listivew 动态刷新单个item

2022-10-31 12:31:40

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>

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