[英]How to set Text like Placeholder in JTextfield in swing
我想在加載表單時將一些文本放在文本字段中,以指示用戶,當用戶單擊該文本文件時,文本會自動刪除。
txtEmailId = new JTextField();
txtEmailId.setText("Email ID");
我已經編寫了上面的代碼,但是當用戶單擊我要刪除的文本按鈕時,它會顯示文本並保持原樣。
有什么辦法可以完成這項任務嗎?
我用來覆蓋文本字段的繪制方法,直到我最終得到更多的自定義文本字段,然后我才真正想要......
然后我發現這個提示 API使用簡單,不需要你擴展任何組件。 它還有一個不錯的“伙伴”API
這現在已包含在 SwingLabs、 SwingX 庫中,這使得它更易於使用......
例如(這里使用 SwingX-1.6.4)
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import org.jdesktop.swingx.prompt.PromptSupport;
public class PromptExample {
public static void main(String[] args) {
new PromptExample();
}
public PromptExample() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JTextField bunnies = new JTextField(10);
JTextField ponnies = new JTextField(10);
JTextField unicorns = new JTextField(10);
JTextField fairies = new JTextField(10);
PromptSupport.setPrompt("Bunnies", bunnies);
PromptSupport.setPrompt("Ponnies", ponnies);
PromptSupport.setPrompt("Unicorns", unicorns);
PromptSupport.setPrompt("Fairies", fairies);
PromptSupport.setFocusBehavior(PromptSupport.FocusBehavior.HIDE_PROMPT, bunnies);
PromptSupport.setFocusBehavior(PromptSupport.FocusBehavior.HIGHLIGHT_PROMPT, ponnies);
PromptSupport.setFocusBehavior(PromptSupport.FocusBehavior.SHOW_PROMPT, unicorns);
PromptSupport.setFontStyle(Font.BOLD, bunnies);
PromptSupport.setFontStyle(Font.ITALIC, ponnies);
PromptSupport.setFontStyle(Font.ITALIC | Font.BOLD, unicorns);
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
frame.add(bunnies, gbc);
frame.add(ponnies, gbc);
frame.add(unicorns, gbc);
frame.add(fairies, gbc);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}
JTextField busqueda = new JTextField(20);
add(busqueda);
busqueda.setHorizontalAlignment(SwingConstants.CENTER);
if (busqueda.getText().length() == 0) {
busqueda.setText("Buscar");
busqueda.setForeground(new Color(150, 150, 150));
}
busqueda.addFocusListener(new FocusListener() {
@Override
public void focusGained(FocusEvent e) {
busqueda.setText("");
busqueda.setForeground(new Color(50, 50, 50));
}
@Override
public void focusLost(FocusEvent e) {
if (busqueda.getText().length() == 0) {
busqueda.setText("Buscar");
busqueda.setForeground(new Color(150, 150, 150));
}
}
});
你可以下載這個 NetBeans 插件,你可以用它來創建一個只有一行的占位符。
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