PhotoViewAttacher.java 文件源码

private void checkImageViewScaleType() {
    ImageView imageView = getImageView();

    /**
     * PhotoView's getScaleType() will just divert to this.getScaleType() so
     * only call if we're not attached to a PhotoView.
     */
    if (null != imageView && !(imageView instanceof IPhotoView)) {
        if (!ScaleType.MATRIX.equals(imageView.getScaleType())) {
            throw new IllegalStateException(
                    "The ImageView's ScaleType has been changed since attaching a PhotoViewAttacher");
        }
    }
}