android - 在 ListView 中更改 TextView 的文本时出现问题

Question

我是这个 android 开发的新手，在 listview 中设置 textview 的文本时遇到问题。

问题:

Activity 1 中的 ListView

======================
型号
====================
颜色
====================
风格
====================
制作
====================

当我在 ListView 中单击“模型” View 时。下面显示

Activity 2 中的 ListView

======================
丰田
====================
捷豹
====================
本田
====================
斯布鲁
====================

Activity 1 的结果

======================
型号
====================
颜色 -------------- 丰田
====================
风格
====================
制作
====================

我在找什么:

======================
型号 -------------- 丰田
====================
颜色
====================
风格
====================
制作
====================

这里是初始 Activity 。当我在 ListView 中单击“模型”时，将显示另一个 Activity 以及汽车模型列表。 (使用 startactivtiyforresult() 调用新 Activity )

在第二个 Activity 中，当我单击任何模型名称时，它会关闭当前 Activity 并将所选模型名称传递给第一个 Activity 。此模型名称在 OnActivityResult 方法中设置为 TextView

我的自定义适配器

class CustomAdapter extends ArrayAdapter<String> {

    Context context;
    String[] titles;


    public CustomAdapter(Context context, String[] titles) {
        super(context, R.layout.dashboard_row_layout, R.id.row_textview, titles);

        this.context = context;
        this.titles = titles;
    }

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

        View row = convertView;
        ViewHolder holder;
        if(row==null)
        {
            LayoutInflater inflater = (LayoutInflater)context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
            row = inflater.inflate(R.layout.dashboard_row_layout, parent, false);
            holder = new ViewHolder(row);
            row.setTag(holder);
        }
        //((TextView)row.findViewById(R.id.row_textview)).setText(titles[position]);
        else
        {
            holder = (ViewHolder)row.getTag();
        }
        holder.textview.setText(titles[position].toString());

        return row;
    }
}

class ViewHolder
{
    TextView textview;
    ViewHolder(View v)
    {
        textview = (TextView) v.findViewById(R.id.row_textview);
    }
}

OnActivityResultMethod

@Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (resultCode)
            {
                case Activity.RESULT_OK:
                    //selectedModel = data.getStringExtra("response");
                      setDateTextView.setText(data.getStringExtra("response"));
            }
    }

fragment 的OnCreateView

@Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        final View rootView = inflater.inflate(R.layout.fragment_vehicle_information, container, false);

        SeparatedListAdapter adapter = new SeparatedListAdapter(this.getActivity());
        adapter.addSection("Plate Information", new CustomAdapter(this.getActivity(),getResources().getStringArray(R.array.plateInformationArrayList)));
        adapter.addSection("Vehicle Information", new CustomAdapter(this.getActivity(),getResources().getStringArray(R.array.vehicleInformationArrayList)));
        ((ListView)rootView.findViewById(R.id.veh_information_listView)).setAdapter(adapter);

        //Click Listener for listview with custom view
        ((ListView)rootView.findViewById(R.id.veh_information_listView)).setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                if(((TextView)view.findViewById(R.id.row_textview)).getText().toString().equalsIgnoreCase("Expiration")){
                    DateDialog dialog = new DateDialog(getActivity(), (TextView)view.findViewById(R.id.statename_textView));
                    dialog.returnDateDialog().show();
                }
                else if(((TextView)view.findViewById(R.id.row_textview)).getText().toString().equalsIgnoreCase("Model")){
                    setDateTextView = (TextView)view.findViewById(R.id.statename_textView);
                    startActivityForResult(new Intent(getActivity(), VehicleInformationDetails.class),  1);
                }

            }
        });


        return rootView;
    }

第二个 Activity

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_searchable_listview, container, false);
    ListView listview = (ListView)rootView.findViewById(R.id.searchable_listView);
    MyAdapter adapter = new MyAdapter(context, array);
    listview.setAdapter(adapter);
    listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            TextView textView = (TextView)view.findViewById(R.id.list_item_title);
            Intent returnIntent = new Intent();
            returnIntent.putExtra("response", textView.getText().toString());
            getActivity().setResult(Activity.RESULT_OK, returnIntent);
            getActivity().finish();
        }
    });
    SetActionBarTitle(this.actionBarTitle);

    return rootView;

}

希望这个解释对您有所帮助。请帮助我。

Answer 1

尝试从适配器外部直接更改列表项内的 TextView 的文本是不可靠的。一方面， View 将不匹配适配器的支持数据。此外，您的适配器不会尝试清除辅助 TextView 的任何现有内容，因此当您的 ListView 回收其 View 时，您将遇到很多像这样的异常问题。

因此删除所有引用 setDateTextView 的行。相反，您需要一个自定义类来表示列表项的所有可能数据，如下所示:

public class MyListItem {
    public String title;
    public String state;

    public MyListItem(String title){
        this(title, "");
    }

    public MyListItem(String title, String state){
        this.title = title;
        this.state = state;
    }
}

然后将其用作自定义适配器的对象类型:

class CustomAdapter extends ArrayAdapter<MyListItem> {

    public CustomAdapter(Context context, MyListItem[] listItems) {
        super(context, R.layout.dashboard_row_layout, listItems);
    }

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

        View row = convertView;
        ViewHolder holder;
        if(row==null)
        {
            LayoutInflater inflater = (LayoutInflater)getContext().getSystemService(context.LAYOUT_INFLATER_SERVICE);
            row = inflater.inflate(R.layout.dashboard_row_layout, parent, false);
            holder = new ViewHolder(row);
            row.setTag(holder);
        }
        else
        {
            holder = (ViewHolder)row.getTag();
        }

        holder.titleTextview.setText(getItem(position).title);
        holder.stateTextview.setText(getItem(position).state);

        return row;
    }
}

class ViewHolder
{
    TextView titleTextview;
    TextView stateTextview;
    ViewHolder(View v)
    {
        titleTextview= (TextView) v.findViewById(R.id.row_textview);
        stateTextview= (TextView) v.findViewById(R.id.statename_textView);
    }
}

最后，在您的 onActivityResult() 中，告诉适配器更改适当行的内容数组的值。您必须将这些变量设置为成员变量，但可以这样做:

switch (resultCode)
{
    case Activity.RESULT_OK:
        mListAdapter.getItem(mModelItemPosition).state = data.getStringExtra("response");
        mListAdapter.notifyDataSetChanged();
        break;
}