hierarchy | 易学教程

Swift: “Attempt to present UIAlertController whose view is not in the window hierarchy!”

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问题 I'm trying to display a UIAlertController when a button is clicked (button click runs certain code, and depending on said outcome - the Alert shows up). The initial ViewController is the default one, and I've created a second one (ConsoleViewController). The user logs in, and upon successful log in, segues to the next view (ConsoleViewController), which displays data (which is in the viewDidLoad() section of the ConsoleViewController). Once the user clicks "Check In", the app captures the GPS

UIViewController摘要

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1、self.view在首次使用时，会用loadView初始化，并触发viewdidload完成以后，继续self.view操作 IOS6.0中，弃用viewDidUnload和viewWillUnload…从而只能使用 didReceiveMemoryWarning ，在以前的ios中，didReceiveMemoryWarning会触发viewDidUnload等，但是现在起，只能自己在内存警告中处理，甚至自己释放self.view。。如果确实释放了sefl.view=nil。则在加载时会重新触发viewDidload 2、手工向tabviewcontroller、navigationcontroller发送viewWillAppear等系列消息，均会导致其向它的栈顶viewcontroller发同名消息。作为container使用的viewcontroller则无此特性, 但是在5.0以后由于(addsubview的作用)系统发的viewWillAppear会向container及其所有childController发送 3、tableViewController的初始化过程：viewWillAppear -> tableViewDatasource method -> viewDidAppear 因为更新数据源最好在 viewWillAppear中进行

MySQL hierarchical storage: searching through all parent/grandparent/etc. nodes given a child node id?

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问题 I'm storing categories using a hierarchical model like so: CATEGORIES id | parent_id | name --------------------- 1 | 0 | Cars 2 | 0 | Planes 3 | 1 | Hatchbacks 4 | 1 | Convertibles 5 | 2 | Jets 6 | 3 | Peugeot 7 | 3 | BMW 8 | 6 | 206 9 | 6 | 306 I then store actual data with one of these category ids like so: CARS vehicle_id | category_id | name ------------------------------- 1 | 8 | Really fast silver Peugeot 206 2 | 9 | Really fast silver Peugeot 306 3 | 5 | Really fast Boeing 747 4 | 3 |

Many-to-Many Hierarchy with Multiple Parents - PHP, MySQL

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问题 I'm trying to create a list of technology books by category, where each book can belong to more than one category, and each category can be both a parent category and a sub-category. Here's an illustration: JavaScript JavaScript Patterns Object-Oriented JavaScript Ajax Ajax Definitive Guide Bulletproof Ajax jQuery Learning jQuery 1.3 PHP jQuery Cookbook PHP PHP in a Nutshell PHP jQuery Cookbook Ajax Ajax Definitive Guide Bulletproof Ajax XML XML Hacks No-Nonsense XML -- As you can see... The

Oracle: Connect By Loop in user data

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问题 I understand when a loop can occur in Oracle. Theoritically it says if a record is both parent to another node and at the same time it is child to it, then it can enter into a loop. But I can't catch why my this particular query is running into a loop. SELECT Empno, Ename, Job FROM Emp START WITH Empno = 7839 CONNECT BY PRIOR Job='PRESIDENT' Can someone please explain me how this data can result into a loop. I made a CONNECT_BY_ISCYCLE check and found that the record looping is KING(President

Setting property value on child instance to a fixed value with Autofixture

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问题 Is it possible to assign a fixed value to a property on a child instance when building a parent with Autofixture? It will add default values to all the properties on the child instance like a charm, but I would like to override and assign a specific value to one of the properties on the child instance. Given this parent/child relationship: public class Person { public string FirstName { get; set; } public string LastName { get; set; } public Address Address { get; set; } } public class

Hierarchy viewer not working with HTC Sensation

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I have htc desire and hierarchy viewer works fine. But when I plug the sensation than nothing happens I have refresh button but afrer clicking on it nothing happens :( where is the problem ? Hierarchy View normally does not support hardware, only the emulator. For API Level 12 devices and higher, you can try embedding ViewServer into your app, though I have not yet tried this. It is also possible that you might have better results with a rooted device, though I have not tried that either. 来源： https://stackoverflow.com/questions/7319664/hierarchy-viewer-not-working-with-htc-sensation

SQL: How to select all parent nodes in Materialized path?

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问题 The MySQL databse stores tree with the help of materialized path data structure. How to select all parents of the given node? I use dot '.' as path separator, and database structure includes 'level' field that indicates the depth of a node in the tree. Lets I have those tree and need all parents of the node 'a.b.d.e': id | path a | a b | a.b c | a.b.c d | a.b.d e | a.b.d.e f | a.f The script should return: a a.b a.b.d a.d.d.e (optional) How to do that in MySQL? 回答1: I've found the solution in

Build hierarchical html tags in PHP from flat data

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问题 How do you build a hierarchical set of tags with data in PHP? For example, a nested list: <div> <ul> <li>foo </li> <li>bar <ul> <li>sub-bar </li> </ul> </li> </ul> </div> This would be build from flat data like this: nested_array = array(); nested_array[0] = array('name' => 'foo', 'depth' => 0) nested_array[1] = array('name' => 'bar', 'depth' => 0) nested_array[2] = array('name' => 'sub-bar', 'depth' => 1) It would be nice if it were nicely formatted like the example, too. 回答1: Edit: Added

Parent/Child hierarchy tree view

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