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我是Java新手,尝试使用GridBagLayout生成我的第一个GUI。使用下面的代码,我得到我的全屏,但不显示组件“label_url_eingabe”和“url_eingabe”(空窗口)。当我最小化窗口时,它们被显示! 当我将窗口大小设置为特定值时,我会得到相同的行为。所以这些组件在我的程序的最初开始时并未显示。Java GridBagLayout组件未全屏显示
package ofb_reader_package;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
public class OFB_Reader_GUI extends JFrame {
// Definition der GUI Komponenten
// Eingabefeld URL
JLabel label_url_eingabe;
JTextField url_eingabe;
//this.OFB_Reader_GUI();
// Eigenschaften Hauptfenster "OFB_Reader_GUI"
public OFB_Reader_GUI() {
// Eigenschaften Hauptfenster
setVisible(true);
setSize(500, 300);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setTitle("Mark's OFB Reader");
setResizable(true);
setExtendedState(JFrame.MAXIMIZED_BOTH);
setLayout(null);
this.label_url_eingabe = new JLabel("URL:");
this.url_eingabe = new JTextField(10);
this.getContentPane().setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
// POSITIONIERUNGEN MIT GRIDBAGLAYOUT
// URL Eingabe Label und Einghabefeld
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0;
c.gridy = 0;
c.ipadx = 35;
c.weightx = 1.0;
c.weighty = 1.0;
c.anchor = GridBagConstraints.NORTHWEST;
this.getContentPane().add(this.label_url_eingabe, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 1;
c.gridy = 0;
c.ipadx = 35;
c.weightx = 1.0;
c.weighty = 1.0;
c.anchor = GridBagConstraints.NORTHWEST;
add(this.url_eingabe, c);
}
}
这是主要的:
package ofb_reader_package;
import javax.swing.*;
public class OFB_Reader_main_class {
public static void main(String[] args){
new OFB_Reader_GUI();
new OFB_Reader_main_class();
}
}
JFrame setVisible是** last **方法调用,而不是第一个。调用JFrame方法的顺序是最重要的**。在打包JFrame并使其可见之前,您必须创建Swing组件并将它们添加到JPanel或JFrame。最后,不要使用空布局。使用[Swing布局](https://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html)创建您的GUI。 –