作为3D Touch的一部分，peek and pop （预览和弹出）个人觉得还是很有意思的，今天就说说如何去实现这一小功能。
一、遵守协议
@interface ViewController ()<UIViewControllerPreviewingDelegate>
@end
二、注册代理，并传入响应3D Touch的视图，并实现三个通知中心（分别为删除、置顶、未读功能）。
注意:注册代理应该放在viewDidLoad里面，而看了很多文章都把registerForPreviewingWithDelegate方法放在tableView的cellForRowAtIndexPath代理方法中，这样写非常不好，因为注册只需要执行一次。
- (void)viewDidLoad {
[super viewDidLoad];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deleteActionClick:) name:MessageDeleteNoti object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(stickActionClick:) name:MessageStickNoti object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(noReadActionClick:) name:MessageNoReadNoti object:nil];
if (@available(iOS 9.0, *)) {
if ([self check3DTouchAvailable]) { // 判断3d touch是否可用
[self registerForPreviewingWithDelegate:(id)self sourceView:self.tableView];
}
}
}
- (BOOL)check3DTouchAvailable {
if (self.traitCollection.forceTouchCapability == UIForceTouchCapabilityAvailable) {
return YES;
}
return NO;
}
- (void)dealloc{
[[NSNotificationCenter defaultCenter] removeObserver:self name:MessageDeleteNoti object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:MessageStickNoti object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:MessageNoReadNoti object:nil];
}
三、实现UIViewControllerPreviewingDelegate协议
可以看看官方API，只有需实现以下两个方法
NS_CLASS_AVAILABLE_IOS(9_0) @protocol UIViewControllerPreviewingDelegate <NSObject>
// If you return nil, a preview presentation will not be performed
- (nullable UIViewController *)previewingContext:(id <UIViewControllerPreviewing>)previewingContext viewControllerForLocation:(CGPoint)location NS_AVAILABLE_IOS(9_0);
- (void)previewingContext:(id <UIViewControllerPreviewing>)previewingContext commitViewController:(UIViewController *)viewControllerToCommit NS_AVAILABLE_IOS(9_0);
@end
3.1 当系统察觉到足够的压力时，会调用previewingContext:commitViewController:代理方法：
- (void)previewingContext:(id<UIViewControllerPreviewing>)previewingContext commitViewController:(UIViewController *)viewControllerToCommit {
// 将配置好的控制器推入导航栈
[self.navigationController pushViewController:viewControllerToCommit animated:YES];
}
3.2 当用户重压区域的出现预览界面，其他区域则会变模糊,在此方法中我们可以把需要的数据传入到下一个界面。
- (UIViewController *)previewingContext:(id<UIViewControllerPreviewing>)previewingContext viewControllerForLocation:(CGPoint)location {
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:location];
if (!indexPath) {
return nil;
}
//防止重复加入
if ([self.presentedViewController isKindOfClass:[nextViewController class]]){
return nil;
}
else {
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:location];
listCell *cell = (listCell *)[self.tableView cellForRowAtIndexPath:indexPath];
CGRect rect = cell.frame;
previewingContext.sourceRect = rect;
NIMRecentSession *recentSession = self.conversationArr[indexPath.row];
if (recentSession.unreadCount > 0) {
[recentSession setValue:@"0" forKey:@"unreadCount"];
}
[self sort];
[self testDataIsNull];
nextViewController *vc = [[nextViewController alloc] initWithSession:recentSession.session];
vc.indexPath = indexPath;
vc.isTop = [recentSession isTop];
vc.isOfficeNotiAccount = recentSession.isOfficeNotiAccount;
return vc;
}
}
四、实现通知方法
- (void)deleteActionClick:(NSNotification *)noti {
NSIndexPath *indexPath = noti.userInfo[@"index"];
NIMRecentSession *recentSession = self.conversationArr[indexPath.row];
[self onDeleteRecentAtIndexPath:recentSession atIndexPath:indexPath];
}
- (void)stickActionClick:(NSNotification *)noti {
NSIndexPath *indexPath = noti.userInfo[@"index"];
NSInteger isTop = [noti.userInfo[@"isTop"] integerValue];
NIMRecentSession *recentSession = self.conversationArr[indexPath.row];
if (isTop) { // 点击了取消置顶
[recentSession setTopFlag:0];
[self sort];
[self testDataIsNull];
}else { // 点击了置顶
[recentSession setTopFlag:1];
[self sort];
[self testDataIsNull];
}
}
- (void)noReadActionClick:(NSNotification *)noti {
NSIndexPath *indexPath = noti.userInfo[@"index"];
NIMRecentSession *recentSession = self.conversationArr[indexPath.row];
[recentSession setValue:@"1" forKey:@"unreadCount"];
[self testDataIsNull];
}
五、添加Peek状态下，上划时的快速操作，即在nextViewController重写方法，通过发送通知告诉上一个界面需要执行的操作。
#pragma mark - UIPreviewActionItem
- (NSArray<id<UIPreviewActionItem>> *)previewActionItems {
UIPreviewAction *noReadAction = [UIPreviewAction actionWithTitle:@"标为未读" style:UIPreviewActionStyleDefault handler:^(UIPreviewAction * _Nonnull action, UIViewController * _Nonnull previewViewController) {
NSLog(@"标为未读");
[[NSNotificationCenter defaultCenter] postNotificationName:MessageNoReadNoti object:nil userInfo:@{@"index":self.indexPath}];
}];
UIPreviewAction *stickAction = [UIPreviewAction actionWithTitle:@"置顶" style:UIPreviewActionStyleDefault handler:^(UIPreviewAction * _Nonnull action, UIViewController * _Nonnull previewViewController) {
NSLog(@"置顶");
[[NSNotificationCenter defaultCenter] postNotificationName:MessageStickNoti object:nil userInfo:@{@"index":self.indexPath,@"isTop":@(self.isTop)}];
}];
UIPreviewAction *cancelStickAction = [UIPreviewAction actionWithTitle:@"取消置顶" style:UIPreviewActionStyleDefault handler:^(UIPreviewAction * _Nonnull action, UIViewController * _Nonnull previewViewController) {
NSLog(@"取消置顶");
[[NSNotificationCenter defaultCenter] postNotificationName:MessageStickNoti object:nil userInfo:@{@"index":self.indexPath,@"isTop":@(self.isTop)}];
}];
UIPreviewAction *deleteAction = [UIPreviewAction actionWithTitle:@"删除" style:UIPreviewActionStyleDestructive handler:^(UIPreviewAction * _Nonnull action, UIViewController * _Nonnull previewViewController) {
NSLog(@"删除");
[[NSNotificationCenter defaultCenter] postNotificationName:MessageDeleteNoti object:nil userInfo:@{@"index":self.indexPath}];
}];
if (self.isOfficeNotiAccount) {
return @[noReadAction, deleteAction];
}
return self.isTop ? @[noReadAction, cancelStickAction, deleteAction] : @[noReadAction, stickAction, deleteAction];
}
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