MyAlertView（UIAlertView 的子类）有这个方法：
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if (self.clickedButtonAtIndexBlock != NULL)
self.clickedButtonAtIndexBlock(buttonIndex);
}
我的问题是创建警报视图时如何定义回调？显然这是错误的：
alert.clickedButtonAtIndexBlock = ^{
NSLog(@"clicked: %d", buttonIndex);
}
我写了一篇关于如何（以及为什么）将块回调添加到警报视图、操作表和动画的博客文章：
http://blog.innovattic.com/uikitblocks/
如果您只想要一个有效的实现，您可以从 GitHub 下载源文件：
https://github.com/Innovattic/UIKit-Blocks
用法：
UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"My easy alert"
message:@"Would you like to perform some kind of action?"
cancelButtonTitle:@"No"
otherButtonTitles:@"Yes", nil];
[alert setHandler:^(UIAlertView* alert, NSInteger buttonIndex) {
NSLog(@"Perform some kind of action");
} forButtonAtIndex:[alert firstOtherButtonIndex]];
[alert show];
尝试做这样的事情（我还没有测试过）：
.h
typedef void (^MyClickedIndexBlock)(NSInteger index);
@interface YouInterface : YourSuperclass
@property (nonatomic, strong) MyClickedIndexBlock clickedIndexBlock;
@end
.m
//where you have to call the block
if (self.clickedIndexBlock != nil)
self.clickedIndexBlock(buttonIndex);
// where you want to receive the callback
alert.clickedIndexBlock = ^(NSInteger index){
NSLog(@"%d", index);
};
检查这个OpinionzAlertView我在几个项目中使用过它，对我很有用。这是示例：
OpinionzAlertView *alert = [[OpinionzAlertView alloc] initWithTitle:@"title"
message:@"message"
cancelButtonTitle:@"No, thanks"
otherButtonTitles:@[@"Done"]
usingBlockWhenTapButton:^(OpinionzAlertView *alertView, NSInteger buttonIndex) {
NSLog(@"buttonIndex: %li", (long)buttonIndex);
NSLog(@"buttonTitle: %@", [alertView buttonTitleAtIndex:buttonIndex]);
}];
[alert show];
我希望它对你有帮助。
试试这个
假设您创建了一个名为 MyCustomAlert 的类，并将其声明为该变量。
MyCustomAlert *myCustomAlert = [[MyCustomAlent alloc] init];
你可以把它放在你的头文件中。
- (void)setCompletion:(void (^)(int selectedButtonIndex))completion;
你会把它放在你的实现文件中
typedef void (^IntBlock)(int intBlock);
IntBlock _completion;
- (void)setCompletion:(void (^)(int selectedButtonIndex))completion{
_completion = completion;
}
现在在您声明“myCustomAlert”的项目中。如果你输入
[myCustomAlert setCompletion: // And select the autocomplete item
你最终会得到这个
[myCustomAlert setCompletion:<#^(int intBlock)completion#>]
值 <#^(int intBlock)completion#> 将显示为像这样的气泡。
当您按回车键时，它将填写块供您使用。
[myCustomAlert setCompletion:^(int selectedButtonIndex) {
}
当您想在自定义类中触发 _completion 块时，您可以在代码中的某处调用它，如下所示。
- (void) callCompletionWithButtonIndex:(int) index{
if (_completion != nil) _completion(index);
}
希望能消除复杂性。
我编写了一个简单的类 LMSVBlocks 来轻松显示警报并在 1 行中获取块回调。希望您会发现它对此有用
https://github.com/sourabhverma/LMSVBlocks
概念：要使 UIAlertView 块兼容，您需要另一个类（例如 LMSVBlockAlert）来处理委托方法，当 UIAlertView 委托将给出回调时，LMSVBlockAlert 类可以在块中发送回调。
代码： （LMSVBlockAlert.m）
将 LMSVBlockAlert 的所有实例维护在一个数组中，以便它们具有强引用
static NSMutableArray *_LMSVblockHandlersArray = nil;
将块处理程序保留在 LMSVBlockAlert
@interface LMSVBlockAlert() <UIAlertViewDelegate>
@property (nonatomic, copy) void (^cancelCompletionBlock)();
@property (nonatomic, copy) void (^confirmCompletionBlock)();
@end
当触发新警报时，创建具有 UIAlertView 和委托回调的 LMSVBlockAlert 新实例
+(LMSVBlockAlert*)newInstance{
LMSVBlockAlert *newIns = [[LMSVBlockAlert alloc] init];
[LMSVBlockAlert updateHandlerArrayWith:newIns];
return newIns;
}
当在 LMSVBlockAlert 中触发警报委托时，发送回调以阻止并从内存中清除它
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
switch (buttonIndex) {
case 0://Cancel
{
if(_cancelCompletionBlock){
_cancelCompletionBlock();
}
}
break;
case 1://OK
{
if(_confirmCompletionBlock){
_confirmCompletionBlock(alertView);
}
}
break;
default:
break;
}
[_LMSVblockHandlersArray removeObject:self];
}
现在你可以有两个简单的方法可以给你 UIAlertView 回调
+(UIAlertView*)promptAlertTwoBtn:(NSString*)msg title:(NSString*)title onCancel:(void (^)())onCancel onConfirm:(void (^)())onConfirm{
return [[LMSVBlockAlert newInstance] showAlertMainWithTitle:title msg:msg onCancel:^{
onCancel();
} onConfirm:^(UIAlertView *alertView) {
onConfirm();
}];
}
-(UIAlertView*)showAlertMainWithTitle:(NSString*)title msg:(NSString*)msg onCancel:(void (^)())onCancel onConfirm:(void (^)(UIAlertView*))onConfirm{
UIAlertView *newAlert = nil;
newAlert = [[UIAlertView alloc]
initWithTitle:title
message:msg
delegate:self
@"Cancel"
otherButtonTitles:@"Confirm", nil];
[newAlert show];
self.cancelCompletionBlock = onCancel;
self.confirmCompletionBlock = onConfirm;
return newAlert;
}
最后 希望你发现它有用..
您可以简单地使用来自 github 的这些类别类。
这为 AlertView 和操作表提供了 Dismiss 块。
例如。
UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"AlertView+Block" message:@"WithBlocks" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"newAlertViewWithTextFields",@"newAlertViewWithSingleTextField", nil];
[alert showWithFinishBlock:^(UIAlertView *alertView, NSInteger buttonIndex)
{ if (buttonIndex == 0) { } else if (buttonIndex == 1) { } }];
除此之外，它还提供文本字段的方法..
-(void) showWithFinishBlock:(FinishBlock_)block_; //-- AlertView with TextField [simple or secure]
-(void) showWithTextFieldBlock:(TextFieldBlock_)block_ secure:(BOOL)isSecure; //-- AlertView with two textfields username & password
您可以查看与它捆绑的示例。我希望它对你有帮助。
我用 Swift 写了一个简单的扩展，希望对你有帮助
import UIKit
extension UIAlertView {
func show(completion: (alertView: UIAlertView, buttonIndex: Int) -> Void){
self.delegate = AlertViewDelegate(completion: completion)
self.show()
}
class func showInput(title: String?, message: String?, cancellable: Bool, completion: (text: String?) -> Void){
var strOK = NSLocalizedString("OK",comment: "OK")
var strCancel = NSLocalizedString("Cancel",comment: "Cancel")
var alert = UIAlertView(title: title, message: message, delegate: nil, cancelButtonTitle: cancellable ? strCancel : strOK)
alert.alertViewStyle = UIAlertViewStyle.PlainTextInput
if(cancellable) {
alert.addButtonWithTitle(strOK)
}
alert.show { (alertView, buttonIndex) -> Void in
if(cancellable && alertView.cancelButtonIndex == buttonIndex) {
completion(text: nil)
return
}
completion(text: alertView.textFieldAtIndex(0)?.text)
}
}
private class AlertViewDelegate : NSObject, UIAlertViewDelegate {
var completion : (alertView: UIAlertView, buttonIndex: Int) -> Void
var retainedSelf : NSObject?
init(completion: (UIAlertView, Int) -> Void ) {
self.completion = completion
super.init()
self.retainedSelf = self
}
func alertView(alertView: UIAlertView, didDismissWithButtonIndex buttonIndex: Int) {
var retain = self
retain.retainedSelf = nil
retain.completion(alertView: alertView, buttonIndex: buttonIndex)
}
}
}