GWT 文本框上的即时值更改处理程序 [英] Instant value change handler on a GWT textbox

问题描述

我想在输入 GWT 文本框时立即更新文本字段.我的问题是 ValueChangeEvent 和 ChangeEvent 处理程序仅在 TextBox 失去焦点时触发.我想过使用 KeyPressEvent 但是当用鼠标执行复制粘贴时什么也不会发生.

I would like to update a text field instantly when typing in a GWT TextBox. My problem is that ValueChangeEvent and ChangeEvent handlers only fire when the TextBox loses focus. I thought about using the KeyPressEvent but then nothing would happen when performing a copy paste with the mouse.

最简单的方法是什么?

推荐答案

您可以捕获 ONPASTE 事件并手动触发 ValueChangeEvent.像这样:

You could catch the ONPASTE event and manually fire a ValueChangeEvent. Something like this:

public void onModuleLoad() {
    final Label text = new Label();
    final ExtendedTextBox box = new ExtendedTextBox();
    box.addValueChangeHandler(new ValueChangeHandler<String>() {

        @Override
        public void onValueChange(ValueChangeEvent<String> event) {
            text.setText(event.getValue());
        }

    });
    box.addKeyUpHandler(new KeyUpHandler() {

        @Override
        public void onKeyUp(KeyUpEvent event) {
            text.setText(box.getText());
        }
    });

    RootPanel.get().add(box);
    RootPanel.get().add(text);
}

private class ExtendedTextBox extends TextBox {

    public ExtendedTextBox() {
        super();
        sinkEvents(Event.ONPASTE);
    }

    @Override
    public void onBrowserEvent(Event event) {
        super.onBrowserEvent(event);
        switch (DOM.eventGetType(event)) {
            case Event.ONPASTE:
                Scheduler.get().scheduleDeferred(new ScheduledCommand() {

                    @Override
                    public void execute() {
                        ValueChangeEvent.fire(ExtendedTextBox.this, getText());
                    }

                });
                break;
        }
    }
}

已在 Firefox 3.6.1 上测试.

Tested on firefox 3.6.1.

这篇关于GWT 文本框上的即时值更改处理程序的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！