class MainWindow {
    Sashform sashform;
    Tree child1 = null;
    Table child2 = null;

    MainWindow(Shell shell) {
        sashform = new SashForm(shell,SWT.NONE);
    }

    // Not called from constructor because it needs data not available at that time
    void CreateFirstChild() {  
        ...
        Tree child1 = new Tree(sashform,SWT.NONE);
    }

    void CreateSecondChild() {
        ...
        Table child2 = new Table(sashform,SWT.NONE);
    }    
}

我不知道这些方法将以什么顺序提前知道.如何确保child1位于左侧,而child2位于右侧？或者,在创建sashform之后,有没有办法改变他们的顺序？

目前我最好的想法是把这样的占位符：

class MainWindow {
    Sashform sashform;
    private Composite placeholder1;
    private Composite placeholder2;
    Tree child1 = null;
    Table child2 = null;

    MainWindow(Shell shell) {
        sashform = new SashForm(shell,SWT.NONE);
        placeholder1 = new Composite(sashform,SWT.NONE);
        placeholder2 = new Composite(sashform,SWT.NONE);
    }

    void CreateFirstChild() {  
        ...
        Tree child1 = new Tree(placeholder1,SWT.NONE);
    }

    void CreateSecondChild() {
        ...
        Table child2 = new Table(placeholder2,SWT.NONE);
    }    
}