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