public Graphics getGraphics() {
if (peer instanceof LightweightPeer) {
// This is for a lightweight component, need to
// translate coordinate spaces and clip relative
// to the parent.
if (parent == null) return null;
Graphics g = parent.getGraphics();
if (g == null) return null;
if (g instanceof ConstrainableGraphics) {
((ConstrainableGraphics) g).constrain(x, y, width, height);
} else {
g.translate(x,y);
g.setClip(0, 0, width, height);
}
g.setFont(getFont());
return g;
} else {
ComponentPeer peer = this.peer;
return (peer != null) ? peer.getGraphics() : null;
}
}
Component没得调用Graphics的构造方法，但是他是如何创建这个对象的昵。
------解决方案--------------------
你要想调用重写paint方法，然后参数是Graphics
你可以看到最后一句话peer.getGraphics()，这个东西是在sun包里面，不知道有没源码
你再看Graphics源码，有create无参数的重载方法，是抽象的，留给子类实现
随便找个子类看下
- Java code
public Graphics create() { DebugGraphics debugGraphics; debugGraphics = new DebugGraphics(); debugGraphics.graphics = graphics.create(); debugGraphics.debugOptions = debugOptions; debugGraphics.buffer = buffer; return debugGraphics; }