[TIMOB-3166] significant memory leak with thumbnails in tableview

Memory management is a priority for 1.7.0. Examples like this help a great deal, especially since they include some information about the original data being used.

I created another example that better displays the image memory issue in the tableview. When running the code below just keep hitting "Refresh" and you will see the "available memory" as the title. Eventually it gets so low that it crashes.

   var win = Titanium.UI.createWindow({fullscreen:false,backgroundColor:'#fff',title:Ti.Platform.availableMemory});
   var button = Ti.UI.createButton({title:'Refresh',width:40, height:30});
   
   var tableView = Ti.UI.createTableView({
       separatorStyle:Ti.UI.iPhone.TableViewSeparatorStyle.NONE
   });
   win.add(tableView);
   
   button.addEventListener('click', function() {
       load();
   });
   
   win.rightNavButton = button;
   
   var navGroup = Ti.UI.iPhone.createNavigationGroup({
       window:win
   });
   
   var main = Ti.UI.createWindow();
   main.add(navGroup);
   main.open();
   
   load();
   
   function load() {
       var xhr = Titanium.Network.createHTTPClient();
       xhr.onload = function() {
           var list = JSON.parse(this.responseText).List;
           var rowData = [];
           for (var i = 0,count = list.length; i < count; i += 4) {
               var row = Ti.UI.createTableViewRow({
                   height:'auto',
                   selectedBackgroundColor: '#fff',
                   backgroundSelectedColor: '#fff',
                   className:'tvRow'
               }),imgDimensions = 80;
   
   
               var offSet = 0;
               for (var j = 0; j < 4; j++) {
                   var photo = list[i + j];
                   if (photo) {
                       var photoView = Ti.UI.createImageView({
                           top:0,
                           left:offSet,
                           height:imgDimensions,
                           width:imgDimensions,
                           image:photo.ThumbnailUrl
                       });
                       row.add(photoView);
                       offSet += imgDimensions;
                   }
               }
               rowData.push(row);
           }
           tableView.setData(rowData);
           win.title = Ti.Platform.availableMemory;
       };
       var url = "http://api.plixi.com/api/tpapi.svc/json/photos";
       xhr.open("GET", url);
       xhr.send();
   }
   

Sorry for so many code posts :) But I think I have the perfect example of what is going wrong....please use the following instead of the previous two :) If you click the "Launch" button and then click the back button over and over again you will see the "available memory" continue to lower and eventually crash. I really think that closing the photosWindow should release all the memory it uses, rather than leaking. Also please test this using the real device and NOT the simulator.

   var xhr = Titanium.Network.createHTTPClient();
   
   var launchWindow = Titanium.UI.createWindow({fullscreen:false,backgroundColor:'#fff'});
   launchWindow.addEventListener('focus', function() {
       launchWindow.title = Ti.Platform.availableMemory;
   });
   
   var launchButton = Ti.UI.createButton({title:'Launch',width:100, height:100});
   launchWindow.add(launchButton);
   
   launchButton.addEventListener('click', function() {
       var photosWindow = Titanium.UI.createWindow({fullscreen:false,backgroundColor:'#fff',title:Ti.Platform.availableMemory});
       var refreshButton = Ti.UI.createButton({title:'Refresh',width:40, height:30});
   
       var tableView = Ti.UI.createTableView({
           separatorStyle:Ti.UI.iPhone.TableViewSeparatorStyle.NONE
       });
       photosWindow.add(tableView);
   
       refreshButton.addEventListener('click', function() {
           load();
       });
   
       photosWindow.rightNavButton = refreshButton;
   
       photosWindow.addEventListener('close', function() {
           photosWindow.close();
           launchWindow.title = Ti.Platform.availableMemory;
       });
   
       navGroup.open(photosWindow, {animate:true});
       load();
       function load() {
           xhr.onload = function() {
               var list = JSON.parse(this.responseText).List;
               var rowData = [];
               for (var i = 0,count = list.length; i < count; i += 4) {
                   var row = Ti.UI.createTableViewRow({
                       height:'auto',
                       selectedBackgroundColor: '#fff',
                       backgroundSelectedColor: '#fff',
                       className:'tvRow'
                   }),imgDimensions = 80;
   
   
                   var offSet = 0;
                   for (var j = 0; j < 4; j++) {
                       var photo = list[i + j];
                       if (photo) {
                           var photoView = Ti.UI.createImageView({
                               top:0,
                               left:offSet,
                               height:imgDimensions,
                               width:imgDimensions,
                               image:photo.ThumbnailUrl
                           });
                           row.add(photoView);
                           offSet += imgDimensions;
                       }
                   }
                   rowData.push(row);
               }
               tableView.setData(rowData);
               photosWindow.title = Ti.Platform.availableMemory;
           };
           var url = "http://api.plixi.com/api/tpapi.svc/json/photos";
           xhr.open("GET", url);
           xhr.send();
       }
   });
   
   var navGroup = Ti.UI.iPhone.createNavigationGroup({
       window:launchWindow
   });
   
   var main = Ti.UI.createWindow();
   main.add(navGroup);
   main.open();
   

I wanted to mention that the last code post is using suggestions made by folks in the Q&Q forum...to call photosWindow.close on the close event and to use a single HttpClient.

Also when the memory gets really low I see things like this in the debug console in XCode:

[INFO] Due to memory conditions, 0 of 3244 images were unloaded from cache.

Why would it unload 0 images if it got a memory warning? Seems like this is a big issue too.

Once again, not picking up the github commit.

TESTING:

There are two levels of testing that need to be conducted.

INSTRUMENTS

• Run the 3rd provided sample code (or bugtests 3166 - semi-automated). It will help to put the 'refresh' load() call on a timer (inside an anonymous callback function) to semi-automate the test.
• Click 'launch'
• Click 'refresh' (or, click it repeatedly if not automating... but you'll have to click it 100s of times.)
• NOTE: The 'free memory' number provided by the app is NOT accurate.
• Watch the memory. With each reload of the images, it should spike and then decrease (slightly). This is the tableview purging its views. Keep the app running for as long as possible.
• Eventually, there will be a memory warning. When this occurs, memory should drop SHARPLY and there should also be a message in the console indicating that the image cache was purged ("[INFO] Due to memory conditions, X of Y image cache entries were unloaded from cache.")
• NOTE: Especially in the case of automation, there may be a crash. Whether this is caused by instrumentation or by internal issues, I'm unsure.

W/OUT INSTRUMENTS

• Run 3rd provided sample code (or bugtests 3166 - semi-automated). Again, put the load() call for the 'refresh' button on a timer for semi-automation.
• Click 'launch'
• Click 'refresh' (or, again, click repeatedly if not automated)
• Eventually there will be memory warnings.
• The app should NOT crash.

(from [10c2ba87ab69e00ee963e38bd272ab5c8438aec4]) [#3166] Properly handle the case where modalDelegate is 'self', which is pretty much always. https://github.com/appcelerator/titanium_mobile/commit/10c2ba87ab69e00ee963e38bd272ab5c8438aec4"> https://github.com/appcelerator/titanium_mobile/commit/10c2ba87ab69...

Would it be possible to back port this to 1.6.x? We cannot wait until the end of May for 1.7

You can just get a CI build or pull directly from github. This will not be backported to 1.6.x.