java 在 JPanel 上重新绘制/刷新 JLabel
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Repainting/refreshing JLabels on a JPanel
提问by thomas
I'm having trouble getting my JLabels in a 2D array to update during runtime.
我无法在运行时更新二维数组中的 JLabel。
The program I'm working on is a variant of Connect Four. I create a 2D array of JLabels, which all default to an ImageIcon containing an image of a blank slot. Players 1 and 2 choose their colors, and on a player's turn, he can click to drop a piece into a column (gravity causes the piece to fall to the bottom or until it lands atop another piece).
我正在开发的程序是 Connect Four 的变体。我创建了一个 JLabel 的 2D 数组，它们都默认为包含空白插槽图像的 ImageIcon。玩家 1 和 2 选择他们的颜色，在轮到玩家时，他可以点击将一个棋子放入一列（重力导致棋子落到底部或直到它落在另一个棋子上）。
I'm pretty positive that my addToColumn method is working fine. My only problem is that I can't seem to get any of the JLabels to update. Here's the method I'm working on:
我非常肯定我的 addToColumn 方法工作正常。我唯一的问题是我似乎无法更新任何 JLabel。这是我正在研究的方法：
p1, p2, and current are Player objects. grid[][] is a 2D array of integers set to 0, 1, or 2 to more easily track who owns which tiles. tiles[][] is my 2D array of JLabels.
p1、p2 和 current 是 Player 对象。grid[][] 是一个 2D 整数数组，设置为 0、1 或 2，以便更轻松地跟踪谁拥有哪些图块。tiles[][] 是我的 JLabel 的二维数组。
public void addToColumn(int column) { // drop a tile in the specified column
int i = 0;
while (grid[column][5-i] != 0) i++; // move upward through the 6 rows of tiles
// until we find an empty one
if (current == p1) grid[column][5-i] = 1; // update to the current player's value
else grid[column][5-i] = 2;
tiles[column][5-i] = new JLabel(findColorIcon(current.getColor()));
tiles[column][5-i].setIcon(findColorIcon(current.getColor()));
repaint();
now with those last two lines changing the JLabel in tiles[][], obviously I don't need both, not sure which way is better... that's just some of what I've tried, to no avail. (my getColor() method returns a Color, and findColorIcon(Color c) returns the corresponding JLabel with that color of tile).
现在最后两行更改了tile [] []中的JLabel，显然我不需要两者，不确定哪种方式更好......这只是我尝试过的一些方法，但无济于事。（我的 getColor() 方法返回一个颜色，而 findColorIcon(Color c) 返回具有该瓷砖颜色的相应 JLabel）。
and yes, I have added in my paintComponent method too:
是的，我也添加了我的paintComponent方法：
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
}
I've been stuck on this for a while now, and I feel like I'm missing something obvious. any suggestions?
我已经坚持了一段时间了，我觉得我错过了一些明显的东西。有什么建议？
回答by trashgod
I don't see that your paintComponent()method does anything. In particular, replacing a JLabelrequires that you validate()the container. As an alternative, you might like to see how this simple gameuses the Model–View–Controller pattern and draws colored icons.
我看不出你的paintComponent()方法有什么作用。特别是，替换 aJLabel需要您validate()的容器。作为替代方案，您可能想看看这个简单的游戏如何使用模型-视图-控制器模式并绘制彩色图标。
Addendum: This related exampledescribes how to replace just the Icon, rather than the entire JLabel. In contrast, this exampleshows how to validate()a container after replacing components.
附录：此相关示例描述了如何仅替换Icon. 而不是整个JLabel. 相比之下，这个例子展示了如何validate()在替换组件后创建一个容器。
