Skip to main content

Refreshing Android MediaStore

The Android MediaStore maintains the metadata of audio, video and image files in the underlying filesystem for convenient consumption by relevant Android apps (eg. music player).

The problem is when manipulating the SD card content with an Android file manager, sometimes the metadata cache becomes out of sync with the actual filesystem. So for example if you rename or delete a folder using a file manager, then connect the device via a USB cable to your PC to be accessed via MTP, the old folder may appear in Windows Explorer. Clicking "Refresh" does not work to update the content. The only way to refresh the cache is to reboot the device.

Another method I found recently is to run an app that forces MediaStore to refresh its cache. There are many apps available for this purpose if you search for "rescan sd" in the app store. A lot of them won't work with Android 6.x (Mashmallow) and will crash when you try. One ad-free app that works  under Mashmallow is Rescan SD Card.



It is a very simple app, but it does take a while to rescan the entire SD card. For my case with a few thousand files, it took 3 to 4 minutes to complete the process.

On the topic of MTP, it is a horrible protocol for file transfer. We used to have USB mass storage, where the SD card is mounted as a drive under Windows Explorer. But this is all but gone in the latest devices and can only be found in some custom ROMs.

Anyway, mounting the SD card as a drive has its own problems because it needs to dismount the storage from Android apps during the usage duration, which can cause all sorts of unexpected problems. Recent devices mostly only support PTP (which is practically useless for anything) and MTP.

MTP is horrible because it is extremely finicky. It can hang when transferring large files. It can hang when you are just renaming a folder. When it hangs, the only workaround is to reboot the device.

Why not use wireless? Wireless transfer apps such as AirDroid or SendAnywhere is not practical when you are trying to transfer large files (eg. video files > 500MB). In addition, when you are out and about, and your PC is connected to a WiFi hotspot, while your phone is connected to 4G, it is a pain to juggle the connections so that the quota on your 4G broadband will not be affected. Simplest is to use a USB cable, which is fast and reliable. Too bad the underlying protocol is garbage.

We need a better standard for wired file transfer over USB, and so far none is forthcoming.

Comments

Popular posts from this blog

Adding "Stereo Mixer" to Windows 7 with Conexant sound card

This procedure worked for my laptop (Thinkpad E530) with a Conexant 20671 sound card, but I suspect it will work for other sound cards in the Conexant family. I was playing with CamStudio to do a video capture of a Flash-based cartoon so that I can put it on the WDTV media player and play it on the big screen in the living room for my kids. The video capture worked brilliantly, but to do a sound capture, I needed to do some hacking. Apparently, there was this recording device called "Stereo Mixer" that was pretty standard in the Windows XP days. This allowed you to capture whatever was played to the speaker in all its digital glory. Then under pressure from various organizations on the dark side of the force, Microsoft and soundcard makers starting disabling this wonderful feature from Windows Vista onwards. So after much Googling around, I found out that for most sound cards, the hardware feature is still there, just not enabled on the software side. Unfortunately, to

Hacking a USB-C to slim tip adapter cable to charge the Thinkpad T450s

This hack is inspired by this post . A year ago, I bought an adapter cable for my wife's Thinkpad X1 Carbon (2nd Gen) that allows her to power her laptop with a 60W-capable portable battery (20V x 3A). A USB-C cable goes from the battery into the adapter, which converts it to the slim tip output required by the laptop. Everything works out of the box, so I didn't give much thought about it. Recently, I decided to buy a similar cable for my Thinkpad T450s. I know technically it should work because the T450s can go as low as 45W (20V x 2.25A) in terms of charging (though I have the 65W charger - 20V x 3.25A).  I went with another adapter cable because it was cheaper and also I prefer the single cable design. So imagine my surprise when the cable came and I plugged it into my laptop and it didn't work! The power manager just cycle in and out of charging mode before giving up with an error message saying there is not enough power. After much research and reading the Thinkwiki

Using Google Dashboard to manage your Android device backup

I used to use AppBrain/Fast Web Install to keep track of which apps I have installed on my phone, and to make it easier to reinstall those apps when the phone gets wiped or replaced. But AppBrain had been going down the tubes, and Fast Web Install had always been a hit-and-miss affair. Android's own "backup to the cloud" system had previously been even more unusable. There isn't a place where you can see what has been backed up. And when you setup a new phone with your Google account, you just have to wait and pray that your favorite apps will be restored to the phone. Typically all the stars have to be aligned just right for this to happen. More often than not, after waiting for an hour or so and nothing happens, you just curse under your breath and proceed to install your favorites apps manually via the Play Store. But I just looked again recently and was pleasantly surprised that things are much more civilized now. Firstly there is a place now where you can loo