recycleview on android

purushottam yadav

unread,

Jul 9, 2021, 10:32:17 AM7/9/21

to Kivy users support

I want to display the images in the android device , using recycleview .

when recycle view is called , it is calling one function ( takingper(self) ) to take permissions and this function calls other function to load images into recycleview .

In this case apk is crashing on android just after starting , only blackscreen is displayed for 5 secs . nothng I found in logs related to recycleview .

when i tried to display images that are captured only today , In this case apk is taking 15 secs to display the images on the black screen . but it is working fine , but why 15 secs just to display images . ?

from kivy.app import App

from kivy.lang import Builder

from kivy.uix.recycleview import RecycleView

from kivy.uix.image import Image

from kivy.properties import (

AliasProperty,

BooleanProperty,

BoundedNumericProperty,

ListProperty,

NumericProperty,

ObjectProperty,

OptionProperty,

StringProperty,

)

from plyer import storagepath

from kivy.uix.recycleview import RecycleView

from kivy.uix.recycleview.views import RecycleDataViewBehavior

import glob

from kivy.utils import platform

Builder.load_string('''

<Piccollect>:

#on_release: app.calll(root.source)

<RV>:

viewclass: 'Piccollect'

RecycleGridLayout:

orientation: 'lr-tb'

cols: 4

spacing: ['5dp' , '10dp']

padding: ['5dp']

#default_size: None, dp(rv.width/self.cols*.6)

default_size_hint: 1, None

size_hint_y: None

height: self.minimum_height

''')

class RV(RecycleView):

def __init__(self, **kwargs):

super(RV, self).__init__(**kwargs)

self.takingper()

def takingper(self):

# only Request permissions on Android , not loading images path

if platform == 'android' :

from android.permissions import Permission, request_permissions

def call__back(permission, results):

if all([res for res in results]):

print("Got all permissions>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>")

self.per = True

return self.loadaddress()

#print("called loadaddress function ======================")

else:

print("Did not get all permissions>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>")

request_permissions([Permission.WRITE_EXTERNAL_STORAGE, Permission.READ_EXTERNAL_STORAGE], call__back)

def loadaddress(self):

#this piece of code is for formatting the date string as required

from datetime import date

# calling the today

# function of date class

today = date.today()

if len(str(today.month)) == 1 :

self.m = "0" + str(today.month)

else :

self.m = str(today.month)

if len(str(today.day)) == 1 :

self.d = "0" + str(today.day)

else :

self.d = str(today.day)

self.dddate = str(today.year) + str(self.m) + str(self.d)

# self.dddate will be 20210709 as todays date is 9/7/2021

print(str(self.dddate) , "date>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>")

if platform == 'android':

print("loading....=============================")

#In this case apk is taking 15 secs to display the images on the screen

self.data = [{'source': file} for file in glob.glob(f"/storage/emulated/0/DCIM/Camera/IMG_{self.dddate}_*.*")] #when i want to collect today captured images

# In this case apk is crashing on android just after starting , only blackscreen is displayed for 5 secs

#self.data = [{'source': file} for file in glob.glob(f"/storage/emulated/0/DCIM/Camera/IMG_*.*")] #when i want to collect all the captured images (800 images ) in the device

print(self.data)

print(len(self.data))

class Piccollect(Image):

source = StringProperty('')

print("created=====================================================")

def on_touch_down( self, touch ):

if self.collide_point( *touch.pos ):

print("selecting......" , self.source)

#k.calll(self.source)

class TestApp(App):

def build(self):

return RV()

if __name__ == '__main__':

TestApp().run()

Robert

unread,

Jul 9, 2021, 1:11:52 PM7/9/21

to Kivy users support

In this case apk is crashing on android just after starting , only blackscreen is displayed for 5 secs . nothng I found in logs related to recycleview .

when i tried to display images that are captured only today , In this case apk is taking 15 secs to display the images on the black screen . but it is working fine , but why 15 secs just to display images . ?

As I understand, it takes a long time with a smaller amount of work and crashes with more work.

Perhaps the work is too hard?

1) I think there are other posts in this group about using lots of images with RV, Elliot would know better than me, I know nothing about RV. (but perhaps one solution might be loading thumbnails)

2) Android is very picky about UI responsiveness so slow tasks must not be in the UI thread. I'm gonna guess an unresponsive UI thread is the cause of the crash. But there may still be a latency issue, it may well benefit up to the number of threads equal to the number of cores - 1.

Oh, wait, that was you https://groups.google.com/g/kivy-users/c/wgQZnJqU13s/m/0hnxN9ufBAAJ

purushottam yadav

unread,

Jul 10, 2021, 7:46:34 AM7/10/21

to Kivy users support

what about this code this works fine on android without any delay , what is making above code crash but not this .

this below code is displaying 1000 images , previous code should display 800 images .

self.data = [{'source' : "download.jpg " } for x in range(1000) ]

class Piccollect(Image):

source = StringProperty(' ')

print("created=====================================================")

def on_touch_down( self, touch ):

if self.collide_point( *touch.pos ):

print("selecting......" , self.source)

class TestApp(App):

def build(self):

return RV()

if __name__ == '__main__':

TestApp().run()

Robert

unread,

Jul 10, 2021, 12:39:43 PM7/10/21

to Kivy users support

Presumably because this is only one file.

Message has been deleted

purushottam yadav

unread,

Jul 12, 2021, 9:24:46 AM7/12/21

to Kivy users support

Any suggestions from Elliot and any other member of this group about how to display large number of widgets in android ?

Elliot Garbus

unread,

Jul 12, 2021, 10:19:26 AM7/12/21

to kivy-...@googlegroups.com

Some suggestions.

Here are a few things I see in your code.

I suspect your issue is: You have redefined source in Piccollect. Image has an attribute source. You have added a kivy property named source. Just use self.source of Image.

Use a ListProperty to for the rv data.

In the kv code add it…

<RV>:

data: self.rv_data

viewclass: 'Piccollect'

RecycleGridLayout:

orientation: 'lr-tb'

cols: 4

spacing: ['5dp' , '10dp']

padding: ['5dp']

#default_size: None, dp(rv.width/self.cols*.6)

default_size_hint: 1, None

size_hint_y: None

height: self.minimum_height

And in Python:

class RV(RecycleView):

rv_data = ListProperty()

I also suggest you move your permission code, takingper() to the on_start method of app. The __init__ of recycle view is an odd place for this code.

Make sure your code is running on a desktop, then add the android specifics.

--
You received this message because you are subscribed to the Google Groups "Kivy users support" group.
To unsubscribe from this group and stop receiving emails from it, send an email to kivy-users+...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/kivy-users/d962bf45-6173-4c5e-ad9d-7b9492008659n%40googlegroups.com.

purushottam yadav

unread,

Jul 18, 2021, 2:35:00 PM7/18/21

to Kivy users support

This is a memory issue . Someone online suggested me that

"if your code works with few images, then your code is not broken. i would assume there's a memory issue here and simply too much data. try running it on a more powerful desktop and see if it works in principle... "

After this I used AsyncImage for piccollect instead of Image .

This can be useful as it prevents your application from waiting until the image is loaded. If you want to display large images or retrieve them from URL’s, using AsyncImage will allow these resources to be retrieved on a background thread without blocking your application.

class Piccollect(AsyncImage): , Now there is no delay on starting the app in all the cases , but it has delay to display images in all the cases .

when I tried to display few images , there was no delay to start but default images were displayed for a while ( 2 secs ) , and actually images where displayed .

when I tried to display all the images , there was no delay to start but default images were displayed for a while ( 2 secs ) , and actually images started to display and again APK CRASHED , and my phone got hanged for a while .

Below are screen shots during that 2 secs of loading the images .

Now the problem is that while displaying few images APK did not CRASH but CRASHED when tried to display all the images in the android device .

I guess , this is because of loading alot of data at once .

why this is happening and how to handle this issue ?

WhatsApp Image 2021-07-18 at 11.32.25 PM.jpeg

WhatsApp Image 2021-07-18 at 11.32.25 PM (1).jpeg

Elliot Garbus

unread,

Jul 18, 2021, 2:50:22 PM7/18/21

to kivy-...@googlegroups.com

Share a minimal executable that demonstrates the issue.

From: purushottam yadav
Sent: Sunday, July 18, 2021 11:35 AM
To: Kivy users support
Subject: Re: [kivy-users] Re: recycleview on android