badtechnique.java

翁剀JAVA语言那门课程的教案 很多人都看多他的视频教程可惜没有ppt的教案

//: BadTechnique.java
// It's possible to override components this way,
// but the listener approach is much better, so
// why would you?
import java.awt.*;
import java.awt.event.*;

class Display {
	public static final int
		EVENT = 0, COMPONENT = 1,
		MOUSE = 2, MOUSE_MOVE = 3,
		FOCUS = 4, KEY = 5, ACTION = 6,
		LAST = 7;

	public String[] evnt;

	Display() {
		evnt = new String[LAST];
		for(int i = 0; i < LAST; i++)
			evnt[i] = new String();
	}
	
	public void show(Graphics g) {
		for(int i = 0; i < LAST; i++)
			g.drawString(evnt[i], 0, 10 * i + 10);
	}
}

class EnabledPanel extends Panel {
	Color c;
	int id;
	Display display = new Display();

	public EnabledPanel(int i, Color mc) {
		id = i;
		c = mc;
		setLayout(new BorderLayout());
		add(new MyButton(), BorderLayout.SOUTH);
		// Type checking is lost. You can enable and
		// process events that the component doesn't
		// capture:
		enableEvents(
			// Panel doesn't handle these:
			AWTEvent.ACTION_EVENT_MASK |
			AWTEvent.ADJUSTMENT_EVENT_MASK |
			AWTEvent.ITEM_EVENT_MASK |
			AWTEvent.TEXT_EVENT_MASK |
			AWTEvent.WINDOW_EVENT_MASK |
			// Panel can handle these:
			AWTEvent.COMPONENT_EVENT_MASK |
			AWTEvent.FOCUS_EVENT_MASK |
			AWTEvent.KEY_EVENT_MASK |
			AWTEvent.MOUSE_EVENT_MASK |
			AWTEvent.MOUSE_MOTION_EVENT_MASK |
			AWTEvent.CONTAINER_EVENT_MASK);
		// You can enable an event without
		// overriding its process method.
	}

	// To eliminate flicker:
	public void update(Graphics g) {
		paint(g);
	}

	public void paint(Graphics g) {
		g.setColor(c);
		Dimension s = getSize();
		g.fillRect(0, 0, s.width, s.height);
		g.setColor(Color.black);
		display.show(g);
	}

	public void processEvent(AWTEvent e) {
		display.evnt[Display.EVENT]= e.toString();
		repaint();
		super.processEvent(e);
	}

	public void
		processComponentEvent(ComponentEvent e) {
		switch(e.getID()) {
		case ComponentEvent.COMPONENT_MOVED:
			display.evnt[Display.COMPONENT] =
				"Component moved";
			break;
		case ComponentEvent.COMPONENT_RESIZED:
			display.evnt[Display.COMPONENT] =
				"Component resized";
			break;
		case ComponentEvent.COMPONENT_HIDDEN:
			display.evnt[Display.COMPONENT] =
				"Component hidden";
			break;
		case ComponentEvent.COMPONENT_SHOWN:
			display.evnt[Display.COMPONENT] =
				"Component shown";
			break;
		default:
		}
		repaint();
		// Must always remember to call the "super"
		// version of whatever you override:
		super.processComponentEvent(e);
	}
	
	public void processFocusEvent(FocusEvent e) {
		switch(e.getID()) {
		case FocusEvent.FOCUS_GAINED:
			display.evnt[Display.FOCUS] =
				"FOCUS gained";
			break;
		case FocusEvent.FOCUS_LOST:
			display.evnt[Display.FOCUS] =
				"FOCUS lost";
			break;
		default:
		}
		repaint();
		super.processFocusEvent(e);
	}
	
	public void processKeyEvent(KeyEvent e) {
		switch(e.getID()) {
		case KeyEvent.KEY_PRESSED:
			display.evnt[Display.KEY] =
				"KEY pressed: ";
			break;
		case KeyEvent.KEY_RELEASED:
			display.evnt[Display.KEY] =
				"KEY released: ";
			break;
		case KeyEvent.KEY_TYPED:
			display.evnt[Display.KEY] =
				"KEY typed: ";
			break;
		default:
		}
		int code = e.getKeyCode();
		display.evnt[Display.KEY] +=
			KeyEvent.getKeyText(code);
		repaint();
		super.processKeyEvent(e);
	}

	public void processMouseEvent(MouseEvent e) {
		switch(e.getID()) {
		case MouseEvent.MOUSE_CLICKED:
			requestFocus(); // Get FOCUS on click
			display.evnt[Display.MOUSE] =
				"MOUSE clicked";
			break;
		case MouseEvent.MOUSE_PRESSED:
			display.evnt[Display.MOUSE] =
				"MOUSE pressed";
			break;
		case MouseEvent.MOUSE_RELEASED:
			display.evnt[Display.MOUSE] =
				"MOUSE released";
			break;
		case MouseEvent.MOUSE_ENTERED:
			display.evnt[Display.MOUSE] =
				"MOUSE entered";
			break;
		case MouseEvent.MOUSE_EXITED:
			display.evnt[Display.MOUSE] =
				"MOUSE exited";
			break;
		default:
		}
		display.evnt[Display.MOUSE] +=
			", x = " + e.getX() +
			", y = " + e.getY();
		repaint();
		super.processMouseEvent(e);
	}

	public void
		processMouseMotionEvent(MouseEvent e) {
		switch(e.getID()) {
		case MouseEvent.MOUSE_DRAGGED:
			display.evnt[Display.MOUSE_MOVE] =
				"MOUSE dragged";
			break;
		case MouseEvent.MOUSE_MOVED:
			display.evnt[Display.MOUSE_MOVE] =
				"MOUSE moved";
			break;
		default:
		}
		display.evnt[Display.MOUSE_MOVE] +=
			", x = " + e.getX() +
			", y = " + e.getY();
		repaint();
		super.processMouseMotionEvent(e);
	}
}

class MyButton extends Button {
	int clickCounter;
	String label = "";

	public MyButton() {
		enableEvents(AWTEvent.ACTION_EVENT_MASK);
	}

	public void paint(Graphics g) {
		g.setColor(Color.green);
		Dimension s = getSize();
		g.fillRect(0, 0, s.width, s.height);
		g.setColor(Color.black);
		g.drawRect(0, 0, s.width - 1, s.height - 1);
		drawLabel(g);
	}

	private void drawLabel(Graphics g) {
		FontMetrics fm = g.getFontMetrics();
		int width = fm.stringWidth(label);
		int height = fm.getHeight();
		int ascent = fm.getAscent();
		int leading = fm.getLeading();
		int horizMargin =
			(getSize().width - width)/2;
		int verMargin =
			(getSize().height - height)/2;
		g.setColor(Color.red);
		g.drawString(label, horizMargin,
			verMargin + ascent + leading);
	}

	public void processActionEvent(ActionEvent e) {
		clickCounter++;
		label = "click #" + clickCounter +
			" " + e.toString();
		repaint();
		super.processActionEvent(e);
	}
}

public class BadTechnique extends Frame {
	BadTechnique() {
		setLayout(new GridLayout(2,2));
		add(new EnabledPanel(1, Color.cyan));
		add(new EnabledPanel(2, Color.lightGray));
		add(new EnabledPanel(3, Color.yellow));
		// You can also do it for Windows:
		enableEvents(AWTEvent.WINDOW_EVENT_MASK);
	}

	public void processWindowEvent(WindowEvent e) {
		System.out.println(e);
		if(e.getID() == WindowEvent.WINDOW_CLOSING) {
			System.out.println("Window Closing");
			System.exit(0);
		}
	}

	public static void main(String[] args) {
		Frame f = new BadTechnique();
		f.setTitle("Bad Technique");
		f.setSize(700,700);
		f.setVisible(true);
	}
} ///:~