Develop Reference

Android Tablet is restarting by itself

I have a custom android tablet and we have created an application which is used for home automation.I have installed the application in it and it works fine. I got the comments from the client saying that the tablet restarts by itself at night. I tried to catch the log by connecting it to eclipse but it didnt happend here. Will the tablet restart by itself under any circumstances ? , The tablet is a samsung ARM with 512mb ram and 4gb sdcard in it which runs on android version 2.2.

You have not provided any code, which leads me to assume the following. Unless you have the permission of PowerManager, you app has no control over the device's off/on state.
You also mentioned, on testing, you were not able to pinpoint the issue that the client talked about. This is very important information, and it helps strengthen my conclusion. Again, if the above criterion is correct (you don't have powermanager) then, it could be the clients tablet is just messed up...
The reebooting is actually a common problem:
http://forums.androidcentral.com/samsung-galaxy-tab-pro-8-4/453390-why-my-tablet-randomly-rebooting-resetting.html
Here, user B. Diddy states:
It's hard to say. Random reboots can happen because of problems with
the firmware, but can also be due to some app you installed that is
making the system unstable, or perhaps some bad bit of data that is in
the system cache. A corrupt SD card can also cause problems. Here are
some things you can try:
Unmount your SD card in Settings>Storage, remove it, and reboot. Use the tablet for a while (like a few days) without the SD card and
see if the random reboots recur. If they don't, plug it back in again,
and see if the reboots start again.
Boot into Safe Mode, which temporarily disables all 3rd party apps: Safe mode: Samsung Galaxy Tab 4 | T-Mobile Support. (I couldn't find
steps specifically for the Tab Pro, so I'm assuming the steps for the
Tab 4 are the same.) This might not be an effective troubleshooting
method if the random reboots don't occur very often, because it's hard
to expect anyone to use their tablet for several days in Safe Mode,
thus being unable to access any of the 3rd party apps you installed.
Boot into Recovery Mode and wipe the cache partition, which doesn't erase any personal data. Follow the steps in this video, and make sure
you select Wipe Cache Partition, and not Wipe Data/Factory Reset.
So, let me know if your app uses the PowerManager permission. If it doesn't you're good to go, and it is probably a faulty tablet.
Ruchir

Android development with no screen

I have a hobby android app idea that basically just uses Android's sensors and logs them long term for several days (external battery). The sensors needed are in $200 phones, and I can get ones for under $100 if the screen doesnt work.
My question is, is it pretty easy to make an app that starts and loads via debugging, keeps running when disconnected and when I connect I can extract the log file, or would this so be difficult I would be ahead just to spend the extra $100?

As mentioned, turning on USB debugging without the screen isn't possible. You can't enable USB debugging over USB for security reasons, so your only option would be to use hardware commands to put the device in firmware download mode (presumably it will have a way to do that), then load a custom OS which allows USB debugging by default.
Personally I think that's more than $100 worth of work, so I'd just go with the working device. Then you can use it for other stuff down the line.
Alternately, you can probably get a replacement screen for not too much, and for most devices changing the screen is relatively easy. I'd look into that option as well.

The first barrier you may find is that you must activate the Developer Options in the settings and the USB Debugging. And when you connect to the computer, you must accept that cumputer as the Debugger.
I don't know if it's possible to do it without a working screen.

App will keep running & yes you can can extract the log file when connecting again.
But the problem is in the first step. if your screen if not working, then how would you add your workstation as a trusted device in your "display not working device". I doubt if there is such way, because we need to do several things like switching on developer options, usb debugging etc.
I hope you got your answer.

Android phone reboots on uninstall

I am developing an app and when I uninstall the phone kind of semi-reboots.
This is my old post:
I have a strange problem with my phone. I am using SAMSUNG GALAXY 5
(GT-I5500) with Android 2.2 on it (not rooted).
I am an android developer and I have been doing pretty advanced apps.
However, sometimes when I am testing and installing an application the
phone reboots.
I'm starting it trough Eclipse but I do not know what exactly what
causes the phone to reboot.
It is not heat for sure, as I keep my phone cool enough.
It is not from the app source itself as the phone doesn't reboot while I am using the application but on installing time
It is not storage I think, because I have 26 MB internal and 1GB external memory free and the app is no more than 2 MB.
So my question is what could cause the phone to reboot?
In this context I define "reboot" as the phone showing the initial SAMSUNG screen, like normal booting but without the prompt for PIN. This is why I conclude it is something like semi-reboot or I do not exactly know.

Having experienced the same problem, I found that deleting dalvik cache and formatting cache partition helped - I can't tell which one of those two did the trick, but I can now happily uninstall apps again, without the device spontaneously rebooting.
Both operations I was able to perform in recovery mode, using ClockWorkMod rescue system, and they are non-destructive. No actual data or apps are lost, only next reboot takes longer, due to dalvik cache being rebuilt.
Today, close to a month later, that problem showed again, so I was able to test which of those two action fixes it. Turns out it was erasing the cache. Dalvik cache was left alone, deletion was possible afterwars nevertheless.

I have this exact problem with my LG G4. Whenever I try to uninstall an app the phone will just reboot. Luckily there is a way to remove unwanted apps if your phone has an expandable memory option through micro SD. Just transfer the unwanted app on the SD card then remove the card. The app will no longer exist on your phone. You can then just delete the app from your SD card using a PC. This doesn't help resolve the actual OS issue on your device but at least it's a quick fix for anyone who's looking to free up some space. Hope it helps!

Spontaneous reboots under unclear conditions, one of the "fun" things you get for free with Android. Not on each and every device, OS version or combination thereof, but quite too often.
With the following instructions you will loose all your data on your phone.
Try this: Get into the recovery mode (adb reboot recovery or start the phone with pressing (and holding) volume down, then press and hold the center key, then power on), then wipe data/factory reset, wipe cache partition.
(I experienced similar reboots but not with an I5500, so I don't know if this will help in this situation. It helped with a Motorola Milestone/Droid after upgrading to Android 2.2.)

I was able to fix this problem by wiping the davilk-cache thanks to Deleted User's experience. However, wiping the cache partition was not necessary in my case. I'm rooted stock Android 4.4.2 KitKat on a Galaxy Tab 3 SM-T210R.

Debugging directly on the device

I don't expect you to correct my code, since it should be working, at least works on emulator. Unfortunately gives different output on the devices. My question is:
How to debug in such cases, when the device is not working as the emulator, and what could cause that (device model, a custom ROM?)
I heard some rumors some time ago, about possibility using the device instead an emulator somehow connected to the SDK. Could you also confirm or deny that?

You'll find it's not uncommon to find little quirks between devices. Many developers will have several physical devices to test their software on.
You can find information on using a physical device for debugging (including using it inside Eclipse, just as you would the emulator) on the Android website: http://developer.android.com/guide/developing/device.html

Yes you can do that. Just put your device into debugging mode, and connect it to the computer with the micro-usb port on the device. You will also need to download the drivers from the manufactures website.

How to set the Usb connection mode?

I'm writing an application which is supposed to dump data on the SD card and then another application on a pc which should read the data when the device is connected to the pc (in disc drive mode).
On my HTC Legend there is a dialog to choose between: Charge only, HTC Sync, Disk drive..
Is there a possibility to set the mode with which the device is connecting to the pc
or at least an intent to ask the user to switch the mode?

I haven't found a way of setting the mode programmatically, but I believe you can bring up the settings menu programmatically by invoking the same activity that the system invokes from the notification area. Unfortunately this appears to be manufacturer-specific: on my phone it is com.htc.android.psclient.SwitchUsbSettings.

On HTC devices, open the ConnectToPC service (whilst USB is not plugged in) in Manage Apps (ICS - probably applies to Gingerbread too; don't remember), and hit Clear Data. Then, plug the USB back again, and you should have the option to "Don't ask again" available. Select your desired mode, check the box, and accept.

CompanionLink does this when you request a USB sync in their android app: it flushes data to SD, then exports the SD as storage (a "disk drive") on the USB, then waits for the user to manually signal the android app when the PC is finished using the SD, and then undoes the SD export to USB again. Though the CompanionLink app can be very frustrating to use, at least this part of it is (largely) reliable.
Unfortunately I don't know the technical details, may well need to figure them out myself one of these months. If you can't get any traction with android docs, perhaps you could study what CompanionLink does on android to implement this. The sequence I describe above is when it is configured to sync over USB against a (PC-based) Palm Desktop.
As an aside, it appears that the reason for this highly-convoluted process is that the SD card's FS is accessed directly and at least the presently-used card FAT FS can only support a single client: the phone itself or USB. imo it would be extremely helpful if concurrent shared access to the SD were possible, but this would likely require deep android changes.

For anyone having this issue with an HTC One M8, this is a bit off the wall, but makes the point to think outside the box. A USB connection resulted in the device charging, that was it.
The solution was the combination of a different USB cable, uninstalling an application called Battery Doctor (which apparently likes to manage everything around your battery), AND USB Network Setting - turn ON Smart Network Sharing...Seemingly unrelated...but this combination got my connected with MobileGo for Android to manage and back up files,contacts and settings.
Hope this helps someone.

Yes .In Android there is a way to change the behaviour of the devices`s USB mode when the device is connected with the PC.
I used a Motorola Milestone[running 2.1] and i was able to switch between the following modes :
PC Suite[developed by Motorola],MemoryCardAccess and Charge alone.
If you need to access phone memory I think you should turn ON "USB Debugging Mode " in your device.Am not sure about it though,I feel it may be handy !!