android - 更改可滚动 ListView 的背景颜色

Question

我有一个可滚动的 ListView ，可以在其中选择多行。选择时，背景颜色变为绿色，如果再次选择，它又变回原来的颜色。

我设法让它工作，但我遇到的问题是当我滚动时，我没有选择的其他行被突出显示为绿色。我认为这是因为 View 正在被重用/回收，但我不确定如何解决该问题。

代码:

public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    myDB = new DatabaseHandler(getActivity());
    listViewSchools = (ListView)getView().findViewById(R.id.listViewFromDB);


    if (myDB.getSchoolCount() != 0){
        SchoolsList.addAll(myDB.getAllSchools());
        isSelected = new boolean[SchoolsList.size()];
    }
    populateSchoolsView();


    listViewSchools.setOnItemClickListener(new AdapterView.OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
            t_school item = SchoolsList.get(position);
            if (isSelected[position]) {
                v.setBackgroundColor(getResources().getColor(R.color.orig));
                isSelected[position] = false;
            }
            else if (!isSelected[position]) {
                v.setBackgroundColor(getResources().getColor(R.color.green));
                isSelected[position] = true;
            }
            schoolAdapter.notifyDataSetChanged();

        }
    });
 }

private void populateSchoolsView() {
    schoolAdapter = new SchoolListAdapter();
    listViewSchools.setAdapter(schoolAdapter);
    schoolAdapter.notifyDataSetChanged();

}

private class SchoolListAdapter extends ArrayAdapter<t_school> {
    public SchoolListAdapter() {
        super(getActivity(), R.layout.itemschool_layout, SchoolsList);
    }

    @Override
    public View getView(int position, View view, ViewGroup parent) {
        View row = view;
        ViewHolder holder = new ViewHolder();
        if (row == null) {
            row = getActivity().getLayoutInflater().inflate(R.layout.itemschool_layout, parent, false);
            holder.name = (TextView) row.findViewById(R.id.school_name);
            row.setTag(holder);
        }
        else{
            holder = (ViewHolder)row.getTag();
        }

        t_school currentSchool = SchoolsList.get(position);

        if(currentSchool!=null){
            holder.name.setText(currentSchool.getInfo());

        }

        return row;
    }
}

public class ViewHolder
{
    TextView name;

}

编辑

我尝试实现 getItemViewType() 和 getViewTypeCount()，但我不确定我是否在正确的轨道上。我按照本教程进行引用:http://android.amberfog.com/?p=296但我可以使用更多指导来了解我在这些方法中缺少的内容，以及我是否在 getView() 中正确使用它们。

编辑代码:

public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    myDB = new DatabaseHandler(getActivity());
    if(myDB.getSchoolCount()==0)
        Toast.makeText(getActivity().getApplicationContext(), "Please Import Data", Toast.LENGTH_LONG).show();
    listViewSchools = (ListView)getView().findViewById(R.id.listViewFromDB);

    registerForContextMenu(listViewSchools);


    listViewSchools.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
            longClickedItemIndex = position;
            return false;
        }
    });

    if (myDB.getSchoolCount() != 0){
        SchoolsList.addAll(myDB.getAllSchools());
        isSelected = new boolean[SchoolsList.size()];
    }
    populateSchoolsView();


    listViewSchools.setOnItemClickListener(new AdapterView.OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
            t_school item = SchoolsList.get(position);
            if (isSelected[position]) {
                v.setBackgroundColor(getResources().getColor(R.color.orig));
                isSelected[position] = false;
            }
            else if (!isSelected[position]) {
                v.setBackgroundColor(getResources().getColor(R.color.green));
                isSelected[position] = true;
            }
            schoolAdapter.notifyDataSetChanged();

        }
    });

}

private void populateSchoolsView() {
    schoolAdapter = new SchoolListAdapter();
    listViewSchools.setAdapter(schoolAdapter);
    schoolAdapter.notifyDataSetChanged();

}

private class SchoolListAdapter extends ArrayAdapter<t_school> {
    public SchoolListAdapter() {
        super(getActivity(), R.layout.itemschool_layout, SchoolsList);
    }

    @Override
    public int getViewTypeCount() {
        return 2;
    }

    @Override
    public int getItemViewType(int position) {
        return isSelected[position] ? 1 : 0;
    }

    @Override
    public View getView(int position, View view, ViewGroup parent) {
        View row = view;
        ViewHolder holder;
        int type = getItemViewType(position);

        if (row == null) {
            holder = new ViewHolder();
            switch ((type)) {
                case 1:
                    row = getActivity().getLayoutInflater().inflate(R.layout.itemschool_layout, parent, false);
                    holder.name = (TextView) row.findViewById(R.id.school_name);
                    break;

                case 0:
                    row = getActivity().getLayoutInflater().inflate(R.layout.itemschool_layout, parent, false);
                    holder.name = (TextView) row.findViewById(R.id.school_name);
                    break;

            }
            row.setTag(holder);
        }
        else{
            holder = (ViewHolder)row.getTag();
        }

        t_school currentSchool = SchoolsList.get(position);
        if(currentSchool!=null){
            holder.name.setText(currentSchool.getSchool_info());

        }

        return row;
    }
}

public class ViewHolder
{
    TextView name;

}   

Answer 1

你过期的是Listview的回收机制。

您更改了 Listitem 的外观，并在向下滚动时再次获得相同的 Item。

您始终可以重置颜色，但最简单的解决方案是提供 2 种项目类型。

@Override
public int getViewTypeCount() {
    return 2;
}

@Override
public int getItemViewType(int position) {
    return isSelected[position] ? 1 : 0;
}

这样 ListView 就可以为您提供相同类型的回收项目。