Java:我该如何做& quot; onclick& quot;"为TextField? [英] Java: How do I do a "onclick" for TextField?

问题描述

我想让我的文本字段在有人单击时清除文本.我该怎么办?

I want to make my text field clear the text when someone clicks it. How can I do this?

推荐答案

在 java.awt.TextField 上，您可以像这样添加 MouseListener

on java.awt.TextField you can add a MouseListener like so

TextField field = new TextField();
field.addMouseListener(new MouseListener() {

    public void mouseClicked(MouseEvent e) {

    }

    public void mousePressed(MouseEvent e) {

    }

    public void mouseReleased(MouseEvent e) {

    }

    public void mouseEntered(MouseEvent e) {

    }

    public void mouseExited(MouseEvent e) {

    }

});

原因是 java.awt.TextField 是 java.awt.TextComponent 的子类(而后者又是 java的子类.awt.Component ). Component 类具有 addMouseListener()方法.

The reason being that java.awt.TextField is a subclass of java.awt.TextComponent (which, in turn, is a subclass of java.awt.Component). The Component class has a addMouseListener() method.

或者，您可以将 MouseListener 替换为 java.awt.event.MouseAdapter ，使其封装所有 MouseListener ， MouseWheelListener 和 MouseMotionListener 方法.

Alternatively, you can replace MouseListener with java.awt.event.MouseAdapter has it encapsulates all of MouseListener, MouseWheelListener and MouseMotionListener methods.

来自JavaDoc( MouseAdapter 的):

From JavaDoc (of MouseAdapter):

用于的抽象适配器类接收鼠标事件.中的方法这个班是空的.这节课存在是为了方便创建侦听器对象.

An abstract adapter class for receiving mouse events. The methods in this class are empty. This class exists as convenience for creating listener objects.

鼠标事件可让您跟踪何时按下，释放，单击鼠标，当它进入一个组件，何时退出以及何时鼠标滚轮已移动.

Mouse events let you track when a mouse is pressed, released, clicked, moved, dragged, when it enters a component, when it exits and when a mouse wheel is moved.

这篇关于Java:我该如何做& quot; onclick& quot;"为TextField?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！