1.先上测试界面截图
image.png
懒得写布局的话，可以直接复制粘贴
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.zzb.greendaodemo.MainActivity">
<EditText
android:id="@+id/et_time"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="请输入保存时间"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="时间格式输入例如: 2017-10-18 19:30"/>
<EditText
android:id="@+id/et_description"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="请输入保存内容"
/>
<Button
android:id="@+id/btn_save"
android:layout_width="match_parent"
android:layout_height="60dp"
android:text="保存数据"/>
<EditText
android:id="@+id/et_query_time"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="请输入查询时间"
/>
<Button
android:id="@+id/btn_get"
android:text="获取当前时间数据"
android:layout_width="match_parent"
android:layout_height="60dp"/>
<Button
android:id="@+id/btn_get_all"
android:text="获取所有数据"
android:layout_width="match_parent"
android:layout_height="60dp"/>
<TextView
android:id="@+id/tv_show_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</LinearLayout>
2.实体类
一个实体类，对应一张表单
@Entity
public class WorkLogBean {
@Id(autoincrement = true)
@Unique
private Long id; //主键自增长，不可重复,作为不同记录对象的标识，传入参数对象时不要传入
//时间戳
@Property(nameInDb = "TIMELONG")
private Long timeLong;
//时间对应格式字符串
@Property(nameInDb = "TIMESTR")
private String timeStr;
//内容描述
@Property(nameInDb = "DESCRIPTION")
private String description;
}
然后点击Android Studio
image.png
小锤子，之后 bean类会变成这样
package com.zzb.greendaodemo.db;
import org.greenrobot.greendao.annotation.Entity;
import org.greenrobot.greendao.annotation.Id;
import org.greenrobot.greendao.annotation.Property;
import org.greenrobot.greendao.annotation.Unique;
import org.greenrobot.greendao.annotation.Generated;
/**
* Created by ZZB on 2017/6/28.
*/
@Entity
public class WorkLogBean {
@Id(autoincrement = true)
@Unique
private Long id; //主键自增长，不可重复,作为不同记录对象的标识，传入参数对象时不要传入
//时间戳
@Property(nameInDb = "TIMELONG")
private Long timeLong;
//时间对应格式字符串
@Property(nameInDb = "TIMESTR")
private String timeStr;
//内容描述
@Property(nameInDb = "DESCRIPTION")
private String description;
@Generated(hash = 5215746)
public WorkLogBean(Long id, Long timeLong, String timeStr, String description) {
this.id = id;
this.timeLong = timeLong;
this.timeStr = timeStr;
this.description = description;
}
@Generated(hash = 1301884914)
public WorkLogBean() {
}
public Long getId() {
return this.id;
}
public void setId(Long id) {
this.id = id;
}
public Long getTimeLong() {
return this.timeLong;
}
public void setTimeLong(Long timeLong) {
this.timeLong = timeLong;
}
public String getTimeStr() {
return this.timeStr;
}
public void setTimeStr(String timeStr) {
this.timeStr = timeStr;
}
public String getDescription() {
return this.description;
}
public void setDescription(String description) {
this.description = description;
}
@Override
public String toString() {
return "WorkLogBean{" +
"id=" + id +
", timeLong=" + timeLong +
", timeStr='" + timeStr + '\'' +
", description='" + description + '\'' +
'}';
}
}
以及会自动生成其余类
image.png
DaoMaster、DaoSession、WorkLogBeanDao都是自动生成的
现在开始假如我们的需求是这样的：
①点击按钮可以从数据库中获取到全部的内容
②全部内容都展示在listView上，然后点击条目的时候，删除这个条目
③一直需要判断现实中时间，数据库中是否保存了时间，保存了时间，就需要处理一些逻辑。。
根据上面的需求，接下来新建一个类DbUtils，开始封装我们的工具类：
image.png
package com.zzb.greendaodemo.db;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import com.zzb.greendaodemo.BaseApplication;
import org.greenrobot.greendao.query.DeleteQuery;
import org.greenrobot.greendao.query.QueryBuilder;
import java.util.List;
/**
* Created by ZZB on 2017/6/28.
*/
public class DbUtils {
private static DbUtils dbUtils;
/**数据库名称*/
private final static String dbName = "worklog.db";
private DaoMaster.DevOpenHelper openHelper;
private Context context;
private DbUtils() {
context = BaseApplication.mContext;
openHelper = new DaoMaster.DevOpenHelper(context, dbName, null);
}
/**
* 获取单例
*
* @return
*/
public static DbUtils getInstance() {
if (dbUtils == null) {
synchronized (DbUtils.class) {
if (dbUtils == null) {
dbUtils = new DbUtils();
}
}
}
return dbUtils;
}
/**
* 获取可读数据库
*/
private SQLiteDatabase getReadableDatabase() {
if (openHelper == null) {
openHelper = new DaoMaster.DevOpenHelper(context, dbName, null);
}
SQLiteDatabase db = openHelper.getReadableDatabase();
return db;
}
/**
* 获取可写数据库
*/
private SQLiteDatabase getWritableDatabase() {
if (openHelper == null) {
openHelper = new DaoMaster.DevOpenHelper(context, dbName, null);
}
SQLiteDatabase db = openHelper.getWritableDatabase();
return db;
}
/**
* 保存或替换
* @param bean
*/
public void saveData(WorkLogBean bean) {
DaoMaster daoMaster = new DaoMaster(getWritableDatabase());
DaoSession daoSession = daoMaster.newSession();
WorkLogBeanDao chatListDao = daoSession.getWorkLogBeanDao();
chatListDao.insertOrReplace(bean);
}
/**
* 通过时间查找所有列表，按时间倒序
*/
public List<WorkLogBean> queryAllData() {
try {
DaoMaster daoMaster = new DaoMaster(getReadableDatabase());
DaoSession daoSession = daoMaster.newSession();
WorkLogBeanDao chatListDao = daoSession.getWorkLogBeanDao();
QueryBuilder<WorkLogBean> qb = chatListDao.queryBuilder();
qb.orderDesc(WorkLogBeanDao.Properties.TimeLong);
List<WorkLogBean> chatLists = qb.list();
return chatLists;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 分页查询,每页10条数据,按时间降序
* @param page 查询的页数，从0开始
* @return
*/
public List<WorkLogBean> queryPageLists(int page) {
try {
DaoMaster daoMaster = new DaoMaster(getReadableDatabase());
DaoSession daoSession = daoMaster.newSession();
WorkLogBeanDao chatListDao = daoSession.getWorkLogBeanDao();
QueryBuilder<WorkLogBean> qb = chatListDao.queryBuilder();
qb.orderDesc(WorkLogBeanDao.Properties.TimeLong).offset(page * 10).limit(10);;
List<WorkLogBean> chatLists = qb.list();
return chatLists;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 获取此时间对应的对象
* @return
*/
public List<WorkLogBean> queryDataFromTime(String timeStr) {
try {
DaoMaster daoMaster = new DaoMaster(getReadableDatabase());
DaoSession daoSession = daoMaster.newSession();
WorkLogBeanDao chatListDao = daoSession.getWorkLogBeanDao();
QueryBuilder<WorkLogBean> qb = chatListDao.queryBuilder();
qb.where(WorkLogBeanDao.Properties.TimeStr.eq(timeStr));
List<WorkLogBean> chatLists = qb.list();
return chatLists;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 将此时间的数据删除
* @param timeStr
*/
public void deleteDataFromTime(String timeStr) {
try {
DaoMaster daoMaster = new DaoMaster(getReadableDatabase());
DaoSession daoSession = daoMaster.newSession();
WorkLogBeanDao chatListDao = daoSession.getWorkLogBeanDao();
QueryBuilder<WorkLogBean> qb = chatListDao.queryBuilder();
DeleteQuery<WorkLogBean> bd = qb.where(WorkLogBeanDao.Properties.TimeStr.eq(timeStr)).buildDelete();
bd.executeDeleteWithoutDetachingEntities();
} catch (Exception e) {
e.printStackTrace();
}
}
}
好了，下面可以直接使用了，在我们的MainActivity中：
package com.zzb.greendaodemo;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import com.zzb.greendaodemo.db.DbUtils;
import com.zzb.greendaodemo.db.WorkLogBean;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.OnClick;
public class MainActivity extends AppCompatActivity {
@BindView(R.id.et_time)
EditText etTime;
@BindView(R.id.et_description)
EditText etDescription;
@BindView(R.id.et_query_time)
EditText etQueryTime;
@BindView(R.id.tv_show_content)
TextView tvShowContent;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ButterKnife.bind(this);
}
@OnClick({R.id.btn_save, R.id.btn_get, R.id.btn_get_all})
public void onClick(View view) {
switch (view.getId()) {
case R.id.btn_save: //保存数据
String time = etTime.getText().toString().trim();
long timeLong = parseStrToLong(time);
String description = etDescription.getText().toString().trim();
WorkLogBean workLogBean = new WorkLogBean();
workLogBean.setTimeStr(time);
workLogBean.setTimeLong(timeLong);
workLogBean.setDescription(description);
DbUtils.getInstance().saveData(workLogBean);
break;
case R.id.btn_get: //查询指定时间数据
String quertTime = etQueryTime.getText().toString().toString();
List<WorkLogBean> datas = DbUtils.getInstance().queryDataFromTime(quertTime);
tvShowContent.setText(datas == null ? "查询数据为空" : datas.toString());
break;
case R.id.btn_get_all: //查询所有数据
List<WorkLogBean> list = DbUtils.getInstance().queryAllData();
tvShowContent.setText(list == null ? "查询数据为空" : list.toString() );
break;
}
}
/**
* @param timeStr
* @return
*/
private long parseStrToLong(String timeStr) {
try {
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm");
return simpleDateFormat.parse(timeStr).getTime();
} catch (ParseException e) {
e.printStackTrace();
}
return -1;
}
private String parseLongToStr(Long timeLong) {
try {
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm");
return simpleDateFormat.format(new Date(timeLong));
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
所有的操作已经完成了，我们可以直接运行看效果了：
点击保存数据之后，又点击获取当前时间后的效果
image.png
点击获取所有数据的效果：
image.png
如果想深入的学习、应用，可以看我的另一篇文章，在真实项目中的实际应用：
http://www.jianshu.com/p/b1b2d3333fca
并附上Demo下载链接：
https://github.com/xiaozhu1989/greenDaoDemo/
