android中Bitmap数据如何释放

    public void recycle() {
        if (!mRecycled) {
            if (nativeRecycle(mNativeBitmap)) {
                // return value indicates whether native pixel object was actually recycled.
                // false indicates that it is still in use at the native level and these
                // objects should not be collected now. They will be collected later when the
                // Bitmap itself is collected.
                mBuffer = null;
                mNinePatchChunk = null;
            }
            mRecycled = true;
        }
    }

    /**
     * Free the native object associated with this bitmap, and clear the
     * reference to the pixel data. This will not free the pixel data synchronously;
     * it simply allows it to be garbage collected if there are no other references.
     * The bitmap is marked as "dead", meaning it will throw an exception if
     * getPixels() or setPixels() is called, and will draw nothing. This operation
     * cannot be reversed, so it should only be called if you are sure there are no
     * further uses for the bitmap. This is an advanced call, and normally need
     * not be called, since the normal GC process will free up this memory when
     * there are no more references to this bitmap.
     */

    private static class BitmapFinalizer {
        private final int mNativeBitmap;

        BitmapFinalizer(int nativeBitmap) {
            mNativeBitmap = nativeBitmap;
        }

        @Override
        public void finalize() {
            try {
                super.finalize();
            } catch (Throwable t) {
                // Ignore
            } finally {
                nativeDestructor(mNativeBitmap);
            }
        }
    }