android 玩转ContentProvider之二－－实现多个ContentProvider对多张表进行操作
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";
}
}
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);
}
}
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);
}
}
Leader.java
package com.jacp.pojos;
public class Leader {
public String name;
public String title;
public int level;
}
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）：
如有遗漏不当之处，欢迎批评指正！