Missing return UITableViewCell

问题:

I am sure this question have been asked before but I can't find an answer that solves my problem with nested if-else and switch-case logic.
I have a UITableView with two sections, each sections has two custom cells. That is it it. 4 cells. But no matter what I do I get "Missing return in a function expected to return UITableViewCell"

Question How can I change this setup so that I get an else statement at the bottom that will satisfy swift logic?

Any help would be very much appreciated

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {      if indexPath.section == 0{          switch (indexPath.row) {         case 0:             let cell0: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell0", forIndexPath: indexPath) as! SettingsCell         cell0.backgroundColor = UIColor.redColor()         break          case 1:             let cell1: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell1", forIndexPath: indexPath) as! SettingsCell         cell1.backgroundColor = UIColor.whiteColor()          break          default:             break         }     }      if indexPath.section == 1{          switch (indexPath.row) {         case 0:             let cell10: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell10", forIndexPath: indexPath) as! SettingsCell         cell10.backgroundColor = UIColor.redColor()         break          case 1:             let cell11: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell11", forIndexPath: indexPath) as! SettingsCell         cell11.backgroundColor = UIColor.whiteColor()          break          default:             break          }     } } 

回答1:

• Declare the cell at the start of the method,
• assign a value to the cell depending on section and row number,
• throw a fatalError() in all cases that "should not occur",
• return the cell.

Also note that the break statements are not needed. The default behavior in Swift is not to fall through to the next case.

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {      let cell: SettingsCell      switch(indexPath.section) {     case 0:         switch (indexPath.row) {         case 0:             cell = tableView.dequeueReusableCellWithIdentifier("cell0", forIndexPath: indexPath) as! SettingsCell             cell.backgroundColor = UIColor.redColor()          case 1:             cell = tableView.dequeueReusableCellWithIdentifier("cell1", forIndexPath: indexPath) as! SettingsCell             cell.backgroundColor = UIColor.whiteColor()          default:             fatalError("Unexpected row \(indexPath.row) in section \(indexPath.section)")         }     case 1:         switch (indexPath.row) {         case 0:             cell = tableView.dequeueReusableCellWithIdentifier("cell10", forIndexPath: indexPath) as! SettingsCell             cell.backgroundColor = UIColor.redColor()          case 1:             cell = tableView.dequeueReusableCellWithIdentifier("cell11", forIndexPath: indexPath) as! SettingsCell             cell.backgroundColor = UIColor.whiteColor()          default:             fatalError("Unexpected row \(indexPath.row) in section \(indexPath.section)")          }     default:         fatalError("Unexpected section \(indexPath.section)")      }     return cell } 

The fatalError() error function is marked as @noreturn, so the compiler knows that program execution will not continue from the default cases. (This also helps to find logic errors in the program.)

The compiler verifies that a value is assigned to cell in all other cases.

The possibility to initialize a constant (let cell ...) in this way is new in Swift 1.2.

---

Alternatively, you can create a cell and return it "immediately" in each case:

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {      switch(indexPath.section) {     case 0:         switch (indexPath.row) {         case 0:             let cell = tableView.dequeueReusableCellWithIdentifier("cell0", forIndexPath: indexPath) as! SettingsCell             cell.backgroundColor = UIColor.redColor()             return cell          case 1:             let cell = tableView.dequeueReusableCellWithIdentifier("cell1", forIndexPath: indexPath) as! SettingsCell             cell.backgroundColor = UIColor.whiteColor()             return cell          default:             fatalError("Unexpected row \(indexPath.row) in section \(indexPath.section)")         }     case 1:         switch (indexPath.row) {         case 0:             let cell = tableView.dequeueReusableCellWithIdentifier("cell10", forIndexPath: indexPath) as! SettingsCell             cell.backgroundColor = UIColor.redColor()             return cell          case 1:             let cell = tableView.dequeueReusableCellWithIdentifier("cell11", forIndexPath: indexPath) as! SettingsCell             cell.backgroundColor = UIColor.whiteColor()             return cell          default:             fatalError("Unexpected row \(indexPath.row) in section \(indexPath.section)")          }     default:         fatalError("Unexpected section \(indexPath.section)")     } } 

Again, calling fatalError() solves the "missing return expected" compiler error.

This pattern can be useful if there are different kinds of cells (with different classes) created in each case.

回答2:

You must return a cell, if the section is number 2 this methods won't be returning anything, well it's the case when u specify secitons more than two. Solution

• Second "if" will be "else" part
• Limit number of section

回答3:

You're missing in you method the return statement.

Example with return statement.

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {      if indexPath.section == 0{          switch (indexPath.row) {         case 0:             let cell: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell0", forIndexPath: indexPath) as! SettingsCell         cell.backgroundColor = UIColor.redColor()         break          case 1:             let cell: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell1", forIndexPath: indexPath) as! SettingsCell         cell.backgroundColor = UIColor.whiteColor()          break          default:             let cellId: NSString = "Cell"             var cell: UITableViewCell = tableView.dequeueReusableCellWithIdentifier(cellId) as UITableViewCell             break         }     }      if indexPath.section == 1{          switch (indexPath.row) {         case 0:             let cell: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell10", forIndexPath: indexPath) as! SettingsCell         cell.backgroundColor = UIColor.redColor()         break          case 1:             let cell: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell11", forIndexPath: indexPath) as! SettingsCell         cell.backgroundColor = UIColor.whiteColor()          break          default:              let cellId: NSString = "Cell"              var cell: UITableViewCell = tableView.dequeueReusableCellWithIdentifier(cellId) as UITableViewCell             break          }     }     return cell } 

回答4:

you can use else if like this :

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {  if indexPath.section == 0{      switch (indexPath.row) {     case 0:         let cell: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell0", forIndexPath: indexPath) as! SettingsCell     cell.backgroundColor = UIColor.redColor()     break      case 1:         let cell: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell1", forIndexPath: indexPath) as! SettingsCell     cell.backgroundColor = UIColor.whiteColor()      break      default:         break     }       else if indexPath.section == 1{      switch (indexPath.row) {     case 0:         let cell: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell10", forIndexPath: indexPath) as! SettingsCell     cell.backgroundColor = UIColor.redColor()     break      case 1:         let cell: SettingsCell! = tableView.dequeueReusableCellWithIdentifier("cell11", forIndexPath: indexPath) as! SettingsCell     cell.backgroundColor = UIColor.whiteColor()      break      default:         break      } } return cell } } 

it may help you try it

文章来源: Missing return UITableViewCell