Question

我有一个问题..我的java applet上画了一个图像和一个for循环使x每次向上移动5 ..但它留下了旧图像一点然后它将擦除它..

for(int tohouse = 0; tohouse <= 520; tohouse+=2) {
  try {
    x+=5;
    tohouse+=10;

    if (pos == 0) {
      rectX+=5;
      g.drawImage(picture1,x,150,this);
      pos = 1;
    } else if (pos == 1) {
      rectX+=4;
      g.drawImage(picture2,x,150,this);
      pos = 2;
    } else if (pos == 2) {
      rectX+=5;
      g.drawImage(picture3,x,150,this);
      pos = 0;
    }
  }
}

见图像：

Answer 1

您无法通过paintComponent()或paint()方法循环播放动画。这些方法要求您在特定的时间点绘制自己（即当前帧）。

相反，你需要将你的精灵“移动”的逻辑与“渲染”你的精灵分开。寻找像这样的东西

private int x;

protected void paintComponent(Graphics g) {
    //draw the images at location x
}

// elsewhere, initialize a javax.swing.Timer to increment x every 15 ms
new Timer(15, new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        x += 5;
        repaint();
    }
}.start();

Answer 2

试试这个：

for(int tohouse = 0; tohouse <= 520; tohouse+=2)
{
    try
    {
        switch(pos){
        case 0:
            rectX+=5;
            g.drawImage(picture1,x,150,this);
            pos = 1;
            break;
        case 1:
              rectX+=4;
                g.drawImage(picture2,x,150,this);
                pos = 2;
            break;
        case 2:
            rectX+=5;
            g.drawImage(picture3,x,150,this);
            pos = 0;
            break;
        default: // add some default behavior here
            break;
        }
    } catch(Exception e){
        // do something
    }
}

Answer 3

你需要告诉java重绘框架。'

只需在repaint()上使用JComponent图片所在的for循环结尾处。像这样：

for(int tohouse = 0; tohouse <= 520; tohouse+=2) {
  try {
  //Process the changes
  }
  component.repaint(); // where component is what the image is added to.
}

Java图像绘画问题

3 个答案: