Android内容提供者ContentProvider用法实例分析

本文实例讲述了Android内容提供者ContentProvider用法。分享给大家供大家参考，具体如下：

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);
 }
}

希望本文所述对大家Android程序设计有所帮助。