java - SWT：在复合中重新定位/刷新按钮并根据可见组件设置复合大小

Question

我想根据它们的可见性属性重绘组合中的按钮。我根据其中存在的按钮进行合成以调整大小，并且我正在使用以下代码来刷新合成。 问题：下面的代码工作正常，但按钮永远不会在复合中重新定位 请帮助。代码中是否缺少要重新定位的东西？

public void redraw_buttons() {
    int offsetButton = 5;
            int buttonHeight =28*3;

            for (Control kid : compositeButtons.getChildren()) {
                if (kid.getClass() == Button.class) {
                    if(kid.getVisible() == true){       
                        kid.setLocation(0, 0);//layout(true, true);
                        kid.setSize(50,60);
                        kid.redraw();
                        kid.pack();
                        compositeButtons.redraw();
                        kid.setRedraw(true);
                        kid.setBounds(10, offsetButton, 259, buttonHeight);
                        kid.redraw();
                        offsetButton = offsetButton + buttonHeight; 
                    }}
                        }
            compositeButtons.redraw();
        }

同样为了在复合材料上创建按钮，我正在使用以下代码

// 初始化复合---

compositeButtons = new Composite(shell, SWT.BORDER);
            compositeButtons.setLayout(null);
            FormData fd_compositeButtons = new FormData();
            fd_compositeButtons.top = new FormAttachment(lblUserLoggedinOnServer, 6);
            fd_compositeButtons.bottom = new FormAttachment(textRecentLog, -6);
            fd_compositeButtons.right = new FormAttachment(textRecentLog, 0, SWT.RIGHT);
            fd_compositeButtons.left = new FormAttachment(0, 30);
            compositeButtons.setLayoutData(fd_compositeButtons);

            compositeButtons.layout(true, true);
                    getShell().layout(true, true);

// 添加按钮到复合 -

int offsetButton = 5;
            int buttonHeight =28*3;

            MakeAppointmentRequestButton = new Button(compositeButtons, SWT.NONE);
            MakeAppointmentRequestButton.setBounds(10, offsetButton, 259, buttonHeight);
            //MakeAppointmentRequestButton.layout(true, true);
            MakeAppointmentRequestButton.setRedraw(true);
            MakeAppointmentRequestButton.setText("Make Appointment");

            offsetButton = offsetButton + buttonHeight; 

            GotoAppointmentRequestButton = new Button(compositeButtons, SWT.NONE);
            GotoAppointmentRequestButton.setBounds(10, offsetButton, 259, buttonHeight);//(10, offsetButton, 259, 28*3);
            GotoAppointmentRequestButton.setRedraw(true);
            GotoAppointmentRequestButton.setText("Goto Appointment");

            offsetButton = offsetButton + buttonHeight; 

            CancelAppointmentRequestButton= new Button(compositeButtons, SWT.NONE);
            CancelAppointmentRequestButton.setBounds(10, offsetButton, 259, buttonHeight);//(10,  28*3+5, 259, 28*3);
            CancelAppointmentRequestButton.setRedraw(true);
            CancelAppointmentRequestButton.setText("Cancel Appointment");

            offsetButton = offsetButton + buttonHeight;

我已经看到各种链接也尝试了 pack()、redraw() 属性。但是问题：即使在调用自定义函数 redraw_buttons(); 时，按钮也永远不会重新定位。

请帮忙。代码中是否缺少要重新定位的东西？请建议这样做的方法。我是 SWT 的新手。

谢谢..

******* 编辑 新 更新 ********

错误是由于

1.)redraw_buttons()函数未在主线程上调用。

_appLoader.display.getDefault().asyncExec(new Runnable() {
    public void run() {
_appLoader.MyObj.redraw_buttons();
}
});
// This gave access to main thread.

2.) 复合框架没有在 redraw_buttons() 中调整大小；

// Code: On Which I am still working upon.

我应该调整外壳的大小吗？请建议。

谢谢你的帮助。

Answer 1

这里有一些代码应该做你想做的，或者至少告诉你如何实现它：

public static void main(String[] args)
{
    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setLayout(new GridLayout(2, true));

    // Stretch first label horizontally
    Label upperLeft = new Label(shell, SWT.NONE);
    upperLeft.setText("Label 1 name");
    upperLeft.setLayoutData(new GridData(SWT.BEGINNING, SWT.BEGINNING, true, false));

    // Stretch second label horizontally but align to the right
    Label upperRight = new Label(shell, SWT.NONE);
    upperRight.setText("time");
    upperRight.setLayoutData(new GridData(SWT.END, SWT.BEGINNING, true, false));

    // Stretch button comp in both directions
    Composite buttonComp = new Composite(shell, SWT.BORDER);
    buttonComp.setLayout(new GridLayout(1, true));
    GridData buttonData = new GridData(SWT.FILL, SWT.FILL, true, true);
    buttonData.horizontalSpan = 2;
    buttonComp.setLayoutData(buttonData);

    Button one = new Button(buttonComp, SWT.PUSH);
    one.setText("Button 1");
    one.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
    Button two = new Button(buttonComp, SWT.PUSH);
    two.setText("Button 2");
    two.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
    Button three = new Button(buttonComp, SWT.PUSH);
    three.setText("Button 3");
    three.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

    // Stretch third label horizontally
    Label lowerLeft = new Label(shell, SWT.NONE);
    lowerLeft.setText("Label 2");
    lowerLeft.setLayoutData(new GridData(SWT.BEGINNING, SWT.BEGINNING, true, false));

    // Stretch fourth label horizontally
    Label lowerRight = new Label(shell, SWT.NONE);
    lowerRight.setText("Label 3");
    lowerRight.setLayoutData(new GridData(SWT.BEGINNING, SWT.BEGINNING, true, false));

    shell.pack();
    shell.open();
    while (!shell.isDisposed())
    {
        if (!display.readAndDispatch())
            display.sleep();
    }
    display.dispose();
}

这是它启动时的样子：

调整大小后：

Answer 2

代替

(kid.getClass() == Button.class)

总是使用

(kid instanceof Button)