android 玩转ContentProvider之二－－实现多个ContentProvider对多张表进行操作

android 玩转ContentProvider之二－－实现多个ContentProvider对多张表进行操作

分类： android技巧总结 2012-03-17 23:44  841人阅读  评论(0)  收藏  举报

本人原创作品，谢绝转载！

    上一篇android 玩转ContentProvider之一－－实现ContentProvider操作数据库讲了ContentProvider基本用法，下面提高一下，实现两个ContentProvider分别对表进行操作。

    其它地方跟一个ContentProvider操作一张表都是一样的，唯一区别是authority，在声明的时候要注意，因为要声明两个ContentProvider，所以authority也要不一样，否则就会因为找不到对应的ContentProvider处理而出现下面的异常：

03-17 15:29:17.494: E/AndroidRuntime(529): Caused by: java.lang.IllegalArgumentException: Unknown URI content://com.jacp.provider.demo.company/leaders
03-17 15:29:17.494: E/AndroidRuntime(529): at com.jacp.demo.provider.ProgrammerProvider.insert(ProgrammerProvider.java:88)
03-17 15:29:17.494: E/AndroidRuntime(529): at android.content.ContentProvider$Transport.insert(ContentProvider.java:174)
03-17 15:29:17.494: E/AndroidRuntime(529): at android.content.ContentResolver.insert(ContentResolver.java:587)
03-17 15:29:17.494: E/AndroidRuntime(529): at com.jacp.demo.ContentProviderDemoActivity.insertLeader(ContentProviderDemoActivity.java:78)
03-17 15:29:17.494: E/AndroidRuntime(529): at com.jacp.demo.ContentProviderDemoActivity.testLeader(ContentProviderDemoActivity.java:69)
03-17 15:29:17.494: E/AndroidRuntime(529): at com.jacp.demo.ContentProviderDemoActivity.onCreate(ContentProviderDemoActivity.java:24)
03-17 15:29:17.494: E/AndroidRuntime(529): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
03-17 15:29:17.494: E/AndroidRuntime(529): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)

    下面贴代码，有些要注意的地方也在代码中做了注释。

SQLite数据库直接操作类：

DatabaseHelper.java

 package com.jacp.database;

 import android.content.Context;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;

 import com.jacp.demo.provider.Provider;

 public class DatabaseHelper extends SQLiteOpenHelper {
     private static final String DATABASE_NAME = "jacp_demo.db";
     private static final int DATABASE_VERSION = 1;

     public DatabaseHelper(Context context) {
         super(context, DATABASE_NAME, null, DATABASE_VERSION);
     }

     @Override
     public void onCreate(SQLiteDatabase db) {
         // 创建programmer表
         db.execSQL("CREATE TABLE " + Provider.ProgrammerColumns.TABLE_NAME + " ("
                 + Provider.ProgrammerColumns._ID + " INTEGER PRIMARY KEY,"
                 + Provider.ProgrammerColumns.NAME + " TEXT,"
                 + Provider.ProgrammerColumns.AGE + " INTEGER"
                 + ");");

         // 创建leader表
         db.execSQL("CREATE TABLE " + Provider.LeaderColumns.TABLE_NAME + " ("
                 + Provider.LeaderColumns._ID + " INTEGER PRIMARY KEY,"
                 + Provider.LeaderColumns.NAME + " TEXT,"
                 + Provider.LeaderColumns.TITLE + " TEXT,"
                 + Provider.LeaderColumns.LEVEL + " INTEGER"
                 + ");");
     }

     @Override
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
         db.execSQL("DROP TABLE IF EXISTS " + Provider.ProgrammerColumns.TABLE_NAME);
         db.execSQL("DROP TABLE IF EXISTS " + Provider.LeaderColumns.TABLE_NAME);
         onCreate(db);
     }
 }

保存跟数据库及表有关的常量：
Provider.java

 package com.jacp.demo.provider;

 import android.net.Uri;
 import android.provider.BaseColumns;

 /**
  * 保存数据库中的常量
  * @author jacp
  *
  */
 public class Provider {

     public static final String CONTENT_TYPE = "vnd.android.cursor.dir/vnd.jacp.demo";

     public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/vnd.jacp.demo";

     /**
      * 保存programmer表中用到的常量
      * @author jacp
      *
      */
     public static final class ProgrammerColumns implements BaseColumns {
         // 注意两张表的authority要不一样
         public static final String AUTHORITY = "com.jacp.provider.demo.programmer";
         public static final Uri CONTENT_URI = Uri.parse("content://"+ AUTHORITY +"/programmers");
         public static final String TABLE_NAME = "programmer";
         public static final String DEFAULT_SORT_ORDER = "age desc";

         public static final String NAME = "name";
         public static final String AGE = "age";

     }

     /**
      * 保存leader表中用到的常量
      * @author mayliang
      *
      */
     public static final class LeaderColumns implements BaseColumns {
         public static final String AUTHORITY = "com.jacp.provider.demo.leader";
         public static final Uri CONTENT_URI = Uri.parse("content://"+ AUTHORITY +"/leaders");
         public static final String TABLE_NAME = "leader";
         public static final String DEFAULT_SORT_ORDER = "level desc";

         public static final String NAME = "name";
         public static final String TITLE = "title";
         public static final String LEVEL = "level";

     }

 }

对leader表进行增删改查操作的ContentProvider类：

LeaderProvider.java

 package com.jacp.demo.provider;

 import java.util.HashMap;

 import android.content.ContentProvider;
 import android.content.ContentUris;
 import android.content.ContentValues;
 import android.content.UriMatcher;
 import android.database.Cursor;
 import android.database.SQLException;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteQueryBuilder;
 import android.net.Uri;
 import android.text.TextUtils;

 import com.jacp.database.DatabaseHelper;

 /**
  * 对leader表进行操作的ContentProvider
  * @author jacp
  *
  */
 public class LeaderProvider extends ContentProvider {

     private static HashMap sLeadersProjectionMap;

     private static final int LEADERS = 1;
     private static final int LEADER_ID = 2;

     private static final UriMatcher sUriMatcher;

     private DatabaseHelper mOpenHelper;

     @Override
     public boolean onCreate() {
         mOpenHelper = new DatabaseHelper(getContext());
         return true;
     }

     @Override
     public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
             String sortOrder) {
         SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
         qb.setTables(Provider.LeaderColumns.TABLE_NAME);

         switch (sUriMatcher.match(uri)) {
         case LEADERS:
             qb.setProjectionMap(sLeadersProjectionMap);
             break;

         case LEADER_ID:
             qb.setProjectionMap(sLeadersProjectionMap);
             qb.appendWhere(Provider.LeaderColumns._ID + "=" + uri.getPathSegments().get(1));
             break;

         default:
             throw new IllegalArgumentException("Unknown URI " + uri);
         }

         // If no sort order is specified use the default
         String orderBy;
         if (TextUtils.isEmpty(sortOrder)) {
             orderBy = Provider.LeaderColumns.DEFAULT_SORT_ORDER;
         } else {
             orderBy = sortOrder;
         }

         // Get the database and run the query
         SQLiteDatabase db = mOpenHelper.getReadableDatabase();
         Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, orderBy);

         // Tell the cursor what uri to watch, so it knows when its source data changes
         c.setNotificationUri(getContext().getContentResolver(), uri);
         return c;
     }

     @Override
     public String getType(Uri uri) {
         switch (sUriMatcher.match(uri)) {
         case LEADERS:
             return Provider.CONTENT_TYPE;
         case LEADER_ID:
             return Provider.CONTENT_ITEM_TYPE;
         default:
             throw new IllegalArgumentException("Unknown URI " + uri);
         }
     }

     @Override
     public Uri insert(Uri uri, ContentValues initialValues) {
         // Validate the requested uri
         if (sUriMatcher.match(uri) != LEADERS) {
             throw new IllegalArgumentException("Unknown URI " + uri);
         }

         ContentValues values;
         if (initialValues != null) {
             values = new ContentValues(initialValues);
         } else {
             values = new ContentValues();
         }

         // Make sure that the fields are all set
         if (values.containsKey(Provider.LeaderColumns.NAME) == false) {
             values.put(Provider.LeaderColumns.NAME, "");
         }

         if (values.containsKey(Provider.LeaderColumns.TITLE) == false) {
             values.put(Provider.LeaderColumns.TITLE, "");
         }

         if (values.containsKey(Provider.LeaderColumns.LEVEL) == false) {
             values.put(Provider.LeaderColumns.LEVEL, 0);
         }

         SQLiteDatabase db = mOpenHelper.getWritableDatabase();
         long rowId = db.insert(Provider.LeaderColumns.TABLE_NAME, Provider.LeaderColumns.NAME, values);
         if (rowId > 0) {
             Uri noteUri = ContentUris.withAppendedId(Provider.LeaderColumns.CONTENT_URI, rowId);
             getContext().getContentResolver().notifyChange(noteUri, null);
             return noteUri;
         }

         throw new SQLException("Failed to insert row into " + uri);
     }

     @Override
     public int delete(Uri uri, String where, String[] whereArgs) {
         SQLiteDatabase db = mOpenHelper.getWritableDatabase();
         int count;
         switch (sUriMatcher.match(uri)) {
         case LEADERS:
             count = db.delete(Provider.LeaderColumns.TABLE_NAME, where, whereArgs);
             break;

         case LEADER_ID:
             String noteId = uri.getPathSegments().get(1);
             count = db.delete(Provider.LeaderColumns.TABLE_NAME, Provider.LeaderColumns._ID + "=" + noteId
                     + (!TextUtils.isEmpty(where) ? " AND (" + where + ')' : ""), whereArgs);
             break;

         default:
             throw new IllegalArgumentException("Unknown URI " + uri);
         }

         getContext().getContentResolver().notifyChange(uri, null);
         return count;
     }

     @Override
     public int update(Uri uri, ContentValues values, String where, String[] whereArgs) {
         SQLiteDatabase db = mOpenHelper.getWritableDatabase();
         int count;
         switch (sUriMatcher.match(uri)) {
         case LEADERS:
             count = db.update(Provider.LeaderColumns.TABLE_NAME, values, where, whereArgs);
             break;

         case LEADER_ID:
             String noteId = uri.getPathSegments().get(1);
             count = db.update(Provider.LeaderColumns.TABLE_NAME, values, Provider.LeaderColumns._ID + "=" + noteId
                     + (!TextUtils.isEmpty(where) ? " AND (" + where + ')' : ""), whereArgs);
             break;

         default:
             throw new IllegalArgumentException("Unknown URI " + uri);
         }

         getContext().getContentResolver().notifyChange(uri, null);
         return count;
     }

     static {
         sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
         sUriMatcher.addURI(Provider.LeaderColumns.AUTHORITY, "leaders", LEADERS);
         sUriMatcher.addURI(Provider.LeaderColumns.AUTHORITY, "leaders/#", LEADER_ID);

         sLeadersProjectionMap = new HashMap();
         sLeadersProjectionMap.put(Provider.LeaderColumns._ID, Provider.LeaderColumns._ID);
         sLeadersProjectionMap.put(Provider.LeaderColumns.NAME, Provider.LeaderColumns.NAME);
         sLeadersProjectionMap.put(Provider.LeaderColumns.TITLE, Provider.LeaderColumns.TITLE);
         sLeadersProjectionMap.put(Provider.LeaderColumns.LEVEL, Provider.LeaderColumns.LEVEL);
     }
 }

对programmer表进行增删改查操作的ContentProvider类：

ProgrammerProvider.java

 package com.jacp.demo.provider;

 import java.util.HashMap;

 import android.content.ContentProvider;
 import android.content.ContentUris;
 import android.content.ContentValues;
 import android.content.UriMatcher;
 import android.database.Cursor;
 import android.database.SQLException;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteQueryBuilder;
 import android.net.Uri;
 import android.text.TextUtils;

 import com.jacp.database.DatabaseHelper;

 /**
  * 对programmer表进行操作的ContentProvider
  * @author jacp
  *
  */
 public class ProgrammerProvider extends ContentProvider {

     private static HashMap sprogrammersProjectionMap;

     private static final int PROGRAMMERS = 1;
     private static final int PROGRAMMERS_ID = 2;

     private static final UriMatcher sUriMatcher;

     private DatabaseHelper mOpenHelper;

     @Override
     public boolean onCreate() {
         mOpenHelper = new DatabaseHelper(getContext());
         return true;
     }

     @Override
     public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
             String sortOrder) {
         SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
         qb.setTables(Provider.ProgrammerColumns.TABLE_NAME);

         switch (sUriMatcher.match(uri)) {
         case PROGRAMMERS:
             qb.setProjectionMap(sprogrammersProjectionMap);
             break;

         case PROGRAMMERS_ID:
             qb.setProjectionMap(sprogrammersProjectionMap);
             qb.appendWhere(Provider.ProgrammerColumns._ID + "=" + uri.getPathSegments().get(1));
             break;

         default:
             throw new IllegalArgumentException("Unknown URI " + uri);
         }

         // If no sort order is specified use the default
         String orderBy;
         if (TextUtils.isEmpty(sortOrder)) {
             orderBy = Provider.ProgrammerColumns.DEFAULT_SORT_ORDER;
         } else {
             orderBy = sortOrder;
         }

         // Get the database and run the query
         SQLiteDatabase db = mOpenHelper.getReadableDatabase();
         Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, orderBy);

         // Tell the cursor what uri to watch, so it knows when its source data changes
         c.setNotificationUri(getContext().getContentResolver(), uri);
         return c;
     }

     @Override
     public String getType(Uri uri) {
         switch (sUriMatcher.match(uri)) {
         case PROGRAMMERS:
             return Provider.CONTENT_TYPE;
         case PROGRAMMERS_ID:
             return Provider.CONTENT_ITEM_TYPE;
         default:
             throw new IllegalArgumentException("Unknown URI " + uri);
         }
     }

     @Override
     public Uri insert(Uri uri, ContentValues initialValues) {
         // Validate the requested uri
         if (sUriMatcher.match(uri) != PROGRAMMERS) {
             throw new IllegalArgumentException("Unknown URI " + uri);
         }

         ContentValues values;
         if (initialValues != null) {
             values = new ContentValues(initialValues);
         } else {
             values = new ContentValues();
         }

         // Make sure that the fields are all set
         if (values.containsKey(Provider.ProgrammerColumns.NAME) == false) {
             values.put(Provider.ProgrammerColumns.NAME, "");
         }

         if (values.containsKey(Provider.ProgrammerColumns.AGE) == false) {
             values.put(Provider.ProgrammerColumns.AGE, 0);
         }

         SQLiteDatabase db = mOpenHelper.getWritableDatabase();
         long rowId = db.insert(Provider.ProgrammerColumns.TABLE_NAME, Provider.ProgrammerColumns.NAME, values);
         if (rowId > 0) {
             Uri noteUri = ContentUris.withAppendedId(Provider.ProgrammerColumns.CONTENT_URI, rowId);
             getContext().getContentResolver().notifyChange(noteUri, null);
             return noteUri;
         }

         throw new SQLException("Failed to insert row into " + uri);
     }

     @Override
     public int delete(Uri uri, String where, String[] whereArgs) {
         SQLiteDatabase db = mOpenHelper.getWritableDatabase();
         int count;
         switch (sUriMatcher.match(uri)) {
         case PROGRAMMERS:
             count = db.delete(Provider.ProgrammerColumns.TABLE_NAME, where, whereArgs);
             break;

         case PROGRAMMERS_ID:
             String noteId = uri.getPathSegments().get(1);
             count = db.delete(Provider.ProgrammerColumns.TABLE_NAME, Provider.ProgrammerColumns._ID + "=" + noteId
                     + (!TextUtils.isEmpty(where) ? " AND (" + where + ')' : ""), whereArgs);
             break;

         default:
             throw new IllegalArgumentException("Unknown URI " + uri);
         }

         getContext().getContentResolver().notifyChange(uri, null);
         return count;
     }

     @Override
     public int update(Uri uri, ContentValues values, String where, String[] whereArgs) {
         SQLiteDatabase db = mOpenHelper.getWritableDatabase();
         int count;
         switch (sUriMatcher.match(uri)) {
         case PROGRAMMERS:
             count = db.update(Provider.ProgrammerColumns.TABLE_NAME, values, where, whereArgs);
             break;

         case PROGRAMMERS_ID:
             String noteId = uri.getPathSegments().get(1);
             count = db.update(Provider.ProgrammerColumns.TABLE_NAME, values, Provider.ProgrammerColumns._ID + "=" + noteId
                     + (!TextUtils.isEmpty(where) ? " AND (" + where + ')' : ""), whereArgs);
             break;

         default:
             throw new IllegalArgumentException("Unknown URI " + uri);
         }

         getContext().getContentResolver().notifyChange(uri, null);
         return count;
     }

     static {
         sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
         sUriMatcher.addURI(Provider.ProgrammerColumns.AUTHORITY, "programmers", PROGRAMMERS);
         sUriMatcher.addURI(Provider.ProgrammerColumns.AUTHORITY, "programmers/#", PROGRAMMERS_ID);

         sprogrammersProjectionMap = new HashMap();
         sprogrammersProjectionMap.put(Provider.ProgrammerColumns._ID, Provider.ProgrammerColumns._ID);
         sprogrammersProjectionMap.put(Provider.ProgrammerColumns.NAME, Provider.ProgrammerColumns.NAME);
         sprogrammersProjectionMap.put(Provider.ProgrammerColumns.AGE, Provider.ProgrammerColumns.AGE);
     }
 }

保存leader表的数据对象：

Leader.java

 package com.jacp.pojos;

 public class Leader {

     public String name;
     public String title;
     public int level;
 }

保存Programmer表的数据对象：

Programmer.java

 package com.jacp.pojos;

 public class Programmer {

     public String name;
     public int age;
 }

Activity测试：

 package com.jacp.demo;

 import android.app.Activity;
 import android.content.ContentValues;
 import android.database.Cursor;
 import android.net.Uri;
 import android.os.Bundle;
 import android.text.TextUtils;
 import android.util.Log;

 import com.jacp.demo.provider.Provider;
 import com.jacp.pojos.Leader;
 import com.jacp.pojos.Programmer;

 public class ContentProviderDemoActivity extends Activity {

     private static final String TAG = "ProviderActivity";

     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);

         testLeader();
         testProgrammer();
     }

     private void testProgrammer() {
         Programmer p = new Programmer();
         p.name = "jacp";
         p.age = 99;
         int id = insertProgrammer(p);
         queryProgrammer(id);
     }

     private int insertProgrammer(Programmer programmer) {
         ContentValues values = new ContentValues();
         values.put(Provider.ProgrammerColumns.NAME, programmer.name);
         values.put(Provider.ProgrammerColumns.AGE, programmer.age);
         Uri uri = getContentResolver().insert(Provider.ProgrammerColumns.CONTENT_URI, values);
         Log.i(TAG, "insert uri="+uri);
         String lastPath = uri.getLastPathSegment();
         if (TextUtils.isEmpty(lastPath)) {
             Log.i(TAG, "insert failure!");
         } else {
             Log.i(TAG, "insert success! the id is " + lastPath);
         }

         return Integer.parseInt(lastPath);
     }

     private void queryProgrammer(int id) {
         Cursor c = getContentResolver().query(Provider.ProgrammerColumns.CONTENT_URI, new String[] { Provider.ProgrammerColumns.NAME, Provider.ProgrammerColumns.AGE }, Provider.ProgrammerColumns._ID + "=?", new String[] { id + "" }, null);
         if (c != null && c.moveToFirst()) {
             Programmer p = new Programmer();
             p.name = c.getString(c.getColumnIndexOrThrow(Provider.ProgrammerColumns.NAME));
             p.age = c.getInt(c.getColumnIndexOrThrow(Provider.ProgrammerColumns.AGE));
             c.close(); // 用完Cursor要释放资源，如果Cursor没有关闭系统会打出Error级别的Log
             Log.i(TAG, "programmer.name="+p.name+"---programmer.age="+p.age);
         } else {
             Log.i(TAG, "query failure!");
         }
     }

     private void testLeader() {
         Leader leader = new Leader();
         leader.name = "jacky";
         leader.title = "CTO";
         leader.level = 30;
         int id = insertLeader(leader);
         queryLeader(id);
     }

     private int insertLeader(Leader leader) {
         ContentValues values = new ContentValues();
         values.put(Provider.LeaderColumns.NAME, leader.name);
         values.put(Provider.LeaderColumns.TITLE, leader.title);
         values.put(Provider.LeaderColumns.LEVEL, leader.level);
         Uri uri = getContentResolver().insert(Provider.LeaderColumns.CONTENT_URI, values);
         Log.i(TAG, "insert uri="+uri);
         String lastPath = uri.getLastPathSegment();
         if (TextUtils.isEmpty(lastPath)) {
             Log.i(TAG, "insert failure!");
         } else {
             Log.i(TAG, "insert success! the id is " + lastPath);
         }

         return Integer.parseInt(lastPath);
     }

     private void queryLeader(int id) {
         Cursor c = getContentResolver().query(Provider.LeaderColumns.CONTENT_URI, new String[] { Provider.LeaderColumns.NAME, Provider.LeaderColumns.TITLE, Provider.LeaderColumns.LEVEL }, Provider.LeaderColumns._ID + "=?", new String[] { id + "" }, null);
         if (c != null && c.moveToFirst()) {
             Leader leader = new Leader();
             leader.name = c.getString(c.getColumnIndexOrThrow(Provider.LeaderColumns.NAME));
             leader.title = c.getString(c.getColumnIndexOrThrow(Provider.LeaderColumns.TITLE));
             leader.level = c.getInt(c.getColumnIndexOrThrow(Provider.LeaderColumns.LEVEL));
             Log.i(TAG, "leader.name="+leader.name+"---leader.title="+leader.title+"---leader.level="+leader.level);
         } else {
             Log.i(TAG, "query failure!");
         }
     }
 }

Manifest.xml文件中的注册（要注意的地方，下面已标注）：

 xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.jacp.demo"
     android:versionCode="1"
     android:versionName="1.0" >

     <uses-sdk android:minSdkVersion="8" />

     <application
         android:icon="@drawable/ic_launcher"
         android:label="@string/app_name" >
         <activity
             android:label="@string/app_name"
             android:name=".ContentProviderDemoActivity" >
             <intent-filter >
                 <action android:name="android.intent.action.MAIN" />

                 <category android:name="android.intent.category.LAUNCHER" />
             intent-filter>
         activity>


         <provider android:name=".provider.ProgrammerProvider"
             android:authorities="com.jacp.provider.demo.programmer" />

         <provider android:name=".provider.LeaderProvider"
             android:authorities="com.jacp.provider.demo.leader" />
     application>

 manifest>

demo下载地址： http://download.csdn.net/detail/maylian7700/4150144

如有遗漏不当之处，欢迎批评指正！