Android开发之利用ListView动态刷新某个Item

前言

本文实现的是使用ViewHolder来刷新某项数据，而不用每次都全部刷新数据。下面话不多说，来看看详细的介绍。

实现方法

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> 

总结

以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作能带来一定的帮助，如果有疑问大家可以留言交流。