Android 为什么在重新使用位图时总是出现异常？ 背景

从API 11开始，您可以在解码新位图时重新使用位图，这样解码器就不需要重新创建全新的大型对象

这是使用类似以下代码的方式完成的（摘自）：

其优点非常明显：在某些情况下使用更少的内存，对GC的压力更小，并且性能更好，因为您不需要创建更多的大型对象

唯一的问题是两个映像必须具有相同的大小和配置

问题 即使代码在项目本身（在res文件夹中）的资源中工作得很好，但在处理放入内部存储器的图像文件时，我似乎总是会遇到下一个错误：

java.lang.IllegalArgumentException: Problem decoding into existing bitmap

我尝试了位图选项的多个不同标志：

bitmapOptions.inPurgeable = true;
bitmapOptions.inInputShareable = true;
bitmapOptions.inMutable = true;
bitmapOptions.inScaled = false;
bitmapOptions.inSampleSize = 1;
bitmapOptions.inPreferredConfig = Config.RGB_565; //i've set the created bitmap to be of this type too, of course

我还尝试了BitmapFactory的decodeFile和decodeStream

下面是一个示例代码，说明存在问题（基于我所写的示例）：

问题 为什么我不断地得到这个错误，我怎样才能修复它

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我发现了一些类似的问题，但没有一个答案。

使用webP文件时，这个很酷的技巧似乎有问题

我只需要使用jpg或png

bitmapOptions.inPurgeable = true;
bitmapOptions.inInputShareable = true;
bitmapOptions.inMutable = true;
bitmapOptions.inScaled = false;
bitmapOptions.inSampleSize = 1;
bitmapOptions.inPreferredConfig = Config.RGB_565; //i've set the created bitmap to be of this type too, of course

@Override
public void onCreate(final Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_bitmap_allocation);

    final int[] imageIDs = { R.drawable.a, R.drawable.b, R.drawable.c, R.drawable.d, R.drawable.e, R.drawable.f };

    final CheckBox checkbox = (CheckBox) findViewById(R.id.checkbox);
    final TextView durationTextview = (TextView) findViewById(R.id.loadDuration);
    final ImageView imageview = (ImageView) findViewById(R.id.imageview);

    // Create bitmap to be re-used, based on the size of one of the bitmaps
    mBitmapOptions = new BitmapFactory.Options();
    mBitmapOptions.inJustDecodeBounds = true;
    BitmapFactory.decodeResource(getResources(), R.drawable.a, mBitmapOptions);
    mCurrentBitmap = Bitmap.createBitmap(mBitmapOptions.outWidth, mBitmapOptions.outHeight, Bitmap.Config.ARGB_8888);
    mBitmapOptions.inJustDecodeBounds = false;
    mBitmapOptions.inBitmap = mCurrentBitmap;
    mBitmapOptions.inSampleSize = 1;
    mBitmapOptions.inPreferredConfig = Config.ARGB_8888;
    BitmapFactory.decodeResource(getResources(), R.drawable.a, mBitmapOptions);
    imageview.setImageBitmap(mCurrentBitmap);

    // When the user clicks on the image, load the next one in the list
    imageview.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(final View v) {
            mCurrentIndex = (mCurrentIndex + 1) % imageIDs.length;
            Options bitmapOptions = new Options();
            bitmapOptions.inPreferredConfig = Config.ARGB_8888;
            if (checkbox.isChecked()) {
                // Re-use the bitmap by using BitmapOptions.inBitmap
                bitmapOptions = mBitmapOptions;
                bitmapOptions.inBitmap = mCurrentBitmap;
            }
            final long startTime = System.currentTimeMillis();
            //
            File tempFile = null;
            try {
                tempFile = File.createTempFile("temp", ".webp", getApplicationContext().getCacheDir());
                FileOutputStream fileOutputStream;
                final Bitmap bitmap = BitmapFactory.decodeResource(getResources(), imageIDs[mCurrentIndex]);
                bitmap.compress(CompressFormat.WEBP, 100, fileOutputStream = new FileOutputStream(tempFile));
                fileOutputStream.flush();
                fileOutputStream.close();
            final InputStream inputStream = new FileInputStream(tempFile);
            mCurrentBitmap = BitmapFactory.decodeStream(inputStream,null,bitmapOptions);
            inputStream.close();
            } catch (final IOException e1) {
                e1.printStackTrace();
            }
            imageview.setImageBitmap(mCurrentBitmap);

            // One way you can see the difference between reusing and not is through the
            // timing reported here. But you can also see a huge impact in the garbage
            // collector if you look at logcat with and without reuse. Avoiding garbage
            // collection when possible, especially for large items like bitmaps,
            // is always a good idea.
            durationTextview.setText("Load took " + (System.currentTimeMillis() - startTime));
        }
    });
}