排序列表的升序和降序android java

Question

我有一个包含数据的List<> 。 如何对它进行升序和降序排序？

List<Data> data = new ArrayList<>();

        data.add(new Data("Batman vs Superman", "Following the destruction of Metropolis, Batman embarks on a personal vendetta against Superman ", R.drawable.ic_action_movie));
        data.add(new Data("X-Men: Apocalypse", "X-Men: Apocalypse is an upcoming American superhero film based on the X-Men characters that appear in Marvel Comics ", R.drawable.ic_action_movie));
        data.add(new Data("Captain America: Civil War", "A feud between Captain America and Iron Man leaves the Avengers in turmoil.  ", R.drawable.ic_action_movie));
        data.add(new Data("Kung Fu Panda 3", "After reuniting with his long-lost father, Po  must train a village of pandas", R.drawable.ic_action_movie));
        data.add(new Data("Warcraft", "Fleeing their dying home to colonize another, fearsome orc warriors invade the peaceful realm of Azeroth. ", R.drawable.ic_action_movie));
        data.add(new Data("Alice in Wonderland", "Alice in Wonderland: Through the Looking Glass ", R.drawable.ic_action_movie));

这是我的数据课

public class Data {
    public String title;
    public String description;
    public int imageId;

    Data(String title, String description, int imageId) {
        this.title = title;
        this.description = description;
        this.imageId = imageId;
    }

}

Answer 1

让您的类实现Comparable接口，这可以让Java处理大部分繁重的工作。

public class Data implements Comparable<Data>{
    @Override
    public int compareTo(Data another) {
        return this.title.compareTo(another.title);
        // can also compareToIgnoreCase if not case sensitive
    }
}

然后只需调用Collections.sort(data);

这将根据Data类中的compareTo函数对数据进行排序。

Answer 2

您可以使用Java8，如下所示：

data.sort（（数据d1，数据d2）-> d1.title.compareTo（d2.title））;

在您的代码中，我建议不要直接使用“ public”公开类字段，而应使用getter和setter（封装字段）。

data.sort（（数据d1，数据d2）-> d1.getTitle（）。compareTo（d2.getTitle（）））;