CustomVIew(MyView)에서 TouchEvent(Move, Zoom in/out)

처음에 직접 하다가 zoom에서 막혔는데,

stackover flow보니까 잘 설명해놓은게 있네요 ㅎㅎ

영어만 있길래 한글로 옮겼습니다.

MainActivity

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public class MainActivity extends Activity {       @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(new TouchExampleView(this,null,0));     }       @Override     public boolean onCreateOptionsMenu(Menu menu) {         // Inflate the menu; this adds items to the action bar if it is present.         getMenuInflater().inflate(R.menu.main, menu);         return true;     }   }

TouchExampleView

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public class TouchExampleView extends View {     private Drawable mIcon;     private float mPosX;     private float mPosY;       private float mLastTouchX;     private float mLastTouchY;       private static final int INVALID_POINTER_ID = -1;     private ScaleGestureDetector mScaleDetector;     private float mScaleFactor = 1.f;       // The ‘active pointer’ is the one currently moving our object.     private int mActivePointerId = INVALID_POINTER_ID;       public TouchExampleView(Context context) {         this(context, null, 0);     }       public TouchExampleView(Context context, AttributeSet attrs) {         this(context, attrs, 0);     }       public TouchExampleView(Context context, AttributeSet attrs, int defStyle) {         super(context, attrs, defStyle);         mIcon = context.getResources().getDrawable(R.drawable.ic_launcher);         mIcon.setBounds(0, 0, mIcon.getIntrinsicWidth(),                 mIcon.getIntrinsicHeight());         mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());     }       @Override     public void onDraw(Canvas canvas) {         super.onDraw(canvas);           canvas.save();         canvas.translate(mPosX, mPosY);         canvas.scale(mScaleFactor, mScaleFactor);         mIcon.draw(canvas);         canvas.restore();     }       @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;     }       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, 5.0f));               invalidate();             return true;         }     } }