java - 将 JTextField 或 JComboBox 的光标移动到开头

Question

我有一个包含一些文本的 JTextField。当我单击文本字段时，光标移动到字段的末尾。我希望光标在聚焦时移动到字段的开头。

我对可编辑的 JComboBox 也有同样的问题。

我怎样才能在焦点上实现这种光标定位？

Answer 1

/**
* On gaining focus place the cursor at the start of the text.
*/
public class CursorAtStartFocusListener extends FocusAdapter {

    @Override
    public void focusGained(java.awt.event.FocusEvent evt) {
        Object source = evt.getSource();
        if (source instanceof JTextComponent) {
            JTextComponent comp = (JTextComponent) source;
            comp.setCaretPosition(0);
        } else {
            Logger.getLogger(getClass().getName()).log(Level.INFO,
                    "A text component expected instead of {0}",
                    source.getClass().getName());
        }
    }
}

jTextField1.addFocusListener(new CursorAtStartFocusListener());
jComboBox1.getEditor().getEditorComponent().addFocusListener(new CursorAtStartFocusListener());
// Only one instance of CursorAtStartFocusListener needed.