ScaleGestureDetector funktioniert nicht über recyclerview

Question

Ich habe ein Projekt, wo ich eine RecyclerView mit ScaleGestureDetector zoomen muss. Es funktioniert, während Pinch Zoom außerhalb der RecyclerView aber nicht auf Pinching über RecyclerView arbeitet. Ich habe seit einiger Zeit darum gekämpft, das zu beheben, aber ich konnte es nicht lösen. Jede Hilfe wird sehr geschätzt. Danke im Voraus!!

Hier ist mein Java-Code

recyclerView.addOnItemTouchListener(new GalleryAdapter.RecyclerTouchListener(getApplicationContext(), recyclerView, new GalleryAdapter.ClickListener() { 
      @Override 
      public void onClick(View view, int position) { 
       Bundle bundle = new Bundle(); 
       bundle.putSerializable("images", images); 
       bundle.putInt("position", position); 

       FragmentTransaction ft = getSupportFragmentManager().beginTransaction(); 
       SlideshowDialogFragment newFragment = SlideshowDialogFragment.newInstance(); 
       newFragment.setArguments(bundle); 
       newFragment.show(ft, "slideshow"); 
      } 

      @Override 
      public void onLongClick(View view, int position) { 

      } 
     })); 

scaleGestureDetector = new ScaleGestureDetector(
       this, new MySimpleOnScaleGestureListener(textMsg, recyclerView, factor)); 

private class MySimpleOnScaleGestureListener 
      extends ScaleGestureDetector.SimpleOnScaleGestureListener{ 

     TextView viewMessage; 
     RecyclerView viewMyImage; 

     float factor; 

     public MySimpleOnScaleGestureListener(TextView v, RecyclerView iv ,float f) { 
      super(); 
      viewMessage = v; 
      viewMyImage = iv; 
      factor = f; 
     } 

     @Override 
     public boolean onScaleBegin(ScaleGestureDetector detector) { 
      //factor = 10.0f; 
      return true; 
      //return super.onScaleBegin(detector); 
     } 

     @Override 
     public boolean onScale(ScaleGestureDetector detector) { 

      float scaleFactor = detector.getScaleFactor() - 1; 
      factor += scaleFactor; 
      viewMessage.setText(String.valueOf(scaleFactor) 
        + "\n" + String.valueOf(factor)); 
      viewMyImage.setScaleX(factor); 
      viewMyImage.setScaleY(factor); 
      return true; 
      //return super.onScale(detector); 
     } 
    } 

Answer 1

Recycleview Gezoomte in & durch die Verwendung dieser Klasse gezoomt werden.

import android.content.Context; 
import android.graphics.Canvas; 
import android.support.annotation.NonNull; 
import android.support.v7.widget.RecyclerView; 
import android.util.AttributeSet; 
import android.view.MotionEvent; 
import android.view.ScaleGestureDetector; 


public class PinchRecyclerView extends RecyclerView { 
    private static final int INVALID_POINTER_ID = -1; 
    private int mActivePointerId = INVALID_POINTER_ID; 
    private ScaleGestureDetector mScaleDetector; 
    private float mScaleFactor = 1.f; 
    private float maxWidth = 0.0f; 
    private float maxHeight = 0.0f; 
    private float mLastTouchX; 
    private float mLastTouchY; 
    private float mPosX; 
    private float mPosY; 
    private float width; 
    private float height; 


    public PinchRecyclerView(Context context) { 
     super(context); 
     if (!isInEditMode()) 
      mScaleDetector = new ScaleGestureDetector(getContext(), new ScaleListener()); 
    } 

    public PinchRecyclerView(Context context, AttributeSet attrs) { 
     super(context, attrs); 
     if (!isInEditMode()) 
      mScaleDetector = new ScaleGestureDetector(getContext(), new ScaleListener()); 
    } 

    public PinchRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) { 
     super(context, attrs, defStyleAttr); 
     if (!isInEditMode()) 
      mScaleDetector = new ScaleGestureDetector(getContext(), new ScaleListener()); 
    } 

    @Override 
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
     width = MeasureSpec.getSize(widthMeasureSpec); 
     height = MeasureSpec.getSize(heightMeasureSpec); 
     super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
    } 

    @Override 
    public boolean onInterceptTouchEvent(MotionEvent ev) { 
     try { 
      return super.onInterceptTouchEvent(ev); 
     } catch (IllegalArgumentException ex) { 
      ex.printStackTrace(); 
     } 
     return false; 
    } 

    @Override 
    public boolean onTouchEvent(@NonNull MotionEvent ev) { 
     super.onTouchEvent(ev); 
     final int action = ev.getAction(); 
     mScaleDetector.onTouchEvent(ev); 
     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 = (action & MotionEvent.ACTION_POINTER_INDEX_MASK) 
         >> MotionEvent.ACTION_POINTER_INDEX_SHIFT; 
       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; 

       if (mPosX > 0.0f) 
        mPosX = 0.0f; 
       else if (mPosX < maxWidth) 
        mPosX = maxWidth; 

       if (mPosY > 0.0f) 
        mPosY = 0.0f; 
       else if (mPosY < maxHeight) 
        mPosY = maxHeight; 

       mLastTouchX = x; 
       mLastTouchY = y; 

       invalidate(); 
       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 = (action & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT; 
       final int pointerId = ev.getPointerId(pointerIndex); 
       if (pointerId == mActivePointerId) { 
        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(Canvas.MATRIX_SAVE_FLAG); 
     canvas.translate(mPosX, mPosY); 
     canvas.scale(mScaleFactor, mScaleFactor); 
     canvas.restore(); 
    } 

    @Override 
    protected void dispatchDraw(@NonNull Canvas canvas) { 
     canvas.save(Canvas.MATRIX_SAVE_FLAG); 
     if (mScaleFactor == 1.0f) { 
      mPosX = 0.0f; 
      mPosY = 0.0f; 
     } 
     canvas.translate(mPosX, mPosY); 
     canvas.scale(mScaleFactor, mScaleFactor); 
     super.dispatchDraw(canvas); 
     canvas.restore(); 
     invalidate(); 
    } 

    private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener { 
     @Override 
     public boolean onScale(ScaleGestureDetector detector) { 
      mScaleFactor *= detector.getScaleFactor(); 
      mScaleFactor = Math.max(1.0f, Math.min(mScaleFactor, 3.0f)); 
      maxWidth = width - (width * mScaleFactor); 
      maxHeight = height - (height * mScaleFactor); 
      invalidate(); 
      return true; 
     } 
    } 
} 

Hoffe es wird dir helfen !!