android 玩轉ContentProvider之二--實現多個ContentProvider對多張表進行操作
本人原創作品,謝絕轉載!
其它地方跟一個ContentProvider操作一張表都是一樣的,唯一區別是authority,在宣告的時候要注意,因為要宣告兩個ContentProvider,所以authority也要不一樣,否則就會因為找不到對應的ContentProvider處理而出現下面的異常:
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)
下面貼程式碼,有些要注意的地方也在程式碼中做了註釋。
SQLite資料庫直接操作類:
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) { // 建立programmer表 db.execSQL("CREATE TABLE " + Provider.ProgrammerColumns.TABLE_NAME + " (" + Provider.ProgrammerColumns._ID + " INTEGER PRIMARY KEY," + Provider.ProgrammerColumns.NAME + " TEXT," + Provider.ProgrammerColumns.AGE + " INTEGER" + ");"); // 建立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); } }
儲存跟資料庫及表有關的常量:
Provider.java
對leader表進行增刪改查操作的ContentProvider類:package com.jacp.demo.provider; import android.net.Uri; import android.provider.BaseColumns; /** * 儲存資料庫中的常量 * @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"; /** * 儲存programmer表中用到的常量 * @author jacp * */ public static final class ProgrammerColumns implements BaseColumns { // 注意兩張表的authority要不一樣 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"; } /** * 儲存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;
/**
* 對leader表進行操作的ContentProvider
* @author jacp
*
*/
public class LeaderProvider extends ContentProvider {
private static HashMap<String, String> 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<String, String>();
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);
}
}
對programmer表進行增刪改查操作的ContentProvider類:
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;
/**
* 對programmer表進行操作的ContentProvider
* @author jacp
*
*/
public class ProgrammerProvider extends ContentProvider {
private static HashMap<String, String> 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<String, String>();
sprogrammersProjectionMap.put(Provider.ProgrammerColumns._ID, Provider.ProgrammerColumns._ID);
sprogrammersProjectionMap.put(Provider.ProgrammerColumns.NAME, Provider.ProgrammerColumns.NAME);
sprogrammersProjectionMap.put(Provider.ProgrammerColumns.AGE, Provider.ProgrammerColumns.AGE);
}
}
儲存leader表的資料物件:
Leader.java
package com.jacp.pojos;
public class Leader {
public String name;
public String title;
public int level;
}
儲存Programmer表的資料物件:
Programmer.java
package com.jacp.pojos;
public class Programmer {
public String name;
public int age;
}
Activity測試:
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要釋放資源,如果Cursor沒有關閉系統會打出Error級別的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檔案中的註冊(要注意的地方,下面已標註):
<?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>
<!-- 這個地方的兩個provider的authories要不一樣,否則找不到對應ContentProvider處理出現 java.lang.IllegalArgumentException: Unknown URI異常 -->
<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下載地址:http://download.csdn.net/detail/maylian7700/4150144如有遺漏不當之處,歡迎批評指正!