[ANDROID] 터치 이벤트와 캔버스의 이미지

터치 이벤트와 캔버스의 이미지

해결법

1. ---

   1.당신은이를 사용할 수 있습니다 :

   당신은이를 사용할 수 있습니다 :

   import android.content.Context;
   import android.graphics.Canvas;
   import android.graphics.drawable.BitmapDrawable;
   import android.util.AttributeSet;
   import android.util.Log;
   import android.view.MotionEvent;
   import android.view.ScaleGestureDetector;
   import android.view.View;
   
   public class MyImageView extends View {
   
   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 MyImageView(Context context) {
           this(context, null, 0);
       mImage = getResources().getDrawable(R.drawable.imagename);
   
           mImage.setBounds(0, 0, mImage.getIntrinsicWidth(), mImage.getIntrinsicHeight());
       }
   
       public MyImageView(Context context, AttributeSet attrs) {
           this(context, attrs, 0);
       }
   
       public MyImageView(Context context, AttributeSet attrs, int defStyle) {
           super(context, attrs, defStyle);
           mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
       }
   
       @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
       public void onDraw(Canvas canvas) {
           super.onDraw(canvas);
   
           canvas.save();
           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;
           }
       }
   
   }
   

from https://stackoverflow.com/questions/5743328/image-in-canvas-with-touch-events by cc-by-sa and MIT license