BitmapFactory.decodeResource在Android 2.2中返回可变的位图，在Android 1.6中返回不可变的位图

BitmapFactory.decodeResource在Android 2.2中返回可变的位图，在Android 1.6中返回不可变的位图

您可以将不可变位图转换为可变位图。

我找到了一种仅使用一个位图的内存的可接受解决方案。

将源位图原始保存（RandomAccessFile）到磁盘上（没有ram内存），然后释放源位图（现在，内存中没有位图），然后，文件信息将加载到另一个位图。通过这种方式，可以制作一次仅在内存中存储一​​个位图的位图副本。

在此处查看完整的解决方案和实现：Android：将不可变位图转换为可变

我对该解决方案进行了改进，现在可以与任何类型的位图（ARGB_8888，RGB_565等）一起使用，并删除临时文件。看我的方法：

/*
* Converts a immutable bitmap to a mutable bitmap. This operation doesn’t allocates
* more memory that there is already allocated.
*
* @param imgIn - Source image. It will be released, and should not be used more
* @return a copy of imgIn, but muttable.



/
public static Bitmap convertToMutable(Bitmap imgIn) {
try {
//this is the file going to use temporally to save the bytes.
// This file will not be a image, it will store the raw image data.
File file = new File(Environment.getExternalStorageDirectory() + File.separator + “temp.tmp”);

    //Open an RandomAccessFile    //Make sure you have added uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"    //into AndroidManifest.xml file    RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw");    // get the width and height of the source bitmap.    int width = imgIn.getWidth();    int height = imgIn.getHeight();    Config type = imgIn.getConfig();    //Copy the byte to the file    //Assume source bitmap loaded using options.inPreferredConfig = Config.ARGB_8888;    FileChannel channel = randomAccessFile.getChannel();    MappedByteBuffer map = channel.map(MapMode.READ_WRITE, 0, imgIn.getRowBytes()*height);    imgIn.copyPixelsToBuffer(map);    //recycle the source bitmap, this will be no longer used.    imgIn.recycle();    System.gc();// try to force the bytes from the imgIn to be released    //Create a new bitmap to load the bitmap again. Probably the memory will be available.     imgIn = Bitmap.createBitmap(width, height, type);    map.position(0);    //load it back from temporary     imgIn.copyPixelsFromBuffer(map);    //close the temporary file and channel , then delete that also    channel.close();    randomAccessFile.close();    // delete the temp file    file.delete();} catch (FileNotFoundException e) {    e.printStackTrace();} catch (IOException e) {    e.printStackTrace();}return imgIn;

}
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