Java ArrayList集合错误：我的代码的哪一部分是错误的？

我将被要求写一个移动数组列表，做一些操作，如添加，删除，更新和显示。然而，当谈到在arraylist中对对象进行排序时，我有点困惑

我指的是

驾驶舱

    //Create an arraylist of Mobile
    ArrayList<Mobile> themobile = new ArrayList<>();
    Scanner input = new Scanner(System.in);

    System.out.println("Welcome to Mobile");
    System.out.println("Please select a number in the following: ");

    while (true) {  
        //A list of options 
        System.out.println("1. Diplay the next mobile.");
        System.out.println("2. Display the previous mobile.");
        System.out.println("3. Add a new mobile.");
        System.out.println("4. Remove a new mobile");
        System.out.println("5. Update a mobile.");
        System.out.println("0. Exit");

        //prompt user input
        int choice = input.nextInt();

        switch(choice) {
            case 1:
                //displayNext(themobile);
                break;
            case 2:
                //displayPrevious(themobile);
                break;
            case 3:
                addMobile(themobile);
                break;
            case 4:
                removeMobile(themobile);
                break;
            case 5: 
                updateMobile(themobile);
                break;
            case 0:
                System.out.println("Thank you for using a Mobile arraylist");
                System.exit(0);

        }
    }

    Collections.sort((themobile, new MobileByBrandName());
    System.out.println("Sorted by brand name" + themobile);

    Collections.sort(themobile, new MobileByMoNum());
    System.out.println("Sorted by brand name" + themobile);

    Collections.sort(themobile, new MobileByInS());
    System.out.println("Sorted by brand name" + themobile);

}

非常感谢您的帮助和澄清。谢谢

作为此代码

while (true) {  

永不退出，此循环下的代码无法访问

可能

系统退出（0）可能只会在

循环时中断

注意
在
开关中断开
不会断开
而
循环
当
循环从未到达
后的代码。您需要编写一些逻辑来打破while循环。解决此问题的一个简单方法是：

int choice = -1;
while (choice != 0) {
    choice = input.nextInt();
    switch (choice) {
        //...other cases
        case 0:
            System.out.println("Thank you for using a Mobile arraylist");
    }
}
Collections.sort(...);
System.out.println(...);

在循环时把这些线放进去

Collections.sort((themobile, new MobileByBrandName());
System.out.println("Sorted by brand name" + themobile);

Collections.sort(themobile, new MobileByMoNum());
System.out.println("Sorted by brand name" + themobile);

Collections.sort(themobile, new MobileByInS());
System.out.println("Sorted by brand name" + themobile);

此外，您还可以使用
Comparator.comparating
简化比较操作，该操作从java 8开始提供。比如：

Comparator<Mobile> comparator = Comparator.comparing(new Function<Mobile,
    @Override
    public String apply(Mobile t) {
        return t.getBrandName();
    }
}).thenComparingInt(new ToIntFunction<Mobile>() {

    @Override
    public int applyAsInt(Mobile t) {
        return t.getModelNumber();
    }
}).thenComparingInt(new ToIntFunction<Mobile>() {
    @Override
    public int applyAsInt(Mobile t) {
        return t.getInternalMemoryS();
    }
});

Collections.sort(themobile, comparator);

Comparator Comparator=Comparator.comparating（新函数）我们看不到包含
Collections.sort（移动）的实际代码
实际出现。根据代码中的逻辑，很可能这一行代码在逻辑上不可访问。这就是为什么我想知道我的逻辑的哪一部分出错。请发布这一行的整个方法
Collections.sort（themobile，new MobileByBrandName（））
我指的是@Simone001你的问题与
可比性无关
它与打破你的循环有关。
int choice = -1;
while (choice != 0) {
    choice = input.nextInt();
    switch (choice) {
        //...other cases
        case 0:
            System.out.println("Thank you for using a Mobile arraylist");
    }
}
Collections.sort(...);
System.out.println(...);

Collections.sort((themobile, new MobileByBrandName());
System.out.println("Sorted by brand name" + themobile);

Collections.sort(themobile, new MobileByMoNum());
System.out.println("Sorted by brand name" + themobile);

Collections.sort(themobile, new MobileByInS());
System.out.println("Sorted by brand name" + themobile);

Comparator<Mobile> comparator = Comparator.comparing(new Function<Mobile,
    @Override
    public String apply(Mobile t) {
        return t.getBrandName();
    }
}).thenComparingInt(new ToIntFunction<Mobile>() {

    @Override
    public int applyAsInt(Mobile t) {
        return t.getModelNumber();
    }
}).thenComparingInt(new ToIntFunction<Mobile>() {
    @Override
    public int applyAsInt(Mobile t) {
        return t.getInternalMemoryS();
    }
});

Collections.sort(themobile, comparator);