java - 从 ArrayList 中删除具有相似值的对象

Question

我正在使用 ArrayList ，这里我想从 Arraylist 中删除具有相似值的对象。我尝试了 stackoverflow 上发布的许多解决方案，但由于代码无法正常工作，我的代码出现了问题。我得到了重复的列表。

Here is my code :

public class StateCityModel {

    private String id ;
    private String code ;
    private String name ;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getName() {
        return name;
    }

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

    @Override
    public boolean equals(Object obj) {

        if (!(obj instanceof StateCityModel))
            return false;

        return id.equals(((StateCityModel) obj).getId());

    }

    @Override
    public int hashCode() {
        return (id == null) ? 0 : id.hashCode();
    }
}

Code add values in the ArrayList

    businessTypeListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView , View view , int position , long l) {
 businessTypeObj = clubsList.get(position);
                    selectedBusinessTypeList.add(businessTypeObj);
                }

            }
        });

Code to remove objects with similar values .

Set<StateCityModel> unique = new LinkedHashSet<StateCityModel>(selectedBusinessTypeList);
            selectedBusinessTypeList = new ArrayList<StateCityModel>(unique);

完成上述代码后，我在 selectedBusinessTypeList 中获取具有相似值的对象。

请帮帮我，我找不到上面代码中的错误。

Answer 1

你也可以这样做

第 1 步:仅在 arraylist 中插入 id 不相同的数据，这样之后就不需要从 arraylist 中删除重复元素。

businessTypeListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> adapterView , View view , int position , long l) {
     businessTypeObj = clubsList.get(position);
                        selectedBusinessTypeList.add(businessTypeObj);
                    }

                }
            });

替换为

businessTypeListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView , View view , int position , long l) {
                }

    StateCityModel stateCityModel = new StateCityModel();
    stateCityModel = clubsList.get(position);;

    if (!selectedBusinessTypeList.contains(stateCityModel)){
         selectedBusinessTypeList.add(stateCityModel);
    }

}

});

第 2 步:删除不需要的内容

Set<StateCityModel> unique = new LinkedHashSet<StateCityModel>(selectedBusinessTypeList);
            selectedBusinessTypeList = new ArrayList<StateCityModel>(unique);