android - Android 中的光标错误告诉我列不存在

Question

我的应用程序需要返回一个包含一堆引号的游标，具体取决于选择的作者。现在，我正在对应用程序进行硬编码，因此它只会返回一位作者的引述。

错误发生在我的游标适配器参数中，设置“to”列，它告诉我这个列“quote”不存在。

我已经尝试将 to 参数更改为 KEY_QUOTE，甚至尝试更改实际数据库列的名称，但现在仍然很高兴。

我做错了什么？

以下是此操作中使用的代码块。

1. 创建数据库表，引用
2. 填充此表
3. 查询报价
4. 打开数据库连接，创建游标(我得到实际错误的地方，使用“from”参数)

1.

private static final String CREATE_QUOTE_TABLE = 

            "create table " + QUOTES_TABLE +
            " (_id integer primary key autoincrement, " + 
            "auth_name text not null, " +
            "myQuote text not null, " +
            "category text not null);";

2.

public long populateQuotes(){

    ContentValues initialValues = new ContentValues();

    long[] rowIds = new long[authorName.length];

    // Add wilson quotes category: Anthropology
    for(int i = 0; i < 3; i++){
        initialValues.put(KEY_AUTHNAME, authorName[3]);
        initialValues.put(KEY_QUOTE, quoteRAW[i]);
        initialValues.put(KEY_CATEGORY, category[0]);
        rowIds[i] = qmDB.insertOrThrow(QUOTES_TABLE, null, initialValues);
    }
    // Add wilson quotes category: RAW
    for(int i = 3; i < 5; i++){
        initialValues.put(KEY_AUTHNAME, authorName[3]);
        initialValues.put(KEY_QUOTE, quoteRAW[i]);
        initialValues.put(KEY_CATEGORY, category[1]);
        rowIds[i] = qmDB.insertOrThrow(QUOTES_TABLE, null, initialValues);

    }
    // Add wilson quotes category: Philosophy
    for(int i = 5; i < 11; i++){
        initialValues.put(KEY_AUTHNAME, authorName[3]);
        initialValues.put(KEY_QUOTE, quoteRAW[i]);
        initialValues.put(KEY_CATEGORY, category[2]);
        rowIds[i] = qmDB.insertOrThrow(QUOTES_TABLE, null, initialValues);

    }
    // Add wilson quotes category: General Semantics
    for(int i = 11; i < 12; i++){
        initialValues.put(KEY_AUTHNAME, authorName[3]);
        initialValues.put(KEY_QUOTE, quoteRAW[i]);
        initialValues.put(KEY_CATEGORY, category[3]);
        rowIds[i] = qmDB.insertOrThrow(QUOTES_TABLE, null, initialValues);

    }
    // Add wilson quotes category: Humor
    for(int i = 11; i < 12; i++){
        initialValues.put(KEY_AUTHNAME, authorName[3]);
        initialValues.put(KEY_QUOTE, quoteRAW[i]);
        initialValues.put(KEY_CATEGORY, category[4]);
        rowIds[i] = qmDB.insertOrThrow(QUOTES_TABLE, null, initialValues);

    }

    return rowIds[0];
}

3.

public Cursor getQuotes(){

    /*
    return qmDB.query(QUOTES_TABLE, new String[]{
            KEY_QUOTE
            },
            KEY_AUTHNAME + "=" + "'Robert Anton Wilson'",
            null,
            null,
            null,
            null);*/



    //String who = authorName[position];
    return qmDB.rawQuery("SELECT _id as _id from Quotes WHERE auth_name = ?",
            new String[]{"'Robert Anton Wilson'"});

}

4.

// Create DB connection and open.
    dbm = new MyDBManager(this);
    dbm.open();

    // Call for the quotes to be queried, store results in cursor.
    myCursor = dbm.getQuotes();
    myCursor.moveToFirst();

    // Column quote does not exist?
    SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, R.layout.quoterow,                myCursor, new String[]{"myQuote"}, new int[]{R.id.quote});
    this.setListAdapter(mAdapter);

    myCursor.close();

为了进一步说明，我包含了错误日志:

05-01 18:38:13.876: ERROR/AndroidRuntime(1455): FATAL EXCEPTION: main
05-01 18:38:13.876: ERROR/AndroidRuntime(1455): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.QuoteMachine/com.QuoteMachine.Quote}: java.lang.IllegalArgumentException: column 'myQuote' does not exist
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2787)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2803)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.app.ActivityThread.access$2300(ActivityThread.java:135)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2136)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.os.Looper.loop(Looper.java:144)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.app.ActivityThread.main(ActivityThread.java:4937)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at java.lang.reflect.Method.invokeNative(Native Method)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at java.lang.reflect.Method.invoke(Method.java:521)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at dalvik.system.NativeStart.main(Native Method)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455): Caused by: java.lang.IllegalArgumentException: column 'myQuote' does not exist
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:314)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.widget.SimpleCursorAdapter.findColumns(SimpleCursorAdapter.java:312)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.widget.SimpleCursorAdapter.<init>(SimpleCursorAdapter.java:87)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at com.QuoteMachine.Quote.onCreate(Quote.java:42)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1069)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2751)
05-01 18:38:13.876: ERROR/AndroidRuntime(1455):     ... 11 more

Answer 1

在 CREATE_QUOTE_TABLE 中，您使用“quote text not null,”，并且在您显示的 logcat 中:Caused by: java.lang.IllegalArgumentException: column 'myQuote' does not exist。 KEY_QUOTE 的值是多少？它应该与表中的列名相匹配。

测试这个查询:

return qmDB.rawQuery("SELECT _id, myQuote, auth_name, category FROM Quotes WHERE auth_name=?", 
    new String[]{"'Robert Anton Wilson'"});

我相信您的问题不是查询试图检索不存在的列。我认为问题是您创建的游标没有您的适配器所需的所有信息(即，游标没有列，没有表)。