Java - 使用 JNA 的 Windows 任务栏 - 如何将窗口图标 (HICON) 转换为 Java 图像？

Question

我正在尝试将应用程序切换器添加到我正在处理的更大项目中。它需要在 Windows XP/Vista/7/8 上运行。我正在使用 Java 1.7。下面是我创建的示例应用程序，用于演示我遇到的一些问题。我是 JNA 的新手。

非常感谢'Hovercraft Full of Eels' 的 this answer (以及许多其他!)构成测试应用程序的基础。

这是我的问题:

1. 图像绘制 - 我从窗口图标中获取的图像是黑白绘制的。我从 this answer 修改了 getImageForWindow 中的代码麦克道尔(谢谢!)。有没有更好的方法将 HICON 对象转换为 java.awt.Image？我注意到 com.sun.jna.platform.win32.W32API.HICON 中有一个名为“fromNative”的方法，但我不知道如何使用它。

2. 获取图标 - 我用来获取图标句柄的调用 GetClassLongW(hWnd, GCL_HICON) 不会从 64 位窗口返回图标。我想为此我需要 GetClassLongPtr，但我似乎无法通过 JNA 访问它。

3. 根据 Alt-tab 弹出窗口获取正确的窗口列表 - 我试图复制在 this C++ answer 中完成的操作但我无法设法获得用 Java 实现的第二次(GetAncestor 等)和第三次(STATE_SYSTEM_INVISIBLE)检查。我使用了一个糟糕的替代品，它排除了标题为空白的窗口(忽略了一些合法的窗口)。

注意:运行此示例需要 JNA 和 Platform jar:

    package test;

import static test.WindowSwitcher.User32DLL.*;
import static test.WindowSwitcher.Gdi32DLL.*;
import com.sun.jna.Native;
import com.sun.jna.Pointer;
import com.sun.jna.platform.win32.WinDef.HWND;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.util.Vector;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.WindowConstants;

public class WindowSwitcher
{
    public static void main(String args[])
    {
        JFrame JF = new JFrame();
        JPanel JP = new JPanel(new GridLayout(0, 1));

        JF.getContentPane().add(JP);

        Vector<WindowInfo> V = getActiveWindows();
        for (int i = 0; i < V.size(); i++)
        {
            final WindowInfo WI = V.elementAt(i);
            JButton JB = new JButton(WI.title);

            if(WI.image != null)
            {
                JB.setIcon(new ImageIcon(WI.image));
            }

            JB.addActionListener(new ActionListener()
            {
                @Override
                public void actionPerformed(ActionEvent e)
                {
                    SetForegroundWindow(WI.hWnd);
                }
            });

            JP.add(JB);
        }

        JF.setSize(600,50+V.size()*64);
        JF.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        JF.setAlwaysOnTop(true);
        JF.setFocusableWindowState(false);
        JF.setVisible(true);
    }

    public static Vector<WindowInfo> getActiveWindows()
    {
        final Vector<WindowInfo> V = new Vector();

        EnumWindows(new WNDENUMPROC()
        {
            public boolean callback(Pointer hWndPointer, Pointer userData)
            {
                HWND hWnd = new HWND(hWndPointer);

                // Make sure the window is visible
                if(IsWindowVisible(hWndPointer))
                {
                    int GWL_EXSTYLE = -20;
                    long WS_EX_TOOLWINDOW = 0x00000080L;

                    // Make sure this is not a tool window
                    if((GetWindowLongW(hWndPointer, GWL_EXSTYLE) & WS_EX_TOOLWINDOW) == 0)
                    {
                        // Get the title bar text for the window
                        char[] windowText = new char[512];
                        GetWindowTextW(hWnd, windowText, windowText.length);
                        String wText = Native.toString(windowText);

                        // Make sure the text is not null or blank
                        if(!(wText == null || wText.trim().equals("")))
                        {
                            // Get the icon image for the window (if available)
                            Image image = getImageForWindow(hWnd, wText);

                            // This window is a valid taskbar button, add a WindowInfo object to the return vector
                            V.add(new WindowInfo(wText, hWnd, image));
                        }
                    }
                }

                return true;
            }
        }, null);

        return V;
    }

    public static Image getImageForWindow(HWND hWnd, String wText)
    {
        // Get an image from the icon for this window
        int hicon = GetClassLongW(hWnd, GCL_HICON);

        if(hicon == 0)
            return null;

        Pointer hIcon = new Pointer(hicon);

        int width = 64;
        int height = 64;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
        draw(image, hIcon, DI_NORMAL);
        BufferedImage mask = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        draw(mask, hIcon, DI_MASK);
        applyMask(image, mask);

        return image;
    }
    public static void draw(BufferedImage image, Pointer hIcon, int diFlags)
    {
        int width = image.getWidth();
        int height = image.getHeight();

        Pointer hdc = CreateCompatibleDC(Pointer.NULL);
        Pointer bitmap = CreateCompatibleBitmap(hdc, width, height);

        SelectObject(hdc, bitmap);
        DrawIconEx(hdc, 0, 0, hIcon, width, height, 0, Pointer.NULL, diFlags);

        for (int x = 0; x < width; x++)
        {
            for (int y = 0; y < width; y++)
            {
                int rgb = GetPixel(hdc, x, y);
                image.setRGB(x, y, rgb);
            }
        }

        DeleteObject(bitmap);
        DeleteDC(hdc);
    }
    private static void applyMask(BufferedImage image,
            BufferedImage mask)
    {
        int width = image.getWidth();
        int height = image.getHeight();
        for (int x = 0; x < width; x++)
        {
            for (int y = 0; y < height; y++)
            {
                int masked = mask.getRGB(x, y);
                if ((masked & 0x00FFFFFF) == 0)
                {
                    int rgb = image.getRGB(x, y);
                    rgb = 0xFF000000 | rgb;
                    image.setRGB(x, y, rgb);
                }
            }
        }
    }

    static class User32DLL
    {
        static
        {
            Native.register("user32");
        }

        public static native int GetWindowTextW(HWND hWnd, char[] lpString, int nMaxCount);

        public static native boolean EnumWindows(WNDENUMPROC lpEnumFunc, Pointer arg);

        public static interface WNDENUMPROC extends com.sun.jna.win32.StdCallLibrary.StdCallCallback
        {
            boolean callback(Pointer hWnd, Pointer arg);
        }

        public static native boolean IsWindowVisible(Pointer hWnd);

        public static native boolean SetForegroundWindow(HWND hWnd);

        public static native int GetWindowLongW(Pointer hWnd, int nIndex);

        public static int GCL_HICON = -14;
        public static int GCL_HICONSM = -34;
        public static native int GetClassLongW(HWND hWnd, int nIndex);

        /** @see #DrawIconEx(Pointer, int, int, Pointer, int, int, int, Pointer, int) */
        public static final int DI_COMPAT = 4;
        public static final int DI_DEFAULTSIZE = 8;
        public static final int DI_IMAGE = 2;
        public static final int DI_MASK = 1;
        public static final int DI_NORMAL = 3;
        public static final int DI_APPBANDING = 1;

        /** http://msdn.microsoft.com/en-us/library/ms648065(VS.85).aspx */
        public static native boolean DrawIconEx(Pointer hdc, int xLeft,
                int yTop, Pointer hIcon, int cxWidth, int cyWidth,
                int istepIfAniCur, Pointer hbrFlickerFreeDraw,
                int diFlags);
    }

    static class Gdi32DLL
    {
        static
        {
            Native.register("gdi32");
        }

        /** http://msdn.microsoft.com/en-us/library/dd183489(VS.85).aspx */
        public static native Pointer CreateCompatibleDC(Pointer hdc);

        /** http://msdn.microsoft.com/en-us/library/dd183488(VS.85).aspx */
        public static native Pointer CreateCompatibleBitmap(Pointer hdc, int nWidth, int nHeight);

        /** http://msdn.microsoft.com/en-us/library/dd162957(VS.85).aspx */
        public static native Pointer SelectObject(Pointer hdc, Pointer hgdiobj);

        /** http://msdn.microsoft.com/en-us/library/dd145078(VS.85).aspx */
        public static native int SetPixel(Pointer hdc, int X, int Y, int crColor);

        /** http://msdn.microsoft.com/en-us/library/dd144909(VS.85).aspx */
        public static native int GetPixel(Pointer hdc, int nXPos, int nYPos);

        /** http://msdn.microsoft.com/en-us/library/dd183539(VS.85).aspx */
        public static native boolean DeleteObject(Pointer hObject);

        /** http://msdn.microsoft.com/en-us/library/dd183533(VS.85).aspx */
        public static native boolean DeleteDC(Pointer hdc);
    }
}
class WindowInfo
{
    String title;
    HWND hWnd;
    Image image;

    public WindowInfo(String title, HWND hWnd, Image image)
    {
        this.title = title;
        this.hWnd = hWnd;
        this.image = image;
    }
}

Answer 1

我找到了适合我的目的的解决方法。这比我第一次尝试要简单得多!我现在使用 sun.awt.shell.ShellFolder 获取图标，不幸的是，这是一个未记录/不受支持的类，可能会在未来的 Java 版本中删除。还有另一种使用 FileSystemView 获取图标的方法，但返回的图标对于我的目的来说太小了(在我下面的示例中被注释掉了 - getImageForWindowIcon 方法)。

此解决方法基于 this SO answer by aleroot .我获取进程文件路径(用于打开窗口的 exe 文件，我将其与其他窗口详细信息存储在 WindowInfo 对象中)，然后使用 ShellFolder 获取与该文件关联的图标。 注意:这并不总是提供正确的图标(例如，用于运行 Netbeans 进程的文件是 java.exe，因此您得到的是 Java 图标，而不是 Netbeans 图标!)。但在大多数情况下，它运行良好!

解决方法解决了上面的问题 1 和 2，但如果有人有更好的解决方案，请告诉我。我对问题 3 一无所获，但我现在必须做的是窗口列表。

这是我更新的代码...注意:运行此示例需要 JNA 和 Platform jar:

    package test;

import static test.WindowSwitcher.User32DLL.*;
import static test.WindowSwitcher.Kernel32.*;
import static test.WindowSwitcher.Psapi.*;
import com.sun.jna.Native;
import com.sun.jna.Pointer;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.ptr.PointerByReference;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.util.Vector;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.WindowConstants;
import sun.awt.shell.ShellFolder;

public class WindowSwitcher
{
    public static void main(String args[])
    {
        new WindowSwitcher();
    }
    public WindowSwitcher()
    {
        JFrame JF = new JFrame("Window Switcher");
        JPanel JP = new JPanel(new GridLayout(0, 1));

        JF.getContentPane().add(JP);

        Vector<WindowInfo> V = getActiveWindows();
        for (int i = 0; i < V.size(); i++)
        {
            final WindowInfo WI = V.elementAt(i);
            JButton JB = new JButton(WI.title);

            if(WI.image != null)
            {
                JB.setIcon(new ImageIcon(WI.image));
            }

            JB.addActionListener(new ActionListener()
            {
                @Override
                public void actionPerformed(ActionEvent e)
                {
                    SetForegroundWindow(WI.hWnd);
                }
            });

            JP.add(JB);
        }

        JF.setSize(600,50+V.size()*64);
        JF.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        JF.setAlwaysOnTop(true);
        JF.setFocusableWindowState(false);
        JF.setVisible(true);
    }

    private Vector<WindowInfo> getActiveWindows()
    {
        final Vector<WindowInfo> V = new Vector();

        EnumWindows(new WNDENUMPROC()
        {
            public boolean callback(Pointer hWndPointer, Pointer userData)
            {
                HWND hWnd = new HWND(hWndPointer);

                // Make sure the window is visible
                if(IsWindowVisible(hWndPointer))
                {
                    int GWL_EXSTYLE = -20;
                    long WS_EX_TOOLWINDOW = 0x00000080L;

                    // Make sure this is not a tool window
                    if((GetWindowLongW(hWndPointer, GWL_EXSTYLE) & WS_EX_TOOLWINDOW) == 0)
                    {
                        // Get the title bar text for the window (and other info)
                        WindowInfo info = getWindowTitleAndProcessDetails(hWnd);

                        // Make sure the text is not null or blank
                        if(!(info.title == null || info.title.trim().equals("")))
                        {
                            // Get the icon image for the window (if available)
                            info.image = getImageForWindow(info);

                            // This window is a valid taskbar button, add a WindowInfo object to the return vector
                            V.add(info);
                        }
                    }
                }

                return true;
            }
        }, null);

        return V;
    }

    private static final int MAX_TITLE_LENGTH = 1024;
    private WindowInfo getWindowTitleAndProcessDetails(HWND hWnd)
    {
        if(hWnd == null)
            return null;

        char[] buffer = new char[MAX_TITLE_LENGTH * 2];
        GetWindowTextW(hWnd, buffer, MAX_TITLE_LENGTH);
        String title = Native.toString(buffer);

        PointerByReference pointer = new PointerByReference();
        GetWindowThreadProcessId(hWnd, pointer);    //GetForegroundWindow()
        Pointer process = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, false, pointer.getValue());
        GetModuleBaseNameW(process, null, buffer, MAX_TITLE_LENGTH);
        String Sprocess = Native.toString(buffer);
        GetModuleFileNameExW(process, null, buffer, MAX_TITLE_LENGTH);
        String SprocessFilePath = Native.toString(buffer);

        return new WindowInfo(title, Sprocess, SprocessFilePath, hWnd, null);
    }

    private Image getImageForWindow(WindowInfo info)
    {
        if(info.processFilePath == null || info.processFilePath.trim().equals(""))
            return null;

        try
        {
            File f = new File(info.processFilePath);

            if(f.exists())
            {
                // https://stackoverflow.com/questions/10693171/how-to-get-the-icon-of-another-application
                // http://www.rgagnon.com/javadetails/java-0439.html
                ShellFolder sf = ShellFolder.getShellFolder(f);
                if(sf != null)
                    return sf.getIcon(true);

                // Image returned using this method is too small!
                //Icon icon = FileSystemView.getFileSystemView().getSystemIcon(f);
            }
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        return null;
    }

    static class Psapi
    {
        static
        {
            Native.register("psapi");
        }

        public static native int GetModuleBaseNameW(Pointer hProcess, Pointer hmodule, char[] lpBaseName, int size);

        public static native int GetModuleFileNameExW(Pointer hProcess, Pointer hmodule, char[] lpBaseName, int size);
    }

    static class Kernel32
    {

        static
        {
            Native.register("kernel32");
        }
        public static int PROCESS_QUERY_INFORMATION = 0x0400;
        public static int PROCESS_VM_READ = 0x0010;

        public static native Pointer OpenProcess(int dwDesiredAccess, boolean bInheritHandle, Pointer pointer);
    }

    static class User32DLL
    {
        static
        {
            Native.register("user32");
        }

        public static native int GetWindowThreadProcessId(HWND hWnd, PointerByReference pref);

        public static native int GetWindowTextW(HWND hWnd, char[] lpString, int nMaxCount);

        public static native boolean EnumWindows(WNDENUMPROC lpEnumFunc, Pointer arg);

        public static interface WNDENUMPROC extends com.sun.jna.win32.StdCallLibrary.StdCallCallback
        {
            boolean callback(Pointer hWnd, Pointer arg);
        }

        public static native boolean IsWindowVisible(Pointer hWnd);

        public static native boolean SetForegroundWindow(HWND hWnd);

        public static native int GetWindowLongW(Pointer hWnd, int nIndex);
    }
}
class WindowInfo
{
    String title, process, processFilePath;
    HWND hWnd;
    Image image;

    public WindowInfo(String title, String process, String processFilePath, HWND hWnd, Image image)
    {
        this.title = title;
        this.process = process;
        this.processFilePath = processFilePath;
        this.hWnd = hWnd;
        this.image = image;
    }
}