Databases
StackOverflow2013
Postsdbo
POZoom and Panning ImageView Android
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POZoom and Panning ImageView Android
    primarykey
    data
    text
    <p>I have created a zoom and pan class for an ImageView.</p> <p>Features I am trying to create. - It pans on single finger touch and movement - It zooms and pans on two finger touch and movement</p> <p>For the most part this works very well. It has a slight bug when I do the following: - I pan around with one finger (Status: No problem) - I put down a second finger, zoom and pan (Status: No problem) - I release my second finger (Status: The image jumps a little)</p> <p>Was hoping someone could help me solve this.</p> <p>I am thinking that it must have to do with resetting the mLastTouchX and mLastTouchY in "case MotionEvent.ACTION_POINTER_UP"</p> <p>Any help would greatly be appreciated!</p> <pre><code>import android.content.Context; import android.graphics.Canvas; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.ScaleGestureDetector; import android.widget.ImageView; public class MyImageView extends ImageView { private static final int INVALID_POINTER_ID = -1; private float mPosX; private float mPosY; private float mLastTouchX; private float mLastTouchY; private float mLastGestureX; private float mLastGestureY; private int mActivePointerId = INVALID_POINTER_ID; private ScaleGestureDetector mScaleDetector; private float mScaleFactor = 1.f; public MyImageView(Context context, AttributeSet attrs) { this(context, attrs, 0); mScaleDetector = new ScaleGestureDetector(getContext(), new ScaleListener()); } 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 &amp; MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_DOWN: { if (!mScaleDetector.isInProgress()) { final float x = ev.getX(); final float y = ev.getY(); mLastTouchX = x; mLastTouchY = y; mActivePointerId = ev.getPointerId(0); } break; } case MotionEvent.ACTION_POINTER_1_DOWN: { if (mScaleDetector.isInProgress()) { final float gx = mScaleDetector.getFocusX(); final float gy = mScaleDetector.getFocusY(); mLastGestureX = gx; mLastGestureY = gy; } break; } case MotionEvent.ACTION_MOVE: { // Only move if the ScaleGestureDetector isn't processing a gesture. if (!mScaleDetector.isInProgress()) { final int pointerIndex = ev.findPointerIndex(mActivePointerId); final float x = ev.getX(pointerIndex); final float y = ev.getY(pointerIndex); final float dx = x - mLastTouchX; final float dy = y - mLastTouchY; mPosX += dx; mPosY += dy; invalidate(); mLastTouchX = x; mLastTouchY = y; } else{ final float gx = mScaleDetector.getFocusX(); final float gy = mScaleDetector.getFocusY(); final float gdx = gx - mLastGestureX; final float gdy = gy - mLastGestureY; mPosX += gdx; mPosY += gdy; invalidate(); mLastGestureX = gx; mLastGestureY = gy; } 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() &amp; MotionEvent.ACTION_POINTER_INDEX_MASK) &gt;&gt; MotionEvent.ACTION_POINTER_INDEX_SHIFT; final int pointerId = ev.getPointerId(pointerIndex); if (pointerId == mActivePointerId) { Log.d("DEBUG", "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) { canvas.save(); canvas.translate(mPosX, mPosY); if (mScaleDetector.isInProgress()) { canvas.scale(mScaleFactor, mScaleFactor, mScaleDetector.getFocusX(), mScaleDetector.getFocusY()); } else{ canvas.scale(mScaleFactor, mScaleFactor); } super.onDraw(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; } } } </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USHank
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POZoom and Panning ImageView Android
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POZoom and Panning ImageView Android
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POZoom and Panning ImageView Android
      1. USQuintin Balsdon
      1. VTFavorite
    1. COhm. Tried Your code and observed with small image that then I put second finger the image 'jumps' to it. Is it the bug You're refferring?
      singulars
      1. POZoom and Panning ImageView Android
      1. USsandrstar
    2. COYes, the jump is what I'm trying to solve.
      singulars
      1. POZoom and Panning ImageView Android
      1. USHank
    3. COLooks like it caused by usage of focus coordinates. Will try to debug the code today later.
      singulars
      1. POZoom and Panning ImageView Android
      1. USsandrstar
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload