如何以編程方式在右上角創建信息按鈕？

Question

我想這樣做，但按鈕不會顯示：

// Create a Button to get Help   
UIButton *helpButton = [UIButton buttonWithType:UIButtonTypeInfoDark ] ; 
CGRect buttonRect = helpButton.frame; 

// Calculate the top right corner 
buttonRect.origin.x = self.tableView.frame.size.width - buttonRect.size.width - 8; 
buttonRect.origin.y = self.tableView.frame.size.height - buttonRect.size.height - 8; 
[helpButton setFrame:buttonRect]; 

[helpButton addTarget:self action:@selector(doHelp:) 
forControlEvents:UIControlEventTouchUpInside]; 
[helpButton setEnabled:TRUE]; 
[self.tableView addSubview:helpButton]; 

我究竟做錯了什麼？

UPDATE 修復代碼是在這裏的任何人有興趣：

// Create a Button to get Help   
UIButton *helpButton = [UIButton buttonWithType:UIButtonTypeInfoDark ] ; 
CGRect buttonRect = helpButton.frame; 

// CALCulate the bottom right corner 
buttonRect.origin.x = self.view.frame.size.width - buttonRect.size.width - 8; 
buttonRect.origin.y = buttonRect.size.height - 8; 
[helpButton setFrame:buttonRect]; 

[helpButton addTarget:self action:@selector(doHelp:) forControlEvents:UIControlEventTouchUpInside]; 
[self.view addSubview:helpButton]; 

Answer 1

嘗試將它添加到self.view不self.tableview