在iOS8之前用UIActionSheet和UIAlertView来提供按钮选择和提示性信息，比如UIActionSheet可以这样写：
- UIActionSheet *actionSheet = [[UIActionSheet alloc]
- initWithTitle:@"title,nil时不显示"
- delegate:self
- cancelButtonTitle:@"取消"
- destructiveButtonTitle:@"确定"
- otherButtonTitles:@"第一项", @"第二项",nil];
- actionSheet.actionSheetStyle = UIActionSheetStyleBlackOpaque;
- [actionSheet showInView:self.view];
然后在协议中实现代理:
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
- {
- if (buttonIndex == 0) {
- NSLog(@"确定");
- }else if (buttonIndex == 1) {
- NSLog(@"第一项");
- }else if(buttonIndex == 2) {
- NSLog(@"第二项");
- }else if(buttonIndex == actionSheet.cancleButtonIndex) {
- NSLog(@"取消");
- }
- }
- - (void)actionSheetCancel:(UIActionSheet *)actionSheet{
- }
- -(void)actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger)buttonIndex{
- }
- -(void)actionSheet:(UIActionSheet *)actionSheet willDismissWithButtonIndex:(NSInteger)buttonIndex{
- }
如果需要修改按钮字体、颜色等可以实现以下代理：
- - (void)willPresentActionSheet:(UIActionSheet *)actionSheet {
- for (UIView *subViwe in actionSheet.subviews) {
- if ([subViwe isKindOfClass:[UILabel class]]) {
- UILabel *label = (UILabel *)subViwe;
- label.font = [UIFont systemFontOfSize:16];
- label.frame = CGRectMake(CGRectGetMinX(label.frame), CGRectGetMinY(label.frame), CGRectGetWidth(label.frame), CGRectGetHeight(label.frame)+20);
- }
- if ([subViwe isKindOfClass:[UIButton class]]) {
- UIButton *button = (UIButton*)subViwe;
- if ([button.titleLabel.text isEqualToString:@"确定"]) {
- [button setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
- } else {
- [button setTitleColor:[WTDevice getGreenColor] forState:UIControlStateNormal];
- }
- button.titleLabel.font = [UIFont systemFontOfSize:18];
- }
- }
- }
以上代码（代理部分），在ios7及以下版本中是有效的，但是在iOS8中却不起作用，因为iOS8抛弃了UIActionSheet和UIAlertView，取而代之的是UIAlertController，其使用方法如下(代替UIAlertView)：
- #ifdef __IPHONE_8_0
- if (TARGET_IS_IOS8) {
- UIAlertController *actionSheetController = [UIAlertController alertControllerWithTitle:@"提示"
- message:@"需要设置允许访问相机，操作方法见“设置”->“帮助中心”"
- preferredStyle:UIAlertControllerStyleAlert];
- UIAlertAction *actionCancel = [UIAlertAction actionWithTitle:@"确定"
- style:UIAlertActionStyleDestructive
- handler:^(UIAlertAction * action) {}];
- [actionSheetController addAction:actionCancel];
- [actionSheetController.view setTintColor:[WTDevice getGreenColor]];
- [self presentViewController:actionSheetController animated:YES completion:nil];
- }
- #endif
- if (TARGET_NOT_IOS8) {
- UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示" message:@"需要设置允许访问相机，操作方法见“设置”->“帮助中心”" delegate:self cancelButtonTitle:@"取消" otherButtonTitles:nil];
- [alert show];
- }
代替UIActionSheet：
- #ifdef __IPHONE_8_0
- if (TARGET_IS_IOS8) {
- UIAlertController *actionSheetController = [UIAlertController alertControllerWithTitle:@"action选项"
- message:nil
- preferredStyle:UIAlertControllerStyleActionSheet];
- UIAlertAction *action0 = [UIAlertAction actionWithTitle:@"选项一"
- style:UIAlertActionStyleDefault
- handler:^(UIAlertAction * action) {
- [self customMethod1];
- }];
- [actionSheetController addAction:action0];
- UIAlertAction *action = [UIAlertAction actionWithTitle:@"选项二"
- style:UIAlertActionStyleDefault
- handler:^(UIAlertAction * action) {
- [self <span style="font-family: Arial, Helvetica, sans-serif;">customMethod2</span>];
- }];
- UIAlertAction *action1 = [UIAlertAction actionWithTitle:@"选项三"
- style:UIAlertActionStyleDefault
- handler:^(UIAlertAction * action) {
- [self customMethod3];
- }];
- UIAlertAction *actionCancel = [UIAlertAction actionWithTitle:@"取消"
- style:UIAlertActionStyleCancel
- handler:^(UIAlertAction * action) {}];
- [actionSheetController addAction:action];
- [actionSheetController addAction:action1];
- [actionSheetController addAction:actionCancel];
- [actionSheetController.view setTintColor:[UIColor greenColor]];
- [self presentViewController:actionSheetController animated:YES completion:nil];
- }
- #endif
- if (TARGET_NOT_IOS8) {
- UIActionSheet *as = [[UIActionSheet alloc] initWithTitle:@"action选项" delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:nil otherButtonTitles:@"选项一",@"选项二",@"选项三", nil nil];
- [as showInView:self.view];
- }
至于两者的区别，可以看到，iOS8之前是在controller的view上边又覆盖了一层view，iOS8之后则是present了一个controller并且将代理换成了block，代码显得更加紧凑。
