File f = new File("/sdcard/DCIM/Camera/0.png");

                       FileOutputStream fos = null;

                       try {

                           fos = new FileOutputStream(f);

                           drawBitmap.compress(Bitmap.CompressFormat.PNG, 50, fos);

                       } catch (FileNotFoundException e) {

                           // TODO Auto-generated catch block

                           e.printStackTrace();

                       }

<!-- 在SDCard中创建与删除文件权限 -->

<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>

<!-- 往SDCard写入数据权限 -->

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>