c++ - 同步 : Detecting Pointer/Clicks

Question

我正在尝试检测何时单击/指向/点击标签。我来自 Win32 C++ 和 Java Swing 编程，我知道这两种方法都采用不同的方法来注册事件/输入。

我看过教程，但找不到检测点击的示例。单击是否有常量，这样我就可以在 keyPressEvent 中检测到它(即，像 win32 和 WM_LBUTTONDOWN)？或者我是否需要先注册点击然后调用我自己的函数来处理点击(如 Java 和 .addActionListener())？

我尝试检测下面的点击不起作用:

#include <MAUtil/Moblet.h>
#include <MAUI/Layout.h>
#include <MAUI/ListBox.h>
#include <MAUI/Label.h>
#include <MAUI/EditBox.h>
#include <MAUI/Screen.h>
#include <MAUtil/Environment.h>
#include <madmath.h>
#include <conprint.h>


using namespace MAUtil;
using namespace MAUI;

class MouseScreen : public Screen, public PointerListener
{
    private:
        Label *testLabel;
    public:
        MouseScreen()
        {
            MAExtent screenDim = maGetScrSize();
            Layout* mainLayout  = new Layout( 0, 0, EXTENT_X(screenDim), EXTENT_Y(screenDim), NULL, 1, 3 );
            ListBox* mainListBox = new ListBox( 0, 0, 100, 200, mainLayout,
                                       ListBox::LBO_VERTICAL, ListBox::LBA_LINEAR,
                                       true );
            mainListBox -> setPaddingLeft( 10 );
            mainListBox -> setPaddingRight( 10 );
            mainListBox -> setPaddingTop( 10 );
            mainListBox -> setPaddingBottom( 10 );
            mainListBox -> setBackgroundColor( 900 );
            mainLayout  -> setBackgroundColor( 300 );

            testLabel = new Label( 10, 300, 50, 20, mainLayout );
            //testLabel -> addPointerListener( this );
            testLabel -> setCaption( "Click me" );

            mainLayout -> add( testLabel );
        }

        void pointerPressEvent( MAPoint2d p )
        {
            printf( "clicked" );  // never occurs

            // OR
            if ( testLabel.contains((MouseScreen*)p) )
            {
                printf( "Label clicked" );
            }
            // Should I call parent function
            // PointerListener :: pointerPressEvent( p );
        }

        void pointerMoveEvent( MAPoint2d p ) {}
        void pointerReleaseEvent( MAPoint2d p ) {}
};

class MouseMoblet : public Moblet
{
    public:
        MouseMoblet()
        {
            instance = new MouseScreen();
            instance -> show();
        }

        ~MouseMoblet()
        {
            delete instance;
        }

        void keyPressEvent(int keyCode, int nativeCode)
        {
            // todo: handle key presses
            printf( "Blah" ); // never occurs when I press the mouse, but other KEYS work
        }

        void keyReleaseEvent(int keyCode, int nativeCode)
        {
            // todo: handle key releases
        }

    private:
        MouseScreen *instance;
};

extern "C" int MAMain()
{
    Moblet::run(new MouseMoblet());
    return 0;
};

Answer 1

我可以看到您需要做的一些事情。首先，您需要通过调用 setMain(mainLayout) 将 mainLayout 设置为 Screen 的主要 widget。这使屏幕知道 mainLayout 以便它可以绘制它。完成此操作后，您将能够在屏幕上看到您的小部件，您还应该获得点击事件。

在 pointerPressedEvent 中，您几乎是正确的，testLabel 的 contains 方法采用点而不是屏幕。你在这里应该做的是调用 testLabel->contains( p.x, p.y ) 来评估 testLabel 是否被点击。

完整修改后的代码如下所示:

#include <MAUtil/Moblet.h>
#include <MAUI/Layout.h>
#include <MAUI/ListBox.h>
#include <MAUI/Label.h>
#include <MAUI/EditBox.h>
#include <MAUI/Screen.h>
#include <MAUtil/Environment.h>
#include <madmath.h>
#include <conprint.h>


using namespace MAUtil;
using namespace MAUI;

class MouseScreen : public Screen
{
    private:
        Label *testLabel;
    public:
        MouseScreen()
        {
            MAExtent screenDim = maGetScrSize();
            Layout* mainLayout  = new Layout( 0, 0, EXTENT_X(screenDim), EXTENT_Y(screenDim), NULL, 1, 3 );
            ListBox* mainListBox = new ListBox( 0, 0, 100, 200, mainLayout,
                                       ListBox::LBO_VERTICAL, ListBox::LBA_LINEAR,
                                       true );
            mainListBox -> setPaddingLeft( 10 );
            mainListBox -> setPaddingRight( 10 );
            mainListBox -> setPaddingTop( 10 );
            mainListBox -> setPaddingBottom( 10 );
            mainListBox -> setBackgroundColor( 900 );
            mainLayout  -> setBackgroundColor( 300 );

            testLabel = new Label( 10, 300, 50, 20, mainLayout );
            //testLabel -> addPointerListener( this );
            testLabel -> setCaption( "Click me" );

            mainLayout -> add( testLabel );

            setMain( mainLayout );
        }

        void pointerPressEvent( MAPoint2d p )
        {
            if ( testLabel->contains( p.x, p.y ) )
            {
                printf( "Label clicked" );
            }
        }

        void pointerMoveEvent( MAPoint2d p ) {}
        void pointerReleaseEvent( MAPoint2d p ) {}
};

class MouseMoblet : public Moblet
{
    public:
        MouseMoblet()
        {
            instance = new MouseScreen();
            instance -> show();
        }

        ~MouseMoblet()
        {
            delete instance;
        }

        void keyPressEvent(int keyCode, int nativeCode)
        {
            // todo: handle key presses
            printf( "Blah" ); // never occurs when I press the mouse, but other KEYS work
        }

        void keyReleaseEvent(int keyCode, int nativeCode)
        {
            // todo: handle key releases
        }

    private:
        MouseScreen *instance;
};

extern "C" int MAMain()
{
    Moblet::run(new MouseMoblet());
    return 0;
};

注意:当前的 MoSync UI 系统是为非触摸手机设计的，因此处理指针事件有点做作，不过这将在即将发布的版本中得到改进。

关于是否调用父函数取决于是否要保留默认行为，目前 Screen 的默认实现不执行任何操作。