按钮没有变化

Question

 long totalMilliSeconds = System.currentTimeMillis();
    long totalSeconds = totalMilliSeconds / 1000;
    long currentSecond = totalSeconds % 60;
    long totalMinutes = totalSeconds / 60;
    long currentMinute = totalMinutes % 60;
    long totalHours = totalMinutes / 60;
    long currentHour = totalHours % 24;
    System.out.println("Current time is:" + currentHour + ":" + currentMinute + ":" + currentSecond);


    if(currentHour <= 9 && currentHour >=18)
        readFile.setForeground(YELLOW);
        readFile.setBackground(BLACK);
        graph.setForeground(YELLOW);
        graph.setBackground(BLACK);
        search.setForeground(YELLOW);
        search.setBackground(BLACK);
        snippet.setForeground(YELLOW);
        snippet.setBackground(BLACK);
        prediction.setForeground(YELLOW);
        prediction.setBackground(BLACK);
        export.setForeground(YELLOW);
        export.setBackground(BLACK);
        back.setForeground(YELLOW);
        back.setBackground(BLACK);

程序应该从下午6点到上午9点改变按钮的颜色，但我不确定为什么它在设定的时间之前仍然在变化。任何想法都将不胜感激。

Answer 1

我发现您的代码有两个问题：

• if条件永远不会评估为true。为此，该值必须小于或等于9，同时大于或等于18.

• 缺少大括号（包含所有颜色更改语句）if-statement的主体

  if(currentHour <= 9 && currentHour >=18) {
    readFile.setForeground(YELLOW);
  }
  readFile.setBackground(BLACK);
  graph.setForeground(YELLOW);
  graph.setBackground(BLACK);
  

因此，许多颜色的设置与if条件无关。