android greenDao SQLite數據庫操作工具類使用

上一篇介紹了如何建立類生成工程，現在介紹如何使用。

以下是ExampleDaoGenerator工程代碼,做了一些修改

/*
 * Copyright (C) 2011 Markus Junginger, greenrobot (http://greenrobot.de)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package de.greenrobot.daogenerator.gentest;

import de.greenrobot.daogenerator.DaoGenerator;
import de.greenrobot.daogenerator.Entity;
import de.greenrobot.daogenerator.Property;
import de.greenrobot.daogenerator.Schema;
import de.greenrobot.daogenerator.ToMany;

/**
 * Generates entities and DAOs for the example project DaoExample.
 * 
 * Run it as a Java application (not Android).
 * 
 * @author Markus
 */


public class ExampleDaoGenerator {

    public static void main(String[] args) throws Exception {
    	//該方法第一個參數用來更新數據庫版本號，第二個參數為要生成的DAO類所在包路徑。
        Schema schema = new Schema(1, "de.greenrobot.daoexample");

        //然後進行建表
        addNote(schema);
        //addCustomerOrder(schema);

        //設置要生成DAO文件的目標工程的項目路徑,其中src-gen這個目錄名需要在運行前手動創建，否則會報錯
        new DaoGenerator().generateAll(schema, "../../HelloWorld/src-gen");
    }

    private static void addNote(Schema schema) {
    	/**
    	 *   在使用greenDAO時，一個實體類只能對應一個表，目前沒法做到一個表對應多個實體類，或者多個表共用一種對象類型。
    	 *   後續的升級也不會針對這一點進行擴展。
    	 * */
        Entity note = schema.addEntity("Note");//創建表
        //note.addIdProperty();		//增加ID列
        note.addIdProperty().primaryKey().autoincrement();//設置一個自增長ID列為主鍵：
        note.addStringProperty("text").notNull();//創建非空的列
        note.addStringProperty("comment").unique();//創建唯一的
        //note.addDateProperty("date");
    }

    private static void addCustomerOrder(Schema schema) {
        Entity customer = schema.addEntity("Customer");
        customer.addIdProperty();
        customer.addStringProperty("name").notNull();

        Entity order = schema.addEntity("Order");
        order.setTableName("ORDERS"); // "ORDER" is a reserved keyword
        order.addIdProperty();
        Property orderDate = order.addDateProperty("date").getProperty();
        Property customerId = order.addLongProperty("customerId").notNull().getProperty();
        order.addToOne(customer, customerId);

        ToMany customerToOrders = customer.addToMany(order, customerId);
        customerToOrders.setName("orders");
        customerToOrders.orderAsc(orderDate);
    }

}

上面代碼主要有兩個

Schema schema = new Schema(1, "de.greenrobot.daoexample");

第一個參數為版本號,第二個參數為產生的類放在引用工程的那個地方,需要結合下面代碼

new DaoGenerator().generateAll(schema, "../../HelloWorld/src-gen");

那麼產生的文件將放到

ExampleDaoGenerator工程目錄的上上兩級目錄下的 HelloWorld/src-gen/de/greenrobot/daoexample 目錄下。

1、我們在ExampleDaoGenerator工程下,按下鍵盤的 ctrl+F11 則會自動生成四個java類放到HelloWorld/src-gen/de/greenrobot/daoexample目錄下面

<喎?/kf/ware/vc/" target="_blank" class="keylink">vcD4KPHA+MqGisNHV4jS49sDg0sDAtbXEz+C52MDgt8W1vdK7xvCjrNLAwLW1xMDg1rG907DRIA=="greenDAO-master\DaoCore\src\de"目錄下的內容放到一起4個類一起。

3、將src-gen目錄設置為編譯文件夾

4、根據生成類增加相關代碼，這裡只貼相關用到的代碼

    private DaoMaster daoMaster;
    private DaoSession daoSession;
    private NoteDao noteDao;

    private Cursor cursor;
    private SQLiteDatabase db;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		

	   DevOpenHelper helper = new DaoMaster.DevOpenHelper(MainActivity.this, "Note", null);
        db = helper.getWritableDatabase();
        daoMaster = new DaoMaster(db);
        daoSession = daoMaster.newSession();
        noteDao = daoSession.getNoteDao();
}

		final Button btn6 = (Button) findViewById(R.id.button6);
		btn6.setOnClickListener(new OnClickListener() {
			public void onClick(View v) {
		
        Toast.makeText(MainActivity.this, "長度 ：" + noteDao.count(),
				Toast.LENGTH_SHORT).show();
        Note note = new Note(null, "noteText1", "comment1"); 
		try {
		    noteDao.insert(note);
			
		} catch (Exception e) {
	        Toast.makeText(MainActivity.this, "數據重復 ：" + noteDao.count(),
					Toast.LENGTH_SHORT).show();
		}
    

5、按ctrl+shift+o自動補齊相關類

6、下載APK到手機，即可。

補充:

在調試過程中,修改了生成工程的類之後發現,重新編譯helloworld工程有出現代碼異常的情況 代碼位於"db = helper.getWritableDatabase();"

該問題暫時未知道什麼原因。但有方法解決：在手機端-->在設置界面-->選擇對應的應用(對於我來說,是helloworld這個應用)-->清除數據