Java JNA获取桌面项目位置

问题描述 投票：4回答：1

Goal

获取桌面项/图标的桌面坐标。

Attempt

我已经获得了SysListView32窗口句柄，其中包含使用以下内容的桌面图标：

HWND hWnd_Progman = User32.INSTANCE.FindWindow("Progman", "Program Manager");
HWND hWnd_SHELLDLL_DefView = User32.INSTANCE.FindWindowEx(hWnd_Progman, null, "SHELLDLL_DefView", null);
HWND hWnd_SysListView32 = User32.INSTANCE.FindWindowEx(hWnd_SHELLDLL_DefView, null, "SysListView32", "FolderView");

我已经获得了桌面项目数：

LRESULT result = User32.INSTANCE.SendMessage(hWnd_SysListView32, LVM_GETITEMCOUNT, new WPARAM(), new LPARAM());
long desktopIconCount = result.longValue();

我已设置桌面项位置（验证SysListView32是桌面项的右侧列表视图）。传递的x和y坐标对应于从最左侧监视器的左上角到桌面项目的左上角的偏移量。码：

int itemIndex = 0; // Allows 0 to desktopIconCount - 1.
int x = ...;
int y = ...;
LRESULT res = User32.INSTANCE.SendMessage(hWnd_SysListView32, LVM_SETITEMPOSITION, new WPARAM(itemIndex), new LPARAM((x & 0xFFFF) | (y << 16)));

现在，要获取桌面项目位置，需要将LVM_GETITEMPOSITION发送到SysListView32并包含指向可以将位置写入的地址的指针。但是，此指针必须是属于SysListView32的进程的内存中的有效地址。所以我试图做的是：

  • 获取属于SysListView32的进程。
  • 在该过程中分配内存。
  • 在此内存中写入POINT对象（用于项目位置）。
  • 使用指向此分配内存的指针将LVM_GETITEMPOSITION发送到SysListView32。
  • 从内存中读取这个POINT对象。此时，进程应该已将桌面项位置写入其中。

我用以下代码尝试了这个：

// Get the SysListView32 process handle.
IntByReference processIdRef = new IntByReference();
User32.INSTANCE.GetWindowThreadProcessId(hWnd_SysListView32, processIdRef);
HANDLE procHandle = Kernel32.INSTANCE.OpenProcess(
        Kernel32.PROCESS_VM_OPERATION | Kernel32.PROCESS_VM_WRITE | Kernel32.PROCESS_VM_READ,
        false, processIdRef.getValue());

// Allocate memory in the SysView32 process.
int pointSize = Native.getNativeSize(POINT.class)); // 8 bytes.
LPVOID pMem = MyKernel32.INSTANCE.VirtualAllocEx(procHandle, new LPVOID(), new SIZE_T(pointSize),
        MyKernel32.MEM_COMMIT, MyKernel32.PAGE_READWRITE);

// Put some POINT-sized object in the process its memory.
boolean success = Kernel32.INSTANCE.WriteProcessMemory(
        procHandle, pMem.getPointer(), pMem.getPointer(), pointSize, null);
if(!success) {
    System.out.println("Write error = " + Kernel32.INSTANCE.GetLastError());
    System.exit(1);
}

// Send the LVM_GETITEMPOSITION message to the SysListView32.
int itemIndex = 0; // Allows 0 to desktopIconCount - 1.
LRESULT res = MyUser32.INSTANCE.SendMessage(
        hWnd_SysListView32, LVM_GETITEMPOSITION, new WPARAM(itemIndex), pMem.getPointer());
System.out.println("Message result = " + res.longValue());

// Read the earlier POINT-sized written memory.
POINT point = new POINT();
success = Kernel32.INSTANCE.ReadProcessMemory(
        procHandle, pMem.getPointer(), point.getPointer(), pointSize, null);
if(!success) {
    System.out.println("Read error = " + Kernel32.INSTANCE.GetLastError());
    System.exit(1);
}
System.out.println("Point found: x=" + pos.x + ", y=" + pos.y);

在这里，MyUser32创建如下：

interface MyUser32 extends User32 {
    static MyUser32 INSTANCE =
        (MyUser32) Native.load("user32", MyUser32.class, W32APIOptions.DEFAULT_OPTIONS);
    LRESULT SendMessage(HWND hWnd, int msg, WPARAM wParam, Pointer pointer);
}

和MyKernel32创建如下：

interface MyKernel32 extends Kernel32 {
    static final MyKernel32 INSTANCE =
            (MyKernel32) Native.load("kernel32", MyKernel32.class, W32APIOptions.DEFAULT_OPTIONS);
    static int MEM_COMMIT = 0x1000;
    static int PAGE_READWRITE = 0x04;
    LPVOID VirtualAllocEx(HANDLE hProcess, LPVOID lpAddress, SIZE_T dwSize, int flAllocationType, int flProtect);
}

为完成，使用以下附加静态值：

static final int LVM_FIRST = 0x1000;
static final int LVM_GETITEMCOUNT = LVM_FIRST + 4;
static final int LVM_SETITEMPOSITION = LVM_FIRST + 15;
static final int LVM_GETITEMPOSITION = LVM_FIRST + 16;

Problem

WriteProcessMemory调用经常失败，错误代码为299 ERROR_PARTIAL_COPY，即使没有失败，返回的POINT始终为（0,0）。我希望问题出现在SendMessage或VirtualAllocEx中的MyUser32 / MyKernel32方法声明中，或者我不能正确理解传递给VirtualAllocEx或WriteProcessMemory的对象/指针。

我已经做了很多研究并弄清楚它应该如何在C / C ++中工作，但我找不到任何使用JNA的工作代码示例。

感谢您表现出兴趣并尝试提供帮助，如果您通过我的消息一直这样做。

java position icons desktop jna
1个回答
2
投票

问题是com.sun.jna.Native.getNativeSize（Class）不是在这种情况下使用的正确函数。使用32位JVM时，问题是可见的（64位虚拟机不可见）。

对于结构，上面提到的函数假​​定它们通过引用传递（指向结构的指针），因此函数返回Native.POINTER_SIZE的值。在64位虚拟机上，运气匹配POINT结构的大小。在32位VM上，Native.POINTER_SIZE是4字节，因此只能保存结果结构的一部分。

最相关的部分：要确定JNA中结构的大小，请使用Structure＃size函数。在这种情况下，使用ReadProcessMemory的最终参数也很有帮助。该函数返回读取的字节数并显示差异（4对8）。

进一步的评论：记得释放你分配的内存，并关闭收到的进程句柄。

这是完整的可运行样本（仅缺少导入，使用JNA 5.2测试）：

public class Test {

    private interface Kernel32 extends com.sun.jna.platform.win32.Kernel32 {

        Kernel32 INSTANCE = Native.load("kernel32", Kernel32.class, W32APIOptions.DEFAULT_OPTIONS);

        public Pointer VirtualAllocEx(HANDLE hProcess, Pointer lpAddress, SIZE_T dwSize, int flAllocationType, int flProtect);

        public boolean VirtualFreeEx(HANDLE hProcess, Pointer lpAddress, SIZE_T dwSize, int dwFreeType);

        int MEM_COMMIT = 0x00001000;
        int MEM_RESERVE = 0x00002000;
        int MEM_RESET = 0x00080000;
        int MEM_RESET_UNDO = 0x1000000;
        int MEM_LARGE_PAGES = 0x20000000;
        int MEM_PHYSICAL = 0x00400000;
        int MEM_TOP_DOWN = 0x00100000;
        int MEM_COALESCE_PLACEHOLDERS = 0x00000001;
        int MEM_PRESERVE_PLACEHOLDER = 0x00000002;
        int MEM_DECOMMIT = 0x4000;
        int MEM_RELEASE = 0x8000;
    }

    private static final int LVM_FIRST = 0x1000;
    private static final int LVM_GETITEMCOUNT = LVM_FIRST + 4;
    private static final int LVM_GETITEMPOSITION = LVM_FIRST + 16;

    public static void main(String[] args) throws IOException, InterruptedException {
        // Find the HWND for the "desktop" list view
        HWND hWnd_Progman = User32.INSTANCE.FindWindow("Progman", "Program Manager");
        HWND hWnd_SHELLDLL_DefView = User32.INSTANCE.FindWindowEx(hWnd_Progman, null, "SHELLDLL_DefView", null);
        HWND hWnd_SysListView32 = User32.INSTANCE.FindWindowEx(hWnd_SHELLDLL_DefView, null, "SysListView32", "FolderView");
        // Fetch the icon count
        int itemCount = User32.INSTANCE.SendMessage(hWnd_SysListView32, LVM_GETITEMCOUNT, new WPARAM(), new LPARAM()).intValue();
        System.out.println("Desktop Icons: " + itemCount);

        // Get the SysListView32 process handle.
        IntByReference processIdRef = new IntByReference();
        User32.INSTANCE.GetWindowThreadProcessId(hWnd_SysListView32, processIdRef);
        HANDLE procHandle = Kernel32.INSTANCE.OpenProcess(
                Kernel32.PROCESS_VM_OPERATION | Kernel32.PROCESS_VM_WRITE | Kernel32.PROCESS_VM_READ,
                false, processIdRef.getValue());

        // Allocate memory in the SysView32 process.
        int pointSize = new POINT().size(); // 8 bytes.
        Pointer pMem = Kernel32.INSTANCE.VirtualAllocEx(procHandle, null, new SIZE_T(pointSize),
                Kernel32.MEM_COMMIT, Kernel32.PAGE_READWRITE);

        for (int i = 0; i < itemCount; i++) {

            // Send the LVM_GETITEMPOSITION message to the SysListView32.
            LRESULT res = User32.INSTANCE.SendMessage(
                    hWnd_SysListView32, LVM_GETITEMPOSITION, new WPARAM(i), new LPARAM(Pointer.nativeValue(pMem)));

            if(res.intValue() != 1) {
                throw new IllegalStateException("Message sending failed");
            }

            // Read the earlier POINT-sized written memory.
            POINT point = new POINT();
            IntByReference read = new IntByReference();
            boolean success = Kernel32.INSTANCE.ReadProcessMemory(
                    procHandle, pMem, point.getPointer(), pointSize, read);

            if (!success) {
                System.out.println("Read error = " + Kernel32.INSTANCE.GetLastError());
                System.exit(1);
            }
            point.read();
            System.out.println("Point found: x=" + point.x + ", y=" + point.y);
        }

        // Release allocated memory
        Kernel32.INSTANCE.VirtualFreeEx(procHandle, pMem, new SIZE_T(0), Kernel32.MEM_RELEASE);

        // Close Process Handle
        Kernel32.INSTANCE.CloseHandle(procHandle);
    }
}
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