Android ListView动态刷新某项Item

Posted 2020-10-19 星辰

使用ViewHolder来刷新某项数据，而不用每次都全部刷新数据。

继承BaseAdapter，新建ViewHolder类。

public class TestListAdapter extends BaseAdapter {
    private Context mContext;

    private List<String> strList;

    public TestListAdapter(Context context, List<String> list) {
        super();
        this.mContext = context;
        this.strList = list;
    }

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

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        ViewHolder holder = null;
        if (null == convertView) {
            convertView = LayoutInflater.from(mContext).inflate(R.layout.line, null);

            holder = new ViewHolder();
            holder.iDText = (TextView) convertView.findViewById(R.id.textView_id);
            holder.strText = (TextView) convertView.findViewById(R.id.textView_str);

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

        holder.iDText.setText(position + "");
        String str = strList.get(position);
        holder.strText.setText(str);

        return convertView;
    }

    private static class ViewHolder {
        private TextView iDText;

        private TextView strText;
    }

    public void updataView(int posi, ListView listView) {
        int visibleFirstPosi = listView.getFirstVisiblePosition();
        int visibleLastPosi = listView.getLastVisiblePosition();
        if (posi >= visibleFirstPosi && posi <= visibleLastPosi) {
            View view = listView.getChildAt(posi - visibleFirstPosi);
            ViewHolder holder = (ViewHolder) view.getTag();

            String txt = holder.strText.getText().toString();
            txt = txt + "++;";
            holder.strText.setText(txt);
            strList.set(posi, txt);
        } else {
            String txt = strList.get(posi);
            txt = txt + "++;";
            strList.set(posi, txt);
        }
    }
}

在Activity中，调用updateView()方法，刷新数据。

public class MainActivity extends Activity {
    private MainActivity mContext;

    private EditText idEdit;

    private TextView textView;

    private List<String> strList = new ArrayList<String>();
    private ListView listView;
    private TestListAdapter ListAdapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mContext = this;

        for (int i = 0; i < 100; i++) {
            strList.add("test data");
        }

        idEdit = (EditText) findViewById(R.id.edittext_id);
        textView = (TextView) findViewById(R.id.textview_modify);

        listView = (ListView) findViewById(R.id.listview);
        ListAdapter = new TestListAdapter(mContext, strList);
        listView.setAdapter(ListAdapter);

        //动态刷新
        textView.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                String idStr = idEdit.getText().toString();
                int idInt = Integer.parseInt(idStr);
                ListAdapter.updataView(idInt, listView);//动态修改
            }
        });
    }
}

给出布局文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFFFFF"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:orientation="horizontal" >

        <EditText
            android:id="@+id/edittext_id"
            android:layout_width="200dp"
            android:layout_height="wrap_content"
            android:hint="put modify id" />

        <TextView
            android:id="@+id/textview_modify"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="动态修改"
            android:textColor="#123456" />
    </LinearLayout>

    <ListView
        android:id="@+id/listview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView>

</LinearLayout>