Bitmap 存到文件中

将一个Bitmap 的内容存到file中

//create a file to write bitmap data
File f = File(context.getCacheDir(), filename);
f.createNewFile();

//Convert bitmap to byte array
Bitmap bitmap = your bitmap;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
bitmap.compress(CompressFormat.PNG, 0 /*ignored for PNG*/, bos);
byte[] bitmapdata = bos.toByteArray();

//write the bytes in file
FileOutputStream fos = new FileOutputStream(f);
fos.write(bitmapdata);

思路：将Bitmap的内容，输入到输出流中，然后从输出流中把数据输出到文件中