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[Q] Touchscreen lag

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classicalpunk
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Phone [Q] Touchscreen lag

Hi everyone !

I recently got my digitizer changed (apparently phones don't like faceplants ) and when i got it back I noticed a "slight" change.

Symptom :
When I touch the screen and slide my finger there's a little lag before the move is recorded by the phone, like, I have to move my finger more than 1/2 inch away from the starting point or it consider my finger didn't move from it. (thus resulting in little jumps when sliding through menus or if you wanna draw a circle it start by drawing a straight line ) After the phone catches up however (so, as long as I keep my finger on it) it follow up well just like it has to .

Resolution tested :
Through research I think my problem could come from a change between the dpi of the stock digitizer and the one I got in replacement, so the stock touch_slop value isn't adapted anymore. I tried to change it in my build.prop, but it made no difference and the problem is still here. Although it doesn't mean the problem doesn't come from that (The way Android handles touch_slop has changed in the latest versions) I don't know how to fix it and I need advices. Has someone already encountered that problem ? How can I fix it ?
 
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Firstly, Did you ask SONY to change the digitzer or from an external vendor?
Secondly, was the digitizer flex cable given to you when you purchased the new one?
Thridly, Is the digitizer properly placed on your screen?


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classicalpunk
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Quote:
Originally Posted by Furrydaus View Post
Firstly, Did you ask SONY to change the digitzer or from an external vendor?
External vendor, I firstly went to the official support and they said It would cost me the price of the phone, , so I didn't insist on the "official" way

Quote:
Originally Posted by Furrydaus View Post
Secondly, was the digitizer flex cable given to you when you purchased the new one?
I'm not the one who changed the digitizer, I went to a local tech shop, the only thing I was given was my phone.

Quote:
Originally Posted by Furrydaus View Post
Thirdly, Is the digitizer properly placed on your screen?
Yep, from an external point of view you can't say it has been changed (If you don't mind the big cracks that were there before )
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Quote:
Originally Posted by classicalpunk View Post
External vendor, I firstly went to the official support and they said It would cost me the price of the phone, , so I didn't insist on the "official" way


I'm not the one who changed the digitizer, I went to a local tech shop, the only thing I was given was my phone.


Yep, from an external point of view you can't say it has been changed (If you don't mind the big cracks that were there before )
Ok so the tech shop might be the problem. They might have used an incorrect cable and might have also provide you with a bad digitizer. The Cable is essential as it transfers touch signals to the board and if its faulty or not of good quality the digitizer might as well be useless. For the digitzer you might want to check with them on what digitzer they used and if its those cheap 'china' brand types then it's also not good for your phone. Quickly get to the shop and ask them to help you because a faulty digitzer might break your whole device


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classicalpunk
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Yeah it might be, but as I said, it's only the first "move" that lags, it record the touch at the exact moment I touch the screen and after the first 1/2 inch is past there's no problem anymore so I don't really think the problem is related to that.

Actually, I think there was a similar "problem" a few years back, it was related to the way Android make a difference between a click and a swype. Its create a deadzone around the first point that's touched by your finger, so that every time you click it's not considered as a swype (because biologically you just can't click only ONE pixel). The size of this deadzone was the same on every phone and was related to the touch_slop value. At some point on some "newer" phone the size of the digitizer was bigger but not the dpi and so the deadzone began to be a hindrance more than a conveniance, cause its size grew with the size of the screen. I was then decided to change the way it was handled by the system and a new method has been implemented, using mtouchslope value, that's not just a number of pixel but that's calculated from the dpi value of the digitizer. SO I think that the digitizer I got isn't the same as the stock one (just like you said) but I think there's a way for me to fix the problem in a more "software-way". The only thing I don't know here, is how can I change the digitizer's dpi value that's stored inside the phone.
Before : Xperia Play R800i - Xperia NXT 2 - Android 2.3.7 - Rooted - Unlocked BootLoader - DoomKernel v14

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Furrydaus
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Quote:
Originally Posted by classicalpunk View Post
Yeah it might be, but as I said, it's only the first "move" that lags, it record the touch at the exact moment I touch the screen and after the first 1/2 inch is past there's no problem anymore so I don't really think the problem is related to that.

Actually, I think there was a similar "problem" a few years back, it was related to the way Android make a difference between a click and a swype. Its create a deadzone around the first point that's touched by your finger, so that every time you click it's not considered as a swype (because biologically you just can't click only ONE pixel). The size of this deadzone was the same on every phone and was related to the touch_slop value. At some point on some "newer" phone the size of the digitizer was bigger but not the dpi and so the deadzone began to be a hindrance more than a conveniance, cause its size grew with the size of the screen. I was then decided to change the way it was handled by the system and a new method has been implemented, using mtouchslope value, that's not just a number of pixel but that's calculated from the dpi value of the digitizer. SO I think that the digitizer I got isn't the same as the stock one (just like you said) but I think there's a way for me to fix the problem in a more "software-way". The only thing I don't know here, is how can I change the digitizer's dpi value that's stored inside the phone.
Dude you should have used the reply funtion so I could reply more quickly
Anyways there is Resolution Changer by NoMone in the Play Store that deals with the resolution changes and DPI too. >>>

Regards,
Furrydaus


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classicalpunk
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Quote:
Originally Posted by Furrydaus View Post
Dude you should have used the reply funtion so I could reply more quickly
Anyways there is Resolution Changer by NoMone in the Play Store that deals with the resolution changes and DPI too. >>>

Regards,
Furrydaus
Yeah, I already looked for that, and the dpi value that's changed by this app is also present in the build.prop file but it only changes the dpi of the lcd screen and not the digitizer's one, so it doesn't really help me in this case. But thanks for your concern anyway
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Furrydaus
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Quote:
Originally Posted by classicalpunk View Post
Yeah, I already looked for that, and the dpi value that's changed by this app is also present in the build.prop file but it only changes the dpi of the lcd screen and not the digitizer's one, so it doesn't really help me in this case. But thanks for your concern anyway
Well thats a shame... How about you seek more help from your local tech shop? I'm sure they'll be more than happy to tell more!
No problem mate! I hope I've helped you in any ways possible! Hope you have a great day ahead!

Regards,
Furrydaus


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