Develop Reference

Wait for activity to display

Currently I have a button that loads an activity.
That activity has a ListView in it that for whatever reason takes a fairly long time to load(not waiting for data, the data is already in memory). The problem is that while it's rendering the list, the UI is waiting where the button was clicked, and doesn't change screen until the list has fully loaded.
What I'd like, is to only display the list once the activity is loaded, so at least something happens as soon as they press the button(responsive UI is important).
Currently, my hack around solution to this, is to spawn a thread, wait for 50 milliseconds, and then set the adapter for my list(using runOnUiThread). Of course, if the activity takes longer than 50ms to load on some phones, then it'll have to load the entire list to load the activity again.
Current relevant code:
#Override
public void onPostResume() {
super.onPostResume();
new Thread(new Runnable() {
#Override
public void run() {
final AdapterData data = getData();
try {
Thread.sleep(50);
} catch (InterruptedException e) {
e.printStackTrace();
}
mActivity.runOnUiThread(new Runnable() {
#Override
public void run() {
myAdapter = new MyAdapter(MyActivity.this, data);
lvMyList.setAdapter(myAdapter);
}
});
}
}).start();
}
I just changed variable names in the code, but that's not relevant. This is just so you can see my general solution.
I feel like there should be some kind of callback that's called when the activity finishes creating. I thought that onPostResume waited for the activity to finish loading, but that did not work. It still hung.

you can use IdleHandler
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.xxx);
final AdapterData data = getData();
IdleHandler handler = new IdleHandler() {
#Override
public boolean queueIdle() {
myAdapter = new MyAdapter(MyActivity.this, data);
lvMyList.setAdapter(myAdapter);
return false;
}
};
Looper.myQueue().addIdleHandler(handler);
}

How to update a ListView inside a message listener?

I'm building a chat application, so I'm using two ListViews: one that shows the online friends and one for the chat itself, that receives the messages and so on. I'm using the XMPP protocol and the Smack Library for Android.
The Smack Library give me Listeners which are activated every time a friend status changes(online/offline) and the other one when the user receives a message. Here's how I declare the adapter and call an AsyncTask when the user press a button:
peopleList = (ListView) findViewById(R.id.peopleList);
adapter = new MyAdapter(this, people);
peopleList.setAdapter(adapter);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
new ConnectAndLoad(MainActivity.this).execute();
}
});
Inside the AsyncTask, I connect to the server inside the doInBackground method and inside the onPostExecute I create the listener which adds the user to the array list of the listview and call adapter.notifyDataSetChanged();
public class ConnectAndLoad extends AsyncTask<String, Integer, Boolean> {
private ProgressDialog dialog;
public ConnectAndLoad(Activity activity)
{
this.dialog = new ProgressDialog(activity);
this.dialog.setTitle("Loading..");
this.dialog.setMessage("Connecting to the server..");
dialog.show();
}
#Override
protected Boolean doInBackground(String... arg0) {
MyConnectionManager.getInstance().setConnectionConfiguration(getApplicationContext());
MyConnectionManager.getInstance().connect();
MyConnectionManager.getInstance().login();
return true;
}
protected void onPostExecute(Boolean boo)
{
MyConnectionManager.getInstance().bored();
Roster roster = Roster.getInstanceFor(MyConnectionManager.getInstance().getConnection());
try
{
if (!roster.isLoaded()) roster.reloadAndWait();
}
catch (Exception e)
{
Log.e(TAG, "reload");
}
roster.addRosterListener(new RosterListener() {
public void entriesDeleted(Collection<String> addresses) {
}
public void entriesUpdated(Collection<String> addresses) {
}
public void entriesAdded(Collection<String> addresses) {
}
#Override
public void presenceChanged(Presence presence) {
people.add(new People(presence.getFrom(), presence.getStatus()));
adapter.notifyDataSetChanged();
}
});
dialog.dismiss();
}
}
And below is my Custom Adapter:
public class PeopleAdapter extends ArrayAdapter<People> {
private ArrayList<People> events_list = new ArrayList<>();
Context context;
public PeopleAdapter(Context context, ArrayList<People> users) {
super(context, 0, users);
this.context = context;
this.events_list = users;
}
#Override
public View getView(final int position, View convertView, ViewGroup parent) {
People user = getItem(position);
if (convertView == null) {
convertView = LayoutInflater.from(getContext()).inflate(R.layout.people_list, parent, false);
}
TextView tvName = (TextView) convertView.findViewById(R.id.name);
TextView tvStatus = (TextView) convertView.findViewById(R.id.status);
tvName.setText(user.name);
tvStatus.setText(user.status);
convertView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(context, "You Clicked " + events_list.get(position).name, Toast.LENGTH_SHORT).show();
Intent i = new Intent(context, ConversationActivity.class);
i.putExtra("user", events_list.get(position).name);
context.startActivity(i);
}
});
return convertView;
}
}
I mean what I want to do I think it's a simple thing, every single chat app does it, is basically update the list view automatically but I'm having two problems:
The listview ONLY updates after I click on it. So it basically works
but I have to click on the listview..
I receive this error every time the list view updates (the app keeps working though):
Exception in packet listener: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.

I can give you a simple solution. Make local Activity variable in the ConnectAndLoad class
private Activity activity;
public ConnectAndLoad(Activity activity)
{
...
activity.activity= activity;
}
Instead on directly calling adapter.notifyDataSetChanged(); use
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
adapter.notifyDataSetChanged();
}
});
It seems like presenceChanged() called in another thread. But be careful and make sure you delete RosterListener when activity gets destroyed or it can lead to the memory leaks i.e activity is already destroyed but you keep getting notifications about presence change.

java.lang.IllegalStateException:Make sure the content of your adapter is not modified from a background thread, but only from the UI thread

java.lang.IllegalStateException: The 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. Make sure your adapter calls notifyDataSetChanged() when its content changes. [in ListView(2131296513, class xyz.ScrollDetectableListView) with Adapter(class android.widget.HeaderViewListAdapter)]
I am getting above exception sometimes while scrolling through the dynamic listview and then clicking on item.I researched a lot but unable to find the exact reason that why i am getting this error sometimes and how it can be resolved?
private ScrollDetectableListView mFListView;
public FAdapter mFAdapter;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_feed_view, container, false);
View headerView = getActivity().getLayoutInflater().inflate(R.layout.view_feed_header, null);
try{
mFListView = (ScrollDetectableListView) rootView.findViewById(R.id.feed_list_view);
mFContainer = (SwipeRefreshLayout) rootView.findViewById(R.id.feed_container);
mFListView.addHeaderView(headerView);
mFListView.setEmptyView(rootView.findViewById(R.id.empty_view));
mFContainer.setColorSchemeResources(R.color.green, R.color.pink, R.color.fbcolor,
R.color.instagramcolor, R.color.googlecolor, R.color.flickrcolor);
mFView = getActivity().getLayoutInflater().inflate(R.layout.view_footer, null);
ImageView rotateImageView = (ImageView) mFooterView.findViewById(R.id.spinner);
Animation rotation = AnimationUtils.loadAnimation(getActivity(), R.anim.rotate);
rotation.setFillAfter(false);
rotateImageView.startAnimation(rotation);
mFContainer.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh()
{
initializeFListView();
}
});
initializeFListView();
mProgressDialog.setVisibility(View.VISIBLE);
mHActivity.setDataChangedListener(new DataChangedListener() {
#Override
public void onDataChanged() {
mFContainer.setRefreshing(true);
mProgressDialog.setVisibility(View.GONE);
initializeFListView();
}
});
}catch(Exception e){}
return rootView;
}
public void initializeFListView()
{
FApi.getTrending(getActivity(), xyz, new APIResponseListener() {
#Override
public void onResponse(Object response) {
setFeedAdapter((List<Video>) response);
}
#Override
public void onError(VolleyError error) {
if (error instanceof NoConnectionError) {
String errormsg = getResources().getString(R.string.no_internet_error_msg);
Toast.makeText(getActivity(), errormsg, Toast.LENGTH_LONG).show();
}
}
});
}
private void setFAdapter(List<Video> response)
{try {
List<Video> videos = response;
mFAdapter = new FAdapter(getActivity(), videos, mProfileClickListener, mCommentClickListener);
mFListView.setOnScrollListener(new EndlessScrollListenerFeedView(getActivity(), mFListView, mFView, mFAdapter, videos, mFType, ""));
mFListView.setAdapter(mFAdapter);
mProgressDialog.setVisibility(View.GONE);
if (mFContainer.isRefreshing()) {
mFContainer.setRefreshing(false);
}
if (mFAdapter.getCount() < mCount) {
mFView.setVisibility(View.GONE);
mFListView.removeFooterView(mFooterView);
}
}catch(Exception e){}
}
}

My suggestion try to set ur list adapter on UI Thread,,,
private void setFAdapter(List<Video> response)
{
try {
List<Video> videos = response;
mFAdapter = new FAdapter(getActivity(), videos, mProfileClickListener, mCommentClickListener);
mFListView.setOnScrollListener(new EndlessScrollListenerFeedView(getActivity(), mFListView, mFView, mFAdapter, videos, mFType, ""));
runOnUiThread(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
mFListView.setAdapter(mFAdapter);
}
});
mProgressDialog.setVisibility(View.GONE);
if (mFContainer.isRefreshing()) {
mFContainer.setRefreshing(false);
}
if (mFAdapter.getCount() < mCount) {
mFView.setVisibility(View.GONE);
mFListView.removeFooterView(mFooterView);
}
}catch(Exception e){}
}
}

Keep one singleton class object in hand. So that you can synchronize two thread on it. Care to be taken to not to block the ui thread.
Reduce number of interfaces to only one method to start preparing data for your list and only one method to call your notifydatasetchanged/setAdapter on list.
Means there should be only one method like prepareData() which will be executed by a background thread. synchronise this method on your singleton object.
MyListAdaper adapter = null;
// Call this from a background thread
public void prepareData() {
synchronized (SingleTonProvider.getInstance()) {
List<AnyDataTypeYouWant> data = null;
// populate data here by your application logic.
adapter = new MyListAdaper(data);
}
}
And have only one method to refresh list.
// Also Call this from a background thread only
public void refreshList() {
synchronized (SingleTonProvider.getInstance()) {
runOnUiThread(new Runnable() {
#Override
public void run() {
mFListView.setAdapter(adapter);
}
});
}
}
have no other code on any place to prepare data and set data on list.
Call the methods I mentioned from a background thread only.
I just gave general solution to your problem. You have to work on your specific case by yourself.

Android TableLayout with over 1000 rows loading very slowly

I'm looking for a way to speed up the creation of a TableLayout with over 1000 rows. Is there a way to create a TableLayout entirely on a separate thread or a way to speed it up?
Here is my method that is creating the table:
private void setTable()
{
final Activity activity = this;
final Handler handler = new Handler();
new Thread(new Runnable()
{
#Override
public void run()
{
for (int x = 0; x < rooms.size(); x++)
{
final int inx = x;
handler.post(new Runnable()
{
#Override
public void run()
{
Methods.createRow(table, rooms.get(inx), null, activity);
TableRow row = (TableRow)table.getChildAt(inx);
row.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View arg0)
{
if (arg0.getTag() != null && arg0.getTag().getClass() == Integer.class)
select((Integer)arg0.getTag());
}
});
}
});
}
}
}).start();
}
I was hoping that using a Handler would at least allow the new Activity to appear before the table was created. The application seems to freeze up for a few seconds when creating tables with a lot of rows. setTable() is being run in my Activity's onStart() method.
Methods.createRow adds a row to the end of the TableView that is passed in.
Edit:
After deciding to try out a ListView, I got much better results with a lot less code.
private void setTable()
{
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, roomNames);
table.setAdapter(adapter);
table.setOnItemClickListener(new OnItemClickListener()
{
#Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3)
{
select(arg2);
}
});
}

First things first.
Why your app freezes:
Handler works like a queue, it queues every post you made and than execute it serially in your main thread.
But the main problem is the amount of data you are trying to show at once, but it is easily solved with an Adapter, you probably can use some default Component for solve this, like ListView or GridView, you can make your custom rows to work around the columns maybe.

Just from guessing on the method name, it seems this line may be slow to run on the main/UI thread:
Methods.createRow(table, rooms.get(inx), null, activity);
I would suggest separating all the heavy database work and UI work with AsyncTask, so it might look something like this:
private OnClickListener rowClickListener = new OnClickListener()
{
#Override
public void onClick(View arg0)
{
if (arg0.getTag() != null && arg0.getTag().getClass() == Integer.class)
select((Integer)arg0.getTag());
}
};
private void setTable()
{
final Activity activity = this;
final Handler handler = new Handler();
new AsyncTask<Void, Void, List<TableRow>>() {
#Override
protected List<TableRow> doInBackground(Void... params) {
// Do all heavy work here
final List<TableRow> rows = new ArrayList<TableRow>(rooms.size());
for (int x = 0; x < rooms.size(); x++)
{
Methods.createRow(table, rooms.get(x), null, activity);
rows.add((TableRow)table.getChildAt(x));
}
return rows;
}
#Override
protected void onPreExecute() {
// maybe show progress indication
}
#Override
protected void onPostExecute(List<TableRow> result) {
// Do all UI related actions here (maybe hide progress indication)
for (final TableRow row : result) {
row.setOnClickListener(rowClickListener);
}
}
};
}
Since I can't tell what is in some methods, you'll just need to ensure you've tried to optimize as best as possible in Methods.createRow(...) and move all the UI related work to the onPostExecute(...) method.

You are stacking the post with all the actions at once. So it same as not using a thread at all as your main thread doing all the work. Try changing to postDelay, and for each room index give it 1 millisecond or more.

How to manage custom adapters onPause , onResume of Activity in Android

I have an adapter used to display messages on the list view alike messages in chat application . I am able to display the content flawlessly once the activity is created , but when I go back and create activity again , adapter don't work as usual .
What I found in debugging is follows:
function receives() is called when message is received and update the
register , as I mentioned above there is no problem to display the
data in list view once the activity is created , but once I go back
and relauch the activity I am not able to display received messages .
Is there something I am missing in onResume() onPause or onStart() method with respect to custom adapter such as registering or decalring the custom adapter again? Thanks for help.
Following is the code of my activity class which uses custom adapter to display sent and received messages:
public class hotListener extends ListActivity {
private XMPPConnection connection;
private IBinder binder;
private Handler mHandler = new Handler();
private ArrayList<String> messages = new ArrayList<String>();
ArrayList<ChatMessage> messagex= new ArrayList<ChatMessage>();;
ChattingAdapter adaptex;
Intent mIntent ;
private ListView listview;
EditText sender_message ;
String msg;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listener);
//messagex.add(new ChatMessage("Hello", false));
adaptex = new ChattingAdapter(getApplicationContext(),messagex);
setListAdapter(adaptex);
Button send_button = (Button) findViewById(R.id.chat_send_message);
sender_message = (EditText) findViewById(R.id.chat_input);
send_button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
msg = sender_message.getText().toString();
sender_message.setText("");
if(!(msg.length()==0)){
messagex.add(new ChatMessage(msg, true));
//addNewMessage(new ChatMessage(msg, true));
adaptex.notifyDataSetChanged();
getListView().setSelection(messagex.size()-1);
}
}
});
if(!isMyServiceRunning()){
System.out.println("seems like service not running");
startService(new Intent(this,xService.class));
System.out.print(" now started ");
}
}
#Override
protected void onStart(){
super.onStart();
Boolean kuch = bindService(new Intent(this,xService.class), mConnection,Context.BIND_AUTO_CREATE);
//System.out.println(kuch);
System.out.println("bind done");
}
private void receives(XMPPConnection connection2) {
//ChatManager chatmanager = connection.getChatManager();
connection2.getChatManager().addChatListener(new ChatManagerListener() {
#Override
public void chatCreated(Chat arg0, boolean arg1) {
arg0.addMessageListener(new MessageListener() {
#Override
public void processMessage(Chat chat, Message message) {
final String from = message.getFrom();
final String body = message.getBody();
mHandler.post(new Runnable() {
ChatMessage kudi = new ChatMessage(body, false);
#Override
public void run() {
messagex.add(kudi);
adaptex.notifyDataSetChanged();
getListView().setSelection(messagex.size()-1);
Toast.makeText(hotListener.this,body,Toast.LENGTH_SHORT).show(); }
});
}
});
}
});
}
private boolean isMyServiceRunning() {
ActivityManager manager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
for(RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)){
if(xService.class.getName().equals(service.service.getClassName())){
return true;
}
}
//System.out.print("false");
return false;
}
#Override
protected void onResume() {
bindService(new Intent(this, xService.class), mConnection, Context.BIND_AUTO_CREATE);
super.onResume();
}
#Override
protected void onPause() {
unbindService(mConnection);
super.onPause();
}
private ServiceConnection mConnection = new ServiceConnection() {
#Override
public void onServiceDisconnected(ComponentName name) {
connection = null;
service = null;
}
#Override
public void onServiceConnected(ComponentName name, IBinder binder) {
//System.out.println("binding in hot listener");
service = ((xService.MyBinder)binder).getService();
connection = service.getConnection();
receives(connection);
Log.wtf("Service","connected");
}
};
void addNewMessage(ChatMessage m)
{
System.out.println("1");
messagex.add(m);
System.out.println("2");
adaptex.notifyDataSetChanged();
System.out.println("3");
getListView().setSelection(messagex.size()-1);
}
}
Here is my custom adapter (there is no problem in custom adapter but adding to make things clear) :
public class ChattingAdapter extends BaseAdapter{
private Context mContext;
private ArrayList<ChatMessage> mMessages;
public ChattingAdapter(Context context, ArrayList<ChatMessage> messages) {
super();
this.mContext = context;
this.mMessages = messages;
}
#Override
public int getCount() {
return mMessages.size();
}
#Override
public Object getItem(int position) {
return mMessages.get(position);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ChatMessage message = (ChatMessage) this.getItem(position);
ViewHolder holder;
if(convertView == null)
{
holder = new ViewHolder();
convertView = LayoutInflater.from(mContext).inflate(R.layout.listitem, parent, false);
holder.message = (TextView) convertView.findViewById(R.id.text1);
convertView.setTag(holder);
}
else
holder = (ViewHolder) convertView.getTag();
holder.message.setText(message.getMessage());
LayoutParams lp = (LayoutParams) holder.message.getLayoutParams();
//Check whether message is mine to show green background and align to right
if(message.isMine())
{ holder.message.setBackgroundResource(R.drawable.msgbox_new_selected_go_up);
lp.gravity = Gravity.RIGHT;
}
//If not mine then it is from sender to show orange background and align to left
else
{
holder.message.setBackgroundResource(R.drawable.msgbox_other_go_up);
lp.gravity = Gravity.LEFT;
}
holder.message.setLayoutParams(lp);
//holder.message.setTextColor(R.color.textColor);
return convertView;
}
private static class ViewHolder
{
TextView message;
}
#Override
public long getItemId(int position) {
//Unimplemented, because we aren't using Sqlite.
return position;
}
}
p.s: I am not storing any messages in sqlite as I dont want to restore messages for now, but I want new messages to be displayed at least onresume of activty. I can display sent messages after pressing send button but no received messages which works fine for the first time activity is created.
EDIT: I did more debugging , it turns out problem is not in resume activity , if I dont use receives() function for first time , and resume activity after going back , then receives() will work , that means , function inside receives() : getListView().setSelection(messagex.size()-1); works only once .
Either first time on receiving message or next time if and only if its not called first time on activity .

I think problem lies when you try to resume activity , you are still running the previous mHandler running and thus your instance of message is not destroyed and when you resume your activity it creates a problem . Make sure your mhandler destroys all instance of objects when unstop is called.

There's no place in your code where you save your messagex ArrayList. When you quit your activity by hitting back, your array get's distroyed (Garbage Collection takes care of it).
When you relaunch your activity your messagex ArrayList is created again, it's a brand new variable.
In fact, you're not relaunching your activity, you're creating a new instance.
EDIT:
I've never worked with the XMPPConnection objects before, but something else worth trying is the following:
When binding to the service, you're calling connection2.getChatManager().addChatListener and also arg0.addMessageListener but when unbinding you're not calling any removeXXX methods. I could be that since you're not removing your listeners, the whole XMPPConnection object still have references to the listeners that live in a dead Activity, and they are not being garbage collected.