DoctorNote医生处方笔记开发记录

1.开发背景
一个开诊所的中医朋友，希望我能给他开发一个记录病人姓名和处方的Android手机app，以便查询病人每次就诊信息，比如上一次的处方，以前他要找个病人上一次的就诊处方，几乎要翻遍一叠厚厚的处方纸张才能找到(他的门诊量还是很大的)，非常麻烦。于是利用周末的两天时间开发了这款DoctorNote软件，软件截图如下：
         
DoctorNote开发过程用了很Android各个方面的知识点，比如ActionBar的使用、自定义ActionBar样式、SQLite的使用、AsyncTask的使用，SearchView的使用和SearchActivity的编写，以及AlertDialog的创建等。现总结如下：

2.项目的创建

项目的开发IDE是Eclipse，File->new->Android Application Project，项目的目录结构如下 图：

3.创建MainActivity
该类继承ListActivity实现OnItemLongClickListener接口，是程序的主界面，主要按姓名展示处方记录，单击可查看修改信息，长按可删除该记录，代码如下：

package com.foxhu.app.doctornote.ui;



import com.foxhu.app.doctornote.R;

import com.foxhu.app.doctornote.db.NoteDB;



import android.os.AsyncTask;

import android.os.Bundle;

import android.app.AlertDialog;

import android.app.ListActivity;

import android.app.SearchManager;

import android.content.Context;

import android.content.DialogInterface;

import android.content.DialogInterface.OnClickListener;

import android.content.Intent;

import android.database.Cursor;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemLongClickListener;

import android.widget.ListView;

import android.widget.SearchView;

import android.widget.SimpleCursorAdapter;

import android.widget.Toast;

/**

 * DoctorNote

 * @author Foxhu

 * @version 1.0

 *

 */

public class MainActivity extends ListActivity implements OnItemLongClickListener{

	public final static String EXTRA_NOTEID = "com.foxhu.app.doctornote.NOTEID"; 

	private final static int ACTIVITY_CREATE = 0;//设置activity返回码

	private final static int ACTIVITY_MODI = 1;//设置activity返回码

	private Context mContext;

	

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		mContext = this;

		setContentView(R.layout.activity_main);

		new LoadAsyncTask().execute();

		getListView().setOnItemLongClickListener(this);

	}

	

	//android.os.AsyncTask<Params, Progress, Result>

	private class LoadAsyncTask extends AsyncTask<Void,Void,Cursor>{



		@Override

		protected Cursor doInBackground(Void... arg0) {

			Cursor cursor = NoteDB.getInstance(getApplicationContext()).getAllNote();

			return cursor;

		}



		@Override

		protected void onPostExecute(Cursor result) {

			super.onPostExecute(result);

			//构造方法

			//public SimpleCursorAdapter (Context context, int layout, Cursor c, String[] from, int[] to, int flags)

			String[] from = new String[]{NoteDB.COLUMN_NAME};

			int[] to = new int[]{android.R.id.text1};

			SimpleCursorAdapter records = new SimpleCursorAdapter(mContext,android.R.layout.simple_list_item_1,result,from,to,0);

			setListAdapter(records);

		}

		

		

	}

	

	

	/**

	 * 处理单击事件,单击条目打开编辑窗口

	 */

	@Override

	protected void onListItemClick(ListView l, View v, int position, long id) {

		super.onListItemClick(l, v, position, id);

		Intent intent = new Intent(this,ModiNoteActivity.class);

		intent.putExtra(EXTRA_NOTEID, id);//传递记录的id

		this.startActivityForResult(intent, ACTIVITY_MODI);

		

	}





	@Override

	public boolean onCreateOptionsMenu(Menu menu) {

		// Inflate the menu; this adds items to the action bar if it is present.

		getMenuInflater().inflate(R.menu.main, menu);

		//设置查询

		SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);

		SearchView searchView = (SearchView) menu.findItem(R.id.search).getActionView();

		searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));

		//searchView.setSubmitButtonEnabled(true);

		return true;

	}





	@Override

	public boolean onOptionsItemSelected(MenuItem item) {

		switch(item.getItemId()){

		case R.id.action_edit:

			Intent intent = new Intent(mContext, EditNoteActivity.class);

            //startActivity(intent);

			this.startActivityForResult(intent, ACTIVITY_CREATE);

            break;

		default:

            break;

		}

		return false;

	}





	@Override

	protected void onActivityResult(int requestCode, int resultCode, Intent data) {

		// TODO Auto-generated method stub

		super.onActivityResult(requestCode, resultCode, data);

		//重新加载数据

		new LoadAsyncTask().execute();

	}

	

	@Override

	protected void onRestart() {

		super.onRestart();

		new LoadAsyncTask().execute();

	}





	@Override

	public boolean onItemLongClick(AdapterView<?> arg0, View arg1, int arg2,

			final long id) {

		AlertDialog.Builder builder = new AlertDialog.Builder(mContext)

										.setTitle(R.string.delete_title)

										.setMessage(R.string.delete_body)

										.setNegativeButton(R.string.delete_cancel, null)

										.setPositiveButton(R.string.delete_ok, new OnClickListener(){

											@Override

											public void onClick(DialogInterface dialog, int which) {

	                                                if (NoteDB.getInstance(getApplicationContext()).deleteNote(id)> 0) {

	                                                        new LoadAsyncTask().execute();

	                                                        Toast.makeText(mContext, R.string.delete_success,

	                                                                        Toast.LENGTH_SHORT).show();

	                                                } else {

	                                                        Toast.makeText(mContext, R.string.delete_fail,

	                                                                        Toast.LENGTH_SHORT).show();

	                                                }

	                                        }

											

										});

		

		builder.create().show();

		

		// TODO Auto-generated method stub

		return false;

	}



}

对应的页面布局文件activity_main.xml如下：

 

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity" >



    <ListView

        android:id="@android:id/list"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:layout_centerHorizontal="true"

        android:layout_centerVertical="true" >

    </ListView>



</RelativeLayout>

(1)onCreate()事件解析
setContentView(R.layout.activity_main);设置布局文件；
new LoadAsyncTask().execute();执行异步任务从SQLite数据库加载全部医生处方数据；
getListView().setOnItemLongClickListener(this);给listview控件条目设置长按监听单击事件；
(2)private class LoadAsyncTask extends AsyncTask<Void,Void,Cursor>
内部类LoadAsyncTask继承AsyncTask类,我们来看一下AsyncTask这个类,这个类的定义一般带有三个泛型参数AsyncTask<Params, Progress, Result>,并且带有4步方法,分别为onPreExecute, doInBackground, onProgressUpdate 和 onPostExecute.一般我们需要后台执行获取数据的任务放在doInBackground()方法,执行结果数据展示部分放在onPostExecute(),该方法的参数即是doInBackground()返回的数据,下面详细介绍下AsyncTask的4步方法:
①.onPreExecute(),在任务执行之前，在UI线程上调用，这步通常用来设置任务，比如在用户界面上显示进度条；
②.doInBackground(Params...),在 onPreExecute()方法执行后立即在后台线程执行,这一步通常用来执行需要花费较长时间的后台计算,异步任务的参数传递给该方法,计算的结果必须在这一步返回,并传递给onPostExecute(Result),这一步也可使用 publishProgress(Progress...)方法来产生一个或多个单位的进度,这些值是发布在在UI线程上 onProgressUpdate(Progress...) 方法中的.
③.onProgressUpdate(Progress...),在 publishProgress(Progress...)方法后在UI线程上调用,它的执行时序是不确定的,这个方法通常用来在用户界面上展示进度,而后台计算仍在执行,例如,它可以用来动态的显示进步条或者在文本框中显示记录.
④.onPostExecute(Result),在后台计算完成后在UI线程上调用,后台计算的执行结果传递该方法作为参数.
(3)ActionBar的创建
ActionBar是3.0以后出来的设计规范，支持Android 3.0+，android:minSdkVersion="11"，如果想在Android 2.1上实现ActionBar需要V7兼容包，我们定义Activity的时候一般这样public class MainActivity extends ActionBarActivity ，Activity要继承ActionBarActivity，为简单起见，本软件采用android:minSdkVersion="11"。
①.实现ActionBar关键是菜单文件的创建，下面是DoctorNote的主界面菜单文件main.xml：

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

 	<item 

 	    android:id="@+id/search"

        android:title="@string/search_title"

        android:icon="@drawable/ic_search"

        android:showAsAction="collapseActionView|ifRoom"

        android:actionViewClass="android.widget.SearchView" />	

    

    <item

        android:id="@+id/action_edit"

        android:icon="@drawable/ic_edit"

        android:showAsAction="ifRoom"

        android:title="@string/action_edit"/>



</menu>

其中第一个item用来定义搜索按钮，第二菜单用于定义编辑按钮，关键我们要注意android:showAsAction属性的应用,
ifRoom:如果有ActionBar有空间就显示该菜单项；
withText：如果没有设定android:icon图标，那么菜单项以文字形式展示，可以与其他关键字联合使用比如ifRoom|withText；
never：不出现在ActionBar中，按设置键可弹出；
always：不管有没有空间，总是出现在ActionBar，通常不建议使用该项，会导致多个item重叠；
collapseActionView:与之相关的动作条目（如在android:actionViewClass中声明的视图类）是可折叠的，比如搜索控件SearchView；

②.在CeateOptionsMenu(Menu menu)方法加载菜单,实现actionbar效果

@Override

	public boolean onCreateOptionsMenu(Menu menu) {

		// Inflate the menu; this adds items to the action bar if it is present.

		getMenuInflater().inflate(R.menu.main, menu);

		//设置查询

		SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);

		SearchView searchView = (SearchView) menu.findItem(R.id.search).getActionView();

		searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));

		//searchView.setSubmitButtonEnabled(true);

		return true;

	}

③.对ActionBar上的按钮添加响应事件

@Override

	public boolean onOptionsItemSelected(MenuItem item) {

		switch(item.getItemId()){

		case R.id.action_edit:

			Intent intent = new Intent(mContext, EditNoteActivity.class);

            //startActivity(intent);

			this.startActivityForResult(intent, ACTIVITY_CREATE);

            break;

		default:

            break;

		}

		return false;

	}

如果选中编辑(新建)菜单则通过intent打开EditNoteActivity.class

(4)SearchView的创建，一般分为5步
①编写菜单文件，res/menu/main.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

 	<item 

 	    android:id="@+id/search"

        android:title="@string/search_title"

        android:icon="@drawable/ic_search"

        android:showAsAction="collapseActionView|ifRoom"

        android:actionViewClass="android.widget.SearchView" />	

    

    <item

        android:id="@+id/action_edit"

        android:icon="@drawable/ic_edit"

        android:showAsAction="ifRoom"

        android:title="@string/action_edit"/>



</menu>

②编写搜索配置文件res/xml/searchable.xml

<?xml version="1.0" encoding="utf-8"?>

<searchable xmlns:android="http://schemas.android.com/apk/res/android"

        android:label="@string/app_name"

        android:hint="@string/search_hint" 

        android:imeOptions="actionSearch"/>

其中android:imeOptions="actionSearch"属性用来设置软键盘是搜索按钮而不是回车
③在onCreateOptionsMenu(Menu menu)方法中对SearchView通过调用setSearchableInfo(getComponentName())方法加载搜索配置信息，当SearchView和搜索配置文件正确关联后，当用户提交查询后SearchView就会通过ACTION_SEARCH intent 开启一个 activity来执行搜索任务
④修改AndroidManifest.xml配置文件，添加

<!-- Searchable -->

        <activity

            android:name="com.foxhu.app.doctornote.ui.SearchableActivity"

            android:launchMode="singleTop" >

            <intent-filter>

                <action android:name="android.intent.action.SEARCH" />

            </intent-filter>

            <meta-data

                android:name="android.app.searchable"

                android:resource="@xml/searchable" />

        </activity>

         <!-- Points to searchable activity so the whole app can invoke search. -->

        <meta-data

            android:name="android.app.default_searchable"

            android:value="com.foxhu.app.doctornote.ui.SearchableActivity"/>

注意属性android:launchMode="singleTop"，singleTop模式将SearchableActivity设为单例模式，用户可以执行多次搜索而无需创建新的Activity实例
⑤创建可搜索的Activity-SearchableActivity，SearchableActivity代码如下：

package com.foxhu.app.doctornote.ui;



import com.foxhu.app.doctornote.db.NoteDB;

import android.app.ListActivity;

import android.app.SearchManager;

import android.content.Context;

import android.content.Intent;

import android.database.Cursor;

import android.os.Bundle;

import android.view.MenuItem;

import android.view.View;

import android.widget.ListView;

import android.widget.SimpleCursorAdapter;

/**

 * DoctorNote

 * @author Foxhu

 * @version 1.0

 *

 */

public class SearchableActivity extends ListActivity {

	private Context mContext;

	//private NoteDB mNoteDB;

	

	@Override

	protected void onListItemClick(ListView l, View v, int position, long id) {

		// TODO Auto-generated method stub

		super.onListItemClick(l, v, position, id);

		Intent intent = new Intent(this,ModiNoteActivity.class);

		intent.putExtra(MainActivity.EXTRA_NOTEID, id);//传递记录的id

		this.startActivity(intent);

	}



	@Override

	protected void onCreate(Bundle savedInstanceState) {

		// TODO Auto-generated method stub

		super.onCreate(savedInstanceState);

		mContext = this;

		//mNoteDB = new NoteDB(mContext, NoteDB.DATABASE_NAME, null, NoteDB.VERSION);

		getActionBar().setDisplayHomeAsUpEnabled(true);//设置返回按钮

		handleIntent(getIntent());

	}



	private void handleIntent(Intent intent) {

		// TODO Auto-generated method stub

		if (Intent.ACTION_SEARCH.equals(intent.getAction())) {

            String query = intent.getStringExtra(SearchManager.QUERY);

            //use the query to search your data somehow

            fillList(query);

        }

	}



	private void fillList(String query) {

		// TODO Auto-generated method stub

		Cursor result = NoteDB.getInstance(getApplicationContext()).queryNoteByName(query);

		String[] from = new String[]{NoteDB.COLUMN_NAME};

		int[] to = new int[]{android.R.id.text1};

		SimpleCursorAdapter records = new SimpleCursorAdapter(mContext,android.R.layout.simple_list_item_1,result,from,to,0);

		setListAdapter(records);

	}



	@Override

	protected void onNewIntent(Intent intent) {

		// TODO Auto-generated method stub

		super.onNewIntent(intent);

		handleIntent(intent);

	}



	@Override

	public boolean onOptionsItemSelected(MenuItem item) {

		switch(item.getItemId()){

		case android.R.id.home:

			finish();

            break;

		default:

            break;

		}

		return super.onOptionsItemSelected(item);

	}



	



}

在onCreate()事件中，通过handleIntent(getIntent())检查ACTION_SEARCH intent来处理查询， 通过String query = intent.getStringExtra(SearchManager.QUERY)来获取查询关键词，然后通过fillList(query)来装载查询结果;

4.创建EditNoteActivity，该类主要用来新建处方

package com.foxhu.app.doctornote.ui;



import com.foxhu.app.doctornote.R;

import com.foxhu.app.doctornote.db.NoteDB;



import android.os.Bundle;

import android.app.Activity;

import android.content.Context;

import android.view.Menu;

import android.view.MenuItem;

import android.widget.EditText;

import android.widget.Toast;

/**

 * DoctorNote

 * @author Foxhu

 * @version 1.0

 *

 */

public class EditNoteActivity extends Activity {

	private Context mContext;

	private EditText mNameText;

	private EditText mPrescriptionText;

	

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		mContext = this; 

		setContentView(R.layout.activity_edit_note);

		mNameText = (EditText) this.findViewById(R.id.notename);

		mPrescriptionText = (EditText) this.findViewById(R.id.noteprescription);

		getActionBar().setDisplayHomeAsUpEnabled(true);//设置返回按钮

	}



	@Override

	public boolean onCreateOptionsMenu(Menu menu) {

		// Inflate the menu; this adds items to the action bar if it is present.

		getMenuInflater().inflate(R.menu.edit_note, menu);

		return true;

	}



	@Override

	public boolean onOptionsItemSelected(MenuItem item) {

		switch(item.getItemId()){

		case R.id.action_save:

			String name = mNameText.getText().toString();

			String prescription = mPrescriptionText.getText().toString();

			if (name.isEmpty()){

				Toast.makeText(mContext, R.string.name_empty,Toast.LENGTH_SHORT).show();

			}else{

				NoteDB.getInstance(getApplicationContext()).insertNote(name, prescription);

				this.finish();

			}

            break;

		case android.R.id.home:

			finish();

            break;

		default:

            break;

		}

		return false;

	}

	

	



}

5.创建ModiNoteActivity，该类主要用来修改处方

package com.foxhu.app.doctornote.ui;



import com.foxhu.app.doctornote.R;

import com.foxhu.app.doctornote.db.NoteDB;

import android.os.Bundle;

import android.app.Activity;

import android.content.Context;

import android.content.Intent;

import android.database.Cursor;

import android.view.Menu;

import android.view.MenuItem;

import android.widget.EditText;

import android.widget.Toast;

/**

 * DoctorNote

 * @author Foxhu

 * @version 1.0

 *

 */

public class ModiNoteActivity extends Activity {

	private Context mContext;

	//private NoteDB mNoteDB;

	private EditText mNameText;

	private EditText mPrescriptionText;

	private long noteId;

	

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		mContext = this; 

		setContentView(R.layout.activity_modi_note);

		//mNoteDB = new NoteDB(mContext, NoteDB.DATABASE_NAME, null, NoteDB.VERSION);

		Intent intent = getIntent();

		noteId = intent.getLongExtra(MainActivity.EXTRA_NOTEID, 0);

		Cursor cursor = NoteDB.getInstance(getApplicationContext()).queryNoteById(noteId);//根据接收的id查询记录详细信息

		mNameText = (EditText) this.findViewById(R.id.modi_notename);

		mPrescriptionText = (EditText) this.findViewById(R.id.modi_noteprescription);

		

		mNameText.setText(cursor.getString(cursor.getColumnIndexOrThrow(NoteDB.COLUMN_NAME)));

		mPrescriptionText.setText(cursor.getString(cursor.getColumnIndexOrThrow(NoteDB.COLUMN_PRESCRIPTION)));

		getActionBar().setDisplayHomeAsUpEnabled(true);//设置返回按钮

		

	}



	@Override

	public boolean onCreateOptionsMenu(Menu menu) {

		// Inflate the menu; this adds items to the action bar if it is present.

		getMenuInflater().inflate(R.menu.modi_note, menu);

		return true;

	}



	@Override

	public boolean onOptionsItemSelected(MenuItem item) {

		switch(item.getItemId()){

		case R.id.action_modi:

			String name = mNameText.getText().toString();

			String prescription = mPrescriptionText.getText().toString();

			if (name.isEmpty()){

				Toast.makeText(mContext, R.string.name_empty,Toast.LENGTH_SHORT).show();

			}else{

				NoteDB.getInstance(getApplicationContext()).updateNote(noteId, name, prescription);

				this.finish();

			}

            break;

		case android.R.id.home:

			finish();

            break;

		default:

            break;

		}

		return false;

	}



}

5.数据库操作类NoteDB
该类继承SQLiteOpenHelper，由于多个Activity都要操作数据库，所以写了一个public static NoteDB getInstance(Context context)单例模式创建数据库操作类NoteDB对象，调用方法为NoteDB.getInstance(getApplicationContext())，代码如下

package com.foxhu.app.doctornote.db;



import java.util.Calendar;



import android.content.ContentValues;

import android.content.Context;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteDatabase.CursorFactory;

import android.database.sqlite.SQLiteOpenHelper;

import android.database.sqlite.SQLiteStatement;

/**

 * DoctorNote

 * @author Foxhu

 * @version 1.0

 *

 */

public class NoteDB extends SQLiteOpenHelper {

	public static NoteDB mInstance = null;

	public static final int VERSION = 1;

	public static final String DATABASE_NAME = "DoctorNote";

	

	private static final String TABLE_NOTE_NAME = "Note";

	private static final String COLUMN_ID = "_id";

	public static final String COLUMN_NAME = "name";

	public static final String COLUMN_PRESCRIPTION = "prescription";

	private static final String COLUMN_CREATETIME = "createtime";



  

	private static final String DATABASE_NOTE_CREATE = "create table Note(_id integer primary key autoincrement, "

														+ "name text not null,"

														+ "prescription text not null,"

														+ "createtime text not null" + ");";

	

	public NoteDB(Context context, String name, CursorFactory factory, int version) {

		super(context, name, factory, version);

	}

	

	//自定义构造函数，只需要传递Activity对象给它即可

	public NoteDB(Context context) {

        this(context, DATABASE_NAME, null, VERSION); 

    }

	 /**

     * 单例模式

     */

    public static NoteDB getInstance(Context context) {

            if (mInstance == null) {

                    mInstance = new NoteDB(context);

            }

            return mInstance;

    }

    

	@Override

	public void onCreate(SQLiteDatabase db) {

		db.execSQL(DATABASE_NOTE_CREATE);

	}



	@Override

	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

		// TODO Auto-generated method stub



	}

	/**

	 * 获取全部数据

	 * @param db

	 * @return

	 */

	public Cursor getAllNote(){

		return this.getReadableDatabase().query(TABLE_NOTE_NAME, new String[] {COLUMN_ID,COLUMN_NAME,COLUMN_PRESCRIPTION,COLUMN_CREATETIME}, null, null, null, null, "_id desc");

		

	}

	

	/**

	 * 插入数据

	 * @param name

	 * @param prescription

	 * @return

	 */

	public long insertNote(String name,String prescription){

		ContentValues values = new ContentValues();

		Calendar calendar = Calendar.getInstance();  

		String created = calendar.get(Calendar.YEAR) + "年" + calendar.get(Calendar.MONTH) + "月"  + calendar.get(Calendar.DAY_OF_MONTH) + "日";

		values.put(COLUMN_NAME, name);

		values.put(COLUMN_PRESCRIPTION, prescription);

		values.put(COLUMN_CREATETIME, created);

		return this.getWritableDatabase().insert(TABLE_NOTE_NAME, null, values);

	}

	

	/**

	 * 根据id删除数据

	 * @param id

	 * @return

	 */

	public int deleteNote(long id){

		return this.getWritableDatabase().delete(TABLE_NOTE_NAME, "_id=?", new String[] { String.valueOf(id) });

	}

	

	/**

	 * 根据id更新数据

	 * @param id

	 * @param name

	 * @param prescription

	 * @return

	 */

	public int updateNote(long id,String name,String prescription){

		ContentValues values = new ContentValues();

		values.put(COLUMN_NAME, name);

		values.put(COLUMN_PRESCRIPTION, prescription);

		return this.getWritableDatabase().update(TABLE_NOTE_NAME, values, "_id=?", new String[] { String.valueOf(id) });

	}

	

	/**

	 * 根据姓名查询数据

	 * @param name

	 * @return

	 */

	public Cursor queryNoteByName(String name){

		return this.getReadableDatabase().query(TABLE_NOTE_NAME, null, "name like ?", new String[] {"%"+name+"%"}, null, null, "_id desc");

	}

	

	/**

	 * 根据id查询详细信息

	 * @param id

	 * @return

	 */

	public Cursor queryNoteById(long id){

		Cursor mcursor = this.getReadableDatabase().query(TABLE_NOTE_NAME, null, "_id=?", new String[] { String.valueOf(id) }, null, null, null,"1");

		if (mcursor != null && mcursor.getCount() !=0){

			mcursor.moveToFirst();

			return mcursor;

		}else{

			return null;

		}

	}

	/**

	 * 获取note表全部记录数

	 * @return

	 */

	public long getNoteCount(){

		SQLiteStatement statement = this.getReadableDatabase().compileStatement("select count(*) from " + TABLE_NOTE_NAME);

		return statement.simpleQueryForLong();

	}

	

	/**

	 * 根据姓名查询记录数

	 * @param name

	 * @return

	 */

	public long getNoteCountByName(String name) {

		SQLiteStatement statement = getReadableDatabase().compileStatement(

				"select count(*) from " + TABLE_NOTE_NAME + " where name=" + name);

		return statement.simpleQueryForLong();

	}

}

github源码： https://github.com/puma007/DoctorNote