Android Question Calling Java Class

prajinpraveen · Feb 10, 2025

Hello Everyone,

I am trying to convert the following java code to B4A

1:

PrintTask printTask = new PrintTask();
printTask.setPrintBitmap(BitmapFactory.decodeResource(context.getResources(), R.drawable.printer));
Printer.getInstance().startPrint(printTask, new PrinterCallback() {

2:

// PrinterTask.Java

package com.pos.device.printer;

import android.graphics.Bitmap;

public class PrintTask {
  public int mStep;
 
  public Bitmap mBitmap;
 
  public PrintTask() {
    throw new RuntimeException();
  }
 
  public int getGray() {
    throw new RuntimeException();
  }
 
  public void setGray(int gray) {
    throw new RuntimeException();
  }
 
  public void addFeedPaper(int step) {
    throw new RuntimeException();
  }
 
  public void setPrintCanvas(PrintCanvas printCanvas) {
    throw new RuntimeException();
  }
 
  public void setPrintBitmap(Bitmap origBitmap) {
    throw new RuntimeException();
  }

  public void setPrintBuffer(byte[] buffer) {
    throw new RuntimeException();
  }
}

B4X:

    Dim bitmap As B4XBitmap = TextToBitmap("Text to Bitmap", 20, xui.Color_Black, "CENTER")
    Dim jo As JavaObject
    Try
        jo = jo.InitializeNewInstance("com.pos.device.printer.PrintTask",Null)
        jo.RunMethod("setPrintBitmap", Array As Object(bitmap))
    Catch
        Log(LastException)
    End Try


java.lang.RuntimeException
    at com.pos.device.printer.PrintTask.<init>(PrintTask.java:20)
    at java.lang.Class.newInstance(Native Method)
    at anywheresoftware.b4j.object.JavaObject.InitializeNewInstance(JavaObject.java:86)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:348)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:157)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:205)
    at anywheresoftware.b4a.debug.Debug.delegate(Debug.java:262)
    at com.test.sfpayments.main._print(main.java:496)
    at com.test.sfpayments.main._activity_create(main.java:488)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:351)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:157)
    at com.test.sfpayments.main.afterFirstLayout(main.java:121)
    at com.test.sfpayments.main.access$000(main.java:33)
    at com.test.sfpayments.main$WaitForLayout.run(main.java:99)
    at android.os.Handler.handleCallback(Handler.java:751)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6121)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1059)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:949)
(Exception) java.lang.Exception:  java.lang.RuntimeException

InitializeStatic initialises the class, but cannot run the SetPrintBitmap Method

3:

    Dim bitmap As B4XBitmap = TextToBitmap("Text to Bitmap", 20, xui.Color_Black, "CENTER")
    Dim jo As JavaObject
    Try
        jo = jo.InitializeStatic("com.pos.device.printer.PrintTask")
        jo.RunMethod("setPrintBitmap", Array As Object(bitmap))
    Catch
        Log(LastException)
    End Try
    
    Log(jo)
    
    Error occurred on line: 592 (Main)
java.lang.IllegalArgumentException: Expected receiver of type com.pos.device.printer.PrintTask, but got java.lang.Class<com.pos.device.printer.PrintTask>
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4j.object.JavaObject.RunMethod(JavaObject.java:132)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.shell.Shell.runVoidMethod(Shell.java:777)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:354)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:157)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:205)
    at anywheresoftware.b4a.debug.Debug.delegate(Debug.java:262)
    at com.test.sfpayments.main._print(main.java:496)
    at com.test.sfpayments.main._activity_create(main.java:488)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:351)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:157)
    at com.test.sfpayments.main.afterFirstLayout(main.java:121)
    at com.test.sfpayments.main.access$000(main.java:33)
    at com.test.sfpayments.main$WaitForLayout.run(main.java:99)
    at android.os.Handler.handleCallback(Handler.java:751)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6121)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1059)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:949)
(Exception) java.lang.Exception:  java.lang.IllegalArgumentException: Expected receiver of type com.pos.device.printer.PrintTask, but got java.lang.Class<com.pos.device.printer.PrintTask>
(Class) class com.pos.device.printer.PrintTask

Any assistance will be greatly appreciated.

Thank you

DonManfred · Feb 10, 2025

prajinpraveen said:
public PrintTask() { throw new RuntimeException(); } public int getGray() { throw new RuntimeException(); } public void setGray(int gray) { throw new RuntimeException(); } public void addFeedPaper(int step) { throw new RuntimeException(); } public void setPrintCanvas(PrintCanvas printCanvas) { throw new RuntimeException(); } public void setPrintBitmap(Bitmap origBitmap) { throw new RuntimeException(); } public void setPrintBuffer(byte[] buffer) { throw new RuntimeException(); }

This can not be the right code. All the code is doing is to create a RuntimeException.

prajinpraveen · Feb 10, 2025

this is what is see when i decompile the jar file. am i missing anything?

DonManfred · Feb 10, 2025

prajinpraveen said:
this is what is see when i decompile the jar file. am i missing anything?

- Do NOT decompile! The decompiler was not able to do its job.
- Use the original SOURCE files.

prajinpraveen · Feb 10, 2025

Thank you. will it help if i provide you with the SDK jar?

aeric · Feb 10, 2025

Is the code editor collapsed?
Can you click the minus button to reveal the code that may be hidden?

prajinpraveen · Feb 10, 2025

Hello Aeric. I trust you are doing well.

I have tried. it is expanded already and cannot expand it further

DonManfred · Feb 10, 2025

aeric said:
Can you click the minus button to reveal the code that may be hidden?

i guess the decompile just fails to decompile the jar and just create this methods.
A point more not to use a decompiler and instead use the sourcejars if there are available....

aeric · Feb 10, 2025

Why decompile the library?
Have you try interact with the jar using #AdditionalJars and JavaObject?

prajinpraveen · Feb 10, 2025

attached is a working project.

aeric · Feb 10, 2025

prajinpraveen said:
InitializeStatic initialises the class, but cannot run the SetPrintBitmap Method

I think InitializeNewInstance is correct.

prajinpraveen said:
java.lang.RuntimeException at com.pos.device.printer.PrintTask.<init>(PrintTask.java:20)

Need to figure out this error.

B4X:

    Try
        Dim jo As JavaObject
        jo.InitializeNewInstance("com.pos.device.printer.PrintTask", Null)
        jo.RunMethod("setPrintBitmap", Array As Object(bitmap))
    Catch
        Log(LastException)
    End Try

Daestrum · Feb 10, 2025

Maybe try

B4X:

    Dim pt As JavaObject
    pt.InitializeStatic("com.pos.device.printer.PrintTask")
    pt.RunMethod("setPrintBitmap",Array("load_your_image_here"))

prajinpraveen · Feb 10, 2025

Daestrum said:

Maybe try

B4X:

    Dim pt As JavaObject
    pt.InitializeStatic("com.pos.device.printer.PrintTask")
    pt.RunMethod("setPrintBitmap",Array("load_your_image_here"))

Thank you.

I have tried this. gives me the following error

Error occurred on line: 592 (Main)
java.lang.IllegalArgumentException: Expected receiver of type com.pos.device.printer.PrintTask, but got java.lang.Class<com.pos.device.printer.PrintTask>
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4j.object.JavaObject.RunMethod(JavaObject.java:132)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runVoidMethod(Shell.java:777)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:354)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:157)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:205)
at anywheresoftware.b4a.debug.Debug.delegate(Debug.java:262)
at com.test.sfpayments.main._print(main.java:496)
at com.test.sfpayments.main._activity_create(main.java:488)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:351)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:157)
at com.test.sfpayments.main.afterFirstLayout(main.java:121)
at com.test.sfpayments.main.access$000(main.java:33)
at com.test.sfpayments.main$WaitForLayout.run(main.java:99)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6121)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1059)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:949)
(Exception) java.lang.Exception: java.lang.IllegalArgumentException: Expected receiver of type com.pos.device.printer.PrintTask, but got java.lang.Class<com.pos.device.printer.PrintTask>
(Class) class com.pos.device.printer.PrintTask

aeric · Feb 10, 2025

aeric said:
I think InitializeNewInstance is correct.

Need to figure out this error.

B4X:

Try Dim jo As JavaObject jo.InitializeNewInstance("com.pos.device.printer.PrintTask", Null) jo.RunMethod("setPrintBitmap", Array As Object(bitmap)) Catch Log(LastException) End Try

Usually I will try to Log the object to see it is successfully initialized.

B4X:

Try
    Dim jo As JavaObject
    jo.InitializeNewInstance("com.pos.device.printer.PrintTask", Null)
    Log(jo)
Catch
    Log(LastException)
End Try

prajinpraveen · Feb 10, 2025

aeric said:
Usually I will try to Log the object to see it is successfully initialized.

B4X:

Try Dim jo As JavaObject jo.InitializeNewInstance("com.pos.device.printer.PrintTask", Null) Log(jo) Catch Log(LastException) End Try

*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create (first time) **
printing
Error occurred on line: 582 (Main)
java.lang.RuntimeException
at com.pos.device.printer.PrintTask.<init>(PrintTask.java:20)
at java.lang.Class.newInstance(Native Method)
at anywheresoftware.b4j.object.JavaObject.InitializeNewInstance(JavaObject.java:86)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:348)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:157)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:205)
at anywheresoftware.b4a.debug.Debug.delegate(Debug.java:262)
at za.co.irays.sfpayments.main._print(main.java:506)
at za.co.irays.sfpayments.main._activity_create(main.java:498)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:351)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:157)
at za.co.irays.sfpayments.main.afterFirstLayout(main.java:131)
at za.co.irays.sfpayments.main.access$000(main.java:43)
at za.co.irays.sfpayments.main$WaitForLayout.run(main.java:109)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6121)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1059)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:949)
** Activity (main) Resume **

Daestrum · Feb 10, 2025

What is it if you initialise as Static instead?

aeric · Feb 10, 2025

prajinpraveen said:
it is null

Do you put the sdk.jar into B4A Additional Libraries folder and add #AdditionalJars: sdk ?

DonManfred · Feb 10, 2025

prajinpraveen said:
IllegalArgumentException: Expected receiver of type com.pos.device.printer.PrintTask, but got java.lang.Class<com.pos.device.printer.PrintTask>

There is an Receiver expected here.

You need to have an receiver for PrintTask i guess.

prajinpraveen · Feb 10, 2025

aeric said:
Do you put the sdk.jar into B4A Additional Libraries folder and add #AdditionalJars: sdk ?

Yes I have

prajinpraveen · Feb 10, 2025

Daestrum said:
What is it if you initialise as Static instead?

I get the error as per post 13

https://www.b4x.com/android/forum/threads/calling-java-class.165540/post-1014973

Android Question Calling Java Class

Active Member

Expert

Active Member

Expert

Active Member

Expert

Active Member

Expert

Expert

Active Member

Attachments

Expert

Expert

Active Member

Expert

Active Member

Expert

Expert

Expert

Active Member

Active Member

Similar Threads

Privacy & Transparency

Privacy & Transparency