我有很多的麻烦刷新列表视图自定义适配器。我一直在网上寻找过去一小时，我似乎无法找到任何解决方案，这将使我的列表视图刷新。

我已经试过notifyDataSetChanged，也listView.invalidate，但似乎没有奏效。任何帮助将大大AP preciated。我可以看到数据使用的logcat被更新，但它没有被刷新的屏幕上，我不知道为什么。

下面是code。

 的ArrayList＆LT;学生＆GT;学生=新的ArrayList＆LT;学生＆GT;（）;

列表视图=（ListView控件）findViewById（R.id.listView）;
适配器=新StudentAdapter（这一点，R.layout.listitemlayout，学生）;
listview.setAdapter（适配器）;
 

自定义适配器

 公共类StudentAdapter扩展ArrayAdapter＆LT;学生＆GT; {

    上下文语境;
    INT layoutResourceId;
    ArrayList的＆LT;学生＆GT;数据= NULL;

    公共StudentAdapter（上下文的背景下，诠释layoutResourceId，ArrayList的＆LT;学生＆GT;数据）{
        超级（上下文，layoutResourceId，数据）;
        this.layoutResourceId = layoutResourceId;
        this.context =背景;
        this.data =数据;
    }

    公共无效updateStudentsList（ArrayList中＆LT;学生＆GT; newlist）{
        data.clear（）;
        数据= newlist;
        this.notifyDataSetChanged（）;
    }

    公共无效updateStudentTime（）{
        对于（学生S：数据）{
            s.updateElapsedTime（）;
        }
        this.notifyDataSetChanged（）;
    }

    @覆盖
    公共查看getView（INT位置，查看convertView，ViewGroup中父）{
        查看排= convertView;
        如果（行== NULL）{
            LayoutInflater充气=（（活动）上下文）.getLayoutInflater（）;
            行= inflater.inflate（layoutResourceId，父母，假）;

            学生学生= data.get（位置）;

            TextView的标题=（TextView中）row.findViewById（R.id.txtTitle）;
            title.setText（student.getFirstname（）++ stu​​dent.getLastname（））;

            TextView的字幕=（TextView中）row.findViewById（R.id.txtSubTitle）;
            subTitle.setText（student.getStudentID（））;

            TextView的持续时间=（TextView中）row.findViewById（R.id.textDuration）;
            duration.setText（student.getElapsedTime（））;
        }
        返回行;
    }
}
 

我使用一个线程，每隔一段时间更新数据。

 可运行可运行=新的Runnable（）{
            公共无效的run（）{
                runOnUiThread（新的Runnable（）{
                    公共无效的run（）{
                        //更新学生在市中心多长时间。
                        adapter.updateStudentTime（）;
                        adapter.notifyDataSetChanged（）;
                        listview.invalidate（）;
                        Log.i（调试，运行UI线程）;
                    }
                }）;
                handler.postDelayed（这一点，1000）;
            }
        };
        handler.postDelayed（可运行，1000）;
 

解决方案

ListView控件将回收的看法，所以你必须在getView设置数据。 我 F（行== NULL）{意味着数据不会刷新，只使用旧数据。

你应该做的是这样的：

 类ViewHolder {
   TextView的称号;
   TextView的字幕;
   TextView的持续时间;
}

@覆盖
公共查看getView（INT位置，查看convertView，ViewGroup中父）{
    查看排= convertView;
    ViewHolder支架=无效;
    如果（行== NULL）{
        LayoutInflater充气=（（活动）上下文）.getLayoutInflater（）;
        行= inflater.inflate（layoutResourceId，父母，假）;

        学生学生= data.get（位置）;
        持有人=新ViewHolder（）;
        holder.title =（TextView中）row.findViewById（R.id.txtTitle）;
        holder.subTitle =（TextView中）row.findViewById（R.id.txtSubTitle）;
        holder.duration =（TextView中）row.findViewById（R.id.textDuration）;
        row.setTag（保持器）;
    } 其他 {
        支架= row.getTag（）;
    }
    holder.title.setText（student.getFirstname（）++ stu​​dent.getLastname（））;
    holder.subTitle.setText（student.getStudentID（））;
    holder.duration.setText（student.getElapsedTime（））;
    返回行;
}
 

I'm having a lot of trouble refreshing a list view with a custom adapter. I've been searching online for the past hour and I can't seem to find any solution that will make my list view refresh.

I've tried notifyDataSetChanged, and also listView.invalidate, but nothing seems to be working. Any help would be greatly appreciated. I can see the data being updated using logcat, but it is not being refreshed on the screen and I have no idea why.

Below is the code.

ArrayList<Student> students = new ArrayList<Student>();

listview = (ListView) findViewById(R.id.listView);
adapter = new StudentAdapter(this, R.layout.listitemlayout, students);  
listview.setAdapter(adapter);

Custom Adapter

public class StudentAdapter extends ArrayAdapter<Student>{

    Context context; 
    int layoutResourceId;    
    ArrayList<Student> data = null;

    public StudentAdapter(Context context, int layoutResourceId, ArrayList<Student> data) {
        super(context, layoutResourceId, data);
        this.layoutResourceId = layoutResourceId;
        this.context = context;
        this.data = data;
    }

    public void updateStudentsList(ArrayList<Student> newlist){
        data.clear();
        data = newlist;
        this.notifyDataSetChanged();
    }

    public void updateStudentTime(){
        for (Student s : data) {
            s.updateElapsedTime();          
        }
        this.notifyDataSetChanged();
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View row = convertView;
        if(row == null){
            LayoutInflater inflater = ((Activity)context).getLayoutInflater();
            row = inflater.inflate(layoutResourceId, parent, false);

            Student student = data.get(position);

            TextView title = (TextView)row.findViewById(R.id.txtTitle);
            title.setText(student.getFirstname() + " " + student.getLastname());

            TextView subTitle = (TextView)row.findViewById(R.id.txtSubTitle);
            subTitle.setText(student.getStudentID());       

            TextView duration = (TextView)row.findViewById(R.id.textDuration);
            duration.setText(student.getElapsedTime());
        }
        return row;
    }
}

I update the data using a thread every so often.

Runnable runnable = new Runnable() {
            public void run() {
                runOnUiThread(new Runnable() {
                    public void run() {
                        // Updates how long the student is in the centre.
                        adapter.updateStudentTime();
                        adapter.notifyDataSetChanged();
                        listview.invalidate();
                        Log.i("Debug", "Running on UI Thread");
                    }
                });
                handler.postDelayed(this, 1000);
            }
        };
        handler.postDelayed(runnable, 1000);

ListView will recycle the view, so you must set data in getView. and if(row == null){ means that data will not refresh, only use the old data.

you should do like this：

Class ViewHolder {
   TextView title;
   TextView subTitle;
   TextView duration;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;
    ViewHolder holder = null;
    if(row == null){
        LayoutInflater inflater = ((Activity)context).getLayoutInflater();
        row = inflater.inflate(layoutResourceId, parent, false);

        Student student = data.get(position);
        holder = new ViewHolder();
        holder.title = (TextView)row.findViewById(R.id.txtTitle);
        holder.subTitle = (TextView)row.findViewById(R.id.txtSubTitle);
        holder.duration = (TextView)row.findViewById(R.id.textDuration);
        row.setTag(holder);
    } else {
        holder = row.getTag();
    }
    holder.title.setText(student.getFirstname() + " " + student.getLastname());
    holder.subTitle.setText(student.getStudentID());   
    holder.duration.setText(student.getElapsedTime());    
    return row;
}