Develop for android java issues

J.Hilk

@Phips04 It does not matter at all what device you attach to your PC,

what does matter is what minimal android version you set inside your manifest. Did you change it there ?

jsulm

This post is deleted!

Phips04

@J-Hilk Which file is that?

Do you mean the *.pro file?

KroMignon

@Phips04 said in Develop for android java issues:

Do you mean the *.pro file?

No, the Android manifest ==> AndroidManifest.xml
Double click on it in QtCreator to start the editor:

Phips04

This is how it actually looks like, the option to set the sdk is disabled.
I made sure, that the sdk's I want to use are installed. (Sry I'm new to qt)

KroMignon

@Phips04 Did you check QtCreator Android configuration?

In Tools/Option/Devices, select tab "Android":

Phips04

Java and android settings are ok, in the android settings there is no "ndk-bundle". But the second entry exists, as I mentioned OpenSSL is not set

KroMignon

@Phips04 said in Develop for android java issues:

in the android settings there is no "ndk-bundle"

This is your problem, ndk-bundle is mandatory for Qt!

Extract from the Qt documentation:
Use the sdkmanager command line tool to update the packages list and then install the essential packages:

cd <ANDROID_SDK_ROOT>/tools/bin/
./sdkmanager --update
./sdkmanager --install "platform-tools" "platforms;android-29" "build-tools;29.0.2" "ndk-bundle"

Phips04

Ok, I did it, but the cmd line reported some errors, and there was no effect in qt creator.

KroMignon

@Phips04 This seems to be a well know issue with Android:

You can try:

cd <ANDROID_SDK_ROOT>\tools\bin\
sdkmanager --sdk_root="<ANDROID_SDK_ROOT>" --update
sdkmanager --sdk_root="<ANDROID_SDK_ROOT>" --install "platform-tools" "platforms;android-29" "build-tools;29.0.2" "ndk-bundle"

Phips04

It worked this way, the bundle is installed now, but I still can't change the minimal android version

J.Hilk

@Phips04 do it by hand than, open the android manifest.xml in a text editor
and change the version there

Phips04

The .xml can be evaluated and I set the entries. Min sdk is 21 (android 5) and target is 27 (android 8.1). The error still is the same

KroMignon

@Phips04 said in Develop for android java issues:

It worked this way, the bundle is installed now, but I still can't change the minimal android version

What do you mean with "you can't"? Is the dropdown combobox grayed out or is the list empty?
Do you have restart Qt Creator after updating SDK root?

Phips04

Yes the combobox was grayed (I set the entries in the xml file via text editor, now I can edit the boxes) and I restarted Qt creator.

KroMignon

@Phips04 I know how have written "Java settings are ok", but which JDK version are you using?

AFAIK, gradle do NOT work with JDK > 11, and recommended version is still JDK 8.

Phips04

I meant qt Creator says Java settings are ok.
I didn't remember that version 8 is the recommended one, installed 15.
I will replace it by 8 now

KroMignon

@Phips04 said in Develop for android java issues:

I didn't remember that version 8 is the recommended one, installed 15.

Yes, it is no clearly defined ==> https://doc.qt.io/qt-5/android-building.html.
JDK 8, still recommended for best compatibility, but starting with Qt 5.15 JDK 11 could be used.

Side note: if you search on internet java.lang.NoClassDefFoundError: Could not initialize class org.codehaus.groovy.vmplugin.v7.Java7, all matches you will found will clearly detail the issue. The gradle version is not compatible with the selected JDK.
For Qt 5.15, the used gradle version is 5.6.4 (just check in <QT_DIR>/5.15.0/android/src/3rdparty/gradle/gradle/wrapper/gradle-wrapper.properties)

Phips04

Ok, now finally it works. This is my very basic UI for testing

This is the sourcecode:

import QtQuick 2.15
import QtQuick.Window 2.15

Window {
Rectangle {
id: rectangle
color: "#09a4cc"
anchors.fill: parent

    Rectangle {
        id: rectangle1
        x: 220
        y: 117
        width: 200
        height: 200
        color: "#4facfe"
        radius: height / 2
        gradient: Gradient {
            GradientStop {
                position: 0
                color: "#4facfe"
            }

            GradientStop {
                position: 1
                color: "#00f2fe"
            }
        }
    }
}

}

What it shows is simply a white screen.🙄

KroMignon

@Phips04 I think you have to set property visible to true of top Window:

import QtQuick 2.15
import QtQuick.Window 2.15

Window {
    visible: true // ==> default value is false!
    Rectangle {
        id: rectangle
        color: "#09a4cc"
        anchors.fill: parent
      ...
   }
}