[英]Vertical Scroll Bar for Radio Buttons
我是一個非常新的java程序員。
我正在嘗試創建一個帶有滾動條的垂直單選按鈕列表。 我的代碼不會以指定大小生成窗口,也不會實際出現滾動條。
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Toolkit;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.swing.Box;
import javax.swing.ButtonGroup;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
public class RadioButtonScroller {
private List<String> abcList = new ArrayList<>(Arrays.asList("Aa", "Bb", "Cc", "Dd", "Ee", "Ff", "Gg", "Hh", "Ii",
"Jj", "Kk", "Ll", "Mm", "Nn", "Oo", "Pp", "Qq", "Rr", "Ss", "Tt", "Uu", "Vv", "Ww", "Xx", "Yy", "Zz"));
private JRadioButton pickButton;
private JFrame jframe = new JFrame("Select one:");
private JScrollPane scrollPane;
private JPanel panel = new JPanel();
private Box vertBox;
public RadioButtonScroller() {
createUI();
}
public void setRadioButtons() {
ButtonGroup group = new ButtonGroup();
for (int i = 0; i < abcList.size(); i++) {
String theseLetters = abcList.get(i);
pickButton = new JRadioButton(theseLetters);
group.add(pickButton);
vertBox.add(pickButton);
}
}
private void createUI() {
//centers on screen
Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
jframe.setLocationRelativeTo(null);
jframe.setLocation(dim.width / 3 - jframe.getSize().width / 3, dim.height / 4 - jframe.getSize().height / 4);
vertBox = Box.createVerticalBox();
jframe.setSize(300, 525);
vertBox.setSize(300, 525);
jframe.setVisible(true);
panel.setLayout(new FlowLayout());
jframe.add(panel);
scrollPane = new JScrollPane(vertBox);
scrollPane.setSize(300, 525);
scrollPane.getVerticalScrollBar();
panel.add(scrollPane);
jframe.pack();
jframe.setVisible(true);
jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setRadioButtons();
}
public static void main(String[] args) {
RadioButtonScroller radioButtonScroller = new RadioButtonScroller();
}
}
我之前已經成功地將 JFrame 與 Vbox 一起使用,但是 JPanel 和 JScrollPane 的添加讓我感到困惑。
(由於某些兼容性問題,我無法使用 JavaFX。必須處於擺動狀態。)
非常感謝。
它是您在panel.setLayout(new FlowLayout());
中使用的布局panel.setLayout(new FlowLayout());
. JScrollPane
流布局“不能很好地工作”。 您可以更改布局,您將獲得一個功能性滾動窗格,而無需做額外的事情。 (為了使流布局與 JScrollPane 一起工作,您必須進一步調查,可能使用組件偵聽器等)
在您的情況下,我將使用具有 1 列、無限行的 GridLayout:
panel.setLayout(new GridLayout(0, 1));
或者一個帶有 y 軸的 BoxLayout:
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
此外,這些行沒有任何作用:
scrollPane.setSize(300, 525);
scrollPane.getVerticalScrollBar();
滾動窗格的大小將從父容器計算,即 JFrame 的內容窗格。
這里有很多布局問題
例如,
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.swing.*;
@SuppressWarnings("serial")
public class RadioButtonScroller2 extends JPanel {
private List<String> abcList = new ArrayList<>(Arrays.asList("Aa", "Bb", "Cc", "Dd", "Ee", "Ff", "Gg", "Hh", "Ii",
"Jj", "Kk", "Ll", "Mm", "Nn", "Oo", "Pp", "Qq", "Rr", "Ss", "Tt", "Uu", "Vv", "Ww", "Xx", "Yy", "Zz"));
private ButtonGroup buttonGroup = new ButtonGroup();
public RadioButtonScroller2() {
JPanel radioPanel = new JPanel(new GridLayout(0, 1));
ItemListener il = itemEvent -> {
if (itemEvent.getStateChange() == ItemEvent.SELECTED) {
AbstractButton btn = (AbstractButton) itemEvent.getSource();
System.out.println("Selection: " + btn.getActionCommand());
}
};
for (String radioText : abcList) {
JRadioButton radioButton = new JRadioButton(radioText);
radioButton.setActionCommand(radioText);
radioButton.addItemListener(il);
radioPanel.add(radioButton);
buttonGroup.add(radioButton);
}
JScrollPane scrollPane = new JScrollPane(radioPanel);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.getViewport().setPreferredSize(new Dimension(150, 200));
setLayout(new BorderLayout());
add(scrollPane);
}
private static void createAndShowGui() {
RadioButtonScroller2 mainPanel = new RadioButtonScroller2();
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
兩個回答都讓我得到了答案,謝謝你們! 非常感謝 George Z. 和 HoverCraft Full of Eels 指出:
panel.setLayout(new FlowLayout());
不會工作。 George Z 明確建議使用:
panel.setLayout (new GridLayout(0, 1));
這對我有用。
雖然 George Z. 明確表示:
scrollPane.setSize(300, 525);
scrollPane.getVerticalScrollBar();
沒有完成任何事情,正是 Hovercraft Full Of Eels 提到的首選大小幫助我一路找到了答案(並找出我試圖用那兩行浪費的代碼完成的工作中出錯的地方)。
充滿鰻魚的氣墊船還幫助我了解了“打包”JFrame 的實際作用。 你們都提供了需要的東西,非常感謝。 這是一個簡短的工作答案:
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.swing.Box;
import javax.swing.ButtonGroup;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
public class RadioButtonScroller {
private List<String> abcList = new ArrayList<>(Arrays.asList("Aa", "Bb", "Cc", "Dd", "Ee", "Ff", "Gg", "Hh", "Ii",
"Jj", "Kk", "Ll", "Mm", "Nn", "Oo", "Pp", "Qq", "Rr", "Ss", "Tt", "Uu", "Vv", "Ww", "Xx", "Yy", "Zz"));
private JRadioButton pickButton;
private JFrame jframe = new JFrame("Select one:");
private JScrollPane scrollPane;
private JPanel panel = new JPanel();
private Box vertBox;
public RadioButtonScroller() {
createUI();
}
public void setRadioButtons() {
ButtonGroup group = new ButtonGroup();
for (int i = 0; i < abcList.size(); i++) {
String theseLetters = abcList.get(i);
pickButton = new JRadioButton(theseLetters);
group.add(pickButton);
vertBox.add(pickButton);
}
jframe.pack();
jframe.setVisible(true);
jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private void createUI() {
// center on screen
Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
jframe.setLocationRelativeTo(null);
jframe.setLocation(dim.width / 3 - jframe.getSize().width / 3, dim.height / 4 - jframe.getSize().height / 4);
vertBox = Box.createVerticalBox();
jframe.setSize(300, 525);
vertBox.setSize(300, 525);
jframe.setVisible(true);
panel.setLayout(new GridLayout(0, 1));
jframe.add(panel);
scrollPane = new JScrollPane(vertBox);
scrollPane.setPreferredSize(new Dimension(300, 525));
panel.add(scrollPane);
setRadioButtons();
}
public static void main(String[] args) {
RadioButtonScroller radioButtonScroller = new RadioButtonScroller();
}
}
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