画绘制方法之外显卡 [英] draw graphics outside of paint method

问题描述

private void draw_shape() {                                         
    Graphics g = getGraphics();
    g.drawLine(0, 0, 100, 100);
    repaint();
}                                        

在paint方法只有那些图形绘制这是paint方法的一部分，因为它的
我想画paint方法之外的形状。
这code绘制线，但它立刻disappeares，我不明白为什么会这样。请大家帮忙

In paint method only those graphics are drawn which is a part of paint method because of which I wanted to draw shapes outside of paint method. This code draws the line but it immediately disappeares, I don't understand why this is happening. please help

推荐答案

该好好尝试一下工作，因为你所得到的电流图形中的秋千重绘线程。基本上是：

This doens't work because you are getting the current Graphics outside of the Swing repaint thread. Basically:

• 您获得当前图形


• 您画了东西


• 然后调用重绘（）将调用的paint（）从而放弃你做的所有组件

• you get the current Graphics
• you draw something on it
• then you call repaint() that will call the paint() of the component thus discarding all you did

要使它工作，你应该重写油漆的对象（的paintComponent 的摆动）方法：

To make it work you should override the paint (paintComponent for Swing) method of your object:

@Override
public void paint(Graphics g) {
  super.paint(g); // if you have children to the component
  g.drawLine(..)
}

然后就叫重绘（）当事情已被修改。

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