Here's what I need to do. I want to use an Android tablet for science research, but I will need to programmatically control the screen/backlight. Specifically, there is a mode where my app will need to communicate with other systems via WiFi, play sounds, and have the touchscreen active, but the backlight must be completely off; in this mode, the device cannot emit any light, or it will interfere with the science. Obviously, this cannot be sleep mode! Is this feasible?
I've looked around a bit, and this sounds really promising, but it isn't crystal-clear (to me, anyway!) whether this will work. Can anyone vouch for that?
Finally, does it matter which tablet I choose? Basically, there seem to be three possibilities: the backlight is controlled with a switch (doubt that is done anymore), the CPU can only turn it on or off, or the CPU can adjust it fully. Writing this makes me feel rather silly about being concerned, but a Samsung rep yesterday told me I can't do this on the Galaxy. Anyone care to recommend a tablet?
Thanks!
Specifically, there is a mode where my app will need to communicate with other systems via WiFi, play sounds, and have the touchscreen active, but the backlight must be completely off
Android does not support "have the touchscreen active, but the backlight must be completely off". And, you do not have the ability to turn the backlight "completely off" programmatically.
I've looked around a bit, and this sounds really promising
That sets the backlight to be low. Some devices may elect to turn the backlight off when it is set low. That is up to the device manufacturer.
Finally, does it matter which tablet I choose?
See above.
Since its a science research I'm going to assume you may not need to divulge this application and want it in a controlled environment. If this is the case, a little creative thinking suggests that since the touch screen will still react to even if covered by a thin layer of plastic (like the screen protectors for instance) you may be able to apply some opaque vinyl on top of the screen (easy to remove) for doing the experiments.
This may not be useful but since to me it sounded like it could I thought I'd share my thoughts with you on this one. Once you've covered the screen with the vinyl, the rest is as usual, keep screen on, and do your magic.
:)
Related
Similar to this iOS-question ( VoiceOver announces dimmed instead of disabled for buttons ) I have the same problem, but for Android devices with Talkback.
Why is Talkback announcing some elements like buttons or checkboxes as "dimmed" instead of "disabled"?
Should I somehow change this, or leave it as Talkback reads it? If I should change it to "disabled / dimmed" so that it's consistent over the whole app, how?
[EDIT]:
Example:
It seems that not only buttons use "dimmed", but check / tick boxes as well.
Also only the english language seems to use "dimmed", in german it's still read as "deaktiviert" (disabled).
Don't change it. TalkBack is responding to properties in ways that users would be accustomed to. Sometimes the default behavior is the most accessible because it is expected, even when it isn't quite ideal.
If you would like an answer to the "why" I would need more information on the particular examples that your talking about. Are there apps that exhibit this behavior? TalkBack updated not too long ago, but I generally hear the "disabled" announcement over the "dimmed" announcement from TalkBack from the "obvious" times that such an announcement would apply. I certainly wouldn't expect there to be a general distinction between the two.
Also, I'm looking through the current version of TalkBack (again TalkBack has been updated recently, so the open source version may not be up to date and available) and can't find the localized string "dimmed" anywhere. There are references to "screen dimmed" but this is certainly different from what you're talking about. Which suggests to me that the "dimmed" announcement is coming from changes in the code that I would recommend be UNDONE, so as to allow the "disabled" announcement that TalkBack users would be accustomed to. This sounds to me like something someone coming from an iOS background wanted to duplicate. The behavior in iOS is to announce disabled things as "dimmed". Duplicating this on Android would absolutely be innapropriate. Let TalkBack do its thing!
Providing code examples would be helpful for me to be more sure about all of these things, your question is quite ambiguous. What types of controls? A Button for example may behave different from a Tab in a TabWidget, and this may be intentional. The way your question is worded, any more specific answers than I have given would be speculative.
EDIT:
The different parts of this announcement:
Every Sunday (0): The text of the control
Tick Box: The calculated role of the control. In stock Android this will announce as "CheckBox" (I'm testing on 7.0, with the current GitHub TalkBack). Samsung would be best off to leave this as "Check Box" from stock Android OS, I don't know why they felt the need to change "Check Box" to "Tick Box" just to be different. Doing things just to be different is annoying, there is no objective difference between "Check Box" and "Tick Box" (licensing???).
Not Selected: The current calculated state of the control. In Stock Android this would read out as "Not Checked". Unless the app is overriding this, Samsung would seem to be mucking with this as well. They should stop doing so, but again, out of your control and best left alone. Samsung users will be used to this. Though ultimately I find "Not Selected" to be a little ambiguous in terms of a CheckBox control. "Not Ticked" I think would be better.
Dimmed: Again, another thing that, unless your code is overriding (which I don't think it can in this case for this bit of calculated state). This is the calculated enable/disabled state of the control. In stock Android this would read out as "disabled". Again, leave this alone. Samsung would ALSO be best to leave this alone.
It would definitely appear that Samsung is doing strange things to the Accessibility read outs of calculated components. I'm not sure what version of Android this Samsung flavor is built off of, but I don't believe those read outs have changed. I know CheckBox and Disabled have been the same since 4.2 - 7.0 (probably Android O as well.). These minor changes fracture the Android Accessibility Ecosystem. For these particular elements, Samsung would definitely be best off just to leave them alone. HOWEVER, given that Samsung has made these changes, you are best off NOT fixing this fragmentation. Let Samsung users and Nexus users and Motorola users experience things in the way they are used to and get accustomed to their devices. Allow default behaviors unless overriding them is absolutely necessary. Hearing "disabled" when your expecting "dimmed" is confusing, not to mention a maintenance nightmare should Samsung decide NOT to override this any more or vice versa. When the OS is "calculating" state and doing so reasonably... let it happen!
We’re porting to Android some interactive iOS apps used to teach young children with learning disabilities. We have hit a major usability issue, because we can't figure out how to disable physical or on-screen navigation buttons (Home and Recent Apps).
Before anyone says “you don’t want to do that”, we fully understand why you would always want these buttons enabled for an able-bodied adult, but these children pose a unique set of accessibility issues. Specifically:
Their fine motor control may be poor - they may inadvertently touch a different area of the screen to the area they intend, or accidentally use more than one finger at once.
They may have weak muscle tone and poor physical strength – so e.g. the bottom of the palm of their hand may drop and touch the screen while trying to just use a finger.
They struggle to achieve and easily become disheartened or disruptive if they fail.
For instance, a typical 5 year old child with Down syndrome will accidentally drop out of the app they are using as a result of inadvertently touching the Home button: when this happens repeatedly, and the adult teacher or parent has to go back into the app for them repeatedly, the child loses interest and focus. Another typical scenario is a young child with Autism, who may freak out completely and need physically restraining if this happens while using their favourite app. Also, many disabled children will try to poke any other button they can find, in search of a response. In any of these situations, a potentially valuable educational session may have to be completely abandoned.
We're aware of SYSTEM_UI_FLAG_HIDE_NAVIGATION and SYSTEM_UI_FLAG_LOW_PROFILE, but these only reduce the visibility of the on-screen buttons until the child touches some other part of the screen, and then they re-appear in a way that’s more distracting than if they were visible all the time.
On iOS there is the “Guided Access” feature that solves this problem trivially. Can we emulate anything similar on Android?
On iOS there is the “Guided Access” feature that solves this problem trivially.
Guided access appears to be a device setting, not something that developers enable unilaterally themselves, thank heavens.
Can we emulate anything similar on Android?
There is no similar device setting in stock Android.
You can download the Android source code, modify it as you see fit, build the results into a ROM mod, and install that ROM mod on devices as you see fit.
Or, you can perhaps work with a device manufacturer creating tablets aimed at children to see if either they have already added this capability to their devices, or would be willing to work with you to add such a capability in a future iteration of their devices.
I am driving some experiments with a pair of a-JAYS Four headphones (having 3 buttons on its wired remote/mic) plugged onto a Galaxy Nexus (ICS 4.0.2).
My issue is that only the middle button is 'recognised' by a test app I have written, i.e. triggering both Intent.ACTION_MEDIA_BUTTON and/or Activity.onKeyDown callback with KeyCode 79 when it is pressed.
Pressing the two other buttons don't trigger any of the previous methods. For info, those headphones and its 3 buttons work on Apple iPhones and Apple computers (at least a MacBookPro 2011), as advertised on the box...
Firstly I thought Android or my device could simply not handle more than one button on a wired jack remote (even if that sounds weird...) but then I had a try with a pair of headphones from HTC (the ones coming with one of their Desire device) having 3 buttons. Middle button would react the same way as my a-JAYS, but the two other buttons are also recognised with KeyCodes 87 and 88, respectively Play Previous and Play Next media keys.
So it seems that either the device or the low levels layers of Android are simply not able to catch certain headphones buttons signals :/ (at least those which are not 87 and 88)
Any idea anyone about how to make Android able to recognise other buttons/signals from such headphones as Apple compatible ones? Would it imply low levels drivers writing for ICS or am I missing something really obvious?
Any help would be much appreciated. Can post my test-app code if needed.
Cheers
The signals/ resistance from the volume control buttons (1.525-1.495 V for volume down, and 1.619-1.587 V for volume up) are currently unable to be recognized through the android framework's software. I believe this has to do with Apple having a patent on the designated volume controls and so Google won't release to developers how the framework recognizes particular signals through the fourth connector on the headphone jack. The center/mic/action buttons on headsets generally work, it shorts the path from ~2V to ~0V and Apple does not own the patent for that. If someone could figure out how to interact with the inputs on their own that would be huge. I am tempted to learn app development and find a workaround.
The problem is more complicated that it seems: http://david.carne.ca/shuffle_hax/shuffle_remote.html .
I have to emphasize that I am no expert on this topic, but from what I have read and tried so far I conclude that it is not impossible to have an Android phone respond to an iPhone headphone's volume buttons, but for some reason the performance is poor/lagging.
There are some apps trying to do the magic, but they are too unreliable for everyday use. I suppose the problem is that triggering the signal may have to be implemented at a lower OS level than most regular apps have access too.
The solution could probably be some kind of a ROM mod...
If you can implement this, I am sure it would be a big deal for the Android community, and maybe a good biz for you.
Kind Regards, your fellow Hungarian
Gergő
You have to press and hold the middle button while plugging the headphones to the jack. That will make the microphone work on an Android. It works on my HTC Thunderbolt.
I believe it's a hardware issue (at least in regards to Apple headphones). If you look at the plug on those they have four contacts instead of the normal three. I'm willing to bet they run their button signals through that extra contact. AFAIK, there is no Android equipment wth jacks to match that.
So, ultimately I don't believe you can make apple earphones with buttons work for android (as far as button functions go).
You have to hold the middle the whole time for it to work. If you let go and not playin music it says accsessary not supported but if u play music and let go it simply stops the music until you hold it again. Maybe tape the middle button shut really tight?
If you look at the four contacts, tip-ring-ring-sleeve (TRRS), and know that MOST headphone sets are:
tip: left
ring 1: right
ring 2: ground
sleeve: mic
(1/4 inch pro audio stereo plugs are known as TRS - tip-ring-sleeve)
although some reverse the ground and mic contacts, what you need to know as far as how the device recognizes the different buttons you have, is that those buttons are making a short between the ground and mic contacts.
(before IR, old school WIRED remotes for VCRs used resistance for different functions)
Now your homework to find out what is going on is:
measure the resistance between ring 2 and the sleeve for each one of your buttons
find out if it is a momentary short, or constant
if you have some other headphone/mic device that works correctly, measure those impedance (resistance) too
I don't know how into this you want to get, but you can buy resistors with the correct impedance to get the functions you want out of the Android device, the question is, do you know what functions the device is capable of, and what those impedances are that trigger that function.
daniel#destinypatrolsoftware.com
Is there a way to display text on lock screen? Like the information about unread SMS messages or like that Music Player on lock screen with Play/Pause buttons.
Thanks
Yes and no. Their is no public API to create or modify the lock screen. Whoever built the OS version on your device created your lock screen. Some of the manufacturers or carriers have added additional things to the lock screen. I've seen some that tie in to the music app, HTC sense has a somewhat customizable lock screen. So if you were willing to create your own rom and flash it to your device you could write your own lockscreen. Short of that the best you can do is write an app that the system thinks is an alternate home screen that has some kind of lock mechanism before the actual home is displayed. Then you set your device not to use a lock screen(so that it won't show both) This is not a great solution however, there are bound to be more ways to access the device if you use a "fake" lock screen like that so if security is an issue I wouldn't mess with it at all.
You might be able to find one of these "fake" lock screens on the market that suites your needs or you could create one that is exactly what you want. You could also search around on XDA for a rom that works with your device, 3rd party roms may be more likely to have the features your looking for on the lock screen.
If you end up making a pretend lock screen by using the home replacement method I strongly suggest you do not distribute something like that on the market. It is insecure and the users are unlikely to realize that there is a difference between that and a legit lock screen. Plus there is no guarantee that this method doesn't get broken at some point.
I want to detect memory leaks in my Android application. Some leaks could be detected while rotating the phone physically so that the activities are constantly recreated.
I'm looking of some sort of physical device that could turn the phone 90 degrees every X seconds. I could build something using lego Mindstorm (that would actually be very cool), but I'm looking for something cheaper.
I also thought of using a clock, but I couldn't find one that has a clock second hand strong enough. Futhermore if the phone rotate 360 degrees after some time the USB cable would become too twisted. I think a device that goes back and forth between horizontal and vertical would be perfect.
My dream testing machine would also allow me to plug a USB cable so that I can run the Monkey tool while constantly rotating the phone.
Why don't you just force the orientation change or destroy and recreate the views every X seconds? I think it's more reliable than a mechanical approach. I can also recommend you this : http://developer.android.com/guide/developing/tools/monkey.html
You need to trigger configuration change somehow. This might be orientation change, hardware keyboard is opened or hidden, or any other change listed here: android:configChanges.
And there is one way to change configuration without using physical approach. You can use "Car Mode" or "Night Mode". Both only work in Android 8+ and can be turned on/off using UiModeManager.
So you can write your custom Service that will periodically call UiModeManager.enableCarMode(0) and UiModeManager.disableCarMode(0);, which in turn will force configuration changes in your Activity under test.
Perhaps http://mindstorms.lego.com/ Lego MindStorms? To be fair, it's about $250 so not really "throwaway cheap" but the advantage of being fully programmable might outweigh that.
As far as I know it's the cheapest robot kit out there which is why universities and schools use it.