Android内容提供者（Content provider）

androidHung 2014-06-04

展开全文

Java代码
package com.jbridge.db;

import com.jbridge.service.DataBaseOpenHelper;

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;

public class PersonContentProvider extends ContentProvider {
    private DataBaseOpenHelper dbOpenHelper;
    private static final int ALLPERSON = 1;
    private static final int PERSON = 2;
    private static final UriMatcher sMatcher = new UriMatcher(
            UriMatcher.NO_MATCH);
    static {
        sMatcher.addURI("com.jbridge.provider.personprovider", "person",
                ALLPERSON);
        sMatcher.addURI("com.jbridge.provider.personprovider", "person/#",
                PERSON);
    }

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        int count = 0;
        switch (sMatcher.match(uri)) {
        case ALLPERSON:// com.jbridge.provider.personprovider/person
            count=db.delete("person", selection,selectionArgs);
            break;
        case PERSON:// com.jbridge.provider.personprovider/person/10
            long personid=ContentUris.parseId(uri);
            //防止他输入时String selection, String[] selectionArgs参数为空，这样就会修改表的所有数据了
            String where=TextUtils.isEmpty(selection)?"personid=?":selection+" and personid=?";
            String[] params=new String[]{String.valueOf(personid)};
            if (!TextUtils.isEmpty(selection)&&selectionArgs!=null) {
                params=new String[selectionArgs.length+1];
                for (int i=0;i<selectionArgs.length;i++) {
                    params[i]=selectionArgs[i];
                }
                params[selectionArgs.length]=String.valueOf(personid);
            }
            count = db.delete("person", where,params);
            break;
        default:
            throw new IllegalArgumentException("Unknow Uri:" + uri);

        }

        return count;
    }

    @Override
    public String getType(Uri uri) {
        switch (sMatcher.match(uri)) {
        case ALLPERSON:// //数据集的MIME类型字符串则应该以vnd.android.cursor.dir/开头
            return "vnd.android.cursor.dir/personprovider.person";
        case PERSON://单一数据的MIME类型字符串应该以vnd.android.cursor.item/开头
            return "vnd.android.cursor.item/personprovider.person";
        default:
            throw new IllegalArgumentException("Unknow Uri:" + uri);
        }
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        long id = 0;
        switch (sMatcher.match(uri)) {
        case ALLPERSON:// com.jbridge.provider.personprovider/person
            id = db.insert("person", "name", values);// 返回值是记录的行号，主键为int实际上就是主键值，主键为text则为行号
            return ContentUris.withAppendedId(uri, id);
        case PERSON:// com.jbridge.provider.personprovider/person/10
            id = db.insert("person", "name", values);// 返回值是记录的行号，主键为int实际上就是主键值，主键为text则为行号
            String path = uri.toString();
            return Uri.parse(path.substring(0, path.lastIndexOf("/")) + id);
        default:
            throw new IllegalArgumentException("Unknow Uri:" + uri);
        }
    }

    @Override
    public boolean onCreate() {
        dbOpenHelper=new DataBaseOpenHelper(this.getContext());
        return false;
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
            String sortOrder) {
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        switch (sMatcher.match(uri)) {
        case ALLPERSON:// com.jbridge.provider.personprovider/person
            return db.query("person",projection, selection, selectionArgs,null, null, sortOrder);
        case PERSON:// com.jbridge.provider.personprovider/person/10
            long personid=ContentUris.parseId(uri);
            //防止他输入时String selection, String[] selectionArgs参数为空，这样就会修改表的所有数据了
            String where=TextUtils.isEmpty(selection)?"personid=?":selection+" and personid=?";
            String[] params=new String[]{String.valueOf(personid)};
            if (!TextUtils.isEmpty(selection)&&selectionArgs!=null) {
                params=new String[selectionArgs.length+1];
                for (int i=0;i<selectionArgs.length;i++) {
                    params[i]=selectionArgs[i];
                }
                params[selectionArgs.length]=String.valueOf(personid);
            }
            return db.query("person",projection, where, params,null, null, sortOrder);

        default:
            throw new IllegalArgumentException("Unknow Uri:" + uri);

        }


    }

    @Override
    //返回值为影响的记录数
    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        int count = 0;
        switch (sMatcher.match(uri)) {
        case ALLPERSON:// com.jbridge.provider.personprovider/person
            count = db.update("person", values, selection,selectionArgs);
            break;
        case PERSON:// com.jbridge.provider.personprovider/person/10
            long personid=ContentUris.parseId(uri);
            //防止他输入时String selection, String[] selectionArgs参数为空，这样就会修改表的所有数据了
            String where=TextUtils.isEmpty(selection)?"personid=?":selection+" and personid=?";
            String[] params=new String[]{String.valueOf(personid)};
            if (!TextUtils.isEmpty(selection)&&selectionArgs!=null) {
                params=new String[selectionArgs.length+1];
                for (int i=0;i<selectionArgs.length;i++) {
                    params[i]=selectionArgs[i];
                }
                params[selectionArgs.length]=String.valueOf(personid);
            }
            count = db.update("person", values, where,params);
            break;
        default:
            throw new IllegalArgumentException("Unknow Uri:" + uri);

        }

        return count;
    }

}