This article describes the synchronization method when ListView data is refreshed in Android. Share it for your reference. The specific implementation method is as follows:
public class Main extends BaseActivity {
private static final String TAG = "tag";
private static final int STATUS_CHANGE = 0;
ExpandableListView mElv;
ArrayList<GroupInfo> mGroupArray;
@Override
public void onCreate(Bundle savedInstanceState) {
(savedInstanceState);
setContentView();
mElv = (ExpandableListView) findViewById(.contact_list);
mStatus = (TextView) findViewById();
mGroupArray = getIntent().getParcelableArrayListExtra("groupArray");// => Get data mExpandableAdapter = new ExpandableAdapter(this, );
(mExpandableAdapter);
// Asynchronously compare server grouping and local grouping HandlerThread handlerThread = new HandlerThread("handler_thread");
();
UpdateGroupHandler myHandler = new UpdateGroupHandler(
());
Message message = ();
();
mHandler = new Handler() {
public void handleMessage(Message msg) {
switch () {
case STATUS_CHANGE:
// Handle UI updates and other operations updateUI();
break;
}
};
};
}
/**
* Send message to update the UI
*/
private void sendMessageToUpdateUI() {
Message msg = new Message();
= STATUS_CHANGE;
(msg);
// Send a message to the Handler and update the UI }
private void updateUI() {
// Detailed update ();
// Update ExpandableListView }
/**
* Asynchronously refresh the grouped handler
*
* @author administrator
*
*/
class UpdateGroupHandler extends Handler {
public UpdateGroupHandler() {
}
public UpdateGroupHandler(Looper looper) {
super(looper);
}
@Override
public void handleMessage(Message msg) {
ContactsManagerDbAdapter dbAdapter = new ContactsManagerDbAdapter(
);
();
// =>doSomeThing...
mGroupArray = groupList;
("========After data is updated,refreshlistview=========");
sendMessageToUpdateUI();
}
}
private class ExpandableAdapter extends BaseExpandableListAdapter {
Activity activity;
LayoutInflater layoutInflater;
public ExpandableAdapter(Activity a, Context context) {
activity = a;
layoutInflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public Object getChild(int groupPosition, int childPosition) {
return (groupPosition).getChildList()
.get(childPosition);
}
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
public int getChildrenCount(int groupPosition) {
return (groupPosition).getChildList().size();
}
public View getChildView(int groupPosition, int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
// .....
return vi;
}
public Object getGroup(int groupPosition) {
return (groupPosition);
}
public int getGroupCount() {
return ();
}
public long getGroupId(int groupPosition) {
return groupPosition;
}
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
GroupInfo groupInfo = (groupPosition);
String string = ();
convertView = (View) (.group_layout,
null);
final TextView textView = (TextView) convertView
.findViewById();
if (textView != null) {
(string);
}
return convertView;
}
public boolean hasStableIds() {
return true;
}
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
}
}
The code is just the extracted part and should not have much impact.
The above collection mGroupArray has data sharing. After testing, there are two types of errors reported:
=>: Invalid location 3, size is 3
=> content of the adapter has changed but ListView did not receive a notification. Make sure the content of your adapter is not modified from a background thread, but only from the UI thread.
The first problem is the data synchronization problem, I solved it but couldn't solve it.
The second problem is that when changing the Adapter content of the adapter, it must be handled in the UI thread.
I updated the data in the child thread UpdateGroupHandler above using the handler to extract the main thread assignment
= groupList;
Well, after the correction, I tested it many times, and found that both problems were solved, but I found that I still didn’t understand the handler enough.
Post the changed code snippet:
@Override
public void onCreate(Bundle savedInstanceState) {
(savedInstanceState);
setContentView();
mElv = (ExpandableListView) findViewById(.contact_list);
mStatus = (TextView) findViewById();
mGroupArray = getIntent().getParcelableArrayListExtra("groupArray");
// => Get data mExpandableAdapter = new ExpandableAdapter(this, );
(mExpandableAdapter);
// Asynchronously compare server grouping and local grouping HandlerThread handlerThread = new HandlerThread("handler_thread");
();
UpdateGroupHandler myHandler = new UpdateGroupHandler(
());
Message message = ();
();
mHandler = new Handler() {
public void handleMessage(Message msg) {
switch () {
case STATUS_CHANGE:
// Handle UI updates and other operations updateUI();
break;
}
};
};
}
/**
* Send message to update the UI
*/
private void sendMessageToUpdateUI(ArrayList<GroupInfo> groupList) {
Message msg = new Message();
= STATUS_CHANGE;
= groupList;
(msg);
// Send a message to the Handler and update the UI}
@SuppressWarnings("unchecked")
private void updateUI(Object obj) {
// Detailed update mGroupArray = (ArrayList<GroupInfo>) obj;
();
// Update ExpandableListView}
/**
* Asynchronously refresh the grouped handler
*
* @author administrator
*
*/
class UpdateGroupHandler extends Handler {
public UpdateGroupHandler() {
}
public UpdateGroupHandler(Looper looper) {
super(looper);
}
@Override
public void handleMessage(Message msg) {
ContactsManagerDbAdapter dbAdapter = new ContactsManagerDbAdapter(
);
();
// =>doSomeThing...
("========After data is updated,refreshlistview=========");
sendMessageToUpdateUI(groupList);
}
}
I hope this article will be helpful to everyone's Android programming design.