0.前言
摆了两天没怎么干活，不过上一篇说的监听器已经更新了——Java这玩意还蛮好用的。这薄薄的一本厚书也要被我看得差不多了，还剩两章看完差不多就能说自己是Java这门语言上的一个小学生了，可喜可贺可喜可贺。之后是继续学习Java，还是unity入个门就要看心情了。不过深度学习这玩意是不会学的了。
今天分享图形化界面的一个小案例，在这个案例中可以看到监听器的使用，图形绘制，还有一些GUI组件的使用。还是蛮不错的。注释我是写了的，但是懒得切换输入法所以写的是英文注释，不过应该没关系。先上效果图：
1.Histogram类
import javax.swing.*;
import java.awt.*;
public class Histogram extends JPanel {
private int[] count;
public void showHistogram(int[] count)
{
this.count=count;
repaint();
}
protected void paintComponent(Graphics g)
{
if(count==null) return;
super.paintComponent(g);
int width = getWidth();
int height = getHeight();
int interval = (width-40)/count.length;
int individualWidth = (int)(((width-40)/24)*0.60);
//Find max count to decide the highest bar
int maxcount=0;
for(int i:count)
{
if(maxcount<i)
{
maxcount=i;
}
}
//x is the start position for the first bar in the histogram
int x = 30;
//draw
g.drawLine(10,height-45,width-10,height-45);
for(int i=0;i<count.length;i++)
{
int barheight = (int)(((double)count[i]/(double) maxcount)*(height-55));
g.drawRect(x,height-45-barheight,individualWidth,barheight);
g.drawString((char)(65+i)+"",x,height-30);
x+=interval;
}
}
public Dimension getPreferredSize()
{
return new Dimension(300,300);
}
}
2.MultipleWindowDemo类（主函数入口）
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class MultipleWindowDemo extends JFrame {
private JTextArea jta;
private JButton jbtShowHisToGram = new JButton( "show histogram");
private Histogram histogram = new Histogram();
//new frame window to show
private JFrame histogramFrame = new JFrame();
public MultipleWindowDemo(){
//store test area in a scroll area
JScrollPane scrollPane = new JScrollPane(jta = new JTextArea());
scrollPane.setPreferredSize(new Dimension(300,300));
jta.setWrapStyleWord(true);
jta.setLineWrap(true);
//Place scroll and button
add(scrollPane,BorderLayout.CENTER);
add(jbtShowHisToGram,BorderLayout.SOUTH);
//listener
jbtShowHisToGram.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
int[] count = countLetters();
histogram.showHistogram(count);
histogramFrame.setVisible(true);
}
});
histogramFrame.add(histogram);
histogramFrame.pack();
histogramFrame.setTitle("Histogram");
}
private int[] countLetters(){
int[] count = new int[26];
String text = jta.getText();
for(int i=0;i<text.length();i++)
{
char character = text.charAt(i);
if((character>='A')&&(character<='Z'))
count[character-'A']++;
if((character>='a')&&(character<='z'))
count[character-'a']++;
}
return count;
}
public static void main(String[] args) {
MultipleWindowDemo frame = new MultipleWindowDemo();
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("CountCharNumberAndShow");
frame.pack();
frame.setVisible(true);
}
}
3.小结与碎碎念
Java提供了一套十分便利的GUI组件，可以迅速搭建一套看得过去的图形用户界面。
PS：我还没阳，不知道能苟到什么时候。