ImageAware的具体实现。
对ImageView的包装。
源码：
/** * Wrapper for Android {@link android.widget.ImageView ImageView}. Keeps weak reference of ImageView to prevent memory * leaks. * * @author Sergey Tarasevich (nostra13[at]gmail[dot]com) * @since 1.9.0 */ public class ImageViewAware extends ViewAware { /** * Constructor. <br /> * References {@link #ImageViewAware(android.widget.ImageView, boolean) ImageViewAware(imageView, true)}. * * @param imageView {@link android.widget.ImageView ImageView} to work with */ public ImageViewAware(ImageView imageView) { super(imageView); } /** * Constructor * * @param imageView {@link android.widget.ImageView ImageView} to work with * @param checkActualViewSize <b>true</b> - then {@link #getWidth()} and {@link #getHeight()} will check actual * size of ImageView. It can cause known issues like * <a href="https://github.com/nostra13/Android-Universal-Image-Loader/issues/376">this</a>. * But it helps to save memory because memory cache keeps bitmaps of actual (less in * general) size. * <p/> * <b>false</b> - then {@link #getWidth()} and {@link #getHeight()} will <b>NOT</b> * consider actual size of ImageView, just layout parameters. <br /> If you set 'false' * it's recommended 'android:layout_width' and 'android:layout_height' (or * 'android:maxWidth' and 'android:maxHeight') are set with concrete values. It helps to * save memory. * <p/> */ public ImageViewAware(ImageView imageView, boolean checkActualViewSize) { super(imageView, checkActualViewSize); } /** * {@inheritDoc} * <br /> * 3) Get <b>maxWidth</b>. */ @Override public int getWidth() {//完善获取imageView大小的方式 int width = super.getWidth(); if (width <= 0) { ImageView imageView = (ImageView) viewRef.get(); if (imageView != null) { width = getImageViewFieldValue(imageView, "mMaxWidth"); // Check maxWidth parameter } } return width; } /** * {@inheritDoc} * <br /> * 3) Get <b>maxHeight</b> */ @Override public int getHeight() { int height = super.getHeight(); if (height <= 0) { ImageView imageView = (ImageView) viewRef.get(); if (imageView != null) { height = getImageViewFieldValue(imageView, "mMaxHeight"); // Check maxHeight parameter } } return height; } @Override public ViewScaleType getScaleType() { ImageView imageView = (ImageView) viewRef.get(); if (imageView != null) { return ViewScaleType.fromImageView(imageView);//依据imageView而定的缩放模式，将imageview的缩放模式归纳为两种 } return super.getScaleType(); } @Override public ImageView getWrappedView() { return (ImageView) super.getWrappedView(); } @Override protected void setImageDrawableInto(Drawable drawable, View view) { ((ImageView) view).setImageDrawable(drawable); if (drawable instanceof AnimationDrawable) { ((AnimationDrawable)drawable).start(); } } @Override protected void setImageBitmapInto(Bitmap bitmap, View view) { ((ImageView) view).setImageBitmap(bitmap); } private static int getImageViewFieldValue(Object object, String fieldName) { int value = 0; try { Field field = ImageView.class.getDeclaredField(fieldName); field.setAccessible(true); int fieldValue = (Integer) field.get(object); if (fieldValue > 0 && fieldValue < Integer.MAX_VALUE) { value = fieldValue; } } catch (Exception e) { L.e(e); } return value; } }