ArrayList 适配器在列表视图中获取错误数据

Posted 2023-05-07

【中文标题】ArrayList 适配器在列表视图中获取错误数据

【英文标题】：ArrayList adapter getting wrong data in listview

【发布时间】：2020-05-12 00:25:38

【问题描述】：

任何人都知道为什么我在使用 listview 填充适配器时在我的 AdapterClass 中得到错误的数据这是我正在使用的代码

public class SchoolAdapter extends ArrayAdapter<SchoolClass> 
    ArrayList<SchoolClass> schoolclass;

    private SchoolAdapter schoolAdapter;



    public SchoolAdapter(Activity activity1, ArrayList<SchoolClass> schoolClassList1)
        super(activity1, R.layout.school_adapter, schoolClassList1);
        this.activity = activity1;
        this.schoolClassList = schoolClassList1;
    


    @NonNull
    @Override
    public View getView (int position, View convertView, @NonNull ViewGroup parent) 
        LayoutInflater inflater = activity.getLayoutInflater();

        @SuppressLint("ViewHolder", "InflateParams") View view = inflater.inflate(R.layout.school_adapter, null, false);
        school_name = view.findViewById(R.id.school_name);
        school_size = view.findViewById(R.id.school_size);
        school_btn  = view.findViewById(R.id.school_btn);

        SchoolClass schoolClass = schoolclass.get(position);

        school_name.setText(schoolClass.getSchoolName());
        school_size.setText(schoolClass.getSchool_Size());

                school_btn.setOnClickListener(new View.OnClickListener() 
            @Override
            public void onClick(View v) 
Toast.makeText(context, "Grant"+schoolClass.getSchoolName(), Toast.LENGTH_SHORT).show();
            
        );


        return view;
    

注意：当我使用 listview.setOnItemClickListerner 时，我得到了正确的数据，但是当我使用任何单击适配器中第一个值的项目时，我得到的结果类似于第 5 个项目，当我单击时第二项同样的事情，当我单击第三项时，我得到的结果就像适配器中的第 8 或第 9 项一样，其他一切似乎都很好，我的代码没有显示任何错误，因为结果已显示，但它不是，正确的结果 注意 2：我使用 json 来检索列表，但只有当我单击适配器中的项目时，当我在 Toast 中得到错误结果时，结果才会正确显示

【问题讨论】：

这是什么schoolClass = schoolClass.get(position);？你能添加更多关于你的适配器的细节吗？

【参考方案1】：

Toast.makeText(context, "Grant "+ schoolclass.get(position).getName, Toast.LENGTH_SHORT).show();

public class SchoolAdapter extends ArrayAdapter<SchoolClass> 
    ArrayList<SchoolClass> schoolclass;
    Context context

    public SchoolAdapter(Context context ,ArrayList<SchoolClass> schoolClassList)
        super(context, R.layout.school_adapter, schoolClassList);
        this.activity = activity1;
        this.schoolClassList = schoolClassList1;
    


    @NonNull
    @Override
    public View getView (int position, View convertView, @NonNull ViewGroup parent) 
        LayoutInflater inflater = activity.getLayoutInflater();

        @SuppressLint("ViewHolder", "InflateParams") View view = inflater.inflate(R.layout.school_adapter, parent, false);
        school_name = view.findViewById(R.id.school_name);
        school_size = view.findViewById(R.id.school_size);
        school_btn  = view.findViewById(R.id.school_btn);

        schoolClass = schoolclass.get(position);

        school_name.setText(schoolClass.getSchoolName());
        school_size.setText(schoolClass.getSchool_Size());

        school_btn.setOnClickListener(new View.OnClickListener() 
            @Override
            public void onClick(View v) 
                Toast.makeText(context, "Grant"+ schoolclass.get(position).getSchoolName(), Toast.LENGTH_SHORT).show();
            
        );

        return view;
    

【参考方案2】：

您的实例（学校班级）名称与列表名称几乎相同。

改变

"schoolClass = schoolClass.get(position);" to
"schoolClass = schoolclass.get(position);"

schoolclass - 是列表； schoolClass - 是你的项目，我认为你混淆了上/下

【讨论】：

我已经更正了这一点并添加了我的代码的更多细节