Android 光标奇怪的行为
经过在大型应用程序中进行多个小时的错误搜索后，我终于找到了该错误。此日志记录捕获了问题：
Log.d(TAG,"buildList, DBresult.getInt(1): "+DBresult.getInt(1));
Log.d(TAG,"buildList, DBresult.getString(1): "+DBresult.getString(1));
Log.d(TAG,"buildList, DBresult.getInt(4): "+DBresult.getInt(4));
Log.d(TAG,"buildList, DBresult.getString(4): "+DBresult.getString(4));
结果输出：
05-06 11:11:20.123: DEBUG/TodoList(18943): buildList, DBresult.getInt(1): 0
05-06 11:11:20.123: DEBUG/TodoList(18943): buildList, DBresult.getString(1): false
05-06 11:11:20.123: DEBUG/TodoList(18943): buildList, DBresult.getInt(4): 0
05-06 11:11:20.123: DEBUG/TodoList(18943): buildList, DBresult.getString(4): true
没有正在运行的后台线程。正如您所看到的，问题在于“0”在某种情况下被解释为 false，而在另一种情况下被解释为 true。由于我完全不知道这是如何发生的，所以我不知道如何继续。什么可能导致这种行为？两列都是“布尔”类型，即 sqlite 中的数字。不幸的是，返回的字符串是正确的值，而整数始终为 0。如果我将数据库导出到我的计算机并使用 SQlite Administrator 检查它，我可以看到值设置正确，只有 getInt() 函数总是返回 0。我知道这在我编写的其他应用程序中有效，但我不知道为什么它停止工作。
我尝试过在2.0、2.0.1和2.1下编译代码，它总是出现。我可以通过获取如下布尔值来使我的应用程序再次运行：
myBool= (DBresult.getString(0).equals("true"));
但这既丑陋又没有优化。欢迎就导致此行为的原因提供任何建议。
干杯，
After many houres of bug searching in a big app, I have finally tracked down the bug. This logging captures the problem:
Log.d(TAG,"buildList, DBresult.getInt(1): "+DBresult.getInt(1));
Log.d(TAG,"buildList, DBresult.getString(1): "+DBresult.getString(1));
Log.d(TAG,"buildList, DBresult.getInt(4): "+DBresult.getInt(4));
Log.d(TAG,"buildList, DBresult.getString(4): "+DBresult.getString(4));
The resulting output:
05-06 11:11:20.123: DEBUG/TodoList(18943): buildList, DBresult.getInt(1): 0
05-06 11:11:20.123: DEBUG/TodoList(18943): buildList, DBresult.getString(1): false
05-06 11:11:20.123: DEBUG/TodoList(18943): buildList, DBresult.getInt(4): 0
05-06 11:11:20.123: DEBUG/TodoList(18943): buildList, DBresult.getString(4): true
There are no backgroung threads running. As you can see the problem is that '0' is interpreted as false on one occasion, and as true on another. Since I am completely lost on how this can happen, I dont know how to proceed. What could possibly result in such a behaviour? Both the columns are of the type "boolean", i.e a numeric in sqlite. Unfortunately the string returned is the correct value, while the integer is always 0. If I export the database to my computer and check it with SQlite Administrator I can see that the values are correctly set, it is only the getInt()-function that always returns 0. I know for a fact that this works in other apps I have coded, and I dont know why this has stopped working.
I have tried compiling the code under 2.0, 2.0.1 and 2.1, and it always appears. I can make my app runnable again by getting boolean values like this:
myBool= (DBresult.getString(0).equals("true"));
but that is both ugly and not optimized. Any suggestions on what is causing this behaviour is welcome.
Cheers,
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我相信我解决了它：
更新数据库接口后，插入之前的所有数据都通过 String.valueOf() 函数转换为字符串。因此，数据库中输入的不是“1”，而是“true”。我的数据库管理工具没有显示出差异。我不知道为什么用 getInt() 函数将其转换为“0”，但这似乎是问题所在。
I do believe I solved it:
After an update to the database interface all data before insertion was converted to string via String.valueOf()-function. So instead of "1", "true" was input into the database. The difference was not shown with my databas management-tools. Why this is coverted to '0' with the getInt()-function I do not know, but this seems to be the problem.