends GestureDetector.SimpleOnGestureListener {
@Override
public boolean onDown(MotionEvent e) {
return true;
}
// event when double tap occurs
@Override
public boolean onDoubleTap(MotionEvent e) {
float x = e.getX();
float y = e.getY();
Log.d("Double Tap", "Tapped at: (" + x + "," + y + ")");
return true;
}
}
}
对不起,我用了这个,但它不起作用。。我也不知道在哪里使用这个…最好是使用长时间的按压。或者你已经在用它做其他的事情了?长按比双按的优势:长按是UI指南中推荐的交互方式,而双按则不是。这是用户的期望;用户可能找不到双击操作,因为他们不会去寻找它,因为它已经在API中处理过了。实现双触会影响单触的处理,因为在处理之前,您必须等待每一次触摸是否都变成双触。