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>