数据库的选择
之前在项目中使用的是Xutils里面封装的数据库模块，操作起来也是简便好用，但是由于xutils的注解采用的是反射机制，在性能上不是很友好，于是拿来GreenDao试着玩玩。
GreenDao git首页可以看到一句介绍
greenDAO is a light & fast ORM solution for Android that maps objects to SQLite databases.
妥，本篇不讲GreenDao的实现原理，说明一下配置过程以及遇到的坑。
gradle配置
外层需要全局引入GreenDao的插件
buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'org.greenrobot:greendao-gradle-plugin:3.2.2'
}
}
然后在内部的gradle apply以及依赖相关的包
apply plugin: 'com.android.application'
//applygreendao插件
apply plugin: 'org.greenrobot.greendao'
compile 'org.greenrobot:greendao:3.2.2'
compile 'net.zetetic:android-database-sqlcipher:3.5.1@aar'
上面compile 'net.zetetic:android-database-sqlcipher:3.5.1@aar'的导入也是在配置过程中遇到的坑后面会解释一下为什么加这一句。
greenDao配置及使用
首先在Application中初始化
public class MyApplication extends Application {
public static MyApplication INSTANCE;
public static final boolean ENCRYPTED = true;
private DaoSession mDaoSession;
@Override
public void onCreate() {
super.onCreate();
INSTANCE = this;
DaoMaster.DevOpenHelper help = new DaoMaster.DevOpenHelper(this, ENCRYPTED ? "bear-db-encrypted" : "bear-db");
//此处有坑
Database db = ENCRYPTED ? help.getEncryptedWritableDb("admin") : help.getWritableDb();
mDaoSession = new DaoMaster(db).newSession();
}
public DaoSession getDaoSession() {
return mDaoSession;
}
}
下面建立一个数据表来试试，那先来个User表来试玩一下。新建UserBean class
@Entity(indexes = {
//index 值是拿表中的account作为索引，且索引是唯一不可重复的
@Index(value = "account",unique = true)
})
public class UserBean {
//声明一个主键值
@Id
public long id;
public String account;
public String passWord;
public String mobile;
public String email;
}
建立完之后点一下Android Studio运行左边的小锤子make project后就会预编译出一个比较长的类了。
@Entity(indexes = {
@Index(value = "account",unique = true)
})
public class UserBean {
@Id
public long id;
public String account;
public String passWord;
public String mobile;
public String email;
@Generated(hash = 1328729131)
public UserBean(long id, String account, String passWord, String mobile,
String email) {
this.id = id;
this.account = account;
this.passWord = passWord;
this.mobile = mobile;
this.email = email;
}
@Generated(hash = 1203313951)
public UserBean() {
}
public long getId() {
return this.id;
}
public void setId(long id) {
this.id = id;
}
public String getAccount() {
return this.account;
}
public void setAccount(String account) {
this.account = account;
}
public String getPassWord() {
return this.passWord;
}
public void setPassWord(String passWord) {
this.passWord = passWord;
}
public String getMobile() {
return this.mobile;
}
public void setMobile(String mobile) {
this.mobile = mobile;
}
public String getEmail() {
return this.email;
}
public void setEmail(String email) {
this.email = email;
}
}
Ok，表已经建立完毕，现在试着插条数据进去玩玩
UserBean userBean = new UserBean();
userBean.setId((long)1);
userBean.setAccount("123456789");
userBean.setPassWord("111111qq");
userBean.setEmail("xxx@xx.com");
userBean.setMobile("123456789");
UserBeanDao dao = MyApplication.INSTANCE.getDaoSession().getUserBeanDao();
开始运行后，Crash 没错就是crash，wocao，明明是按照官网的配置一个个来的嘛。折腾几次终于发现少依赖了一个包，就是前面讲的使用加密的数据库需要导入compile 'net.zetetic:android-database-sqlcipher:3.5.1@aar'。总算是走通了。
greenDao的详细使用以及介绍
可以看其他大神的博客：http://www.jianshu.com/p/e6c52fb7103d
