ContentProvider与数据库结合使用

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package practise.lxm.myProvider;import android.net.Uri;import android.provider.BaseColumns;/** * Created by Administrator on 2015/4/9. * 工具类，提供给调用该ContentProvider的ContentResolver */public class Words {    public static final String AUTHORITY = "lxm.practise.provide";    //单词表列名类    public static class Word implements BaseColumns{        //允许操作的列        public static final String _ID = "_id";        public static final String WORD = "word";        public static final String DETAIL = "detail";        //提供的两个uri        public static final Uri ALL_WORDS = Uri.parse("content://" + AUTHORITY + "/words");        public static final Uri ONE_WORD = Uri.parse("content://" + AUTHORITY + "/word");    }}

package practise.lxm.myProvider;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;/** * Created by Administrator on 2015/4/9. */public class MyProvider extends ContentProvider {    public static final String TABLE_NAME= "words";    //操作数据库    private MySQLiteOpenDataBase dbHelper ;    //UriMatcher    private static UriMatcher uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);    //注册代码    private static final int ALL_WORDS_CODE = 1;    private static final int WORDS_ID_CODE = 2;    static {        uriMatcher.addURI(Words.AUTHORITY,"words",ALL_WORDS_CODE);        uriMatcher.addURI(Words.AUTHORITY,"word/#",WORDS_ID_CODE);    }    @Override    public boolean onCreate() {        dbHelper = new MySQLiteOpenDataBase(this.getContext(),"MyProvider.db3",1);        return true;    }    //查询    @Override    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {        SQLiteDatabase db = dbHelper.getReadableDatabase(); //获取数据库操作对象        switch (uriMatcher.match(uri)){ //查询所有            case ALL_WORDS_CODE:                return db.query(TABLE_NAME,projection,selection,selectionArgs,null,null,sortOrder);            case WORDS_ID_CODE: //根据id查询                long id= ContentUris.parseId(uri);                String wordsWhere = Words.Word._ID + " =" + id;                if(selection != null && selection.length() > 0){                    wordsWhere += " and " + selection;                }                return db.query(TABLE_NAME,projection,wordsWhere,selectionArgs,null,null,sortOrder);            default: //未知                throw new IllegalArgumentException("未知的Uri：" + uri.toString());        }    }    //获取类型    @Override    public String getType(Uri uri) {        switch (uriMatcher.match(uri)){            case ALL_WORDS_CODE: //多项                return "vnd.android.cursor.dir/practise.lxm.myProvider.Word";            case WORDS_ID_CODE: //单项                return "vnd.android.cursor.item/practise.lxm.myProvider.Word";            default: //未知                throw new IllegalArgumentException("未知的Uri：" + uri.toString());        }    }    //新增    @Override    public Uri insert(Uri uri, ContentValues values) {        SQLiteDatabase db = dbHelper.getWritableDatabase();//获取操作数据库对象        switch (uriMatcher.match(uri)){            case ALL_WORDS_CODE:                //新增到数据库                long row_id = db.insert(TABLE_NAME,null,values);                if(row_id > 0) { //新增成功                    Uri newUri = ContentUris.withAppendedId(uri, row_id);                    //通知数据已改变                    getContext().getContentResolver().notifyChange(newUri,null);                    return newUri;                }                break;            default: //未知                throw new IllegalArgumentException("未知的Uri：" + uri.toString() + " code:" + uriMatcher.match(uri));        }        return null;    }    @Override    public int delete(Uri uri, String selection, String[] selectionArgs) {        SQLiteDatabase db = dbHelper.getReadableDatabase();//获取操作数据库对象        int delCount = 0; //删除的数量        switch (uriMatcher.match(uri)){            case WORDS_ID_CODE: //单项                //添加删除条件，id为指定值                long delId = ContentUris.parseId(uri);                String delWhere = Words.Word._ID + "=" + delId;                if(selection != null && selection.length() > 0){                    delWhere += " and " + selection;                }                //执行删除                delCount = db.delete(TABLE_NAME,delWhere,selectionArgs);                break;            case ALL_WORDS_CODE: //删除多项                delCount = db.delete(TABLE_NAME,selection,selectionArgs);            default: //未知                throw new IllegalArgumentException("未知的Uri：" + uri.toString());        }        //通知数据已更改        getContext().getContentResolver().notifyChange(uri,null);        return delCount;    }    @Override    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {        SQLiteDatabase db = dbHelper.getWritableDatabase();//获取操作数据库对象        int updateCount = 0; //更新的数量        switch (uriMatcher.match(uri)){            case WORDS_ID_CODE: //单项                //添加修改条件，id为指定值                long updateId = ContentUris.parseId(uri);                String updateWhere = Words.Word._ID + "=" + updateId;                if(selection != null && selection.length() > 0){                    updateWhere += " and " + selection;                }                //执行删除                updateCount = db.update(TABLE_NAME,values, updateWhere,selectionArgs);                break;            case ALL_WORDS_CODE: //删除多项                updateCount = db.update(TABLE_NAME,values, selection,selectionArgs);            default: //未知                throw new IllegalArgumentException("未知的Uri：" + uri.toString());        }        //通知数据已更改        getContext().getContentResolver().notifyChange(uri,null);        return updateCount;    }}

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