contentprovider用法

一、清单注册

<provider android:name="cn.itcast.db.PersonProvider" 

android:authorities="cn.itcast.providers.personprovider"

android:exported=true/> 前面类名，后面主机名，唯一识别

UriMatcher类使用介绍：

因为Uri代表了要操作的数据，所以我们经常需要解析Uri，并从Uri中获取数据。

Android系统提供了两个用于操作Uri的工具类，分别为UriMatcher 和ContentUris 。掌握它们的使用，会便于我们的开发工作。

UriMatcher类用于匹配Uri，它的用法如下：

首先第一步把你需要匹配Uri路径全部给注册上，如下：

//常量UriMatcher.NO_MATCH表示不匹配任何路径的返回码  

UriMatcher  sMatcher = new UriMatcher(UriMatcher.NO_MATCH);  

//如果match()方法匹配content://com.faith.providers.personprovider/person路径，返回匹配码为1  

sMatcher.addURI(“com.faith.providers.personprovider”, “person”, 1);//添加需要匹配uri，如果匹配就会返回匹配码  

//如果match()方法匹配content://com.faith.providers.personprovider/person/230路径，返回匹配码为2  

sMatcher.addURI(“com.faith.providers.personprovider”, “person/#”, 2);//#号为通配符  

switch (sMatcher.match(Uri.parse("content://com.faith.providers.personprovider/person/10"))) {   

   case 1  

    break;  

   case 2  

    break;  

   default://不匹配  

    break;  

}  

    注册完需要匹配的Uri后，就可以使用sMatcher.match(uri)方法对输入的Uri进行匹配，如果匹配就返回匹配码，匹配码是调用addURI()方法传入的第三个参数，假设匹配content://com.faith.providers.personprovider/person路径，返回的匹配码为1

ContentUris类使用介绍:

ContentUris类用于获取Uri路径后面的ID部分，它有两个比较实用的方法：

withAppendedId(uri, id)用于为路径加上ID部分：  

Uri uri = Uri.parse("content://com.faith.providers.personprovider/person")  

Uri resultUri = ContentUris.withAppendedId(uri, 10);   

//生成后的Uri为：content://com.faith.providers.personprovider/person/10  

  

parseId(uri)方法用于从路径中获取ID部分：  

Uri uri = Uri.parse("content://com.faith.providers.personprovider/person/10")  

long personid = ContentUris.parseId(uri);//获取的结果为:10  

二、在应用程序子包下创建一个ContentProvider类

public class PersonProvider extends ContentProvider {

private DBOpenHelper dbOpenHelper;
private static final UriMatcher MATCHER = new UriMatcher(UriMatcher.NO_MATCH);
private static final int PERSONS = 1;
private static final int PERSON = 2;
//添加要匹配的uri，分两种，一个是整张表，一个是某一行
static{
MATCHER.addURI("cn.itcast.providers.personprovider", "person", PERSONS);
MATCHER.addURI("cn.itcast.providers.personprovider", "person/#", PERSON);//#代表数字
}

//获得数据库操作实例
public boolean onCreate() {
dbOpenHelper = new DBOpenHelper(this.getContext());
return true;}
//添加操作
public Uri insert(Uri uri, ContentValues values) {
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
switch (MATCHER.match(uri)) {
case 1:
long rowid = db.insert("person", "name", values);
Uri insertUri = ContentUris.withAppendedId(uri, rowid);//cn.itcast.providers.personprovider/person/rowid
this.getContext().getContentResolver().notifyChange(insertUri, null);//发出数据变化通知
return insertUri;
default:
throw new IllegalArgumentException("this is unknown Uri" + uri);

}

}
//删除操作
public int delete(Uri uri, String selection, String[] selectionArgs) {
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
int num = 0;
switch (MATCHER.match(uri)) {
case 1:
num = db.delete("person", selection, selectionArgs);
break;
case 2:
long rowid = ContentUris.parseId(uri);
String where = "personid=" + rowid;
if(selection!=null &&!"".equals(selection.trim())){
where += "and" + selection;
}
num = db.delete("person", where, selectionArgs);
break;

default:
throw new IllegalArgumentException("this is unknown Uri:" + uri);
}
return num;
}

public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
int num = 0;
switch (MATCHER.match(uri)) {
case 1:
num = db.update("person", values, selection, selectionArgs);
break;
case 2:
long rowid = ContentUris.parseId(uri);
String where = "personid=" + rowid;
if(selection!=null &&!"".equals(selection.trim())){
where += "and" + selection;
}
num = db.update("person", values, where, selectionArgs);
break;

default:
throw new IllegalArgumentException("this is unknown Uri:" + uri);
}
return num;
}

@Override//外部应用查询内容提供者数据
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
String sortOrder) {

SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
switch (MATCHER.match(uri)) {
case 1:
return db.query("person", null, selection, selectionArgs, null, null, sortOrder);

case 2:
long rowid = ContentUris.parseId(uri);
String where = "personid=" + rowid;
if(selection!=null &&!"".equals(selection.trim())){
where += "and" + selection;
}

return db.query("person", null, where, selectionArgs, null, null, sortOrder);

default:
throw new IllegalArgumentException("this is unknown Uri:" + uri);
}

}

public String getType(Uri uri) {

switch (MATCHER.match(uri)) {
case 1:
return "vnd.android.crsor.dir/person";
case 2:
return "vnd.android.crsor.item/person";
default:
throw new IllegalArgumentException("this is unknown Uri:" + uri);
}

}}

相关测试方法

public class AccessContentProvider extends AndroidTestCase {  

    private final static String TAG = "AccessContentProvider";  

  

    public void testSave() throws Throwable {  

        ContentResolver resolver = this.getContext().getContentResolver();  

        Uri insertUri = Uri.parse("content://com.faith.providers.personprovider/person");  

        ContentValues values = new ContentValues();  

        values.put("name", "meijun");  

        values.put("age", "15");  

        values.put("phone", "199893");  

        Uri uri = resolver.insert(insertUri, values);  

        Log.d(TAG, uri.toString());  

    }  

      

    public void testUpdate() throws Throwable {  

        ContentResolver resolver = this.getContext().getContentResolver();  

        Uri updateUri = Uri.parse("content://com.faith.providers.personprovider/person/6");  

        ContentValues values = new ContentValues();  

        values.put("name", "meijun");  

        values.put("age", "35");  

        values.put("phone", "1998933243");  

        resolver.update(updateUri, values, null, null);  

    }  

      

    public void testQuery() throws Throwable {  

        ContentResolver resolver = this.getContext().getContentResolver();  

        Uri queryUri = Uri.parse("content://com.faith.providers.personprovider/person");  

        Cursor cursor = resolver.query(queryUri, null, null, null, null);  

        while(cursor.moveToNext()){  

            int id = cursor.getInt(cursor.getColumnIndex("id"));  

            String name = cursor.getString(cursor.getColumnIndex("name"));  

            String phone = cursor.getString(cursor.getColumnIndex("phone"));  

            short age = cursor.getShort(cursor.getColumnIndex("age"));  

            Log.d(TAG, "id = " + id + ",name = " + name   

                    + ",phone = " + phone + ",age = " + age);  

        }  

    }  

      

    public void testDelete() throws Throwable {  

        ContentResolver resolver = this.getContext().getContentResolver();  

        Uri deleteUri = Uri.parse("content://com.faith.providers.personprovider/person/6");  

        resolver.delete(deleteUri, null, null);  

    }  

      

    public void testType() throws Throwable {  

        ContentResolver resolver = this.getContext().getContentResolver();  

        Uri typeUri = Uri.parse("content://com.faith.providers.personprovider/person/6");  

        String type = resolver.getType(typeUri);  

        Log.d(TAG, type);  

    }  

}  
http://blog.csdn.net/faith_boys/article/details/8917395