Android development: Dynamically refresh an Item using ListView

Preface

This article implements the use of ViewHolder to refresh a certain data without refreshing all the data every time. Let’s not say much below, let’s take a look at the detailed introduction.

Implementation method

Inherit BaseAdapter and create a new ViewHolder class.

public class TestListAdapter extends BaseAdapter { 
 private Context mContext; 
 
 private List<String> strList; 
 
 public TestListAdapter(Context context, List<String> list) { 
  super(); 
   = context; 
   = list; 
 } 
 
 @Override 
 public int getCount() { 
  // TODO Auto-generated method stub 
  return (); 
 } 
 
 @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 = (mContext).inflate(, null); 
 
   holder = new ViewHolder(); 
    = (TextView) (.textView_id); 
    = (TextView) (.textView_str); 
 
   (holder); 
  } else { 
   holder = (ViewHolder) (); 
  } 
 
  (position + ""); 
  String str = (position); 
  (str); 
 
  return convertView; 
 } 
 
 private static class ViewHolder { 
  private TextView iDText; 
 
  private TextView strText; 
 } 
 
 public void updataView(int posi, ListView listView) { 
  int visibleFirstPosi = (); 
  int visibleLastPosi = (); 
  if (posi >= visibleFirstPosi && posi <= visibleLastPosi) { 
   View view = (posi - visibleFirstPosi); 
   ViewHolder holder = (ViewHolder) (); 
 
   String txt = ().toString(); 
   txt = txt + "++;"; 
   (txt); 
   (posi, txt); 
  } else { 
   String txt = (posi); 
   txt = txt + "++;"; 
   (posi, txt); 
  } 
 } 
}

In Activity, callupdateView()Method, refresh the data.

public class MainActivity extends Activity { 
 private MainActivity mContext; 
 
 private EditText idEdit; 
 
 private TextView textView; 
 
 private List&lt;String&gt; strList = new ArrayList&lt;String&gt;(); 
 private ListView listView; 
 private TestListAdapter ListAdapter; 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
  (savedInstanceState); 
  setContentView(.activity_main); 
 
  mContext = this; 
 
  for (int i = 0; i &lt; 100; i++) { 
   ("test data"); 
  } 
 
  idEdit = (EditText) findViewById(.edittext_id); 
  textView = (TextView) findViewById(.textview_modify); 
 
  listView = (ListView) findViewById(); 
  ListAdapter = new TestListAdapter(mContext, strList); 
  (ListAdapter); 
 
  //Dynamic refresh  (new OnClickListener() { 
 
   @Override 
   public void onClick(View v) { 
    // TODO Auto-generated method stub 
    String idStr = ().toString(); 
    int idInt = (idStr); 
    (idInt, listView);//Dynamic modification   } 
  }); 
 } 
}

Give the layout file:

&lt;LinearLayout xmlns:andro 
 xmlns:tools="/tools" 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" 
 android:background="#FFFFFF" 
 android:orientation="vertical" &gt; 
 
 &lt;LinearLayout 
  android:layout_width="match_parent" 
  android:layout_height="40dp" 
  android:orientation="horizontal" &gt; 
 
  &lt;EditText 
   android: 
   android:layout_width="200dp" 
   android:layout_height="wrap_content" 
   android:hint="put modify id" /&gt; 
 
  &lt;TextView 
   android: 
   android:layout_width="wrap_content" 
   android:layout_height="wrap_content" 
   android:text="Dynamic Modification" 
   android:textColor="#123456" /&gt; 
 &lt;/LinearLayout&gt; 
 
 &lt;ListView 
  android: 
  android:layout_width="match_parent" 
  android:layout_height="wrap_content" &gt; 
 &lt;/ListView&gt; 
 
&lt;/LinearLayout&gt;

Summarize

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