SWT复合 - 重绘问题 [英] SWT composite - redraw problem

问题描述

我有一个复合元素，最初有一个Label。现在我调用dispose（标签）并在同一个容器（复合榆树）中创建另一个标签，但我没有看到新文本。它让我质疑如何在复合上启用重绘，以便新标签（或我可能创建的任何其他组件）将代替旧标签。
这是我的代码（分成重组复合的单元测试）

I have a composite element, that initially has a Label. Now I call dispose on the it (the label) and create another label in the same container (composite elm), but I don't see the new text. It brings me to question how do I enable redraw on the composite, so that the new label (or any other component I might create) will render in place of the old one. Here is the code I have (separated into a unit test for redraw a composite)

private Label createLabel( Composite parent) {
    Label label = new Label(parent, SWT.NONE);
    label.setAlignment(SWT.CENTER);
    label.setLayoutData( new GridData( SWT.CENTER, SWT.CENTER, true, true) );
    return label;
}

private void changeText() {
    assert testCell != null : "Please initialize test cell";
    testCell.getChildren()[0].dispose();
    Label l = createLabel(testCell);
    l.setText("New TexT");
    testCell.redraw();
}

private void draw() {
    Display display = new Display();
    shell = new Shell(display);
    shell.setLayout(new GridLayout(2,false));

    testCell = new Composite(shell,SWT.BORDER);
    testCell.setLayout(new GridLayout());
    Label l = createLabel(testCell);
    l.setText("Old Text");
    Composite btnCell = new Composite(shell,SWT.NONE);
    btnCell.setLayout(new GridLayout());
    Button b = new Button(btnCell, SWT.PUSH);
    b.setText("Change");
    b.addListener(SWT.MouseDown, new Listener() {
        public void handleEvent(Event e) {
            changeText();
        }
    });

正如您所看到的，我在添加新元素后在复合材料上调用redraw。另外，我已经验证在调用dispose之后，testCell.getChildren（）。length按预期返回0，当我创建一个新标签时，我得到相同的表达式返回1，验证新元素确实得到了添加到其父复合容器
我在这里遗漏了什么？

As you can see, I am calling redraw on the composite after I add a new element. Also, I have verified that after the call to dispose, testCell.getChildren().length returns 0, as expected, and when I create a new label, I get the same expression to return 1, verifying that the new element is indeed getting added to its parent composite container Am I missing something here ?

推荐答案

在 changeText中（）函数，

testCell.redraw（）;

行应替换为

testCell.layout（）;

或者，如果你想要要正确调整大小，你应该使用

Or, if you want to resize it correctly you should use

shell.layout（）; 。

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