// 先拼接好一个路径：在内存卡/或是手机内存上做好文件夹
    String filePath = Environment.getExternalStorageDirectory()+savePath;
    File localFile = new File(filePath);
    if (!localFile.exists()) {
      localFile.mkdir();
    }

//拼接好文件路径和名称
    File finalImageFile = new File(localFile, System.currentTimeMillis() + ".jpg");
    if (finalImageFile.exists()) {
      finalImageFile.delete();
    }
    try {
      finalImageFile.createNewFile();
    } catch (IOException e) {
      e.printStackTrace();
    }

    FileOutputStream fos = null;
    try {
      fos = new FileOutputStream(finalImageFile);
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    }

    if (bitmap == null) {
      Toast.makeText(this, "图片不存在", 0).show();
      return;
    }
    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
    try {
      fos.flush();
      fos.close();
      Toast.makeText(this, "图片保存在："+ finalImageFile.getAbsolutePath(), 0).show();
    } catch (IOException e) {
      e.printStackTrace();
    }

    //发广播告诉相册有图片需要更新，这样可以在图册下看到保存的图片了
    Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
    Uri uri = Uri.fromFile(finalImageFile);
    intent.setData(uri);
    sendBroadcast(intent);

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