Android显示大图长图不模糊的方法

1.用到的库：

glide：github.com/bumptech/gl…
SubsamplingScaleImageView: github.com/davemorriss…

2.使用方法：

先使用Glide异步下载图片，再用SubsamplingScaleImageView无损显示大图

fun loadLargeImage(context: Context, res: String, imageView: SubsamplingScaleImageView) {
    imageView.isQuickScaleEnabled = true
    imageView.maxScale = 15F;
    imageView.isZoomEnabled = true;
    imageView.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CUSTOM)

    Glide.with(context).asFile().load(res).into(object : CustomTarget<File?>() {

        override fun onResourceReady(resource: File, glideAnimation: Transition<in File?>?) {
            val sWidth = BitmapFactory.decodeFile(resource.absolutePath).width
            val sHeight = BitmapFactory.decodeFile(resource.absolutePath).height
            val wm = ContextCompat.getSystemService(context, WindowManager::class.java)
            val point = Point()
            wm!!.defaultDisplay.getSize(point)
            val height = point.y//测量不包括标题栏和状态栏的高度
            if (sHeight >= height
                && sHeight / sWidth >= 3) {
                imageView.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CENTER_CROP)
                imageView.setImage(ImageSource.uri(Uri.fromFile(resource)), ImageViewState(0.5f, PointF(0f, 0f), 0))
            } else {
                imageView.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CUSTOM)
                imageView.setImage(ImageSource.uri(Uri.fromFile(resource)))
                imageView.setDoubleTapZoomStyle(SubsamplingScaleImageView.ZOOM_FOCUS_CENTER_IMMEDIATE)
            }
        }

        override fun onLoadCleared(placeholder: Drawable?) {
        }
    })
}
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