Frequent update table view failed on swift - ios

Question

I have a tableview need to be updated very second. The code are as following. I design the headerview to have a dropdown function, when the header tap the rest are displayed. The code will crashes when I am trying to tap the header, the thread stops, xcode is not giving any hint on how and why.
func didListOfBLEDevicesUpdate(newDevice: BLEDevice)
{
println("receivedDevice from scanner every second: \(newDevice.deviceName)")
self.deviceTableView.reloadData()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return BLEDevice.listOfDevices.items.count
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1;
}
func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
return BLEDevice.listOfDevices.items[section].deviceName
}
func tableView(tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
return 1
}
func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
if(IsExpandedMode[indexPath.section] == true){
return 400
}
return 70;
}
func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let headerView = UIView(frame: CGRectMake(0, 0, tableView.frame.size.width, 40))
headerView.backgroundColor = UIColor.grayColor()
headerView.tag = section
let headerString = UILabel(frame: CGRect(x: 10, y: 10, width: tableView.frame.size.width-10, height: 30)) as UILabel
headerString.text = BLEDevice.listOfDevices.items[section].deviceName
headerView .addSubview(headerString)
let headerTapped = UITapGestureRecognizer (target: self, action:"sectionHeaderTapped:")
headerView .addGestureRecognizer(headerTapped)
return headerView
}
func sectionHeaderTapped(recognizer: UITapGestureRecognizer) {
println("Tapping working")
println(recognizer.view?.tag)
var indexPath : NSIndexPath = NSIndexPath(forRow: 0, inSection:(recognizer.view?.tag as Int!)!)
if (indexPath.row == 0) {
var collapsed = self.IsExpandedMode [indexPath.section]
collapsed = !collapsed;
self.IsExpandedMode[indexPath.section] = collapsed
//reload specific section animated
var range = NSMakeRange(indexPath.section, 1)
var sectionToReload = NSIndexSet(indexesInRange: range)
self.deviceTableView.reloadSections(sectionToReload, withRowAnimation:UITableViewRowAnimation.Fade)
}
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell : DeviceTableViewCell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! DeviceTableViewCell
let row = indexPath.row
cell.deviceName!.text = BLEDevice.listOfDevices.items[row].deviceName
cell.connectionStatus.text = BLEDevice.listOfDevices.items[row].connectionStatus
cell.deviceSignalStrengthen.text = BLEDevice.listOfDevices.items[row].RSSI
cell.manufacturerData.text = BLEDevice.listOfDevices.items[row].advertisementPackage.cBAdvertisementDataManufacturerData
cell.serviceUUID.text = BLEDevice.listOfDevices.items[row].advertisementPackage.cBAdvertisementDataServiceUUIDs
cell.serviceData.text = DataConvertHelper.getNSDictionary(BLEDevice.listOfDevices.items[row].advertisementPackage.cBAdvertisementDataServiceData)
cell.TxPowerLevel.text = BLEDevice.listOfDevices.items[row].advertisementPackage.cBAdvertisementDataTxPowerLevel
cell.IsConnectable.text = DataConvertHelper.getBool(BLEDevice.listOfDevices.items[row].advertisementPackage.cBAdvertisementDataIsConnectable)
cell.solicitedServiceUUID.text = BLEDevice.listOfDevices.items[row].advertisementPackage.cBAdvertisementDataSolicitedServiceUUIDs
cell.shortenedLocalName.text = BLEDevice.listOfDevices.items[row].advertisementPackage.cBAdvertisementDataLocalName
return cell
}

Answer 1

Use reload sections and reload rows rather than reloading data

Answer 2

The method you have used to handle the table seems to be rather complex. An alternative would be as follows:
1) Assumption from you code is that each device is associated with a section. As noted in the comments, your cellForRorAtIndexPath method seems to be using [row] to index your data model, but the model is based on [section] as you always return the number of rows as 1 for every section and the number of sections is the number of devices.
2) Rather than using a header view for each section and having to add gesture recognizers, simply create a custom cell to represent the device and make this row 0 of the section.
3) So each device is associated with a section, and row 0 of each section is the header information cell, NOT a header view. Make the header view nil. You can use a header height to leave a gap between sections.
4) Add code to detect selection of cells. When the cell row is 0, its the header cell. If the device is collapsed, set it to be expanded and vice versa and reload the section.
5) Make a new custom cell for you dropdown information. this will be row 1 of any section which is showing information.
6) Update your number of rows in section to return 2 if expanded, or 1 if collapsed.
7) Update cellForRowAtIndexPath to return the header cell for row 0 and the detail cell for row 1. Make sure to fix the [row] indexing to be [section] indexing.
This gives you a table of device header cells, which when clicked insert a detail cell below and when clicked again remove it and no gesture recognizers needed.
You need to make sure that your data model updates are working correctly. Seems from your errors that you are not updating the data model properly: in particular removal of devices.