单击JTextField中的图标，并清除其内容 [英] Click on icon in a JTextField and clear its content
问题描述
我试图创建一个带有图像和提示的JTextField。文本字段的功能是搜索某些书籍的搜索字段。现在，我想再进一步。我想给图像一个函数。例如，如果我点击图片文本字段中的文本应该清除。
为了实现这个实现，我创建了一个新类，并扩展它与JTextField。 p>
这是代码：
public class JSearchTextField extends JTextField implements FocusListener {
/ **
*
* /
private static final long serialVersionUID = 1L;
private String textWhenNotFocused;
private图标图标;
private Insets dummyInsets;
private JTextField dummy;
public JSearchTextField（）{
super（）;
边框border = UIManager.getBorder（TextField.border）;
dummy = new JTextField（Suchen ...）;
this.dummyInsets = border.getBorderInsets（dummy）;
icon = new ImageIcon（JSearchTextField.class.getResource（/ images / clearsearch.png））;
this.addFocusListener（this）;
}
public JSearchTextField（String textWhenNotFocused）{
this（）;
this.textWhenNotFocused = textWhenNotFocused;
}
public void setIcon（ImageIcon newIcon）{
this.icon = newIcon;
}
public String getTextWhenNotFocused（）{
return this.textWhenNotFocused;
}
public void setTextWhenNotFocused（String newText）{
this.textWhenNotFocused = newText;
}
public void paintComponent（Graphics g）{
super.paintComponent（g）;
int textX = 2;
if（！this.hasFocus（）&& this.getText（）。equals（））{
int height = this.getHeight（）;
Font prev = this.getFont（）;
Font italic = prev.deriveFont（Font.ITALIC）;
color prevColor = g.getColor（）;
g.setFont（italic）;
g.setColor（UIManager.getColor（textInactiveText））;
int h = g.getFontMetrics（）。getHeight（）;
int textBottom =（height - h）/ 2 + h - 4;
int x = this.getInsets（）。left;
Graphics2D g2d =（Graphics2D）g;
RenderingHints hints = g2d.getRenderingHints（）;
g2d.setRenderingHint（RenderingHints.KEY_TEXT_ANTIALIASING，
RenderingHints.VALUE_TEXT_ANTIALIAS_ON）;
g2d.drawString（textWhenNotFocused，x，textBottom）;
g2d.setRenderingHints（hints）;
g.setFont（prev）;
g.setColor（prevColor）;
} else {
int iconWidth = icon.getIconWidth（）;
int iconHeight = icon.getIconHeight（）;
int x = dummy.getWidth（）+ dummyInsets.right;
textX = x - 420;
int y =（this.getHeight（） - iconHeight）/ 2;
icon.paintIcon（this，g，x，y）;
}
setMargin（new Insets（2，textX，2，2））;
}
@Override
public void focusGained（FocusEvent arg0）{
this.repaint（）;
}
@Override
public void focusLost（FocusEvent arg0）{
this.repaint（）;
}
}
这是我创建字段的地方;
txtSearchBooks = new JSearchTextField（Buch suchen ...）;
现在回到我的问题。你有什么想法如何给图像一个功能，其中的文本将被自动清除？我试图实现一个MouseListener，并将txtSearchBooks的文本设置为null，但它没有工作。
我希望我没有走错方向。
对不起，将真正感谢得到一些建议。
JTextField 是 JComponent ，这意味着它也是其他组件的容器。您可以使用 add（Component c）方法向其中添加其他组件。 BUT A JTextField 将不显示其添加的组件，除非您向其提供 LayoutManager 。然后它的行为就像一个正常的 JPanel 。
我做了一个小例子，如何管理你需要的。标签显示在右侧，单击它将清除字段。您也可以使用按钮，而不是标签。
请注意，您不需要创建图像对象从头开始，我可以从文件加载它。我以这种方式创建它，使示例不依赖于其他文件。
public class TextFieldWithLabel {
public static void main（String [] args）
{
JFrame frame = new JFrame（）;
frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）;
final JTextField textField = new JTextField（Search ...）;
textField.setLayout（new BorderLayout（））;
//创建虚拟映像...
映像image =新的BufferedImage（25，25，BufferedImage.TYPE_INT_RGB）;
Graphics graphics = image.getGraphics（）;
graphics.setColor（Color.WHITE）;
graphics.fillRect（0，0，25，25）;
graphics.setColor（Color.RED）;
graphics.fillRect（2，11，21，3）;
graphics.fillRect（11，2，3，21）;
JLabel label = new JLabel（new ImageIcon（image））;
textField.add（label，BorderLayout.EAST）;
label.addMouseListener（new MouseAdapter（）{
@Override
public void mouseClicked（MouseEvent e）{
textField.setText（）;
}
}）;
frame.add（textField）;
frame.pack（）;
frame.setLocationRelativeTo（null）;
frame.setVisible（true）;
}
}
I am trying to create a JTextField with an image and a hint. The function of the textfield is a search field to search some books. Now, I like to go a little bit further. I would like to give the image a function. For example, if I click on the image the text in the textfield should be cleared.
To achieve this implementation I created a new class and extended it with JTextField.
This is the code:
public class JSearchTextField extends JTextField implements FocusListener {
/**
*
*/
private static final long serialVersionUID = 1L;
private String textWhenNotFocused;
private Icon icon;
private Insets dummyInsets;
private JTextField dummy;
public JSearchTextField() {
super();
Border border = UIManager.getBorder("TextField.border");
dummy = new JTextField("Suchen...");
this.dummyInsets = border.getBorderInsets(dummy);
icon = new ImageIcon(JSearchTextField.class.getResource("/images/clearsearch.png"));
this.addFocusListener(this);
}
public JSearchTextField(String textWhenNotFocused) {
this();
this.textWhenNotFocused = textWhenNotFocused;
}
public void setIcon(ImageIcon newIcon){
this.icon = newIcon;
}
public String getTextWhenNotFocused() {
return this.textWhenNotFocused;
}
public void setTextWhenNotFocused(String newText) {
this.textWhenNotFocused = newText;
}
public void paintComponent(Graphics g){
super.paintComponent(g);
int textX = 2;
if(!this.hasFocus() && this.getText().equals("")) {
int height = this.getHeight();
Font prev = this.getFont();
Font italic = prev.deriveFont(Font.ITALIC);
Color prevColor = g.getColor();
g.setFont(italic);
g.setColor(UIManager.getColor("textInactiveText"));
int h = g.getFontMetrics().getHeight();
int textBottom = (height - h) / 2 + h - 4;
int x = this.getInsets().left;
Graphics2D g2d = (Graphics2D) g;
RenderingHints hints = g2d.getRenderingHints();
g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
g2d.drawString(textWhenNotFocused, x, textBottom);
g2d.setRenderingHints(hints);
g.setFont(prev);
g.setColor(prevColor);
} else {
int iconWidth = icon.getIconWidth();
int iconHeight = icon.getIconHeight();
int x = dummy.getWidth() + dummyInsets.right;
textX = x - 420;
int y = (this.getHeight() - iconHeight)/2;
icon.paintIcon(this, g, x, y);
}
setMargin(new Insets(2, textX, 2, 2));
}
@Override
public void focusGained(FocusEvent arg0) {
this.repaint();
}
@Override
public void focusLost(FocusEvent arg0) {
this.repaint();
}
}
And this is where I create the fields;
txtSearchBooks = new JSearchTextField("Buch suchen...");
Now back to my question. Do you have any idea how I can give the image a function where the text will be automatically cleared? I tried to implement a MouseListener and set the text of "txtSearchBooks" to null but it hasn't worked.
I hope I didn't go off in the wrong direction.
Sorry for the long post but I would really appreciate to get some advice.
A JTextField is a JComponent, meaning it is also a container for other components. You can use the add(Component c) method to add other components to it. BUT A JTextField won't show its added components unless you provide a LayoutManager to it. Then it behaves just like a normal JPanel.
I made a small example how you can manage what you need. The label is showed to the right, and clicking it will clear the field. You can use a button as well, instead of label.
Please note you don't need to create the Image object from scratch as I do, you can load it from a file. I create it this way so that the example doesn't rely on other files.
public class TextFieldWithLabel {
public static void main(String[] args)
{
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JTextField textField = new JTextField("Search...");
textField.setLayout(new BorderLayout());
//creating dummy image...
Image image = new BufferedImage(25, 25, BufferedImage.TYPE_INT_RGB);
Graphics graphics = image.getGraphics();
graphics.setColor(Color.WHITE);
graphics.fillRect(0, 0, 25, 25);
graphics.setColor(Color.RED);
graphics.fillRect(2, 11, 21, 3);
graphics.fillRect(11, 2, 3, 21);
JLabel label = new JLabel(new ImageIcon(image));
textField.add(label, BorderLayout.EAST);
label.addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent e) {
textField.setText("");
}
});
frame.add(textField);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
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