iOS Force update UIView

[alvises]

Hi,

in my application I have a thread that receives data from a tcp connection. It manages some Outlets like UITextView updating the text. The problem is when the thread modifies the text of a UITextView object, doesn't update the screen. This because the thread doesn't return to the Application Run Loop.
A pseudo code


while(running){
NSString *line = [self receive];
//console is UITextView
console.text = line;
}



The problem is that "console" object doesn't update
What can i do ? The "setNeedDisplay" doesn't work too.

Thanks a lot.

Alvise

 

[detz]

I asked on here a similar question the other day, no response. What I did(might not be the best way) is start a timer that does the long process that when it's done updates the screen back.

 

[DaveGee]

I think you need to look into NSThread to do what you need... and then setup some kind of 'call back to the main thread' (from the 'other thread') when you want to have a refresh... I've go something 'kinda working' that does just that but I'm sure its not the right way to do it so I'm afraid to even post the code. It's really messy and it would be hard to break it out to an easy to digest example.

In short...

I 'thread off' code that listens to a TCP socket and gathers data... I then return to the main thread and continue on my apps merry way...

When the 'thread' gets data it calls back to the main thread where it 'does stuff' (updates an NSMutableArray in my case) and then does a refresh of the table.

Dave

 

[alvises]

Thank you !!
Do you mean that if before i did something like :

-(void)mainloop{
while(running){
NSString *line = [self getLine];
console.text = line;
}
}

To return to mainloop i can do something like


-(void)functionInMainThread{

[NSTimer secheduled...... @selector(newMainloop) repeats:YES];

}

-(void)newMainloopNSTimer*)timer{
NSString *line = [self getLine];
console.text = line;
}



Could work ?
Thanks

Alvise

 

[alvises]

Thank you !!
Do you mean that if before i did something like :

-(void)mainloop{
while(running){
NSString *line = [self getLine];
console.text = line;
}
}

To return to mainloop i can do something like


-(void)functionInMainThread{

[NSTimer secheduled...... @selector(newMainloop) repeats:YES];

}

-(void)newMainloopNSTimer*)timer{
NSString *line = [self getLine];
console.text = line;
}



Could work ?
Thanks

Alvise

YEAAA !!! It Works !!!! Thanks a lot !!


Alvise

 

[detz]

I would think there would be an updateView function because not my code is filled with useless 0.1 second timers.

 

[alvises]

I would think there would be an updateView function because not my code is filled with useless 0.1 second timers.

Detz, now I write a general subclass of UIView that works as "Update Manager" After that I will post it to the forum

 

[detz]

Another way you can do it is to animate the item you want changed. If you animate it it some way(not even visible) the app will start a new animation thread for you and refresh you item.

[UIView beginAnimations:nil context:nil];
...
[UIView commitAnimations];

 

[alvises]

Another way you can do it is to animate the item you want changed. If you animate it it some way(not even visible) the app will start a new animation thread for you and refresh you item.

[UIView beginAnimations:nil context:nil];
...
[UIView commitAnimations];

Thanks ! Could be useful!!

 

[alvises]

Another annoying problem ...
This code is a mainloop

-(IBAction)startMainloopid)sender{
messengerController = [[MulodMessengerController alloc] init];
[NSTimer scheduledTimerWithTimeInterval:0.01 target:messengerController selectorselector(mainloop userInfo:nil repeats:YES];
}


The timer is like a "while" that loops the mainloop method. Mainloop waits to read from TCP socket.
The view is updated(!!) BUT the interaction is TOTALY LOCKED. The user can do NOTHING
What i can do.. why there is no method to force the update manually ? Or a message event to send to runLoop to update the screen..
Thanks.

Alvise

 

[firewood]

animation code

Look at animation game engine code examples, or the Accelerometer demo app. They update the display 10 to 30 times per second (no need to do so faster) with the latest data, if needed.

The trick seems to be to set a timer in the main loop to periodically send setNeedsDisplay to the current view controller, and then check in that view controller's drawRect for anything that needs updating. Don't set the timer to faster than you can update on average or your frame rate will drop and/or the device will lock up.

 

[alvises]

Seems that i need to manage all the gui manually :| Isn't there something simple like "window.display" lile macos X cocoa ?

 

[incorrect.user]

I've almost the same problem:

After clicking on a button in a corresponding action i create a new thread in which make a socket connection and download some data. After each portion of data i add some messages to a UITextView and ofcourse they do not appear immediately (only after that thread returns).

Help, please

 

[incorrect.user]

Here's the solution:

- (void) thread
{
//....
[self performSelectorOnMainThread: @selector(refresh_textview: ) withObject"Some text that u need to output into the UITextview" waitUntilDone:NO];
//....
}

- (void)refresh_textview: (NSString*)text
{
[textview setText:text];
}