封装自适应系统的ZCMAlert (UIAlertView和UIAlertController)
类ZCMAlert是一个用来展示alert框的封装类，iOS version >= 8.0 时自动使用UIAlertController，否则使用UIAlertView。
//
// ZCMAlert.h
// zcm
//
// Created by cnstar on 4/4/2015.
// Copyright (c) 2015年 cnstar. All rights reserved.
//
#import <Foundation/Foundation.h>
//系统版本号
#define SYSTEM_VERSION [[[UIDevice currentDevice] systemVersion] floatValue]
@class ZCMAlertAction;
/**
* 封装自适应系统的ZCMAlert (UIAlertView和UIAlertController)
*/
@interface ZCMAlert : NSObject
@property (nonatomic, readonly) NSString *title;
@property (nonatomic, readonly) NSString *message;
@property (nonatomic, readonly) NSArray *actions;
+(instancetype)alertWithTitle:(NSString *)title message:(NSString *)message;
-(void)show;
-(void)addAction:(ZCMAlertAction *)action;
@end
/**
* ZCMAlertStyle 只针对iOS 8.0及以上有效
*/
typedef NS_ENUM(NSInteger, ZCMAlertStyle) {
ZCMAlertStyleDefault = 0,
ZCMAlertStyleCancel,
ZCMAlertStyleDestructive
};
typedef void(^ZCMAlertActionHandler)(ZCMAlertAction *);
/**
* ZCMAlertAction为alert view上的按钮动作类，一个按钮对应一个handler及一个title
*/
@interface ZCMAlertAction : NSObject
@property (nonatomic, readonly) NSString *title;
@property (nonatomic, readonly) ZCMAlertStyle style;
@property (copy) ZCMAlertActionHandler handler;
+ (instancetype)actionWithTitle:(NSString *)title style:(ZCMAlertStyle)style handler:(void (^)(ZCMAlertAction *action))handler;
@end
//
// ZCMAlert.m
// zcm
//
// Created by cnstar on 4/4/2015.
// Copyright (c) 2015年 cnstar. All rights reserved.
//
#import "ZCMAlert.h"
@interface ZCMAlert ()<UIAlertViewDelegate>
@property (nonatomic, strong) NSString *title;
@property (nonatomic, strong) NSString *message;
@property (nonatomic, strong) NSMutableArray *mutableActions;
@property (nonatomic, strong) id holder;
@end
//做转换 ZCMAlertStyle ——> UIAlertActionStyle
static inline UIAlertActionStyle uistyle(ZCMAlertStyle style) {
switch (style) {
case ZCMAlertStyleCancel:
return UIAlertActionStyleCancel;
break;
case ZCMAlertStyleDestructive:
return UIAlertActionStyleDestructive;
break;
default:
return UIAlertActionStyleDefault;
break;
}
}
@implementation ZCMAlert
-(void)dealloc {
[self dismiss];
self.mutableActions = nil;
self.title = nil;
self.message = nil;
}
-(void)dismiss {
self.holder = nil;
}
+(instancetype)alertWithTitle:(NSString *)title message:(NSString *)message {
return [[ZCMAlert alloc] initWithTitle:title message:message];
}
-(instancetype)initWithTitle:(NSString *)title message:(NSString *)message {
if ((self = [super init])) {
self.title = title;
self.message = message;
}
return self;
}
/**
* show方法，show的时候再根据系统创建不同的alert。
* 如果在init方法就创建alert的话，务必会声明一个id alert变量供addAction使用
* 此时如果用户没有再调用show方法，此时UIAlertController会hold住self，导致不能跑到dealloc而内存泄漏
*/
-(void)show {
if (SYSTEM_VERSION >= 8.0) {
UIAlertController *alert = [UIAlertController alertControllerWithTitle:_title message:_message preferredStyle:UIAlertControllerStyleAlert];
for (ZCMAlertAction *action in _mutableActions) {
[alert addAction:[UIAlertAction actionWithTitle:action.title style:uistyle(action.style) handler:^(UIAlertAction *alertAction) {
[self processForClicked:action];
[self dismiss];
}]];
}
UIViewController *viewController = [UIApplication sharedApplication].keyWindow.rootViewController;
if (!viewController) {
for (UIWindow *window in [UIApplication sharedApplication].windows) {
if (window.rootViewController) {
viewController = window.rootViewController;
}
}
}
[viewController presentViewController:alert animated:YES completion:nil];
} else {
self.holder = self; //在show之前先hold住self，以便能够正常回调action。原因是，如果不hold住当前self的话，show方法结束后self即被释放，此时UIAlertView的delegate=nil，导致不能正常回调
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:_title
message:_message
delegate:self
cancelButtonTitle:nil
otherButtonTitles:nil, nil];
for (ZCMAlertAction *action in _mutableActions) {
[alert addButtonWithTitle:action.title];
}
[alert show];
}
}
-(void)processForClicked:(ZCMAlertAction *)action {
ZCMAlertActionHandler block = action.handler; //此处不直接使用action.handler的原因是，如果多线程操作，刚进入if(action.handler){//此时正好被其他线程修改了action.handler=nil，那么下面调研action.handler()将会crash，因为block已经不存在了}。 ps：此处不会有多线程调用，只是为了时刻保持良好的认知 if (block) {
block(action);
}
}
-(NSArray *)actions {
return _mutableActions;
}
-(void)addAction:(ZCMAlertAction *)action {
if (!_mutableActions) {
self.mutableActions = [NSMutableArray array];
}
if (action) {
[_mutableActions addObject:action];
}
}
#pragma mark - UIAlertView Delegate for iOS < 8.0
-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if (buttonIndex >= 0 && buttonIndex < _mutableActions.count) {
ZCMAlertAction *action = [_mutableActions objectAtIndex:buttonIndex];
[self processForClicked:action];
}
[self dismiss]; //必须调用，把holder置为nil, 否则最后self释放不了，会内存泄漏
}
- (void)alertViewCancel:(UIAlertView *)alertView {
[self dismiss]; //必须调用，把holder置为nil, 否则最后self释放不了，会内存泄漏
}
- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {
[self dismiss]; //必须调用，把holder置为nil, 否则最后self释放不了，会内存泄漏
}
@end
#pragma mark - ZCMAlertAction
@interface ZCMAlertAction ()
@property (nonatomic, strong) NSString *title;
@property (nonatomic, assign) ZCMAlertStyle style;
@end
@implementation ZCMAlertAction
-(void)dealloc {
self.title = nil;
self.handler = nil;
}
+ (instancetype)actionWithTitle:(NSString *)title style:(ZCMAlertStyle)style handler:(void (^)(ZCMAlertAction *action))handler {
return [[ZCMAlertAction alloc] initWithTitle:title style:style handler:handler];
}
- (instancetype)initWithTitle:(NSString *)title style:(ZCMAlertStyle)style handler:(void (^)(ZCMAlertAction *action))handler {
if ((self = [super init])) {
self.title = title;
self.handler = handler;
self.style = style;
}
return self;
}
@end
使用方法如下：
ZCMAlert *alert = [ZCMAlert alertWithTitle:@"提示" message:@"我是提示消息！"];
[alert addAction:[ZCMAlertAction actionWithTitle:@"知道了" style:ZCMAlertStyleDefault handler:^(ZCMAlertAction *action) {
//NSLog(@"----------------------%@", action.title);
}]];
[alert show];
ps:第一次开始写博客，故只会贴代码，记流水帐。难免有错误之处，望大家不吝赐教。谢谢！