Java - 透明的 JScrollPane
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Java - Transparent JScrollPane
提问by test
I have a JTextArea and it's riding ontop of a JScrollPane. Anyways, I know I can use the getViewPort()method to set the opaque of of the view port... but I cannot seem to find any sign of how to do that... anywhere. :S
我有一个 JTextArea，它位于 JScrollPane 之上。无论如何，我知道我可以使用该getViewPort()方法来设置视口的不透明......但我似乎无法找到任何迹象表明如何做到这一点......在任何地方。:S
Here is what I have so far:
这是我到目前为止所拥有的：
if (e.getKeyCode() == KeyEvent.VK_F)
{
if (sp.isVisible())
{
sp.setVisible(false);
}
else
{
sp.setVisible(true);
}
}
回答by Serplat
You need to use setOpaque(false)to make it transparent. Call that both on the JScrollPane, and on it's ViewPort.
您需要使用setOpaque(false)使其透明。在 JScrollPane 和 ViewPort 上调用它。
sp.setOpaque(false); sp.getViewport().setOpaque(false);
You'll also have to call setOpaque(false)on the JTextArea, if you want that transparent as well.
setOpaque(false)如果您也想要透明，您还必须调用JTextArea。
回答by trashgod
Your colloquy with @Serplat suggests that you may be confounding opacityand transparency.
您与@Serplat 的对话表明您可能混淆了不透明度和透明度。
Opacityis a boolean property of Swing components used to optimize drawing:
不透明度是用于优化绘图的 Swing 组件的布尔属性：
true: The component agrees to paint all of the bits contained within its rectangular bounds.false: The component makes no guarantees about painting all the bits within its rectangular bounds.
true：组件同意绘制包含在其矩形边界内的所有位。false：该组件不保证在其矩形范围内绘制所有位。
Transparencyis a means of compositing digital images, as seen in this example.
Considering the distinction may help to clarify your question or focus your search for more information.
考虑区别可能有助于澄清您的问题或集中搜索更多信息。
Addendum: Based on @camickr's example, the example below shows a blue square that "sticks" to the viewport, while the gray checkerboard may be scrolled over it.
附录：基于@camickr 的示例，下面的示例显示了一个“粘”到视口的蓝色方块，而灰色棋盘格可以在它上面滚动。
import java.awt.*;
import javax.swing.*;
/** @see https://stackoverflow.com/questions/2846497 */
public class ScrollPanePaint extends JFrame {
private static final int TILE = 64;
public ScrollPanePaint() {
JViewport viewport = new MyViewport();
viewport.setView(new MyPanel());
JScrollPane scrollPane = new JScrollPane();
scrollPane.setViewport(viewport);
this.add(scrollPane);
this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
this.pack();
this.setLocationRelativeTo(null);
this.setVisible(true);
}
private static class MyViewport extends JViewport {
public MyViewport() {
this.setOpaque(false);
this.setPreferredSize(new Dimension(6 * TILE, 6 * TILE));
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.blue);
g.fillRect(TILE, TILE, 3 * TILE, 3 * TILE);
}
}
private static class MyPanel extends JPanel {
public MyPanel() {
this.setOpaque(false);
this.setPreferredSize(new Dimension(9 * TILE, 9 * TILE));
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.lightGray);
int w = this.getWidth() / TILE + 1;
int h = this.getHeight() / TILE + 1;
for (int row = 0; row < h; row++) {
for (int col = 0; col < w; col++) {
if ((row + col) % 2 == 0) {
g.fillRect(col * TILE, row * TILE, TILE, TILE);
}
}
}
}
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new ScrollPanePaint();
}
});
}
}
回答by sathya
Code for JScrollpane Transparent Background.
JScrollpane 透明背景的代码。
JScrollPane scrollPane = new JScrollPane();
JViewport viewport = new JViewport();
//Component that need to be added in Scroll pane//
viewport.setView(new JPanel());
viewport.setOpaque(false);
scrollPane.setViewport(viewport);
scrollPane.getViewport().setOpaque(false);
scrollPane.setOpaque(false);
// Add Scrollpane to Jframe or JPanel//
add( scrollPane,BorderLayout.CENTER);
