将变量传递给catch - Java

Question

我在Android Studio中制作了一个应用程序,可以让你跟踪你曾经乘坐过山车的次数,并计算出你经历了多少次力量等等.

我希望rideCount变量在退出时保存,所以我让它写入文件.然后,当该活动开始时,它将读取该文件并将其放入rideCount变量中.因为它在退出时写入,所以文件中没有任何内容.

我想要它做这种情况发生时被设置rideCount到0,并调出设置一切了方法,但我似乎无法在传递rideCount变量来捕捉位.有人可以帮忙吗？

预先感谢.

File file = new File("AltonAirCount.txt");

    try{
        Scanner input = new Scanner(file);
        int rideCountFile = input.nextInt();
        final int[] rideCount = {rideCountFile};
        onCreate2(rideCount);
    } catch (FileNotFoundException ex){
       //I want it to set rideCount to 0 here
      //I want it to call up onCreate2 and pass rideCount to it
    }}

.

    public void onBackPressed(int[] rideCount, File file) {

    try {
        PrintWriter output = new PrintWriter(file);
        output.println(rideCount);
        output.close();

    } catch (IOException ex) {


    }
}

Answer 1

rideCountFile 必须在try块之前声明才能被catch块访问.

int rideCountFile;
try{
    Scanner input = new Scanner(file);
    rideCountFile = input.nextInt();
    final int[] rideCount = {rideCountFile};
    onCreate2(rideCount);
} catch (FileNotFoundException ex){
    rideCountFile = 0;
    // call onCreate2 again if you wish
    final int[] rideCount = {rideCountFile};
    onCreate2(rideCount);
}

当然,除非你需要rideCountFile在后面的代码中使用你没有包含的内容,否则你在catch块中根本不需要它,所以代码可以简化为:

try{
    Scanner input = new Scanner(file);
    int rideCountFile = input.nextInt();
    final int[] rideCount = {rideCountFile};
    onCreate2(rideCount);
} catch (FileNotFoundException ex){
    onCreate2(new int[] {0});
}