calculate.java

一个简单的计算器,用java 编写,希望对初学者有所帮助

import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Group;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import com.swtdesigner.SWTResourceManager;

public class calculate {

	private  Text text;
	double a;
	double b;
	int flag=0;
	StringBuffer str;

	/**
	 * Launch the application
	 * 
	 * @param args
	 */
	public calculate(){
		
		final Display display = Display.getDefault();
		final Shell shell = new Shell();
		shell.setSize(500, 375);
		shell.setText("Calculate");
		//

		shell.open();

		final Group aSimpleCalculateGroup = new Group(shell, SWT.NONE);
		aSimpleCalculateGroup.setText("A simple calculate");
		aSimpleCalculateGroup.setFont(SWTResourceManager.getFont("黑体", 10,
				SWT.NONE));
		aSimpleCalculateGroup.setBounds(47, 36, 347, 210);

		text = new Text(aSimpleCalculateGroup, SWT.BORDER | SWT.RIGHT);
		text.setBounds(21, 24, 301, 25);
	
		final Button button_0 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_0.addMouseListener(new MouseAdapter() {
			public void mouseDown(final MouseEvent e) {
				text.setText(text.getText() + "0");
			}
		});
		button_0.setText("0");
		button_0.setBounds(212, 86, 44, 23);

		final Button button_1 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_1.addMouseListener(new MouseAdapter() {
			public void mouseDown(final MouseEvent e) {
				text.setText(text.getText() + "1");
			}
		});
		button_1.setBounds(20, 86, 44, 23);
		button_1.setText("1");

		final Button button_2 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_2.addMouseListener(new MouseAdapter() {
			public void mouseDown(final MouseEvent e) {
				text.setText(text.getText() + "2");
			}
		});
		button_2.setText("2");
		button_2.setBounds(84, 86, 44, 23);

		final Button button_3 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_3.addMouseListener(new MouseAdapter() {
			public void mouseDown(final MouseEvent e) {
				text.setText(text.getText() + "3");
			}
		});
		button_3.setBounds(148, 86, 44, 23);
		button_3.setText("3");

		final Button button_4 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_4.addMouseListener(new MouseAdapter() {
			public void mouseDown(final MouseEvent e) {
				text.setText(text.getText() + "4");
			}
		});
		button_4.setBounds(20, 115, 44, 23);
		button_4.setText("4");

		final Button button_5 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_5.addMouseListener(new MouseAdapter() {
			public void mouseDown(final MouseEvent e) {
				text.setText(text.getText() + "5");
			}
		});
		button_5.setBounds(84, 115, 44, 23);
		button_5.setText("5");

		final Button button_6 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_6.addMouseListener(new MouseAdapter() {
			public void mouseDown(final MouseEvent e) {
				text.setText(text.getText() + "6");
			}
		});
		button_6.setBounds(148, 115, 44, 23);
		button_6.setText("6");

		final Button button_7 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_7.addMouseListener(new MouseAdapter() {
			public void mouseDown(final MouseEvent e) {
				text.setText(text.getText() + "7");
			}
		});
		button_7.setBounds(20, 151, 44, 23);
		button_7.setText("7");

		final Button button_8 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_8.addMouseListener(new MouseAdapter() {
			public void mouseDown(final MouseEvent e) {
				text.setText(text.getText() + "8");
			}
		});
		button_8.setBounds(84, 151, 44, 23);
		button_8.setText("8");

		final Button button_9 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_9.addMouseListener(new MouseAdapter() {
			public void mouseDown(final MouseEvent e) {
				text.setText(text.getText() + "9");
			}
		});
		button_9.setBounds(148, 151, 44, 23);
		button_9.setText("9");

		final Button button_10 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_10.addMouseListener(new MouseAdapter(){
			 public void mouseDown(final MouseEvent e){
				 a = Double.parseDouble(text.getText());
				 flag = 1;
				 text.setText("");
			 }
		});
		button_10.setBounds(212, 115, 44, 23);
		button_10.setText("+");

		final Button button_11 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_11.addMouseListener(new MouseAdapter(){
			public void mouseDown(final MouseEvent e){
				a=Double.parseDouble(text.getText());
				flag = 2;
				text.setText("");
			}
		});
		button_11.setBounds(212, 151, 44, 23);
		button_11.setText("-");

		final Button button_12 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_12.addMouseListener(new MouseAdapter(){
			public void mouseDown(final MouseEvent e){
				a=Double.parseDouble(text.getText());
				flag = 3;
				text.setText("");
			}
		});
		button_12.setBounds(278, 86, 44, 23);
		button_12.setText("*");

		final Button button_13 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_13.addMouseListener(new MouseAdapter(){
			public void mouseDown(final MouseEvent e){
				a=Double.parseDouble(text.getText());
				flag = 4;
				text.setText("");
			}
		});
		button_13.setBounds(278, 115, 44, 23);
		button_13.setText("/");

		final Button button_14 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_14.addMouseListener(new MouseAdapter(){
			public void mouseDown(final MouseEvent e){
				b=Double.parseDouble(text.getText());
				switch(flag){
				case(1):
					text.setText("" + ((int) (a + b)));
					break;
				case(2):
					text.setText("" + ((int) (a - b)));
					break;
				case(3):
					text.setText("" + ((int) (a * b)));
					break;
				case(4):
					text.setText("" + ((int) (a / b)));
					break;
				}
			}
		});
		button_14.setBounds(278, 151, 44, 23);
		button_14.setText("=");

		final Button button_15 = new Button(aSimpleCalculateGroup, SWT.NONE);
		button_15.addMouseListener(new MouseAdapter(){
			public void mouseDown(final MouseEvent e){
				text.setText("");
			}
		});
		button_15.setBounds(278, 55, 44, 23);
		button_15.setText("归零");
		shell.layout();
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch())
				display.sleep();
		  }
	  }
		public static void main(String args[]){
			new calculate();
	}
}