UIAlertView使用詳解
Ios中為我們提供了一個用來彈出提示框的類 UIAlertView，他類似於javascript中的alert 和c#中的MessageBox（）;
UIAlertView 繼承自 UIView （@interface UIAlertView : UIView ）
一、簡單的初始化一個UIAlertView 對象。
UIAlertView* alert = [[UIAlertView alloc] init];
激活 alert ，讓它顯示。
[alert show];
結果將如下：
這樣雖然出現了一個提示框，但是太不過友好，讓人根本無法使用。
二，帶有button的提示框。
UIAlertView 里面包含了另外一種用來初始化的方法。
- (id)initWithTitle:(NSString *)title message:(NSString *)message delegate:(id /*<UIAlertViewDelegate>*/)delegate cancelButtonTitle:(NSString *)cancelButtonTitle otherButtonTitles:(NSString *)otherButtonTitles, ... NS_REQUIRES_NIL_TERMINATION;
帶有一個button。
UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"簡單的提示框" message:@"simple alert" delegate:self cancelButtonTitle:@"ok" otherButtonTitles: nil];
[alert show];
帶有多個button
UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"簡單的提示框" message:@"simple alert" delegate:self cancelButtonTitle:@"ok" otherButtonTitles:@"Button1",@"Button2",@"Button3" ,nil];
[alert show];
要想處理多個button點擊之后做出不同響應，那么必須讓當前控制器類遵循 UIAlertViewDelegate 協議。
UIAlertViewDelegate 里面包含了一個方法（- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex;），用來觸發在點擊button之后的操作，判斷是哪一個button 有兩種方式，一種是更具button 的索引，
另外一種是button的title。
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
NSString* buttonTitle = [alertView buttonTitleAtIndex:buttonIndex];
if([buttonTitle isEqualToString:@"Button1"]){
userOutput.text = buttonTitle;
}if([buttonTitle isEqualToString:@"Button2"]){
userOutput.text = buttonTitle;
}if([buttonTitle isEqualToString:@"Button3"]){
userOutput.text = buttonTitle;
}if([buttonTitle isEqualToString:@"ok"]){
userOutput.text = buttonTitle;
}
}
三 、給提示框添加輸入框，最經典的案例，appstore 下載的時候輸入密碼、
首先，初始化UITextField
userInput = [[UITextField alloc] initWithFrame:CGRectMake(12.0, 70.0, 260.0, 25.0)];
[userInput setBackgroundColor:[UIColor whiteColor ]];
將userInput 添加在 alert上，
[alert addSubview:userInput];
- (IBAction)btnWithTextField:(id)sender {
UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"Please Enter Your Email Address" message:@"simple alert" delegate:self cancelButtonTitle:@"ok" otherButtonTitles: nil];
userInput = [[UITextField alloc] initWithFrame:CGRectMake(12.0, 70.0, 260.0, 25.0)];
[userInput setBackgroundColor:[UIColor whiteColor ]];
[alert addSubview:userInput];
[alert show];
[alert release];
[userInput release];
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
NSMutableString* buttonTitle = [NSMutableString stringWithString:[alertView buttonTitleAtIndex:buttonIndex]];
if([buttonTitle isEqualToString:@"Button1"]){
userOutput.text = buttonTitle;
}if([buttonTitle isEqualToString:@"Button2"]){
userOutput.text = buttonTitle;
}if([buttonTitle isEqualToString:@"Button3"]){
userOutput.text = buttonTitle;
}if([buttonTitle isEqualToString:@"ok"]){
[buttonTitle appendString:userInput.text];
userOutput.text = buttonTitle;
}
}
