Question

我正在尝试创建一个登录页面并使用SQLiteOpenHelper类连接到SQLite数据库。但是SQLiteOpenHelper.java中的默认代码在db.reopenReadWrite（）行显示错误; 我检查过SQLiteDatabase.java文件的方法是reopenReadWrite（）; 你可以帮我解决这个问题吗？

Answer 1

您可以在@hide javadoc attribute中看到the source code隐藏此方法：

/**
 * Reopens the database in read-write mode.
 * If the database is already read-write, does nothing.
 *
 * @throws SQLiteException if the database could not be reopened as requested, in which
 * case it remains open in read only mode.
 * @throws IllegalStateException if the database is not open.
 *
 * @see #isReadOnly()
 * @hide
 */
public void reopenReadWrite() {
    synchronized (mLock) {
        throwIfNotOpenLocked();

        if (!isReadOnlyLocked()) {
            return; // nothing to do
        }

        // Reopen the database in read-write mode.
        final int oldOpenFlags = mConfigurationLocked.openFlags;
        mConfigurationLocked.openFlags = (mConfigurationLocked.openFlags & ~OPEN_READ_MASK)
                | OPEN_READWRITE;
        try {
            mConnectionPoolLocked.reconfigure(mConfigurationLocked);
        } catch (RuntimeException ex) {
            mConfigurationLocked.openFlags = oldOpenFlags;
            throw ex;
        }
    }
}

由于它不是公共API的一部分，因此您无法在不使用Reflection的情况下使用该方法。

最好的方法是使用公共API listed in the SQLiteDatabase documentation中的方法。

您需要的只是SQLiteOpenHelper#getReadableDatabase()方法，该方法会调用getDatabaseLocked()，内部调用db.reopenReadWrite()：

public SQLiteDatabase getReadableDatabase() {
    synchronized (this) {
        return getDatabaseLocked(false);
    }
}

private SQLiteDatabase getDatabaseLocked(boolean writable) {
    if (mDatabase != null) {
        if (!mDatabase.isOpen()) {
            // Darn!  The user closed the database by calling mDatabase.close().
            mDatabase = null;
        } else if (!writable || !mDatabase.isReadOnly()) {
            // The database is already open for business.
            return mDatabase;
        }
    }

    if (mIsInitializing) {
        throw new IllegalStateException("getDatabase called recursively");
    }

    SQLiteDatabase db = mDatabase;
    try {
        mIsInitializing = true;

        if (db != null) {
            if (writable && db.isReadOnly()) {
                db.reopenReadWrite();
            }

        //.......................

无法解决方法＆＃39; reopenReadWrite（）＆＃39;

1 个答案: