GreenDao数据库

greendao 配置

主项目 classpath ‘org.greenrobot:greendao-gradle-plugin:3.2.1’
子项目 apply plugin: ‘org.greenrobot.greendao’

放在android下面

greendao {
schemaVersion 1//数据库版本号
daoPackage ‘com.example.moli2.db’//新建一个db包，把生成的三个包放在里面
targetGenDir ‘src/main/java’//设置DaoMaster、DaoSession、Dao目录
//targetGenDirTest：设置生成单元测试目录
//generateTests：设置自动生成单元测试用例
}

 implementation 'org.greenrobot:greendao:3.2.0'

配置完以后 新建一个数据库要添加的数据的bean类

@Entity
public class SQBean {

  @Id
  Long id;
  @Unique
  String  image;
  String  name;

}

用小锤子锤一下
在db包里生成DaoMaster、DaoSession、Dao

封装GreenDaoUtils一个工具类
package com.example.pxwzoukao415.utils;

import android.database.sqlite.SQLiteDatabase;

import com.example.pxwzoukao415.app.App;
import com.example.pxwzoukao415.db.DaoMaster;
import com.example.pxwzoukao415.db.DaoSession;

public class GreendaoUtils {

public static GreendaoUtils sgreendao;
private final DaoSession daoSession;

private GreendaoUtils(){
    //创建数据库，获取上下文
    DaoMaster.DevOpenHelper devOpenHelper = new DaoMaster.DevOpenHelper(App.context, "users.db");
    //读取数据
    SQLiteDatabase writableDatabase = devOpenHelper.getWritableDatabase();
    //将读取数据存入
    DaoMaster daoMaster = new DaoMaster(writableDatabase);
    daoSession = daoMaster.newSession();

}

public static GreendaoUtils getSgreendao() {
    if (sgreendao==null){
        synchronized (GreendaoUtils.class){
            if (sgreendao==null){
                 sgreendao=new GreendaoUtils();
            }
        }
    }
    return sgreendao;
}

public DaoSession getDaoSession() {
    return daoSession;
}

}

在App里初始化设置
GreendaoUtils.getSgreendao().getDaoSession();

在适配器加入设置的sqBean ,判断

public class ITemAdapter extends XRecyclerView.Adapter<ITemAdapter.IViewHolder> {

private Context context;
private List<ITemBeam.ResultBean> list;
private List<SQBean> sqBeans;

public ITemAdapter(Context context, List<SQBean> sqBeans) {
    this.context = context;
    this.list = new ArrayList<>();
    this.sqBeans = sqBeans;
}

public void setList(List<ITemBeam.ResultBean> list) {
    this.list = list;
    notifyDataSetChanged();
}

public void addList(List<ITemBeam.ResultBean> list) {
    list.addAll(list);
    notifyDataSetChanged();
}

@NonNull
@Override
public IViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
    View view=LayoutInflater.from(context).inflate(R.layout.layout_cyc2,viewGroup,false);
    IViewHolder iViewHolder = new IViewHolder(view);
    return iViewHolder;
}

@Override
public void onBindViewHolder(@NonNull IViewHolder iViewHolder, int i) {
    if (list!=null&&list.size()>0){
        Uri parse = Uri.parse(list.get(i).getLogo());
        iViewHolder.item_img.setImageURI(parse);
        iViewHolder.item_name.setText(list.get(i).getName());
    }else {
        Uri parse = Uri.parse(sqBeans.get(i).getImage());
        iViewHolder.item_img.setImageURI(parse);
        iViewHolder.item_name.setText(sqBeans.get(i).getName());
    }

}

@Override
public int getItemCount() {
    if (list!=null&&list.size()>0){
        return list.size();
    }else {
        return sqBeans.size();
    }
}

public class IViewHolder extends RecyclerView.ViewHolder {
     private SimpleDraweeView item_img;
     private TextView item_name;
    public IViewHolder(@NonNull View itemView) {
        super(itemView);
        item_img=itemView.findViewById(R.id.item_img);
        item_name=itemView.findViewById(R.id.item_name);
    }
}

}

在成功的方法里存入数据到数据库，遍历成功的bean里面的数据

    for (ITemBeam.ResultBean resultBean : iTemBeam.getResult()) {
        GreendaoUtils.getSgreendao().getDaoSession().insertOrReplace(new SQBean(null, resultBean.getLogo(), resultBean.getName()));
    }

新建一个判断网络的方法
//判断网络
public boolean isNetword() {
ConnectivityManager cm = (ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = cm.getActiveNetworkInfo();
return activeNetworkInfo != null && activeNetworkInfo.isAvailable();

}

当无网时取出的数据
if (!isNetword()) {
List sqBeans = GreendaoUtils.getSgreendao().getDaoSession().loadAll(SQBean.class);
iTemAdapter = new ITemAdapter(this,sqBeans);
xrecycler2.setAdapter(iTemAdapter);
}