Android开发之利用ListView动态刷新某个Item

所属分类：软件编程 / Android 阅读数： 26

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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>

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