U盘挂载成功后未发出广播上层无法访问相册音乐文件-优快云博客

本文链接：https://blog.youkuaiyun.com/u012169524/article/details/87712605

我遇到的问题是U盘挂载成功了，storage/udisk节点也存在，通过串口能访问，但是应用不能读取。如果说日志中mountFlags=0说明你的问题跟我一样，正确的应该是mountFlags=VISIBLE。

type=PUBLIC diskId=disk:8,0 partGuid= mountFlags=0 mountUserId=0 
state=UNMOUNTED 
fsType=null fsUuid=null fsLabel=null 
path=null internalPath=null

Android 8.0之前是通过MountService跟vold通信以及发送挂载广播等操作

frameworks/base/services/java/com/android/server/MountService.java

Android 8.0之后MountService代码整合进了StorageManagerService.java

发送挂载/卸载广播

case H_VOLUME_BROADCAST: {
	final StorageVolume userVol = (StorageVolume) msg.obj;
	final String envState = userVol.getState();
	Slog.d(TAG, "Volume " + userVol.getId() + " broadcasting " + envState + " to "
			+ userVol.getOwner());

	final String action = VolumeInfo.getBroadcastForEnvironment(envState);
	if (action != null) {
		final Intent intent = new Intent(action,
				Uri.fromFile(userVol.getPathFile()));
		intent.putExtra(StorageVolume.EXTRA_STORAGE_VOLUME, userVol);
		intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT
				| Intent.FLAG_RECEIVER_INCLUDE_BACKGROUND);
		mContext.sendBroadcastAsUser(intent, userVol.getOwner());
	}
	break;
}

修改如果是USB则设置VolumeInfo.MOUNT_FLAG_VISIBLE