GreenDao的简单使用说明(二)单表的增,删,改,查
通过上一篇文章,我们已经把GreenDao框架架起来了,而且三个基础操作类和Users的用户类也建立起来了,哪么下面我们就来实现一下,对于这个单表的增,删,改,查功能.
这里说明一下,因为是做一个简单的例子,所以这里我对数据库的操作,没有做异步处理.
第一步,我们要先来写一个类BaseApplication.java,此类是用来取得GreenDao中的DaoMaster和DaoSession的,先看代码.
package com.example.cg.greendaolearn.db;
import android.app.Application;
import android.content.Context;
import com.example.cg.greendaolearn.THDevOpenHelper;
import com.guangda.dao.DaoMaster;
import com.guangda.dao.DaoSession;
/**
* 官方推荐将取得DaoMaster对象的方法放到Application层这样避免多次创建生成Session对象。
* Created by cg on 2015/12/29.
*/
public class BaseApplication extends Application {
private static BaseApplication mInstance;
private static DaoMaster daoMaster;
private static DaoSession daoSession;
@Override
public void onCreate() {
super.onCreate();
if(mInstance == null)
mInstance = this;
}
/**
* 取得DaoMaster
*
* @param context 上下文
* @return DaoMaster
*/
public static DaoMaster getDaoMaster(Context context) {
if (daoMaster == null) {
DaoMaster.OpenHelper helper = new THDevOpenHelper(context,"myDb",null);
daoMaster = new DaoMaster(helper.getWritableDatabase());
}
return daoMaster;
}
/**
* 取得DaoSession
*
* @param context 上下文
* @return DaoSession
*/
public static DaoSession getDaoSession(Context context) {
if (daoSession == null) {
if (daoMaster == null) {
daoMaster = getDaoMaster(context);
}
daoSession = daoMaster.newSession();
}
return daoSession;
}
}
第二步,建立一个操作类,把增,删,改,查的方法,全写进去.方便调用.代码如下
DbService.java
package com.example.cg.greendaolearn.db;
import android.content.Context;
import android.text.TextUtils;
import android.util.Log;
import com.guangda.dao.DaoSession;
import com.guangda.dao.UsersDao;
import java.util.List;
import greendao.Users;
/**
* 用户操作类
* Created by cg on 2015/12/29.
*/
public class DbService {
private static final String TAG = DbService.class.getSimpleName();
private static DbService instance;
private static Context appContext;
private DaoSession mDaoSession;
private UsersDao userDao;
private DbService() {
}
/**
* 采用单例模式
* @param context 上下文
* @return dbservice
*/
public static DbService getInstance(Context context) {
if (instance == null) {
instance = new DbService();
if (appContext == null){
appContext = context.getApplicationContext();
}
instance.mDaoSession = BaseApplication.getDaoSession(context);
instance.userDao = instance.mDaoSession.getUsersDao();
}
return instance;
}
/**
* 根据用户id,取出用户信息
* @param id 用户id
* @return 用户信息
*/
public Users loadNote(long id) {
if(!TextUtils.isEmpty(id + "")) {
return userDao.load(id);
}
return null;
}
/**
* 取出所有数据
* @return 所有数据信息
*/
public List loadAllNote(){
return userDao.loadAll();
}
/**
* 生成按id倒排序的列表
* @return 倒排数据
*/
public List loadAllNoteByOrder()
{
return userDao.queryBuilder().orderDesc(UsersDao.Properties.Id).list();
}
/**
* 根据查询条件,返回数据列表
* @param where 条件
* @param params 参数
* @return 数据列表
*/
public List queryNote(String where, String... params){
return userDao.queryRaw(where, params);
}
/**
* 根据用户信息,插件或修改信息
* @param user 用户信息
* @return 插件或修改的用户id
*/
public long saveNote(Users user){
return userDao.insertOrReplace(user);
}
/**
* 批量插入或修改用户信息
* @param list 用户信息列表
*/
public void saveNoteLists(final List list){
if(list == null || list.isEmpty()){
return;
}
userDao.getSession().runInTx(new Runnable() {
@Override
public void run() {
for(int i=0; i 第三步,设置布局文件
1,Toolbar的代码:
当然了,你要是想使用toolbar,还要为其设置样式,style.xml
现在来看一下页面主布局,这个布局其实很简单,就是一个Toolbar,Toolbar上菜单有一个添加的按钮,而且下面是一个listView用来显示用户,点击添加按钮,弹出一个对话框,显示你要添加的项,填写完后,保存,新加的数据就会在listView中显示出来.点击列表项,会弹出对框,上面有删除与修改的选项,可以对此项进行删除与修改,
好,先来看一下activity_one_table.xml文件
接下来,看一下,toolbar菜单栏的布局文件,menu_one_table.xml.主要就是添加了一个添加的按钮
下面是listView列表显示,哪么我们先为这个列表设置一个item的布局.代码比较简单:'
activity_onetable_lv_item.xml
为再为它设计一个Adapter
onetable_adapter.java
package com.example.cg.greendaolearn.adpater;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import com.example.cg.greendaolearn.R;
import java.util.List;
import greendao.Users;
/**
* 用户信息显示Adapter
* Created by cg on 2015/12/29.
*/
public class onetable_adapter extends BaseAdapter {
private LayoutInflater inflater;
private List list_user;
public onetable_adapter(Context context,List list_user) {
this.inflater = LayoutInflater.from(context);
this.list_user = list_user;
}
@Override
public int getCount() {
return list_user.size();
}
@Override
public Object getItem(int position) {
return list_user.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
userInfo uInfo;
if(convertView==null)
{
uInfo = new userInfo();
convertView = inflater.inflate(R.layout.activity_onetable_lv_item,null);
uInfo.uAge = (TextView)convertView.findViewById(R.id.txt_onetable_age);
uInfo.uName = (TextView)convertView.findViewById(R.id.txt_onetable_uName);
uInfo.uSex = (TextView)convertView.findViewById(R.id.txt_onetable_uSex);
uInfo.uTel = (TextView)convertView.findViewById(R.id.txt_onetable_tel);
convertView.setTag(uInfo);
}else
{
uInfo = (userInfo)convertView.getTag();
}
uInfo.uSex.setText(list_user.get(position).getUSex());
uInfo.uTel.setText(list_user.get(position).getUTelphone());
uInfo.uName.setText(list_user.get(position).getUName());
uInfo.uAge.setText(list_user.get(position).getUAge());
return convertView;
}
public class userInfo
{
TextView uName;
TextView uSex;
TextView uAge;
TextView uTel;
}
}
listVIew搞定了.我们来完成点击添加时,弹出的对话框,这里采用的DialogFragment
先看布局文件fragment_onetable_dialog.xml
代码:oneTableDialogFragment.java
package com.example.cg.greendaolearn;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.EditText;
/**
* 用户添加与修改
* Created by cg on 2015/12/30.
*/
public class oneTableDialogFragment extends DialogFragment {
private EditText edit_onetable_name;
private EditText edit_onetable_sex;
private EditText edit_onetable_tel;
private EditText edit_onetable_age;
private String uName; //用户姓名
private String uSex; //用户性别
private String uAge; //用户年纪
private String uTel; //用户电话
private int flag; //flag 标识 0:添加 1:修改
private long uId; //用户id,添加时为0,修改时为正确的id
/**
* 定义点击事件接口
*/
public interface addUserOnClickListener
{
void onAddUserOnClick(long id,String uName, String uSex,String uAge,String uTel,int flag);
}
public oneTableDialogFragment(long uId,String uName, String uSex, String uAge, String uTel,int flag) {
this.uName = uName;
this.uSex = uSex;
this.uAge = uAge;
this.uTel = uTel;
this.flag = flag;
this.uId = uId;
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState)
{
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
// Get the layout inflater
LayoutInflater inflater = getActivity().getLayoutInflater();
View view = inflater.inflate(R.layout.fragment_onetable_dialog, null);
edit_onetable_name = (EditText) view.findViewById(R.id.edit_onetable_name);
edit_onetable_sex = (EditText) view.findViewById(R.id.edit_onetable_sex);
edit_onetable_tel = (EditText) view.findViewById(R.id.edit_onetable_tel);
edit_onetable_age = (EditText)view.findViewById(R.id.edit_onetable_age);
edit_onetable_name.setText(uName);
edit_onetable_age.setText(uAge);
edit_onetable_sex.setText(uSex);
edit_onetable_tel.setText(uTel);
// Inflate and set the layout for the dialog
// Pass null as the parent view because its going in the dialog layout
builder.setView(view)
// Add action buttons
.setTitle("添加用户")
.setPositiveButton("添加",
new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int id)
{
addUserOnClickListener listener = (addUserOnClickListener) getActivity();
listener.onAddUserOnClick(uId,edit_onetable_name.getText().toString(),
edit_onetable_sex.getText().toString(),
edit_onetable_age.getText().toString(),
edit_onetable_tel.getText().toString(),
flag);
}
}).setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
edit_onetable_name.setText("");
edit_onetable_sex.setText("");
edit_onetable_age.setText("");
edit_onetable_tel.setText("");
}
});
return builder.create();
}
}
这里就不多说了,一是代码比较简单,二是里面的注释也比较清楚,大家一眼就明白了.
下面就是对点击item项的时候,弹出的对框进行设计,先看布局,就两个textView
fragment_onetable_itemdialog.xml
代码:oneTableItemDialogFragment.java
package com.example.cg.greendaolearn;
import android.app.DialogFragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.TextView;
/**
* Created by cg on 2015/12/30.
*/
public class oneTableItemDialogFragment extends DialogFragment {
private long id; //用户id
private int postion; //list中的编号
private TextView txt_onetable_update;
private TextView txt_onetable_delete;
public interface EditUserOnClickListener
{
//flag标识,0表示删除,1表示修改
void onEditUserOnClick(long id,int postion,int flag);
}
public oneTableItemDialogFragment(long id,int postion) {
this.id = id;
this.postion = postion;
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
getDialog().requestWindowFeature(Window.FEATURE_NO_TITLE);
View view = inflater.inflate(R.layout.fragment_onetable_itemdialog,container);
return view;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
txt_onetable_update = (TextView)view.findViewById(R.id.txt_onetable_update);
txt_onetable_update.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
EditUserOnClickListener listener = (EditUserOnClickListener) getActivity();
listener.onEditUserOnClick(id,postion,1);
}
});
txt_onetable_delete = (TextView)view.findViewById(R.id.txt_onetable_delete);
txt_onetable_delete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
EditUserOnClickListener listener = (EditUserOnClickListener) getActivity();
listener.onEditUserOnClick(id,postion,0);
}
});
}
}
OK了,现在我们来看一下,主程序的代码:oneTableActivity.java
package com.example.cg.greendaolearn;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;
import com.example.cg.greendaolearn.adpater.onetable_adapter;
import com.example.cg.greendaolearn.db.DbService;
import java.util.ArrayList;
import java.util.List;
import greendao.Users;
public class oneTableActivity extends AppCompatActivity implements oneTableDialogFragment.addUserOnClickListener,oneTableItemDialogFragment.EditUserOnClickListener {
private Toolbar toolbar; //定义toolbar
private ListView lv_oneTable;
private List list_user;
private onetable_adapter oAdapter;
private DbService db;
private oneTableItemDialogFragment oneItemDialog;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_one_table);
toolbar = (Toolbar)this.findViewById(R.id.toolbar);
toolbar.setTitle("单表操作"); // 标题的文字需在setSupportActionBar之前，不然会无效
setSupportActionBar(toolbar);
db = DbService.getInstance(this);
initControls();
initData();
}
/**
* 初始化数据,刚进入页面时加载
*/
private void initData() {
list_user = new ArrayList<>();
list_user = db.loadAllNoteByOrder();
oAdapter = new onetable_adapter(this,list_user);
lv_oneTable.setAdapter(oAdapter);
}
/**
* 初始化控件
*/
private void initControls() {
lv_oneTable = (ListView)findViewById(R.id.lv_oneTable);
lv_oneTable.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView parent, View view, int position, long id) {
Toast.makeText(oneTableActivity.this,list_user.get(position).getUName() + "--" +
list_user.get(position).getId(),Toast.LENGTH_SHORT).show();
oneItemDialog = new oneTableItemDialogFragment(list_user.get(position).getId(),position);
oneItemDialog.show(getFragmentManager(),"编辑");
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_one_table, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.menu_onetable_add) {
oneTableDialogFragment oneDialog = new oneTableDialogFragment(0,"","","","",0);
oneDialog.show(getFragmentManager(),"添加用户");
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onAddUserOnClick(long uId,String uName, String uSex, String uAge, String uTel,int flag) {
Users user = new Users();
if(flag==1) {
user.setId(uId);
}
user.setUSex(uSex);
user.setUTelphone(uTel);
user.setUAge(uAge);
user.setUName(uName);
if(flag==0) {
if (db.saveNote(user) > 0) {
list_user.add(0, user);
oAdapter.notifyDataSetChanged();
}
}else
{
if (db.saveNote(user) > 0) {
int num = 0;
for(Users u:list_user)
{
if(u.getId()==uId)
{
list_user.remove(num);
list_user.add(num,user);
break;
}
num++;
}
oAdapter.notifyDataSetChanged();
}
}
}
@Override
public void onEditUserOnClick(long id,int postion,int flag) {
if(flag==0) {
db.deleteNote(id);
list_user.remove(postion);
oAdapter.notifyDataSetChanged();
oneItemDialog.dismiss();
}else
{
Users updateUser = db.loadNote(id);
oneTableDialogFragment oDialog = new oneTableDialogFragment(updateUser.getId(),updateUser.getUName(),updateUser.getUSex(),
updateUser.getUAge(), updateUser.getUTelphone(),1);
oneItemDialog.dismiss();
oDialog.show(getFragmentManager(),"修改");
}
}
}
运行效果图: