rdd meaning

The true meaning of android:layout_weight is that once the view has this property set (assuming it is valid), the view width is equal to the original width (android:layout_width) plus the amount of space remaining! Meaning: original width + remaining space ratioSet the screen width to L, the width of the two view is Match_parent, the original width is L, two of the view width is L, then the remaining width

Python core style: Avoid using underscores as the start of variable names.Because underscores have special meanings for the interpreter and are symbols used by built-in identifiers, we recommend that programmers avoid using underscores as the starting point for variable names. In general, variable name _xxx is considered " private "and cannot be used outside of a module or class. When a variable is private, it is good practice to use _xxx to represent variables. Because the variable name __xxx_

ANSI and Unicode encoding, TCHAR | LPSTR | LPCSTR | LPWSTR | LPCWSTR | LPTSTR | meaning of LPCTSTR, lpcstrlpwstr One character can be expressed in 1-byte, that is, ANSI encoding; A character can also be expressed in 2-bytes, that is, Unicode encoding (Unicode actually contains more content than 2-bytes ). Visual C ++ supports char and wchar_t as the original data types of ANSI and Unicode. For example char cResponse; // 'Y' or 'N'char sUsername[64];//

content to clipboardPHP Code:if ($a) {Include ("a.php");}and require () is different from include (), no matter what the value of $ A, the following code will include the file a.php into the file:Copy PHP content to clipboardPHP Code:if ($a) {Require ("a.php");}In the case of error handling, the include statement is used, and if an error occurs, the program skips the include statement, although an error message is displayed but the program continues! But Requre will give you a fatal error.Of co

Click to enter _ more _java thousand ask1, what is the meaning of 2 in the Java EE?The meaning of 2 in J2se,j2se,j2me is to be traced back to 1998 years.1998 Java 1.2 release, 1999 released the Java 1.2 Standard Edition, Enterprise Edition, mini version of the three versions, in order to differentiate these three versions, respectively, called Java2se,java2ee,java2me, referred to as J2SE,J2EE,J2ME. Therefor

/** 2, please explain the meaning of the characters ' \ ' in Java, what is the role?*Answer* In Java the backslash ' \ ' represents the meaning of the escape character, which is a marker** When the compiler reads this tag, it knows that the next character is not an ordinary character, but a translated character.* It will operate based on the meaning of the escape

PYTHON Specifies special variables/methods using underscores as variable prefixes and suffixes.There are four main cases1.1. Object # Public2. __object__ # Special, Python system use, user should not define like it3. __object # Private (name mangling during runtime)4. _object # Obey Coding Convention, consider it as privateCore style: Avoid using underscores as the start of variable names .Because underscores have special meanings for the interpreter and are symbols used by the built-in, we reco

;! function () {} (); ;! What's the use?Go from grammar to open. The semicolon in JavaScript indicates the end of the statement, plus at the beginning. It may be for compression and other methods to cut, indicating a new statement starts. So, let's say it's in a separate JS file. The beginning of the semicolon is no matter what the meaning, can be deleted.An exclamation point is a logical operator, which is "non", and is commonly written if (!true) {}

The meaning of the square operation of the adjacency matrix of a direction graph This is an assignment in the first chapter of graph theory algorithm application. Now, the linear algebra is too bad. Hey First code: #include The title requires the matrix to be written after the square of the adjacency matrix of the direction graph, then say the meaning of it, write code nearly one hours, want to

One, what is a single case mode? 1, meaningAs an object's creation pattern, the singleton pattern ensures that a class has only one instance, and instantiates it and provides it globally to the entire system. Instead of creating an instance copy, it returns a reference to an instance stored within a singleton class.2, the single example mode of the three points:(1). A static member variable is required to hold a unique instance of the class:private static $_instance;(2). Constructors and cloning

1 Preface In many foreign computer books and some of the third open source software demo often use two English words foo,bar. What the hell does that mean? From the IT life of the cock Silk circle simple These two words to now I still do not know the true meaning of these two words, today it is necessary to check the summary. 2 explanation on Wikipedia Original: The terms foobar, Foo, bar, Baz and Qux are sometimes, used as placeholder names (also

Security switches are worth learning a lot. Here we mainly introduce the three-layer meaning of Security switches. as the core of the entire network, users who access and access network information should be able to differentiate and control permissions. More importantly,Security SwitchIt should also work with other network security devices to monitor and block unauthorized access and network attacks. Security switches play an important role in the en

understanding the meaning of this statement, we also know the difference between MyObject and _myobject, then, in the use of the time, there is nothing to pay attention to the place, we should also be clear. Yes,MyObject is a property, and _ MyObject is the variable, and the variables we finally manipulate are myObject. So, the same is the access operation, the statementC code Self.namevarptr = [[ObjectName alloc] init] C code

providing specific values. For example:Android:textcolor= "? Android:textdisabledcolor"Note that this is very similar to resource references, except that we use a "?" Prefix instead of "@". When you use this tag, you provide the name of the property resource, which will be looked up in the subject, so you do not need to display the declaration of that type (if the declaration is in the form of Android:attr/android:textdisabledcolor). In addition to using the identifier of this resource to query

1. What is a digital signature? A digital signature is a sign of your program as your own, and when someone sees the signature, they know it's relevant to you .2. Why digital signatures? The simplest and most straightforward answer: system requirements. Android requires every Android app to be digitally signed to install into the system, meaning that if an Android app is not digitally signed, there is no way to install it! Android uses digital signatu

providing specific values. For example:Android:textcolor= "? Android:textdisabledcolor"Note that this is very similar to resource references, except that we use a "?" Prefix instead of "@". When you use this tag, you provide the name of the property resource, which will be looked up in the subject, so you do not need to display the declaration of that type (if the declaration is in the form of Android:attr/android:textdisabledcolor). In addition to using the identifier of this resource to query

Context literal meaning contexts, located in the framework Package Android.content.Context, in fact, the class is a long type, similar to the handle handle in Win32, many methods need to pass the context to identify the caller's instance.The first argument to toast, for example, is the context. Generally in the activity we use this instead, on behalf of the caller's instance for activity, and to a button of the onclick (view view) and other methods, w

http://blog.csdn.net/cnsword/article/details/8034947Companies can use C++11. See Daniel's code imitation use, so now do not know what the use of C + + syntax or c++11 syntax ... I don't know if it's kind of sad.C++11 has revised the keywords, added nullptr, constexpr, Decltype, default, Static_assert , and the original keywords (auto,using,extern ) meaning and purpose have been revised. Here's a look at the changes to auto, using, extern, three keywor

1. Preface.In declarative transactions, you configure a slice, which is a set of methods, such asJava code "Txadvice" transaction-manager="Txmanager" > "find*" read-only="true" propagation=" not_supported"/> The use of propagation, indicating how to use these methods of transactions, is used or not, of which propagation has seven configurations, REQUIRED, SUPPORTS, MANDATORY, Requires_new, Not_ Supported, never, NESTED. The default is required.2. The

Value Meaning REQUIRED Supports the current transaction, and creates a new transaction if there is no current transaction. SUPPORTS Supports the current transaction and is executed in a non-transactional manner if no transaction is currently in use. MANDATORY Supports the current transaction and throws an exception if there is no current transaction. Requires_new Crea