ListView中实现部分刷新的两种方法

ListView在开发中用到的地方非常多,我们经常是全部刷新来更新数据,如果只需要更新某一条数据,该怎么实现呢?我在项目中使用过以下两种方法:

1.通过点击的位置,获取需要刷新那一列对应的控件,然后在控件上显示新的数据。
2.通过点击的位置,在数据源上移除对应位置的数据,并且重新设置新的数据,然后刷新。

先看一下效果图
刷新前

假如我们点击第二条数据里面的刷新按钮,变成下面的效果

刷新后

下面我们看一下这个简单示例的代码:

public class MainActivity extends Activity {

    private ListView lvMain;
    private TestAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        lvMain = (ListView) findViewById(R.id.mListView);
        adapter = new TestAdapter(this,getDatas());
        adapter.setListView(lvMain);
        lvMain.setAdapter(adapter);
        adapter.notifyDataSetChanged();
    }

    //数据源
    private List<StudentBean> getDatas(){
        List<StudentBean> studentList = new ArrayList<StudentBean>();
        for(int i = 0;i < 6; i++){
            StudentBean st = new StudentBean();
            st.setName("孙悟空" + i);
            st.setHobby("打妖怪 " + i);
            studentList.add(st);
        }
        return studentList;
    }
}

adapter里面,主要是按钮点击后,两个方法updateItemView(position) & updateItemData(position),一个是更新ItemView,一个是重新设置数据源来实现更新某一条数据。
这里有个地方需要注意下:View view = mListView.getChildAt(pos - mListView.getFirstVisiblePosition());,位置不要计算错。

public class TestAdapter extends BaseAdapter implements View.OnClickListener{

    private Context ctx;
    private List<StudentBean> studentDatas;

    public TestAdapter(Context ctx, List<StudentBean> studentDatas) {
        this.ctx = ctx;
        this.studentDatas = studentDatas;
    }

    @Override
    public int getCount() {
        return studentDatas == null? 0 : studentDatas.size();
    }

    @Override
    public Object getItem(int position) {
        return studentDatas.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }


    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder = null;
        if(convertView == null){            
            convertView = LayoutInflater.from(ctx).inflate(R.layout.adapter_main_item, parent, false);
            viewHolder = new ViewHolder();
            viewHolder.tvItemTitle = (TextView) convertView.findViewById(R.id.tvItemTitle);
            viewHolder.tvItemContent = (TextView) convertView.findViewById(R.id.tvItemContent);
            viewHolder.btnItemRefresh = (Button) convertView.findViewById(R.id.btnItemRefresh);
            convertView.setTag(viewHolder);
        }else{
            viewHolder = (ViewHolder) convertView.getTag();
        }
        viewHolder.tvItemTitle.setText(studentDatas.get(position).getName());
        viewHolder.tvItemContent.setText(studentDatas.get(position).getHobby());
        viewHolder.btnItemRefresh.setTag(position);
        viewHolder.btnItemRefresh.setOnClickListener(this);
        return convertView;
    }

    @Override
    public void onClick(View v) {
        switch(v.getId()){
        case R.id.btnItemRefresh:
            int position = (int) v.getTag();
            //更新ItemView
            updateItemView(position);
            //重新设置数据源来实现更新一条数据
//          updateItemData(position);
            break;
        }
    }

    private void updateItemView(int pos){
        if(mListView != null){
            View view = mListView.getChildAt(pos - mListView.getFirstVisiblePosition());
            TextView tvItemTitle = (TextView) view.findViewById(R.id.tvItemTitle);
            TextView tvItemContent = (TextView) view.findViewById(R.id.tvItemContent);
            StudentBean stNew = getNewDatas();
            tvItemTitle.setText(stNew.getName());
            tvItemContent.setText(stNew.getHobby());
        }
    }

    private void updateItemData(int pos){
        StudentBean stNew = getNewDatas();
        studentDatas.remove(pos);
        studentDatas.add(pos, stNew);
        notifyDataSetChanged();
    }

    private ListView mListView;
    public void setListView(ListView listView){
        mListView = listView;
    }

    static class ViewHolder{
        TextView tvItemTitle;
        TextView tvItemContent;
        Button btnItemRefresh;
    }

    private StudentBean getNewDatas(){
        StudentBean st = new StudentBean();
        st.setName("二狗子");
        st.setHobby("打土匪");
        return st;
    }
}

StudentBean

public class StudentBean {

    private String name;
    private String hobby;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getHobby() {
        return hobby;
    }

    public void setHobby(String hobby) {
        this.hobby = hobby;
    }
}
posted on 2017-06-18 10:38  lishbo  阅读(4488)  评论(0编辑  收藏  举报