如果你在添加GreenDao依赖的过程中出现了如下错误：
那么可以参考一下如下网址：
https://blog.csdn.net/u013472738/article/details/72895747
我并没有配置Project下的build.gradle，而是只配置了app下的build.gradle，代码如下所示：
apply plugin: 'com.android.application'
apply plugin: 'org.greenrobot.greendao'
android {
compileSdkVersion 27
buildToolsVersion "27.0.1"
defaultConfig {
applicationId "com.example.liang.renyibo"
minSdkVersion 16
targetSdkVersion 27
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
testCompile 'junit:junit:4.12'
compile 'org.greenrobot:greendao:3.2.2'
}
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath 'org.greenrobot:greendao-gradle-plugin:3.2.1'//注意这个greendao的插件得比greendao库的版本号小1才行了，我试了3.2.2版本的插件但是还是报错，3.2.1版本的插件不报错。
}
}
示例代码如下：
在MyApplication文件中
public class MyApplication extends Application {
private static DaoSession daoSession;
@Override
public void onCreate() {
DaoMaster.DevOpenHelper devOpenHelper=new DaoMaster.DevOpenHelper(this,"mydatabase");
SQLiteDatabase sqLiteDatabase=devOpenHelper.getWritableDatabase();
DaoMaster daoMaster=new DaoMaster(sqLiteDatabase);
daoSession=daoMaster.newSession();
}
public static DaoSession getDaoSession() {
return daoSession;
}
}
在MainActivity文件中
...
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.save:
Student student=new Student(2L,"laowang",24,"清徐");
getDaoSession().insert(student);
break;
case R.id.select:
List<Student>list=MyApplication.getDaoSession().loadAll(Student.class);
for(Student student1:list){
Toast.makeText(this, student1.getName()+student1.getDiZhi(), Toast.LENGTH_SHORT).show();
}
break;
case R.id.update:
Student student1=new Student(2L,"laofu",24,"孝义");
MyApplication.getDaoSession().update(student1);
break;
case R.id.delete:
Student student2=new Student(2L,"laofu",24,"孝义");
MyApplication.getDaoSession().delete(student2);//删除数据的时候是根据主键的值进行删除的，与其他值没有关系。
break;
default:
break;
}
...
在Student文件中
@Entity//标记该实体类为greendao的一个表
public class Student {
@Id(autoincrement = true)//该字段为主键
private Long id;
@Unique//该字段的值不能重复
private String name;
@NotNull//该字段不能为空
private int age;
@Property(nameInDb = "address")//给该字段在表中起了一个列名
private String diZhi;
//**********************只需要给实体类设置好字段后，然后make project，即可生成以下代码***************************
@Generated(hash = 814485105)
public Student(Long id, String name, int age, String diZhi) {
this.id = id;
this.name = name;
this.age = age;
this.diZhi = diZhi;
}
@Generated(hash = 1556870573)
public Student() {
}
public Long getId() {
return this.id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return this.age;
}
public void setAge(int age) {
this.age = age;
}
public String getDiZhi() {
return this.diZhi;
}
public void setDiZhi(String diZhi) {
this.diZhi = diZhi;
}
}
在写好实体类的字段后，然后build project，就会生成如下图所示的文件：
参考文章：
https://blog.csdn.net/qq_30379689/article/details/54410838
官方的github地址如下：
https://github.com/greenrobot/greenDAO
另外，这个人的博客写的文章都很好，可以看一看，网址如下：https://blog.csdn.net/qq_30379689/article/list/5
