Question

我有一个动态填充项目的列表视图。每个项目都有图像和文字。我知道这个上下文在其他stackoverflow的问题中如此重复。但是我仍然无法找到解决方案。

首先，我只有这个调用成功地在列表视图中设置每个图像。

imageview.setImageResource(getResuID());

尽管如此，由于滚动和延迟较慢，我希望在google training guide之后对其进行优化。

然后我尝试使用训练中的代码，问题就出现了。现在我从BitmapFactory到处都是null。

我read关于异步任务和GC，我还尝试将缩放移动到 AsyncTask ，这既没有解决问题。

这就是我的所作所为：

从＆＃34; getView＆＃34;调用任务在我的listview适配器中，它从BaseAdapter扩展：

int resID = getResID();
AsyncImageSetter task = (AsyncImageSetter) new AsyncImageSetter(thumb_image,resID).execute();

public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
        // Raw height and width of image
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {

            final int halfHeight = height / 2;
            final int halfWidth = width / 2;

            // Calculate the largest inSampleSize value that is a power of 2 and keeps both
            // height and width larger than the requested height and width.
            while ((halfHeight / inSampleSize) > reqHeight && (halfWidth / inSampleSize) > reqWidth) {
                inSampleSize *= 2;
            }
        }

        return inSampleSize;
    }

    public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId, int reqWidth, int reqHeight) {

        // First decode with inJustDecodeBounds=true to check dimensions
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeResource(res, resId, options);

        // Calculate inSampleSize
        options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

        // Decode bitmap with inSampleSize set
        options.inJustDecodeBounds = false;
        return BitmapFactory.decodeResource(res, resId, options);
    }

    public class AsyncImageSetter extends AsyncTask<Void, Void, Void> {

        private ImageView img;
        private int image_resId;
        private Bitmap bmp; 

        public AsyncImageSetter(  ImageView img, int image_ResId ) {

            this.img = img;
            this.image_resId = image_ResId; 

        }

        @Override
        protected Void doInBackground(Void... params) {
             try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            bmp = (decodeSampledBitmapFromResource(activity.getResources(), image_resId, 100, 100)); 

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {

            img.setImageBitmap(bmp);
            bmp = null;

            super.onPostExecute(result);
        }

    }

接收此日志消息：

01-07 19:57:54.167: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.167: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.277: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.277: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.277: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.306: D/dalvikvm(2141): GC_CONCURRENT freed 1247K, 12% free 10097K/11463K, paused 5ms+6ms
01-07 19:57:54.387: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.387: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.397: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.507: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.507: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.517: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.626: D/skia(2141): --- SkImageDecoder::Factory returned null
01-07 19:57:54.626: D/skia(2141): --- SkImageDecoder::Factory returned null

这是由于GC内存空闲吗？

这很奇怪，但如果不是

bmp = (decodeSampledBitmapFromResource(activity.getResources(), resources.getResID(), 100, 100));

我用

bmp = (decodeSampledBitmapFromResource(activity.getResources(), R.drawable.image1, 100, 100));

它有效＆＃34;罚款＆＃34;。我看到所有listview项目都有重复的图像。

此外，我尝试按照BitmapFun示例来合并缓存，但它确实是高级示例。也许你可以在没有这么多课程的情况下建议我一些更简单的方法。

由于

使用本地资源时，SkImageDecoder :: Factory返回null

0 个答案: