十三、ContentProvider案例

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);
    }
}