onResize不调用

Question

如何编写对调整大小作出反应的小部件？

以下内容不起作用。onResize()在开始时只调用一次。后者更改浏览器窗口大小并不会导致调用此方法，尽管DIVs被调整了大小。

public class MyWidget extends SimpleLayoutPanel {

private Label label;

public MyWidget() {
    label = new Label("A");
    add(label);
}

@Override
public void onResize() {
    super.onResize();
    int width = label.getElement().getClientWidth();
    int height = label.getElement().getClientHeight();
    int fontsize = (width>height?height:width);
    if( fontsize > 0 ) {
        DOM.setStyleAttribute(label.getElement(), "font-size", Integer.toString(fontsize)+"px");
    }
}

}

和主模块

public void onModuleLoad() {

    MyWidget myWidget = new MyWidget();
    DOM.setStyleAttribute(myWidget.getElement(), "position", "fixed");
    DOM.setStyleAttribute(myWidget.getElement(), "top", "0px");
    DOM.setStyleAttribute(myWidget.getElement(), "left", "0px");
    DOM.setStyleAttribute(myWidget.getElement(), "bottom", "0px");
    DOM.setStyleAttribute(myWidget.getElement(), "right", "0px");

    RootPanel rootPanel = RootPanel.get();
    rootPanel.add(myWidget);


}

更新1

基于ResizComposite的版本也不起作用。在这种情况下，onResize根本没有调用。

public class MyWidget extends ResizeComposite  {

private Label label;

public MyWidget() {
    label = new Label("A");
    DOM.setStyleAttribute(label.getElement(), "position", "fixed");
    DOM.setStyleAttribute(label.getElement(), "top", "0px");
    DOM.setStyleAttribute(label.getElement(), "left", "0px");
    DOM.setStyleAttribute(label.getElement(), "bottom", "0px");
    DOM.setStyleAttribute(label.getElement(), "right", "0px");

    SimpleLayoutPanel simpleLayoutPanel = new SimpleLayoutPanel();
    simpleLayoutPanel.add(label);

    initWidget(simpleLayoutPanel);
}

@Override
public void onResize() {

    int width = label.getElement().getClientWidth();
    int height = label.getElement().getClientHeight();
    int fontsize = (width>height?height:width);
    if( fontsize > 0 ) {
        DOM.setStyleAttribute(label.getElement(), "font-size", Integer.toString(fontsize)+"px");
    }

    super.onResize();
}

}

Answer 1

您必须向ProvidesResize小部件(RootLayoutPanel、ResizeLayoutPanel)或HeaderPanel中添加才能使RequiresResize得到尊重。请参阅http://code.google.com/webtoolkit/doc/latest/DevGuideUiPanels.html#Resize