JFrame remove taskbar Icon

Question

I have a JFrame that I minimize to the tray using:

This for showing:

Frame.this.Minimized = false;
Frame.this.setVisible(true);
systemTray.remove(systemTrayIcon);
Frame.this.setExtendedState(JFrame.NORMAL);

And this for hiding:

if (SystemTray.isSupported()) {
    systemTray.add(systemTrayIcon);
    Frame.this.setVisible(false);
    Frame.this.Minimized = true;
}
Frame.this.setExtendedState(JFrame.ICONIFIED);

However, I do NOT want to set the frame invisible.. When I set it invisible, it removes the taskbar icon which I like. Is there a way to remove the taskbar icon of the frame without setting the visibility to false?

The reason is because when I minimize my application, I can send it commands and it executes them but the second that I set its visibility to false, it stops executing any commands from an external application. All I need to do is remove the icon from the taskbar when minimized and show the icon when normal.

Any ideas?

Answer 1

sigh well seeing as there have been no replies for quite some time.. I decided to solve it using C++/JNI, and reflection as follows:

On the Java side:

package apptotray;

import java.awt.*;
import java.io.File;
import java.nio.file.Paths;
import javax.swing.*;

public class AppToTray {

    public static void main(String[] args) {
        JFrame frame = new JFrame("Some Window");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new BorderLayout());
        frame.add(new JPanel(), BorderLayout.CENTER);
        frame.setPreferredSize(new Dimension(500, 500));
        frame.pack();
        frame.setVisible(true);

        System.load(new File("JNI.dll").getAbsolutePath());
        try {
            System.out.println("Icon is showing..");
            Thread.sleep(3000);
        } catch (Exception Ex) {
            Ex.printStackTrace();
        }

        removeFromTaskBar(getWindowHandle(frame));

        try {
            System.out.println("Icon is not showing..");
            Thread.sleep(3000);
        } catch (Exception Ex) {
            Ex.printStackTrace();
        }

        addToTaskBar(getWindowHandle(frame));
        System.out.println("Icon is showing again..");
    }

    public static native void addToTaskBar(long WindowHandle);

    public static native void removeFromTaskBar(long WindowHandle);

    public static long getWindowHandle(java.awt.Frame frame) {
        return (Long)invokeMethod(invokeMethod(frame, "getPeer"), "getHWnd");
    }

    protected static Object invokeMethod(Object o, String methodName) {
        Class c = o.getClass();
        for (java.lang.reflect.Method m : c.getMethods()) {
            if (m.getName().equals(methodName)) {
                try {
                    return m.invoke(o);
                } catch (IllegalAccessException | IllegalArgumentException | java.lang.reflect.InvocationTargetException Ex) {
                    Ex.printStackTrace();
                    break;
                }
            }
        }
        return null;
    }
}

On the JNI/C++ side (Main.cpp):

#include <windows.h>
#include <shobjidl.h>
#include "jni.h"

#if defined _WIN32 || defined _WIN64
extern "C"
{
    const GUID CLSID_TaskbarList = {0x56FDF344, 0xFD6D, 0x11D0, {0x95, 0x8A, 0x00, 0x60, 0x97, 0xC9, 0xA0, 0x90}};

    const GUID IID_ITaskbarList = {0x56FDF342, 0xFD6D, 0x11D0, {0x95, 0x8A, 0x00, 0x60, 0x97, 0xC9, 0xA0, 0x90}};

    const GUID IID_ITaskbarList2 = {0x602D4995, 0xB13A, 0x429b, {0xA6, 0x6E, 0x19, 0x35, 0xE4, 0x4F, 0x43, 0x17}};

    const GUID IID_ITaskList3 = {0xEA1AFB91, 0x9E28, 0x4B86, {0x90, 0xE9, 0x9E, 0x9F, 0x8A, 0x5E, 0xEF, 0xAF}};
}
#endif

extern "C" JNIEXPORT void JNICALL Java_apptotray_AppToTray_addToTaskBar(JNIEnv *, jclass, jlong WindowHandle)
{
    #if defined _WIN32 || defined _WIN64
    ITaskbarList* TaskListPtr;
    CoInitialize(nullptr);
    long Result = !CoCreateInstance(CLSID_TaskbarList, nullptr, CLSCTX_SERVER, IID_ITaskbarList, reinterpret_cast<void**>(&TaskListPtr));
    if (Result) TaskListPtr->AddTab(reinterpret_cast<HWND>(WindowHandle));
    TaskListPtr->Release();
    CoUninitialize();
    #endif
}

extern "C" JNIEXPORT void JNICALL Java_apptotray_AppToTray_removeFromTaskBar(JNIEnv *, jclass, jlong WindowHandle)
{
    #if defined _WIN32 || defined _WIN64
    ITaskbarList* TaskListPtr;
    CoInitialize(nullptr);
    long Result = !CoCreateInstance(CLSID_TaskbarList, nullptr, CLSCTX_SERVER, IID_ITaskbarList, reinterpret_cast<void**>(&TaskListPtr));
    if (Result) TaskListPtr->DeleteTab(reinterpret_cast<HWND>(WindowHandle));
    TaskListPtr->Release();
    CoUninitialize();
    #endif
}

extern "C" bool __stdcall DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
    switch (fdwReason)
    {
        case DLL_PROCESS_ATTACH:
            // attach to process
            // return FALSE to fail DLL load
            break;

        case DLL_PROCESS_DETACH:
            // detach from process
            break;

        case DLL_THREAD_ATTACH:
            // attach to thread
            break;

        case DLL_THREAD_DETACH:
            // detach from thread
            break;
    }
    return TRUE; // succesful
}

Compile the DLL with:

x86_64-w64-mingw32-g++.exe -O2 -Wall -DBUILD_DLL -std=c++11 -c C:\\Users\\Brandon\\Desktop\\JNI\\main.cpp -o obj\\Release\\main.o

x86_64-w64-mingw32-g++.exe -shared -Wl,--output-def=bin\\Release\\libJNI.def -Wl,--out-implib=bin\\Release\\libJNI.a -Wl,--dll obj\\Release\\main.o -o bin\\Release\\JNI.dll -s -static -static-libgcc -static-libstdc++ -lole32 -lshell32 -luser32

Or just use codeblocks to do it.

If anyone else has better ideas, feel free to add them or comment or anything.. I still can't believe I had to use C++/JNI, and reflection to do this.. Ridiculous.. It's the year 2013, Java needs to get with the program.

Answer 2

I know this is VERY late, but I spent a good hour trying to figure this out myself. All you have to do is change your JFrame to a JWindow and you're done. I had a fairly complex JFrame and the only things I had to remove were setUndecorated() and setDefaultCloseOperation() . everything else worked just fine.