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Java：如何执行“onclick”对于文本字段？

发布于 2024-10-05 00:32:15 字数 34 浏览 3 评论 0原文

我想让我的文本字段在有人单击它时清除文本。我该怎么做？

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爱，才寂寞 2024-10-12 00:32:15

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

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 的子类java.awt.TextComponent（它又是 java.awt.Component 的子类）。 Component 类有一个 addMouseListener() 方法。

或者，您可以将 MouseListener 替换为 java.awt.event.MouseAdapter，它封装了所有 MouseListener、MouseWheelListener和 MouseMotionListener 方法。

来自 JavaDoc（MouseAdapter）：

抽象适配器类
接收鼠标事件。中的方法
这个类是空的。本班
存在是为了方便创建
侦听器对象。
鼠标事件可让您跟踪
鼠标按下、释放、单击，
移动、拖动，当它进入
组件，当它退出时以及当
鼠标滚轮已移动。

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) {

    }

});

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.

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

From JavaDoc (of MouseAdapter):

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

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素罗衫 2024-10-12 00:32:15

也许，您需要addMouseListener()。

更新
它将像

TextField a = ...;
  a.addMouseListener(new MouseAdapter(){
   public void mouseReleased(MouseEvent e) {
    //some stuff
   }
});

upd2 一样 smt
将 keyListener 修复为 MouseListener

Probably, you need addMouseListener().

upd
It would be smt like

TextField a = ...;
  a.addMouseListener(new MouseAdapter(){
   public void mouseReleased(MouseEvent e) {
    //some stuff
   }
});

upd2
fix keyListener to MouseListener

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忆离笙 2024-10-12 00:32:15

试试这个：

  TextField.setText("defaultText");

    TextField.addMouseListener(new java.awt.event.MouseAdapter() {
        public void mouseClicked(java.awt.event.MouseEvent evt) {
            reSet(evt);
        }
    });

  TextField.addFocusListener(new java.awt.event.FocusAdapter() {
        public void focusGained(java.awt.event.FocusEvent evt) {
            reSet(evt);
        }
  });

  void reSet(java.awt.event.KeyEvent evt) {
      String temp = jTextField1.getText();
      TextField.setText(temp.equals("defaultText")? "" : temp);
  }

Try this:

  TextField.setText("defaultText");

    TextField.addMouseListener(new java.awt.event.MouseAdapter() {
        public void mouseClicked(java.awt.event.MouseEvent evt) {
            reSet(evt);
        }
    });

  TextField.addFocusListener(new java.awt.event.FocusAdapter() {
        public void focusGained(java.awt.event.FocusEvent evt) {
            reSet(evt);
        }
  });

  void reSet(java.awt.event.KeyEvent evt) {
      String temp = jTextField1.getText();
      TextField.setText(temp.equals("defaultText")? "" : temp);
  }

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