Androidスタジオ：ズーム可能画像ビュー

Question

imageviewをAndroidスタジオで作成するにはzoomableproperties？

Answer 1

..ズームのためのこのイメージビューを使用

import android.content.Context; 
import android.graphics.Matrix; 
import android.graphics.PointF; 
import android.graphics.drawable.Drawable; 
import android.util.AttributeSet; 
import android.util.Log; 
import android.view.MotionEvent; 
import android.view.ScaleGestureDetector; 
import android.view.View; 
import android.widget.ImageView; 

public class TouchImageView extends ImageView { 

Matrix matrix; 

// We can be in one of these 3 states 
static final int NONE = 0; 
static final int DRAG = 1; 
static final int ZOOM = 2; 
int mode = NONE; 

// Remember some things for zooming 
PointF last = new PointF(); 
PointF start = new PointF(); 
float minScale = 1f; 
float maxScale = 3f; 
float[] m; 

int viewWidth, viewHeight; 
static final int CLICK = 3; 
float saveScale = 1f; 
protected float origWidth, origHeight; 
int oldMeasuredWidth, oldMeasuredHeight; 

ScaleGestureDetector mScaleDetector; 

Context context; 

public TouchImageView(Context context) { 
    super(context); 
    sharedConstructing(context); 
} 

public TouchImageView(Context context, AttributeSet attrs) { 
    super(context, attrs); 
    sharedConstructing(context); 
} 

private void sharedConstructing(Context context) { 
    super.setClickable(true); 
    this.context = context; 
    mScaleDetector = new ScaleGestureDetector(context, new ScaleListener()); 
    matrix = new Matrix(); 
    m = new float[9]; 
    setImageMatrix(matrix); 
    setScaleType(ScaleType.MATRIX); 

    setOnTouchListener(new OnTouchListener() { 

     @Override 
     public boolean onTouch(View v, MotionEvent event) { 
      mScaleDetector.onTouchEvent(event); 
      PointF curr = new PointF(event.getX(), event.getY()); 

      switch (event.getAction()) { 
      case MotionEvent.ACTION_DOWN: 
       last.set(curr); 
       start.set(last); 
       mode = DRAG; 
       break; 

      case MotionEvent.ACTION_MOVE: 
       if (mode == DRAG) { 
        float deltaX = curr.x - last.x; 
        float deltaY = curr.y - last.y; 
        float fixTransX = getFixDragTrans(deltaX, viewWidth, 
          origWidth * saveScale); 
        float fixTransY = getFixDragTrans(deltaY, viewHeight, 
          origHeight * saveScale); 
        matrix.postTranslate(fixTransX, fixTransY); 
        fixTrans(); 
        last.set(curr.x, curr.y); 
       } 
       break; 

      case MotionEvent.ACTION_UP: 
       mode = NONE; 
       int xDiff = (int) Math.abs(curr.x - start.x); 
       int yDiff = (int) Math.abs(curr.y - start.y); 
       if (xDiff < CLICK && yDiff < CLICK) 
        performClick(); 
       break; 

      case MotionEvent.ACTION_POINTER_UP: 
       mode = NONE; 
       break; 
      } 

      setImageMatrix(matrix); 
      invalidate(); 
      return true; // indicate event was handled 
     } 

    }); 
} 

public void setMaxZoom(float x) { 
    maxScale = x; 
} 

private class ScaleListener extends 
     ScaleGestureDetector.SimpleOnScaleGestureListener { 
    @Override 
    public boolean onScaleBegin(ScaleGestureDetector detector) { 
     mode = ZOOM; 
     return true; 
    } 

    @Override 
    public boolean onScale(ScaleGestureDetector detector) { 
     float mScaleFactor = detector.getScaleFactor(); 
     float origScale = saveScale; 
     saveScale *= mScaleFactor; 
     if (saveScale > maxScale) { 
      saveScale = maxScale; 
      mScaleFactor = maxScale/origScale; 
     } else if (saveScale < minScale) { 
      saveScale = minScale; 
      mScaleFactor = minScale/origScale; 
     } 

     if (origWidth * saveScale <= viewWidth 
       || origHeight * saveScale <= viewHeight) 
      matrix.postScale(mScaleFactor, mScaleFactor, viewWidth/2, 
        viewHeight/2); 
     else 
      matrix.postScale(mScaleFactor, mScaleFactor, 
        detector.getFocusX(), detector.getFocusY()); 

     fixTrans(); 
     return true; 
    } 
} 

void fixTrans() { 
    matrix.getValues(m); 
    float transX = m[Matrix.MTRANS_X]; 
    float transY = m[Matrix.MTRANS_Y]; 

    float fixTransX = getFixTrans(transX, viewWidth, origWidth * saveScale); 
    float fixTransY = getFixTrans(transY, viewHeight, origHeight 
      * saveScale); 

    if (fixTransX != 0 || fixTransY != 0) 
     matrix.postTranslate(fixTransX, fixTransY); 
} 

float getFixTrans(float trans, float viewSize, float contentSize) { 
    float minTrans, maxTrans; 

    if (contentSize <= viewSize) { 
     minTrans = 0; 
     maxTrans = viewSize - contentSize; 
    } else { 
     minTrans = viewSize - contentSize; 
     maxTrans = 0; 
    } 

    if (trans < minTrans) 
     return -trans + minTrans; 
    if (trans > maxTrans) 
     return -trans + maxTrans; 
    return 0; 
} 

float getFixDragTrans(float delta, float viewSize, float contentSize) { 
    if (contentSize <= viewSize) { 
     return 0; 
    } 
    return delta; 
} 

@Override 
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
    super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
    viewWidth = MeasureSpec.getSize(widthMeasureSpec); 
    viewHeight = MeasureSpec.getSize(heightMeasureSpec); 

    // 
    // Rescales image on rotation 
    // 
    if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight 
      || viewWidth == 0 || viewHeight == 0) 
     return; 
    oldMeasuredHeight = viewHeight; 
    oldMeasuredWidth = viewWidth; 

    if (saveScale == 1) { 
     // Fit to screen. 
     float scale; 

     Drawable drawable = getDrawable(); 
     if (drawable == null || drawable.getIntrinsicWidth() == 0 
       || drawable.getIntrinsicHeight() == 0) 
      return; 
     int bmWidth = drawable.getIntrinsicWidth(); 
     int bmHeight = drawable.getIntrinsicHeight(); 

     Log.d("bmSize", "bmWidth: " + bmWidth + " bmHeight : " + bmHeight); 

     float scaleX = (float) viewWidth/(float) bmWidth; 
     float scaleY = (float) viewHeight/(float) bmHeight; 
     scale = Math.min(scaleX, scaleY); 
     matrix.setScale(scale, scale); 

     // Center the image 
     float redundantYSpace = (float) viewHeight 
       - (scale * (float) bmHeight); 
     float redundantXSpace = (float) viewWidth 
       - (scale * (float) bmWidth); 
     redundantYSpace /= (float) 2; 
     redundantXSpace /= (float) 2; 

     matrix.postTranslate(redundantXSpace, redundantYSpace); 

     origWidth = viewWidth - 2 * redundantXSpace; 
     origHeight = viewHeight - 2 * redundantYSpace; 
     setImageMatrix(matrix); 
    } 
    fixTrans(); 
} 
}