QString与QByteArray的区别 [复制链接]

引用第2楼asdfgsdgasd于2010-05-30 18:53发表的 回 1楼(dbzhang800) 的帖子 :
怎么又是你 ！！！ 我问他们的功能都差不多  有什么区别

Detailed Description

The QByteArray class provides an array of bytes.

QByteArray can be used to store both raw bytes (including '\0's) and traditional 8-bit '\0'-terminated strings. Using QByteArray is much more convenient than using const char *. Behind the scenes, it always ensures that the data is followed by a '\0' terminator, and uses implicit sharing (copy-on-write) to reduce memory usage and avoid needless copying of data.

In addition to QByteArray, Qt also provides the QString class to store string data. For most purposes, QString is the class you want to use. It stores 16-bit Unicode characters, making it easy to store non-ASCII/non-Latin-1 characters in your application. Furthermore, QString is used throughout in the Qt API. The two main cases where QByteArray is appropriate are when you need to store raw binary data, and when memory conservation is critical (e.g., with Qt for Embedded Linux).

...

Detailed Description

The QString class provides a Unicode character string.

QString stores a string of 16-bit QChars, where each QChar corresponds one Unicode 4.0 character. (Unicode characters with code values above 65535 are stored using surrogate pairs, i.e., two consecutive QChars.)

Unicode is an international standard that supports most of the writing systems in use today. It is a superset of US-ASCII (ANSI X3.4-1986) and Latin-1 (ISO 8859-1), and all the US-ASCII/Latin-1 characters are available at the same code positions.

Behind the scenes, QString uses implicit sharing (copy-on-write) to reduce memory usage and to avoid the needless copying of data. This also helps reduce the inherent overhead of storing 16-bit characters instead of 8-bit characters.

In addition to QString, Qt also provides the QByteArray class to store raw bytes and traditional 8-bit '\0'-terminated strings. For most purposes, QString is the class you want to use. It is used throughout the Qt API, and the Unicode support ensures that your applications will be easy to translate if you want to expand your application's market at some point. The two main cases where QByteArray is appropriate are when you need to store raw binary data, and when memory conservation is critical (e.g., with Qt for Embedded Linux).