Android Open Source - RatioImageView Ratio Image View

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License

The source code is released under:

This is free and unencumbered software released into the public domain. Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a co...

Java Source Code

package com.alimuzaffar.ratioimageview;
//ww  w . j a  va2 s.  c om
import java.util.HashMap;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.widget.ImageView;

/**
 * An image view which retains the aspect ratio of the image (makes width match
 * height)
 */
final class RatioImageView extends ImageView {

  private static HashMap<String, DimenPair> mDimenCache = new HashMap<String, DimenPair>();
  
  private String groupId = null;
  private boolean adjustWidth = false;
  
  int cachedWidth = 0;
  int cachedHeight = 0;

  public RatioImageView(Context context) {
    super(context);
  }

  public RatioImageView(Context context, AttributeSet attrs) {
    super(context, attrs);
    
    TypedArray a = context.obtainStyledAttributes(attrs,
          R.styleable.RatioImageView);
       
      final int N = a.getIndexCount();
      for (int i = 0; i < N; ++i)
      {
          int attr = a.getIndex(i);
          switch (attr)
          {
              case R.styleable.RatioImageView_groupId:
                  groupId = a.getString(attr);
                  break;
              case R.styleable.RatioImageView_adjustWidth:
                adjustWidth = a.getBoolean(attr, adjustWidth);
                break;
          }
      }
      a.recycle();

  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    
    if (cachedWidth == 0 && cachedHeight == 0 && groupId != null) {
      if(mDimenCache.containsKey(groupId)) {
        Log.d("RatioImageView", "Using Group Cache. Group Id="+groupId);
        DimenPair pair = mDimenCache.get(groupId);
        cachedWidth = pair.width;
        cachedHeight = pair.height;
        setMeasuredDimension(cachedWidth, cachedHeight);
        return;
      }
    } 
    
    if (cachedWidth > 0 && cachedHeight > 0) {
      Log.d("RatioImageView", "Using Cache. Group Id="+groupId);
      setMeasuredDimension(cachedWidth, cachedHeight);
      return;
    }
    
    Drawable d = getDrawable();
    if (d != null) {
      Log.d("RatioImageView", "Setting size. Group Id="+groupId);
      float ratio = (float) getMeasuredWidth() / (float) d.getIntrinsicWidth();
      int imgHeight = (int) (d.getIntrinsicHeight() * ratio);
      int imgWidth = (int) (d.getIntrinsicWidth() * ratio);
      if(adjustWidth) {
        cachedWidth = imgWidth;
        cachedHeight = getMeasuredHeight();
      } else {
        cachedWidth = getMeasuredWidth();
        cachedHeight = imgHeight;
      }
      setMeasuredDimension(cachedWidth, cachedHeight);
        
      if(groupId != null) {
        addToCache();
      }
    } else {
      setMeasuredDimension(getMeasuredWidth(), getMeasuredWidth());
    }
  }
  
  private void addToCache() {
    mDimenCache.put(groupId, new DimenPair(cachedWidth, cachedHeight));
  }
  
  /***
   * Change the groupId for this image view. This will trigger recalculation of dimensions.
   * 
   * @param groupId String any string or null.
   */
  public void setGroupId(String groupId) {
    if(groupId != null) {
      mDimenCache.remove(groupId);
    }
    this.groupId = groupId;
    cachedWidth = 0;
    cachedHeight = 0;
  }
  
  /***
   * Default: false. If set to true, we will adjust the width to maintain aspect ration instead of the height.
   * 
   * @param adjustWidth
   */
  public void setAdjustWidth(boolean adjustWidth) {
    this.adjustWidth = adjustWidth;
    cachedWidth = 0;
    cachedHeight = 0;
    if(groupId != null) {
      mDimenCache.remove(groupId);
    }
  }
  
  private class DimenPair {
    public DimenPair(int w, int h) {
      this.width = w;
      this.height = h;
    }
    int width;
    int height;
  }
}

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