[英]Java Swing - JLabel width changed when icon or text added?
同一問題,不同背景
由於問題仍然存在,我似乎在接受之前過急。 問題? 當向其添加內容時,JLabel可以自由擴展其父面板。
現在該按照“充滿鰻魚的氣墊船” -ses建議來復制它了,這里是:
import java.awt.*;
import javax.swing.*;
public class TestLabel {
public static void main(String[] args) {
// Var inits
JFrame frame;
JPanel panel;
JLabel label;
Container pane;
GridBagConstraints gbc = new GridBagConstraints();
// Frame, content pane, layout inits
frame = new JFrame("Label Tester");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pane = frame.getContentPane();
pane.setLayout(new GridBagLayout());
gbc.weighty = 1;
gbc.fill = GridBagConstraints.BOTH;
// Add panels (note gbc weighty and fill carries over all instances)
gbc.weightx = 0.3;
gbc.gridx = 0;
gbc.gridy = 0;
panel = new JPanel();
panel.setBackground(Color.GREEN);
frame.add(panel,gbc);
label = new JLabel("THE PANEL IS NOW DISTORTED TO FIT THIS LABEL WHY IS THIS HAPPENING");
//label = new JLabel("");
label.setOpaque(true);
label.setBackground(Color.WHITE);
panel.add(label);
gbc.weightx = 0.7;
gbc.gridx = 1;
gbc.gridy = 0;
panel = new JPanel();
panel.setBackground(Color.RED);
frame.add(panel,gbc);
gbc.weightx = 0.3;
gbc.gridx = 0;
gbc.gridy = 1;
panel = new JPanel();
panel.setBackground(Color.BLUE);
frame.add(panel,gbc);
gbc.weightx = 0.7;
gbc.gridx = 1;
gbc.gridy = 1;
panel = new JPanel();
panel.setBackground(Color.YELLOW);
frame.add(panel,gbc);
frame.pack();
frame.setSize(800,600);
frame.setVisible(true);
}
}
結果:
如您所見,當向其添加文本(或原始問題和圖標)時,綠色面板被迫變寬,並拋棄了我的整個布局。 無論內容如何,我都希望布局保持相同的權重。 出現此問題的原因是因為我試圖將縮放圖像作為圖標添加到標簽,如原始問題所示。
順便說一句, setPreferredSize()
似乎不起作用。
有沒有辦法解決這個問題?
原始問題
當我向其中添加一個Icon時,我的JLabel元素會急劇擴展。 為什么會這樣呢? 這是代碼的適用部分:
// Show label and BG color
redLabel.setBackground(Color.RED);
redLabel.setOpaque(true);
// Grab stretched image (already loaded elsewhere in the code) and turn to icon
Img = Img.getScaledInstance(redLabel.getWidth(),12,Image.SCALE_REPLICATE);
ImageIcon icon = new ImageIcon(Img);
// This line throws everything off!
//It's commented out in the first pic, and included in the second.
redLabel.setIcon(icon);
從第一張圖片中可以看到,我有一個寬度為W的標簽(紅色)。我想做的是將圖標拉伸到寬度W並將其放在標簽中。
當我這樣做時,標簽會展開(我認為恰好是50像素),並且也在左側邊緣(綠色)上擠壓。 有誰知道為什么會這樣嗎?
我已經嘗試了一些太冗長而無法解釋但找不到問題的東西:-/
您的組件得以擴展,因為它為其Icon
分配了必要的空間。
public class JLabelDemo {
private static BufferedImage bi;
public static void main(String[] args) throws IOException{
loadImage();
SwingUtilities.invokeLater(new Runnable(){
@Override
public void run() {
createAndShowGUI();
}
});
}
private static void loadImage() throws IOException{
bi = ImageIO.read(JLabelDemo.class.getResource("../resource/forever-alone.jpg"));
}
private static void createAndShowGUI(){
final JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JPanel panel = new JPanel();
panel.setBackground(Color.YELLOW);
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
final JLabel emptyLabel = new JLabel();
final JLabel textLabel = new JLabel("This label has text only");
final JLabel textAndImageLabel = new JLabel("This label has text and image");
textAndImageLabel.setIcon(new ImageIcon(bi));
panel.add(emptyLabel);
panel.add(textLabel);
panel.add(textAndImageLabel);
frame.add(panel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
System.out.println("Empty label dimensions - " + emptyLabel.getSize());
System.out.println("Text only label dimensions - " + textLabel.getSize());
System.out.println("Image width: " + bi.getWidth() + ", Image height: " + bi.getHeight());
System.out.println("Text and image label dimensions - " +textAndImageLabel.getSize());
}
}
以下輸出到控制台:
Empty label dimensions - java.awt.Dimension[width=0,height=0]
Text only label dimensions - java.awt.Dimension[width=129,height=16]
Image width: 194, Image height: 180
Text and image label dimensions - java.awt.Dimension[width=363,height=180]
考慮使用JLayeredPane在圖層中添加組件。 但是,這樣做時會遇到一些絆腳石和陷阱,例如所添加組件的不透明度,大小和位置。
例如,
import java.awt.*;
import javax.swing.*;
public class TestLabel {
private static final Dimension SIZE = new Dimension(800, 600);
public static void main(String[] args) {
GridBagConstraints gbc = new GridBagConstraints();
JPanel defaultPane = new JPanel();
defaultPane.setLayout(new GridBagLayout());
gbc.weighty = 1;
gbc.fill = GridBagConstraints.BOTH;
// Add panels (note gbc weighty and fill carries over all instances)
gbc.weightx = 0.3;
gbc.gridx = 0;
gbc.gridy = 0;
JPanel panel = new JPanel();
panel.setBackground(Color.GREEN);
defaultPane.add(panel, gbc);
gbc.weightx = 0.7;
gbc.gridx = 1;
gbc.gridy = 0;
panel = new JPanel();
panel.setBackground(Color.RED);
defaultPane.add(panel, gbc);
gbc.weightx = 0.3;
gbc.gridx = 0;
gbc.gridy = 1;
panel = new JPanel();
panel.setBackground(Color.BLUE);
defaultPane.add(panel, gbc);
gbc.weightx = 0.7;
gbc.gridx = 1;
gbc.gridy = 1;
panel = new JPanel();
panel.setBackground(Color.YELLOW);
defaultPane.add(panel, gbc);
defaultPane.setSize(SIZE);
JLabel label = new JLabel("THE PANEL IS NOW DISTORTED TO FIT THIS LABEL WHY IS THIS HAPPENING");
label.setOpaque(true);
label.setBackground(Color.WHITE);
JPanel northPalettePanel = new JPanel();
northPalettePanel.setOpaque(false);
northPalettePanel.add(label);
JPanel palettePanel = new JPanel(new BorderLayout());
palettePanel.setOpaque(false);
palettePanel.setSize(SIZE);
palettePanel.setLocation(0, 0);
palettePanel.add(northPalettePanel, BorderLayout.NORTH);
JLayeredPane layeredPane = new JLayeredPane();
layeredPane.setPreferredSize(SIZE);
layeredPane.add(defaultPane, JLayeredPane.DEFAULT_LAYER);
layeredPane.add(palettePanel, JLayeredPane.PALETTE_LAYER);
JFrame frame = new JFrame("Label Tester");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(layeredPane, BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
}
}
Java搖擺對我來說已經很老了,但是如果我記得很好的話,設置一個首選大小(setPreferredSize())有時可以解決這類問題。也可以嘗試使用setMaximumSize和setMinimumSize進行頂層放置。
您也許可以在Java文檔中找到更多信息: http : //download.oracle.com/javase/tutorial/uiswing/layout/using.html#sizealignment
問候!
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