Save pdf data in storage

[Soni Kumari]

Hi there! I'm working on a project that converts image to pdf. To convert i use base64

data:application/pdf;base64 so how to save this data in device storage.

Please tell me the way, I'd very appreciative 🙏 

[Jumar]

Try this:

var appFolder = "/Internal/Documents/MyFolder";

function writePdfToDocuments(filePath, b64pdf) {
        const perm = "internal"
       
        if( !app.CheckPermission(appFolder) ) {
                app.GetPermission(perm, path => {
                        if (!path) {
                            app.ShowPopup("Permission not granted")
                        }
                        else {
                            writePdfToDocuments(filePath, b64pdf)
                        }
                    })
            return
        }
       
        app.MakeFolder(appFolder)
        app.WriteFile(filePath, b64pdf, "Base64")
        app.ShowPopup("PDF is saved to Documents/MyFolder folder")
    }

Regards

[Soni Kumari]

Thank you so much for this! 

But Is there any more ways to save direct in Documents without permission?

[Jumar]

Saving directly without asking permission is a NO for latest android.

To avoid asking for permission, initiate a download action the way download works for the web. I haven't tried this btw.

[Soni Kumari]

Thanks for replying Jumar!

I was asking because when i convert lots images to pdf in base64 then app get hangs sp there any to fast processing and without app freezing?

[Jumar]

Try running a background nodejs process to handle batch conversion so that your main thread will not hang.

[Soni Kumari]

I don't understand this :(

[Jumar]

When creating an app we are working mostly in the main thread. When we do heavy operation (such as batch image to pdf conversion), this will take some time to complete making our main thread seems like hanging. Luckily, DroidScript supports Nodejs so we can run a nodejs thread in the background which is separated from our main ui thread. You just let nodejs handle heavy processing and then notify the main thread once nodejs finishes the job.

[Soni Kumari]

But how sir! I'm really confused here any demo files

I use js lib to convert image to pdf 

[Alan Hendry]

HI,

When you create a new project/app

there's an option for Node (instead of Native)

then sub-options of Simple and Node Server

They sill create Sample code

Regards, ah

[Jumar]

Hi.

Try this code:

Your main file code: [MyProjectName].js


function OnStart()
{
    lay = app.CreateLayout( "Linear", "VCenter,FillXY" )
     
    txt = app.AddText(lay, "This is your main thread", 1)
   
    callNodeJs = app.AddButton(lay, "Generate pdf in nodejs")
    callNodeJs.SetOnTouch( CallNodeJS )

    app.AddLayout( lay )
   
    node = app.CreateNode();
    node.SetOnReady(node_OnReady);
}

function node_OnReady()
{
    node.Run("node_script.js")
}

function CallNodeJS()
{
    node.Func("GeneratePDF", "Value from main thread")
}

function OnPDFComplete(param1)
{
    app.ShowPopup(param1+": PDF completed...")
}



node_script.js file code:


console.log("Hello from nodejs")

// This function will be called from the main ui thread
function GeneratePDF(param1)
{
    // generate pdf here
    console.log(param1 + ": Generating pdf...")
   
    // call OnPDFComplete() function in the main thread after 4 seconds
    setTimeout(() => {
        parent.Func("OnPDFComplete", "Value from nodejs")
    }, 4000)