十三、ContentProvider案例
PersonContentProvider内容提供者类
package com.ljq.db;
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;
import android.text.TextUtils;
/**
* 内容提供者
*
* 作用：统一数据访问方式，方便外部调用
*
* @author jiqinlin
*
*/
public class PersonContentProvider extends ContentProvider {
// 数据集的MIME类型字符串则应该以vnd.android.cursor.dir/开头
public static final String PERSONS_TYPE = " vnd.android.cursor.dir/person " ;
// 单一数据的MIME类型字符串应该以vnd.android.cursor.item/开头
public static final String PERSONS_ITEM_TYPE = " vnd.android.cursor.item/person " ;
public static final String AUTHORITY = " com.ljq.provider.personprovider " ; // 主机名
/* 自定义匹配码 */
public static final int PERSONS = 1 ;
/* 自定义匹配码 */
public static final int PERSON = 2 ;
public static final Uri PERSONS_URI = Uri.parse( " content:// " + AUTHORITY + " /person " );
private DBOpenHelper dbOpenHelper = null ;
// UriMatcher类用来匹配Uri，使用match()方法匹配路径时返回匹配码
private static final UriMatcher uriMatcher;
static {
// 常量UriMatcher.NO_MATCH表示不匹配任何路径的返回码
uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
// 如果match()方法匹配content: // com.ljq.provider.personprovider/person路径，返回匹配码为PERSONS
uriMatcher.addURI(AUTHORITY, " person " , PERSONS);
// 如果match()方法匹配content: // com.ljq.provider.personprovider/person/230路径，返回匹配码为PERSON
uriMatcher.addURI(AUTHORITY, " person/# " , PERSON);
}
@Override
public boolean onCreate() {
dbOpenHelper = new DBOpenHelper( this .getContext());
return true ;
}
@Override
public Uri insert(Uri uri, ContentValues values){
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
long id = 0 ;
switch (uriMatcher.match(uri)) {
case PERSONS:
id = db.insert( " person " , " name " , values); // 返回的是记录的行号，主键为int，实际上就是主键值
return ContentUris.withAppendedId(uri, id);
case PERSON:
id = db.insert( " person " , " name " , values);
String path = uri.toString();
return Uri.parse(path.substring( 0 , path.lastIndexOf( " / " )) + id); // 替换掉id
default :
throw new IllegalArgumentException( " Unknown URI " + uri);
}
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
int count = 0 ;
switch (uriMatcher.match(uri)) {
case PERSONS:
count = db.delete( " person " , selection, selectionArgs);
break ;
case PERSON:
// 下面的方法用于从URI中解析出id，对这样的路径content: // com.ljq.provider.personprovider/person/10
// 进行解析，返回值为10
long personid = ContentUris.parseId(uri);
String where = " id= " + personid; // 删除指定id的记录
where += ! TextUtils.isEmpty(selection) ? " and ( " + selection + " ) " : "" ; // 把其它条件附加上
count = db.delete( " person " , where, selectionArgs);
break ;
default :
throw new IllegalArgumentException( " Unknown URI " + uri);
}
db.close();
return count;
}
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
int count = 0 ;
switch (uriMatcher.match(uri)) {
case PERSONS:
count = db.update( " person " , values, selection, selectionArgs);
break ;
case PERSON:
// 下面的方法用于从URI中解析出id，对这样的路径content: // com.ljq.provider.personprovider/person/10
// 进行解析，返回值为10
long personid = ContentUris.parseId(uri);
String where = " id= " + personid; // 获取指定id的记录
where += ! TextUtils.isEmpty(selection) ? " and ( " + selection + " ) " : "" ; // 把其它条件附加上
count = db.update( " person " , values, where, selectionArgs);
break ;
default :
throw new IllegalArgumentException( " Unknown URI " + uri);
}
db.close();
return count;
}
@Override
public String getType(Uri uri) {
switch (uriMatcher.match(uri)) {
case PERSONS:
return PERSONS_TYPE;
case PERSON:
return PERSONS_ITEM_TYPE;
default :
throw new IllegalArgumentException( " Unknown URI " + uri);
}
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
switch (uriMatcher.match(uri)) {
case PERSONS:
return db.query( " person " , projection, selection, selectionArgs, null , null , sortOrder);
case PERSON:
// 下面的方法用于从URI中解析出id，对这样的路径content: // com.ljq.provider.personprovider/person/10
// 进行解析，返回值为10
long personid = ContentUris.parseId(uri);
String where = " id= " + personid; // 获取指定id的记录
where += ! TextUtils.isEmpty(selection) ? " and ( " + selection + " ) " : "" ; // 把其它条件附加上
return db.query( " person " , projection, where, selectionArgs, null , null , sortOrder);
default :
throw new IllegalArgumentException( " Unknown URI " + uri);
}
}
}
文件清单
<? xml version="1.0" encoding="utf-8" ?>
< manifest xmlns:android ="http://schemas.android.com/apk/res/android"
package ="com.ljq.sql" android:versionCode ="1"
android:versionName ="1.0" >
< application android:icon ="@drawable/icon"
android:label ="@string/app_name" >
< uses-library android:name ="android.test.runner" />
< activity android:name =".SqlActivity"
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 ="com.ljq.db.PersonContentProvider"
android:authorities ="com.ljq.provider.personprovider" />
</ application >
< uses-sdk android:minSdkVersion ="7" />
< instrumentation
android:name ="android.test.InstrumentationTestRunner"
android:targetPackage ="com.ljq.sql" android:label ="Tests for My App" />
</ manifest >
PersonContentProviderTest内容提供者测试类
package com.ljq.test;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.test.AndroidTestCase;
import android.util.Log;
/**
* 外部访问内容提供者
*
* @author jiqinlin
*
*/
public class PersonContentProviderTest extends AndroidTestCase{
private static final String TAG = " PersonContentProviderTest " ;
public void testSave() throws Throwable{
ContentResolver contentResolver = this .getContext().getContentResolver();
Uri insertUri = Uri.parse( " content://com.ljq.provider.personprovider/person " );
ContentValues values = new ContentValues();
values.put( " name " , " ljq " );
values.put( " phone " , " 1350000009 " );
Uri uri = contentResolver.insert(insertUri, values);
Log.i(TAG, uri.toString());
}
public void testUpdate() throws Throwable{
ContentResolver contentResolver = this .getContext().getContentResolver();
Uri updateUri = Uri.parse( " content://com.ljq.provider.personprovider/person/1 " );
ContentValues values = new ContentValues();
values.put( " name " , " linjiqin " );
contentResolver.update(updateUri, values, null , null );
}
public void testFind() throws Throwable{
ContentResolver contentResolver = this .getContext().getContentResolver();
// Uri uri = Uri.parse("content: // com.ljq.provider.personprovider/person");
Uri uri = Uri.parse( " content://com.ljq.provider.personprovider/person " );
Cursor cursor = contentResolver.query(uri, null , null , null , " id asc " );
while (cursor.moveToNext()){
int personid = cursor.getInt(cursor.getColumnIndex( " id " ));
String name = cursor.getString(cursor.getColumnIndex( " name " ));
String phone = cursor.getString(cursor.getColumnIndex( " phone " ));
Log.i(TAG, " personid= " + personid + " ,name= " + name + " ,phone= " + phone);
}
cursor.close();
}
public void testDelete() throws Throwable{
ContentResolver contentResolver = this .getContext().getContentResolver();
Uri uri = Uri.parse( " content://com.ljq.provider.personprovider/person/1 " );
contentResolver.delete(uri, null , null );
}
}