Development of iOS several ways to make a phone call

1. This method, the call is not back to the original application, will stay in the address book, and is directly dial, not pop-up prompts

Nsmutablestring *str=[[nsmutablestring alloc] initwithformat:@ "tel:%@", @ "186xxxx6979"];
NSLog (@ "str======%@", str);
[[UIApplication sharedapplication] Openurl:[nsurl Urlwithstring:str]];

2. This method, after the completion of * * * will return to the original program, will also pop-up prompts, recommend this

Nsmutablestring *str2=[[nsmutablestring alloc] initwithformat:@ "tel:%@", @ "186xxxx6979"];
NSLog (@ "%@", str2);
UIWebView * Callwebview = [[UIWebView alloc] init];
[Callwebview loadrequest:[nsurlrequest Requestwithurl:[nsurl URLWITHSTRING:STR2]];
[Self.view Addsubview:callwebview];

3. This method will also go back to the original program (note the telprompt here), will also pop-up prompts

Nsmutablestring *str3=[[nsmutablestring alloc] initwithformat:@ "telprompt://%@", @ "186xxxx6979"];
NSLog (@ "str======%@", STR3);
[[UIApplication sharedapplication] Openurl:[nsurl URLWITHSTRING:STR3]];

Note: Be careful with the 3rd one, because there is no telprompt in the Apple Docs. There have been reject cases before.