Android中自定义ContentProvider实例

//以下为testbaidu
mainactivity如下:

package cn.testbaidu;
import android.net.uri;
import android.os.bundle;
import android.view.view;
import android.view.view.onclicklistener;
import android.widget.button;
import android.app.activity;
import android.content.contentresolver;
import android.content.contentvalues;
import android.database.cursor;
/**
* demo描述:
* 应用a(testbaidu)调用另外一个应用(testcontentprovider)
* 中的自定义contentprovider,即:
* 1 自定义contentprovider的使用
* 2 其它应用调用该contentprovider
*
* 测试方法:
* 1 依次测试contentprovider的增查删改(注意该顺序)
* 2 其它应用查询该contentprovider的数据
*
*/
public class mainactivity extends activity {
private button maddbutton;
private button mdeletebutton;
private button mupdatebutton;
private button mquerybutton;
private button mtypebutton;
private contentresolver mcontentresolver;
@override
protected void oncreate(bundle savedinstancestate) {
super.oncreate(savedinstancestate);
setcontentview(r.layout.main);
init();
}
private void init() {
mcontentresolver=this.getcontentresolver();

maddbutton=(button) findviewbyid(r.id.addbutton);
maddbutton.setonclicklistener(new clicklistenerimpl());

mdeletebutton=(button) findviewbyid(r.id.deletebutton);
mdeletebutton.setonclicklistener(new clicklistenerimpl());

mupdatebutton=(button) findviewbyid(r.id.updatebutton);
mupdatebutton.setonclicklistener(new clicklistenerimpl());

mquerybutton=(button) findviewbyid(r.id.querybutton);
mquerybutton.setonclicklistener(new clicklistenerimpl());

mtypebutton=(button) findviewbyid(r.id.typebutton);
mtypebutton.setonclicklistener(new clicklistenerimpl());

}
private class clicklistenerimpl implements onclicklistener{
@override
public void onclick(view v) {
switch (v.getid()) {
case r.id.addbutton:
person person=null;
for (int i = 0; i < 5; i++) {
person=new person("xiaoming"+i, "9527"+i,(8888+i));
testinsert(person);
}
break;
case r.id.deletebutton:
testdelete(1);
break;
case r.id.updatebutton:
testupdate(3);
break;
case r.id.querybutton:
//查询表
//queryfromcontentprovider(-1);

//查询personid=2的数据
testquery(2);
break;
case r.id.typebutton:
testtype();
break;
default:
break;
}

}

}
private void testinsert(person person) {
contentvalues contentvalues=new contentvalues();
contentvalues.put("name", person.getname());
contentvalues.put("phone", person.getphone());
contentvalues.put("salary",person.getsalary());
uri inserturi=uri.parse("content://cn.bs.testcontentprovider/person");
uri returnuri=mcontentresolver.insert(inserturi, contentvalues);
system.out.println("新增数据:returnuri="+returnuri);
}

private void testdelete(int index){
uri uri=uri.parse("content://cn.bs.testcontentprovider/person/"+string.valueof(index));
mcontentresolver.delete(uri, null, null);
}

private void testupdate(int index){
uri uri=uri.parse("content://cn.bs.testcontentprovider/person/"+string.valueof(index));
contentvalues values=new contentvalues();
values.put("name", "hanmeimei");
values.put("phone", "1234");
values.put("salary", 333);
mcontentresolver.update(uri, values, null, null);
}
private void testquery(int index) {
uri uri=null;
if (index<=0) {
//查询表
uri=uri.parse("content://cn.bs.testcontentprovider/person");
} else {
//按照id查询某条数据
uri=uri.parse("content://cn.bs.testcontentprovider/person/"+string.valueof(index));
}

//对应上面的:查询表
//cursor cursor= mcontentresolver.query(uri, null, null, null, null);

//对应上面的:查询personid=2的数据
//注意:因为name是varchar字段的,所以应该写作"name='xiaoming1'"
// 若写成"name=xiaoming1"查询时会报错
cursor cursor= mcontentresolver.query(uri, null, "name='xiaoming1'", null, null);

while(cursor.movetonext()){
int personid=cursor.getint(cursor.getcolumnindex("personid"));
string name=cursor.getstring(cursor.getcolumnindex("name"));
string phone=cursor.getstring(cursor.getcolumnindex("phone"));
int salary=cursor.getint(cursor.getcolumnindex("salary"));
system.out.println("查询得到:personid=" + personid+",name="+name+",phone="+phone+",salary="+salary);
}
cursor.close();
}

private void testtype(){
uri diruri=uri.parse("content://cn.bs.testcontentprovider/person");
string dirtype=mcontentresolver.gettype(diruri);
system.out.println("dirtype:"+dirtype);

uri itemuri=uri.parse("content://cn.bs.testcontentprovider/person/3");
string itemtype=mcontentresolver.gettype(itemuri);
system.out.println("itemtype:"+itemtype);
}
}

person如下:

package cn.testbaidu;
public class person {
private integer id;
private string name;
private string phone;
private integer salary;
public person(string name, string phone,integer salary) {
this.name = name;
this.phone = phone;
this.salary=salary;
}
public person(integer id, string name, string phone,integer salary) {
this.id = id;
this.name = name;
this.phone = phone;
this.salary=salary;
}
public integer getid() {
return id;
}
public void setid(integer id) {
this.id = id;
}
public string getname() {
return name;
}
public void setname(string name) {
this.name = name;
}
public string getphone() {
return phone;
}
public void setphone(string phone) {
this.phone = phone;
}
public integer getsalary() {
return salary;
}
public void setsalary(integer salary) {
this.salary = salary;
}
@override
public string tostring() {
return "person [id=" + id + ", name=" + name + ", phone=" + phone+ ", salary=" + salary + "]";
}



}

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" >
<button
android:id="@+id/addbutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerhorizontal="true"
android:layout_margintop="30dip"
android:text="增加"
android:textsize="20sp" />
<button
android:id="@+id/deletebutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerhorizontal="true"
android:layout_margintop="30dip"
android:layout_below="@id/addbutton"
android:text="删除"
android:textsize="20sp" />
<button
android:id="@+id/updatebutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerhorizontal="true"
android:layout_margintop="30dip"
android:layout_below="@id/deletebutton"
android:text="修改"
android:textsize="20sp" />
<button
android:id="@+id/querybutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerhorizontal="true"
android:layout_margintop="30dip"
android:layout_below="@id/updatebutton"
android:text="查询"
android:textsize="20sp" />
<button
android:id="@+id/typebutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerhorizontal="true"
android:layout_margintop="30dip"
android:layout_below="@id/querybutton"
android:text="类型"
android:textsize="20sp" />
</relativelayout>

//以下为testcontentprovider
mainactivity如下:

package cn.testcontentprovider;
import android.app.activity;
import android.os.bundle;
public class mainactivity extends activity {
@override
protected void oncreate(bundle savedinstancestate) {
super.oncreate(savedinstancestate);
setcontentview(r.layout.main);
}
}

contentprovidertest如下:

package cn.testcontentprovider;
import android.content.contentprovider;
import android.content.contenturis;
import android.content.contentvalues;
import android.content.urimatcher;
import android.database.cursor;
import android.database.sqlite.sqlitedatabase;
import android.net.uri;
/**
* 注意事项:
* 在androidmanifest.xml中注册contentprovider时的属性
* android:exported="true"表示允许其他应用访问.
* 这样testbaidu这个应用才可以访问该处的contentprovider
*/
public class contentprovidertest extends contentprovider {
private dbopenhelper dbopenhelper;
private urimatcher uri_matcher;
private static final int persons = 0;
private static final int person = 1;

@override
public boolean oncreate() {
initurimatcher();
dbopenhelper=new dbopenhelper(getcontext());
return true;
}
//初始化urimatcher
private void initurimatcher(){
uri_matcher=new urimatcher(urimatcher.no_match);
//表示返回所有的person,其中persons为该特定uri的标识码
uri_matcher.adduri("cn.bs.testcontentprovider","person", persons);
//表示返回某一个person,其中person为该特定uri的标识码
uri_matcher.adduri("cn.bs.testcontentprovider","person/#", person);
}
/**
* 插入操作:
* 插入操作只有一种可能:向一张表中插入
* 返回结果为新增记录对应的uri
* 方法db.insert()返回结果为新增记录对应的主键值
*/
@override
public uri insert(uri uri, contentvalues values) {
sqlitedatabase db=dbopenhelper.getwritabledatabase();
switch (uri_matcher.match(uri)) {
case persons:
long rowid=db.insert("person", "name,phone,salary", values);
return contenturis.withappendedid(uri, rowid);
default:
throw new illegalargumentexception("unknown uri"+uri.tostring());
}
}

/**
* 更新操作:
* 更新操作有两种可能:更新一张表或者更新某条数据
* 在更新某条数据时原理类似于查询某条数据,见下.
*/
@override
public int update(uri uri, contentvalues values, string selection, string[] selectionargs) {
sqlitedatabase db=dbopenhelper.getwritabledatabase();
int updatanum=0;
switch (uri_matcher.match(uri)) {
//更新表
case persons:
updatanum=db.update("person", values, selection, selectionargs);
break;
//按照id更新某条数据
case person:
long id=contenturis.parseid(uri);
string where="personid="+id;
if(selection!=null&&!"".equals(selection.trim())){
where=selection+" and "+where;
}
updatanum=db.update("person", values, where, selectionargs);
break;
default:
throw new illegalargumentexception("unknown uri"+uri.tostring());
}
return updatanum;
}

/**
* 删除操作:
* 删除操作有两种可能:删除一张表或者删除某条数据
* 在删除某条数据时原理类似于查询某条数据,见下.
*/
@override
public int delete(uri uri, string selection, string[] selectionargs) {
sqlitedatabase db=dbopenhelper.getwritabledatabase();
int deletednum=0;
switch (uri_matcher.match(uri)) {
//删除表
case persons:
deletednum=db.delete("person", selection, selectionargs);
break;
//按照id删除某条数据
case person:
long id=contenturis.parseid(uri);
string where="personid="+id;
if(selection!=null&&!"".equals(selection.trim())){
where=selection+" and "+where;
}
deletednum=db.delete("person", where, selectionargs);
break;
default:
throw new illegalargumentexception("unknown uri"+uri.tostring());
}
return deletednum;
}
/**
* 查询操作:
* 查询操作有两种可能:查询一张表或者查询某条数据
* 注意事项:
* 在查询某条数据时要注意--因为此处是按照personid来查询
* 某条数据,但是同时可能还有其他限制.例如:
* 要求personid为2且name为xiaoming1
* 所以在查询时分为两步:
* 第一步:
* 解析出personid放入where查询条件
* 第二部:
* 判断是否有其他限制(如name),若有则将其
* 组拼到where查询条件.
* 详细代码见下.
*/
@override
public cursor query(uri uri, string[] projection, string selection, string[] selectionargs, string sortorder) {
sqlitedatabase db=dbopenhelper.getwritabledatabase();
cursor cursor;
switch (uri_matcher.match(uri)) {
//查询表
case persons:
cursor=db.query("person", projection, selection, selectionargs, null, null, sortorder);
break;
//按照id查询某条数据
case person:
//第一步:
long id=contenturis.parseid(uri);
string where="personid="+id;
//第二步:
if(selection!=null&&!"".equals(selection.trim())){
where=selection+" and "+where;
}
cursor=db.query("person", projection, where, selectionargs, null, null, sortorder);
break;
default:
throw new illegalargumentexception("unknown uri"+uri.tostring());
}
return cursor;
}

/**
* 返回当前uri所代表的数据的mime类型.
* 如果该uri对应的数据可能包含多条记录,那么返回
* 字符串应该以"vnd.android.cursor.dir/"开头
* 如果该uri对应的数据只包含一条记录,那么返回
* 字符串应该以"vnd.android.cursor.item/"开头
*/
@override
public string gettype(uri uri) {
switch (uri_matcher.match(uri)) {
case persons:
return "vnd.android.cursor.dir/persons";
case person:
return "vnd.android.cursor.item/person";
default:
throw new illegalargumentexception("unknown uri"+uri.tostring());
}
}
}

dbopenhelper如下:

package cn.testcontentprovider;
import android.content.context;
import android.database.sqlite.sqlitedatabase;
import android.database.sqlite.sqliteopenhelper;
public class dbopenhelper extends sqliteopenhelper {
public dbopenhelper(context context) {
super(context, "contentprovidertest.db", null, 1);
}
@override
public void oncreate(sqlitedatabase db) {
db.execsql("create table person(personid integer primary key autoincrement,name varchar(20),phone varchar(12),salary integer(12))");
}
//当数据库版本号发生变化时调用该方法
@override
public void onupgrade(sqlitedatabase db, int arg1, int arg2) {
//db.execsql("alter table person add phone varchar(12) null");
//db.execsql("alter table person add salary integer null");
}
}

androidmanifest.xml如下:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="cn.testcontentprovider"
android:versioncode="1"
android:versionname="1.0" >
<uses-sdk
android:minsdkversion="8"
android:targetsdkversion="8" />
<uses-permission android:name="android.permission.internet" />
<uses-permission android:name="android.permission.access_network_state" />
<uses-permission android:name="android.permission.write_external_storage" />
<uses-permission android:name="android.permission.mount_unmount_filesystems" />
<application
android:allowbackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/apptheme" >
<activity
android:name="cn.testcontentprovider.mainactivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.main" />
<category android:name="android.intent.category.launcher" />
</intent-filter>
</activity>
<provider
android:name="cn.testcontentprovider.contentprovidertest"
android:authorities="cn.bs.testcontentprovider"
android:exported="true"
/>
</application>
</manifest>