系统文件管理器
http://www.eoeandroid.com/thread-128567-1-1.html
android 实现区域截图
http://www.eoeandroid.com/thread-149439-1-1.html
影院选坐 写着玩的
http://www.eoeandroid.com/thread-151980-1-1.html
继上章
1.在数据库表person添加字段amount
2.在Person类中添加相应的amount
3.在PersonService添加payment()方法
public void payment(){ SQLiteDatabase db = dbOpenHelper.getWritableDatabase(); db.beginTransaction(); //开户事务 try{ db.execSQL("update person set amount=amount-10 where personId=1"); db.execSQL("update person set amount=amount-10 where personId=2"); db.setTransactionSuccessful(); //设置事务的标志为True }finally{ //为何要加try...catch //因为添加了db.setTransactionSuccessful()，若execSQL中出现问题 //则不会执行db.endTransaction() db.endTransaction(); //结束事务，有2种情况：commit, rollback } //事务的提交或回滚是由事务的标志决定的 //如果事务的标志为True,事务就会提交 //否则事务就会回滚，默认情况下事务的标志为false }
4.初始化amount值，便于调用
public void testUpdateAmount() throws Exception{ PersonService service = new PersonService(this.getContext()); Person person1 = service.find(1); Person person2 = service.find(2); person1.setAmount(100); person2.setAmount(200); service.update(person1); service.update(person2); }
5.在单元测试类PersonServiceTest中添加测试方法testPayment()
public void testPayment() throws Exception{ PersonService service = new PersonService(this.getContext()); service.payment(); }
