progressglasspane.java

Jav面板案例 简单易学！大家一起学习

package send;

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Composite;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.LinearGradientPaint;
import java.awt.Paint;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.KeyAdapter;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseMotionAdapter;

import javax.swing.JComponent;

public class ProgressGlassPane extends JComponent {
	private static final int BAR_WIDTH = 200;
	private static final int BAR_HEIGHT = 10;

	private static final Color TEXT_COLOR = new Color(0x333333);

	private static final float[] GRADIENT_FRACTIONS = new float[] { 0.0f, 0.499f, 0.5f, 1.0f };
	private static final Color[] GRADIENT_COLORS = new Color[] { Color.GRAY, Color.DARK_GRAY, Color.BLACK, Color.GRAY };
	private static final Color GRADIENT_COLOR2 = Color.WHITE;
	private static final Color GRADIENT_COLOR1 = Color.GRAY;

	private String message = "Downloading file...";
	private int progress = 0;

	public ProgressGlassPane() {
		/*
		 *屏蔽鼠标事件和tab事件 
		 */
		addMouseListener(new MouseAdapter() {
		});
		addMouseMotionListener(new MouseMotionAdapter() {
		});
		addKeyListener(new KeyAdapter() {
		});
		setFocusTraversalKeysEnabled(false);
		addComponentListener(new ComponentAdapter() {
			public void componentShown(ComponentEvent evt) {
				requestFocusInWindow();
			}
		});

		setBackground(Color.WHITE);
		setFont(new Font("Default", Font.BOLD, 16));
	}

	public int getProgress() {
		return progress;
	}

	public void setProgress(int progress) {
		int oldProgress = this.progress;
		this.progress = progress;

		// 计算距离，局部刷新提高效率
		FontMetrics metrics = getGraphics().getFontMetrics(getFont());
		int w = (int) (BAR_WIDTH * ((float) oldProgress / 100.0f));
		int x = w + (getWidth() - BAR_WIDTH) / 2;
		int y = (getHeight() - BAR_HEIGHT) / 2;
		y += metrics.getDescent() / 2;

		w = (int) (BAR_WIDTH * ((float) progress / 100.0f)) - w;
		int h = BAR_HEIGHT;

		repaint(x, y, w, h);
	}


	protected void paintComponent(Graphics g) {
		// enables anti-aliasing
		Graphics2D g2 = (Graphics2D) g;
		g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

		// gets the current clipping area
		Rectangle clip = g.getClipBounds();

		// sets a 65% translucent composite
		AlphaComposite alpha = AlphaComposite.SrcOver.derive(0.65f);
		Composite composite = g2.getComposite();
		g2.setComposite(alpha);

		// fills the background
		g2.setColor(getBackground());
		g2.fillRect(clip.x, clip.y, clip.width, clip.height);

		// centers the progress bar on screen
		FontMetrics metrics = g.getFontMetrics();
		int x = (getWidth() - BAR_WIDTH) / 2;
		int y = (getHeight() - BAR_HEIGHT - metrics.getDescent()) / 2;

		// draws the text
		g2.setColor(TEXT_COLOR);
		g2.drawString(message, x, y);

		// goes to the position of the progress bar
		y += metrics.getDescent();

		// computes the size of the progress indicator
		int w = (int) (BAR_WIDTH * ((float) progress / 100.0f));
		int h = BAR_HEIGHT;

		// draws the content of the progress bar
		Paint paint = g2.getPaint();

		// bar's background
		Paint gradient = new GradientPaint(x, y, GRADIENT_COLOR1, x, y + h, GRADIENT_COLOR2);
		g2.setPaint(gradient);
		g2.fillRect(x, y, BAR_WIDTH, BAR_HEIGHT);

		// actual progress
		gradient = new LinearGradientPaint(x, y, x, y + h, GRADIENT_FRACTIONS, GRADIENT_COLORS);
		g2.setPaint(gradient);
		g2.fillRect(x, y, w, h);

		g2.setPaint(paint);

		// draws the progress bar border
		g2.drawRect(x, y, BAR_WIDTH, BAR_HEIGHT);

		g2.setComposite(composite);
	}
}