B4J Question Download images from website

[TomDuncan]

Hi All,
Can someone guide me on how to download images from websites.
I need to grab a sites images. I can get these from sources.
Tom

 

[Sandman]

Hi Tom. Wrong forum. And as you post in B4J Questions, might I suggest adding a little bit more information what it is that you need help with?

 

[Erel]

Moved to the questions forum.

 

[MarkusR]

u need to download the page source and then parsing the img tag for the url name. (maybe regular expressions will help.)
not always possible if java script is used.
can also difficult if the url embedding other external pages.

here is a download image example.
https://www.b4x.com/android/forum/threads/b4x-resumable-subs-sleep-wait-for.78601/#content

 

[TomDuncan]

Checked out the download demo. How do I save the image. This is a non UI program.
Also I need to add some text to the image as a time stamp.

 

[MarkusR]

u need to create the file name with correct extention or using a sql database or make a info text file to the image.

see DateTime and DateUtils

create a simple file from string variable

File.WriteString(File.DirApp, "1.txt", "Some text")

save an image

    Dim Job As HttpJob
    '...

    'Dim Image1 As Image

    Dim Out As OutputStream = File.OpenOutput(File.DirApp, "1.png")
    
    Job.GetBitmap.WriteToStream(Out) 'from web request

    'Image1.WriteToStream(Out) 'from image direct
    
    Out.Close

 

[TomDuncan]

This is my modified code and it's error.

Sub DownloadImage(Link As String, filename As String)
    Dim job As HttpJob
    job.Initialize("", Me) 'note that the name parameter is no longer needed.
    job.Download(Link)
    Wait For (job) JobDone(job As HttpJob)
    If job.Success Then
        Dim out As OutputStream = File.OpenOutput(File.DirApp, "test.jpg", False)
           job.GetBitmap.WriteToStream(out) 'from web request
        out.Close
    End If
    job.Release
End Sub

B4J Version: 6.30
Parsing code.    (0.04s)
Compiling code.    (0.13s)
Compiling layouts code.    (0.00s)
Organizing libraries.    (0.00s)
Compiling generated Java code.    Error
B4J line: 134
job.GetBitmap.WriteToStream(out) 'from web re
javac 1.8.0_181
src\b4j\example\main.java:423: error: cannot find symbol
_job._getbitmap().WriteToStream((java.io.OutputStream)(_out.getObject()));
    ^
  symbol:   method _getbitmap()
  location: variable _job of type httpjob
1 error

Also the text is to super some text over the image.

Tom

 

[Erel]

Make sure to use the latest version of jOkHttpUtils2.

 

[TomDuncan]

I think the problem is that this is an non-ui application.
If I use jOkHttpUtils2_NONUI then job.GetBitmap.WriteToStream(out) comes with an error
unknown member: getbitmap
This is a NonUI web server program

Tom

 

[OliverA]

Try

Sub DownloadImage(Link As String, filename As String)
    Dim job As HttpJob
    job.Initialize("", Me) 'note that the name parameter is no longer needed.
    job.Download(Link)
    Wait For (job) JobDone(job As HttpJob)
    If job.Success Then
        Dim out As OutputStream = File.OpenOutput(File.DirApp, "test.jpg", False)
        File.Copy2(job.GetInputStream, out)
        out.Close
    End If
    job.Release
End Sub

Note: This is only going to properly work if all your downloading is an image (in this case a JPG image), not an HTML file containing an image and/or image links.

 

[TomDuncan]

Thanks for that Oliver, works like a charm.

 

[MarkusR]

Make sure to use the latest version of jOkHttpUtils2.

jOkHttpUtils2 - v2.40
jOkHttpUtils2_NONUI - v2.40 < agree this GetBitmap Is missing here
ide said v2.62, have b4j 6.30 installed

 

[OliverA]

agree this GetBitmap Is missing here

Image (in B4J) is a UI component (jFX), therefore GetBitmap is not part of the non-ui version of the library (it would just throw an error).

 

[MarkusR]

Image (in B4J) is a UI component (jFX), therefore GetBitmap is not part of the non-ui version of the library (it would just throw an error).

ah, that is the reason
(for me is a bitmap just pixel data in bytes)