category chooser

The difference between protocol, category and inheritance in OCusing inheritance, polymorphism is a good keep "open to extensions, closed to changes" (OCP) is also the most common approach. Objective C also supports two additional syntaxes to support Ocp:protocol and category. Protocol can only define a set of interfaces, but not the implementation, in disguise is also an abstract class implementation (OC s

#定义函数, open each file, find a blank line, and return the text after the empty line as a string vector with only one element, which is the string after all the text after the empty line is stitched#很多邮件都包含了非ASCII字符, so you can read non-ASCII characters by setting it to Latin1#readLines, read each line as an elementGet.msg {Con Text # The message always begins after the firstMSG Close (Con)Return (Paste (msg, collapse = "\ n"))}#dir读取目录下所有文件Spam.docs#去掉目录下的cmds文件Spam.docs#利用get. msg function to re

This article describes the JS implementation of the four-level left site category menu. Share to everyone for your reference. The implementation methods are as follows: ? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26-27--28 29---30 31--32 33 34 35 36 37 38-39 40 41 42 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 5, 86 87 88 89 90 91 92 93 94 95

Scenery Class Yellow is used as a demonstration color, and green has the same effect. 1, green color combination. This color combination can be used to adjust scenery photos, especially for trees, grasslands and so on have very obvious effect. Its shape is somewhat similar to a less than a symbol. The original image is this: We use this color combination: 2, Yellow color combination This color combination is suitable to enhance the screen of yellow, cr

The Electric Sea newspaper of Photoshop Design cosmetics category Effect chart 1. First, create a new 950x450 pixel, 72 resolution specification document and fill the background with black. 2. Import a material map as a background, which is generally a smart object after the default import (if it is not a right key to the layer and then converted to a smart object). Select Gaussian blur, adjust the parameter radius of 1.3 or

Slide classification, using the drag method.Problems encountered:The sliding code snippet succeeds, but no swipe is performed on the actual phone. Drag other places can take effect, such as the page's tab swipe.The way to try:1. Use the Uirecorder recording tool to try sliding the label, prompting the operation to succeed, but not performing a swipe operation.2, the position is not written to, with App-inspector check the location, in the code after the command line has also checked the correspo

"); $ (". Nav_detailbox"). Stop (). Hide (); }) As you can see from the general layout given before, nav_list_s are the boxes Nav_detailbox is the mouse over the left side of the nav_list_s to show the big box, Nav_detail is the contents of this big box. The above is a small series to introduce the jquery to imitate Jingdong/cat merchandise left category navigation menu effect, hope to help everyone, if you have any questions please give me a

This example for you to share the Java Online Book Mall category module code for your reference, the specific contents are as follows Sql CREATE TABLE ' t_category ' ( ' CID ' char (m) not NULL, ' CNAME ' varchar ' default NULL, ' pid ' char (#) Default NULL, ' desc ' varchar DEFAULT null, ' by ' int (one) not null auto_increment, PRIMARY KEY (' CID '), UNIQUE KEY ' cname ' (' cname '), Key ' Fk_t_category_t_category ' (' pid '), key

logCompared to the classification, tag is more specific, such as we say "tourist scenery" classification, if you really want to divide up, it may be moreSuch as:Tourist scenery--(domestic/overseas)-(province/Municipality)-(county/district), etc.If divided by this level, it will cause a lot of classification waste, because some counties/districts may not have the relevant articlesBut in fact we will generally be divided into two categories, domestic tourism/overseas travelThen add a specific lab

=" +document.form_query.classid.value; ClassID = ""; Theactionscript the suppressed field, generated when the Listrecords () function is invoked Form.action = Form.theActionScript.value + "_delete.asp" +CLASSID; Form.submit (); } } var Openwin_add; var init = " triggered when you click the Add button function Add (PN) { ClassID in the For_query form in Query.inc Auto Select current category ClassID = "classid=" +document.form_query.classid.value; Cla

Label:Report the following error Workaround: Method One: (results do not work) Through shell command, Hadoop/bin/hdfs haadmin-failover--forceactive hadoop2 HADOOP1 (Note that this method was originally forced to switch namenode in manual recovery) Returns results, unsupported, and sincere hints that this command will only work in the case of a manual failover Method Two: (works) I used JPS check the status of the zookeeper cluster, found that no indication of the failure of two, the original is

EMPLOYEE c on b.owner_emp = c.employee_idLeft Join A_c on c.employee_code = A_c.ghLeft join customer_address D on b.customer_business_id = d.customer_business_idLeft join Customer_contact e on b.customer_business_id = e.customer_business_idwhere a.approvestatus = ' Y 'Insert into A_c (GH) Select Employee_code from EMPLOYEESELECT * FROM A_cSelect from a_cust where ADDRESS was not nullSelect from CUSTOMER where customer_code = ' 0080 'Select *from customer_sales where customer_id = ' f16dd932-015

Create a Custom Function:1 DELIMITER $$2 3 Use ' dressv_website ' $$4 5 DROP FUNCTION IF EXISTS ' fn_queryrelation ' $$6 7CREATE definer= ' sa ' @ '% ' FUNCTION ' fn_queryrelation ' (Areaid int,relation TINYINT (1)) RETURNS VARCHAR (4000) CHARSET UTF88 BEGIN9DECLARE stemp VARCHAR (4000);TenDECLARE Stempchd VARCHAR (4000); OneSET stemp ='$'; ASET Stempchd =CAST (Areaid as CHAR); -IF relation=0 Then - While stempchd are not NULL does theSET stemp = CONCAT (Stemp,',', stempchd); -SELECT Group_conca

, (SelectNameMax(Val) Val fromTbGroup byName) bwhereA.name=B.name andA.val=B.valOrder byA.name + --Method 4: - SelectA.* fromTB AInner Join(SelectName,Max(Val) Val fromTbGroup byName) b onA.name=B.name andA.val=B.valOrder byA.name the --Method 5 * SelectA.* fromTB Awhere 1 >(Select Count(*) fromTbwhereName=A.name andVal>A.val)Order byA.name $ /*Panax Notoginseng name Val Memo - ---------- ----------- -------------------- the the third value of a 3 a3:a + B 5 B5b5b5b5b5 A */ the + 　　

WordPress obtains the number of articles under a specified category and its subcategories, and the number of wordpress articles. WordPress obtains the number of articles under a specified category and its subcategories. wordpress obtains the number of articles under a specific category. sometimes we want to obtain the number of articles under a certain

In everyday development, you may encounter the need to add methods to a class. For example, you need to add a printing method to the NSString class. Of course, we can create a new class such as TestString and inherit the NSString class to implement the DisplayString method in the new class teststring. However, there is one obvious flaw in this approach: only the TestString class has the method, and other subclasses of the NSString class, such as nsmutablestring, cannot use the method. Is it poss

Objective-C -- Category Encapsulation is a feature of object-oriented, and OC is no exception, but sometimes we will encounter such a situation. For example, I encapsulate a class and don't want to change it any more, however, as the program functions increase, we need to add a small method to that class. In this case, we do not have to modify or define a subclass in that class, you only need to add a category