Comparator自定义排序

现在有个需求是这样的，应用列表需要排序，优先级 打开=》安装=》其他
效果如下

实际需求效果图

现在来模拟此实现一个demo
关键类StatusComparator，实现自定义排序规则,这里要注意的是状态是一个常量类，而且是前期版本已经建好，所以不能投机取巧直接更改常量类的int值来比较。这里选择了根据类型来判断

public class StatusComparator implements Comparator<DownloadInfo> {

    @Override
    public int compare(DownloadInfo o1, DownloadInfo o2) {

        int status1 = o1.getStatus();
        int status2 = o2.getStatus();
        switch (status1) {
            case InstallState.installComplete:
                if (status2 == InstallState.installComplete) {
                    return 0;
                }
                return -1;
            case InstallState.install:
                if (status2 == InstallState.installComplete) {
                    return 1;
                }
                if(status2 == InstallState.install) {
                    return 0;
                }
                return -1;
            default:
                if (status2 == InstallState.installComplete || status2 == InstallState.install) {
                    return 1;
                }
                return 0;
        }
    }
}

测试类TestComparator

public class TestComparator {
    public static void main(String[] args) {
        DownloadInfo downloadInfo1 = new DownloadInfo("王者荣耀",InstallState.install);
        DownloadInfo downloadInfo2 = new DownloadInfo("连连看",InstallState.installFail);
        DownloadInfo downloadInfo3 = new DownloadInfo("全民超神",InstallState.installing);
        DownloadInfo downloadInfo4 = new DownloadInfo("炉石传说",InstallState.installComplete);
        DownloadInfo downloadInfo5 = new DownloadInfo("三国杀",InstallState.install);
        List<DownloadInfo> downloadInfoList = new ArrayList<>();
        downloadInfoList.add(downloadInfo1);
        downloadInfoList.add(downloadInfo2);
        downloadInfoList.add(downloadInfo3);
        downloadInfoList.add(downloadInfo4);
        downloadInfoList.add(downloadInfo5);

        System.out.println("sort前==============");
        for (int i = 0; i < downloadInfoList.size(); i++) {
            System.out.print(downloadInfoList.get(i).getName()+"\t");
        }
        System.out.println("\nsort后============");
        Collections.sort(downloadInfoList,new StatusComparator());
        //since 1.8+
        //downloadInfoList.sort(new StatusComparator());
        for (int i = 0; i < downloadInfoList.size(); i++) {
            System.out.print(downloadInfoList.get(i).getName()+"\t");
        }
    }
}

亲测，结果可靠

sort前==============
王者荣耀    连连看 全民超神    炉石传说    三国杀 
sort后============
炉石传说    王者荣耀    三国杀 连连看 全民超神    

---

其他相关类
下载类DownloadInfo

public class DownloadInfo {
    private String name;
    private int status;

    public int getStatus() {
        return status;
    }

    public void setStatus(int status) {
        this.status = status;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public DownloadInfo(String name) {
        this.name = name;
    }

    public DownloadInfo(String name, int status) {
        this.name = name;
        this.status = status;
    }

    @Override
    public String toString() {
        return "DownloadInfo{" +
                "name='" + name + '\'' +
                ", status=" + status +
                '}';
    }
}

安装状态InstallState

public class InstallState {
    //等待安装
    public final static int install = 11;
    //安装完成
    public final static int installComplete = 12;
    //安装失败
    public final static int installFail = 13;
    //升级
    public final static int upgrade = 14;
    //忽略升级
    public final static int ignore_upgrade = 15;
    //安装中
    public final static int installing = 16;
}