我想使用预加载的数据库。数据库必须附加到应用程序中,然后才能更新。我对如何连接它以避免问题有很多疑问。我问那些回答问题的专业人士。谢谢您。
如果我的基数大于1 MB,它会弹出一个错误d/asset(909):数据超过uncompress_data_max。可以分解为小于1 MB的片段,并可以更改为增加(“。JPG“。“JPEG”。PNG“,”GIF“,”WAV“,”。MP2“,”MP3“,”“,”AAC“,”MPG“,”“MPEG”。中“。米迪“,”SMF“,”。喷气式飞机“,”“RTTL”。伊姆“,”XMF“,”。MP4“,”M4A“,”M4V“,”.3 gp“,”.3 gpp“,”.3 g2“,”.3 gpp2“,”。AMR“,”AWB“,”“WMA”。“WMV”。哪个选项更好(更容易-更改扩展名)。
“没有这样的android元数据表”可能会失败,但是我手动添加到数据库中,但是如果应用程序是多语言的呢?
在读取数据库时,我使用方法mdb=getreadabledatabase();,但我正在结束一个close reading-mdb.close();正如他们在Internet上所说的,可能不关心任何无法打开数据库文件的错误。这尤其适用于htc设备。
以下报价代码

public class QuestionsDbAdapter extends SQLiteOpenHelper {

private String DATABASE_PATH = "/data/data/YOUR_PACKAGE/";
public static final String DATABASE_NAME = "mantestQuestions";

public static final String TABLE_QUESTIONS = "Questions";
public static final String QUESTIONS_COLUMN_ID = "_id";
public static final String QUESTIONS_COLUMN_QUESTION ="Question";

public static final String TABLE_ANSWERS = "Answers";
public static final String ANSWERS_COLUMN_ID = "_id";
public static final String ANSWERS_COLUMN_QUESTION_ID = "QuestionId";
public static final String ANSWERS_COLUMN_ANSWER = "Answer";
public static final String ANSWERS_COLUMN_POINT = "Point";

private SQLiteDatabase mDb;

private final Context mContext;

private boolean mCreateDatabase = false;
private boolean mUpgradeDatabase = false;

/**
 * Constructor
 * Takes and keeps a reference of the passed context in order to access
 * the application's assets and resources
 * @param context
 */
public QuestionsDbAdapter(Context context) {
    super(context, DATABASE_NAME, null, context.getResources().getInteger(R.integer.questionDbVersion));

    mContext = context;
}

public void initializeDatabase(String path) {
    DATABASE_PATH = path;
    getWritableDatabase();

    if(mUpgradeDatabase) {
        mContext.deleteDatabase(DATABASE_NAME);
    }

    if(mCreateDatabase || mUpgradeDatabase) {
        try {
            copyDatabase();
        } catch (IOException e) {
            throw new Error("Error copying database");
        }
    }
}

private void copyDatabase() throws IOException {
    close();

    InputStream input = mContext.getAssets().open(DATABASE_NAME);

    String outFileName = DATABASE_PATH + DATABASE_NAME;

    OutputStream output = new FileOutputStream(outFileName);

    // Transfer bytes from the input file to the output file
    byte[] buffer = new byte[1024];
    int length;
    while ((length = input.read(buffer)) > 0) {
        output.write(buffer, 0, length);
    }

    output.flush();
    output.close();
    input.close();

    getWritableDatabase().close();
}

public QuestionsDbAdapter open() throws SQLException {
    mDb = getReadableDatabase();
    return this;
}

public void CleanUp() {
    mDb.close();
}

@Override
public void onCreate(SQLiteDatabase db) {
    mCreateDatabase = true;
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    mUpgradeDatabase = true;
}

/**
 * Public helper methods
 */

public Cursor getQuestionById(long rowId) throws SQLException {
    Cursor cursor = mDb.query(true, TABLE_QUESTIONS,
            new String[] { QUESTIONS_COLUMN_ID, QUESTIONS_COLUMN_QUESTION }, QUESTIONS_COLUMN_ID + "=" + rowId,
            null, null, null, null, null);

    return cursor;
}

public Cursor getAnswerById(long rowId) throws SQLException {
    Cursor cursor = mDb.query(true, TABLE_ANSWERS,
            new String[] { ANSWERS_COLUMN_ID, ANSWERS_COLUMN_QUESTION_ID, ANSWERS_COLUMN_ANSWER, ANSWERS_COLUMN_POINT },
            ANSWERS_COLUMN_ID + "=" + rowId,
            null, null, null, null, null);

    return cursor;
}

public Cursor getAnswersByQuestionId(long questionId) throws SQLException {
    Cursor cursor = mDb.query(true, TABLE_ANSWERS, new String[] {ANSWERS_COLUMN_ANSWER, ANSWERS_COLUMN_POINT},
            ANSWERS_COLUMN_QUESTION_ID + "=" + questionId, null, null, null, null, null);

    return cursor;
}

public long getCount() {
    String sql = "SELECT COUNT(*) FROM " + TABLE_QUESTIONS;
    SQLiteStatement statement = mDb.compileStatement(sql);
    long count = statement.simpleQueryForLong();
    return count;
}
}

最佳答案

不需要这个混乱的代码这里是很好的解决方案,你Android SQLiteAssetHelper

07-24 09:47
查看更多