CCNode的init()方法和onEnter()方法: 一、调用顺序 显示FirstScene时: FirstLayer::init FirstLayer::onEnter(init方法之后会调用此方法,如果使用了CCTransitionScene,将会在过渡效果开始以后调用此方法) FirstLayer::onEnterTransitionDidFinish(在使
CCNode的init()方法和onEnter()方法:一、调用顺序
显示FirstScene时:
FirstLayer::init
FirstLayer::onEnter(init方法之后会调用此方法,如果使用了CCTransitionScene,将会在过渡效果开始以后调用此方法)
FirstLayer::onEnterTransitionDidFinish(在使用了CCTransitionScene,会在过渡效果结束以后调用此方法)
由FirstScene切换到OtherScene时:
OtherLayer::init
FirstLayer::onExitTransitionDidFinish(在使用CCTransitionScene时,将会在过渡效果开始以后调用此方法)
FirstLayer::onExit(在dealloc方法之前会调用这个方法,如果调用了CCTransitionScene,将会在过渡效果结束以后调用此方法)FirstLayer::dealloc
OtherLayer::onEnter
OtherLayer::onEnterTransitionDidFinish
二、调用情况
1.调用的顺序先init(),后onEnter()。
2.init()在类的对象被创建使调用一次且仅此一次。
3.onEnter在该类被载入场景的时候被调用,可能会发生多次。
4.CCLayer* pLayer = new CExampleLayer();
这种情况下,只调用onEnter。
5.CCLayer* pLayer = CExampleLayer::create();
这样情况下,先调用init,再调用onEnter。
函数onEnterTransitionDidFinish和onExitTransitionDidStart是否被调用,取决于是否使用了场景切换特效CCTransitionScene。而onEnter和onExit则必然会在场景切换过程中的摸个时间点被调用。还要注意,在使用onEnter和onExit函数时,必须要调用父类中相同的方法避免丢失用户触碰信息以及内存泄露问题。

InnoDBBufferPool reduces disk I/O by caching data and indexing pages, improving database performance. Its working principle includes: 1. Data reading: Read data from BufferPool; 2. Data writing: After modifying the data, write to BufferPool and refresh it to disk regularly; 3. Cache management: Use the LRU algorithm to manage cache pages; 4. Reading mechanism: Load adjacent data pages in advance. By sizing the BufferPool and using multiple instances, database performance can be optimized.

Compared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.

MySQL is worth learning because it is a powerful open source database management system suitable for data storage, management and analysis. 1) MySQL is a relational database that uses SQL to operate data and is suitable for structured data management. 2) The SQL language is the key to interacting with MySQL and supports CRUD operations. 3) The working principle of MySQL includes client/server architecture, storage engine and query optimizer. 4) Basic usage includes creating databases and tables, and advanced usage involves joining tables using JOIN. 5) Common errors include syntax errors and permission issues, and debugging skills include checking syntax and using EXPLAIN commands. 6) Performance optimization involves the use of indexes, optimization of SQL statements and regular maintenance of databases.

MySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.

MySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.

MySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.

SQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.

The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA


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