Question

我在android中为ListView创建了一个适配器，它的行为非常奇怪。列表视图传递一个对象列表，按一些规则排序（比较数字，哇......）。现在，当视图中显示列表时，会显示重复条目，它们不会被排序，条目丢失，当我滚动列表时，即使条目更改！发生了什么事？

以下是适配器的代码，如果有必要，我可以发布更多代码：

public class StatViewAdapter  extends BaseAdapter {

    Activity activity;
    ArrayList<Entry> entries;

    TextView txtName;
    TextView txtOK;
    TextView txtNOK;
    TextView txtHist;
    TextView txtPrandom;
    TextView txtPhist;
    TextView txtPtotal;

    //public StatViewAdapter(Activity activity, ArrayList<HashMap<String, String>> list){
    public StatViewAdapter(Activity activity,  ArrayList<Entry> entries){

        super();
        this.activity=activity;
        this.entries = entries;

        Collections.sort(this.entries, new Comparator<Entry>() {
            @Override
            public int compare(Entry o1, Entry o2) {
                if (o1.getPriority() > o2.getPriority()) {
                    return 1;
                }
                if (o1.getPriority() < o2.getPriority()) {
                    return -1;
                }
                return 0;

            }
        });

        for (int i=0;i<this.entries.size();i++) {
            String name = this.entries.get(i).name();
            int p = this.entries.get(i).getPriority();
            System.out.println(String.format("%s:  %d", name, p));
        }


    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        //return list.size();
        return this.entries.size();
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return this.entries.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }



    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub

        LayoutInflater inflater=this.activity.getLayoutInflater();

        if(convertView == null){

            convertView=inflater.inflate(R.layout.list_view, null);

            txtName=(TextView) convertView.findViewById(R.id.listname);
            txtOK=(TextView) convertView.findViewById(R.id.listok);
            txtNOK=(TextView) convertView.findViewById(R.id.listnok);
            txtHist=(TextView) convertView.findViewById(R.id.listhist);
            txtPrandom =(TextView) convertView.findViewById(R.id.listprandom);
            txtPhist=(TextView) convertView.findViewById(R.id.listphist);
            txtPtotal=(TextView) convertView.findViewById(R.id.listptot);
        }

        Entry entry = this.entries.get(position);
        txtName.setText(entry.name());
        txtOK.setText(Integer.toString(entry.number_ok));
        txtNOK.setText(Integer.toString(entry.number_nok));
        txtHist.setText(entry.history);
        txtPrandom.setText(Integer.toString(entry.randomIndex));
        txtPhist.setText(Integer.toString(entry.histIndex));
        txtPtotal.setText(Integer.toString(entry.getPriority()));

        return convertView;
    }

}

Answer 1

public View getView(int position, View convertView, ViewGroup parent)的目的是将给定position处对象的数据绑定到视图。视图可能是循环视图（convertView），或者您需要在方法中创建一个视图。问题是您不应该在txtName中保留对这些视图的引用（txtOk，Adapter）。

public class StatViewAdapter  extends BaseAdapter {

    Activity activity;
    ArrayList<Entry> entries;

    //TextView txtName;
    //TextView txtOK;
    // ...

    public StatViewAdapter(Activity activity,  ArrayList<Entry> entries){
    // ...

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        LayoutInflater inflater=this.activity.getLayoutInflater();

        if(convertView == null){
            convertView=inflater.inflate(R.layout.list_view, null);
        }

        TextView txtName=(TextView) convertView.findViewById(R.id.listname);
        TextView txtOK=(TextView) convertView.findViewById(R.id.listok);
        // ...

        Entry entry = this.entries.get(position);
        txtName.setText(entry.name());
        txtOK.setText(Integer.toString(entry.number_ok));
        // ....

        return convertView;
    }

它有效，但它仍然不是一个好方法，你可能想要使用RecyclerView或实现ViewHolder模式。

ViewHolder模式的想法是，每次绑定视图时都不必调用findViewById，因为它的计算成本很高并且可能导致滚动滞后。

您可能希望使用RecyclerView，因为它是一个更新，更灵活的视图，可以执行ListView相同的工作，并且内置ViewHolder模式

为什么我的listview在android中表现奇怪？

1 个答案: