Java classes for pyjnius

Question

I have created a Java class to use in python with pyjnius but I can't use it as pyjnius can't find it, the pyjnius documentation says that I have to move the Java classes to src/org And I have done it but have not been successful, could someone tell me how can I go about using my Java classes with pyjnius please.

Answer 1

Make sure you tell buildozer where is the java source that you package.

for example, if you have java/org/test/TestClass.java you could do.

android.add_src = java/

make sure your java package matches what you expect to import from jnius.

package org.test;

from jnius import autoclass
autoclass('org.test.TestClass')

---

a full example

app/main.py

"""Demonstrate loading custom java code using jnius
"""
from kivy.app import App
from jnius import autoclass


class Application(App):
    """see module documentation
    """

    def test_jnius(self, name):
        """Lookup our test class, instanciate and call its method
        """
        cls = autoclass("org.test.TestClass")
        result = cls(name).get_result()
        self.root.ids.result_box.text = result


if __name__ == "__main__":
    Application().run()

app/application.kv

FloatLayout:
    BoxLayout:
        orientation: 'vertical'
        size_hint: .5, .5
        pos_hint: {'center': (.5, .5)}
        spacing: '20dp'

        Label:
            text: 'Please enter your name'

        TextInput:
            id: ti
            multiline: False
            size_hint_y: None
            height: self.minimum_height

        Button:
            text: 'hit me!'
            on_release: app.test_jnius(ti.text)
            size_hint_y: None
            height: '38dp'

        Label:
            id: result_box

buildozer.spec

[app]
title = Kivy With Java App
package.name = kivyjavaapp
package.domain = org.test
source.dir = app/
source.include_exts = py,png,jpg,kv,atlas
version = 0.1
requirements = python3,kivy
orientation = portrait
fullscreen = 0
android.add_src = java/
android.arch = armeabi-v7a
android.allow_backup = True
ios.kivy_ios_url = https://github.com/kivy/kivy-ios
ios.kivy_ios_branch = master
ios.ios_deploy_url = https://github.com/phonegap/ios-deploy
ios.ios_deploy_branch = 1.10.0
ios.codesign.allowed = false

[buildozer]
log_level = 2
warn_on_root = 1

java/org/test/TestClass.java

package org.test;
import java.lang.String;

public class TestClass {
    private String _name;

    public TestClass(String name) {
        _name = name;
    }

    public String get_result() {
        return "Hello " + _name;
    }
}

(optional, if you want to test your java code on desktop, building it with ant all and export CLASSPATH=build/ before running python app/main.py)

build.xml

<project>
    <property name="ant.build.javac.source" value="1.7" />
    <property name="ant.build.javac.target" value="1.7" />

    <target name="clean">
      <delete dir="build"/>
    </target>

    <target name="test-compile">
        <mkdir dir="build"/>
        <javac srcdir="java/" destdir="build"
               includeantruntime='false'
               encoding="UTF-8"/>
    </target>

    <target name="jar" depends="test-compile">
        <jar destfile="build/org.test.jar" basedir="build/">
        </jar>
    </target>

    <target name="all" depends="jar,test-compile"/>
</project>

you can find this full example in this repository https://github.com/tshirtman/android_jnius_custom_java