3D Touch 的第二個功能：預覽和彈出視圖
1、創建一個viewcontroller作爲window的rootviewcontroller（xcode7 這個需要設置，否則會崩潰）
2、創建一個預覽視圖控制器peekViewController，展示peek的內容,同時實現
3、viewcontroller控制器簽署協議
UIViewControllerPreviewingDelegate(該協議是iOS9新特性)
4、在viewdidload裏面檢測是否支持3D Touch，設置代理
//必須進行是否支持3D Touch，3D Touch可以被關閉，還有一些ios設備不支持
if (self.traitCollection.forceTouchCapability == UIForceTouchCapabilityAvailable) {
[self registerForPreviewingWithDelegate:self sourceView:self.view];
}
5、在viewcontroller裏實現協議方法
//peek
- (nullable UIViewController *)previewingContext:(id <UIViewControllerPreviewing>)previewingContext viewControllerForLocation:(CGPoint)location NS_AVAILABLE_IOS(9_0)
{
PeekViewController *vc = [[PeekViewController alloc]init];
//設置預覽視圖的大小
vc.preferredContentSize = CGSizeMake(0, 330);
//設置點擊位置出現的白色塊的大小
previewingContext.sourceRect = CGRectMake(20, location.y - 10, [UIScreen mainScreen].bounds.size.width - 40, 50);
return vc;
}
//pop 方法
- (void)previewingContext:(id <UIViewControllerPreviewing>)previewingContext commitViewController:(UIViewController *)viewControllerToCommit NS_AVAILABLE_IOS(9_0)
{
//可以進行視圖跳轉等操作
[self.Navgationviewcontroller pushViewController:viewControllerToCommit animated:NO completion:nil];
}
6、在peekviewcontroller裏面實現
-(NSArray<id<UIPreviewActionItem>> *)previewActionItems方法
-(NSArray<id<UIPreviewActionItem>> *)previewActionItems
{
NSMutableArray *actionItemArray = [NSMutableArray array];
UIPreviewAction *action1 = [UIPreviewAction actionWithTitle:@"自定義1" style:UIPreviewActionStyleSelected handler:^(UIPreviewAction * _Nonnull action, UIViewController * _Nonnull previewViewController) {
//實現自己的邏輯處理
}];
UIPreviewAction *action2 = [UIPreviewAction actionWithTitle:@"自定義2" style:UIPreviewActionStyleSelected handler:^(UIPreviewAction * _Nonnull action, UIViewController * _Nonnull previewViewController) {
}];
[actionItemArray addObject:action1];
[actionItemArray addObject:action2];
return actionItemArray;
}