java - UriMatcher匹配不正确

首先，我筛选了有关SO主题的许多问题，但仍未能给出正确的答案。

这是我的代码的（简化方式）版本：

private static UriMatcher
        uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

private static final int
        HOMEWORK_TABLE_REQUEST = 1,
        CLASS_TABLE_REQUEST = 2,
        SETTINGS_TABLE_REQUEST = 3,
        HOMEWORK_ITEM_REQUEST = 4,
        CLASS_ITEM_REQUEST = 5,
        SETTINGS_ITEM_REQUEST = 6;

static {
    uriMatcher.addURI("org.dvc.homeworkReminder.homeworkProvider", "homework", HOMEWORK_TABLE_REQUEST);
    uriMatcher.addURI("org.dvc.homeworkreminder.homeworkProvider", "homework/#", HOMEWORK_ITEM_REQUEST);
    uriMatcher.addURI("org.dvc.homeworkReminder.homeworkProvider", "class", CLASS_TABLE_REQUEST);
    uriMatcher.addURI("org.dvc.homeworkreminder.homeworkProvider", "class/#", CLASS_ITEM_REQUEST);
    uriMatcher.addURI("org.dvc.homeworkReminder.homeworkProvider", "settings", SETTINGS_TABLE_REQUEST);
    uriMatcher.addURI("org.dvc.homeworkreminder.homeworkProvider", "settings/#", SETTINGS_ITEM_REQUEST);
}

这是我的查询方法：

@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
    Cursor cursor = null;
    Log.i("dfg", "Query method called");
    Log.i("dfg", "Uri = " + uri.toString());
    Log.i("dfg", "Match: " + uriMatcher.match(uri));
    switch(uriMatcher.match(uri)) {
        case HOMEWORK_ITEM_REQUEST:
            Log.i("dfg", "HOMEWORK_ITEM_REQUEST");
            cursor = database.readCursorById(Integer.parseInt(uri.getLastPathSegment()));
            break;
        case HOMEWORK_TABLE_REQUEST:
            Log.i("dfg", "HOMEWORK_TABLE_REQUEST");
            cursor = database.readAllHomework();
            break;
        case CLASS_ITEM_REQUEST:
        case CLASS_TABLE_REQUEST:
        case SETTINGS_ITEM_REQUEST:
        case SETTINGS_TABLE_REQUEST:
            cursor = null;
            break;
        default:
            cursor = null;
            break;
    }
    return cursor;
}

我没有针对类请求或设置请求的实现，所以这就是为什么我只默认返回null的原因。发生的是我的switch语句一直下降到default:，并在以后的代码中引起了NPE的麻烦。您会发现我的代码中有5条Log语句。将以下内容打印到LogCat。 （为什么总叫logcat？）

Query method called
Uri = content://org.dvc.homeworkReminder.homeworkProvider/homework/24
Match: -1

现在正在测试的uri应该与我添加的第二个模式匹配，对吗？我还了解了Uri.parse()方法如何在另一个线程上与UriMatcher的通配符混淆，因此我使用以下代码构建了上述打印的Uri：

Uri returnUri = new Uri.Builder().scheme(ContentResolver.SCHEME_CONTENT).authority("org.dvc.homeworkReminder.homeworkProvider").appendPath("homework").appendPath(String.valueOf(id)).build();

那里的id变量取决于其他与实际无关的东西。

我的问题是为什么UriMatcher不起作用，我将如何解决它？

固定：

我在以下几行有不正确的大写：

uriMatcher.addURI("org.dvc.homeworkreminder.homeworkProvider", "homework/#", HOMEWORK_ITEM_REQUEST);
uriMatcher.addURI("org.dvc.homeworkreminder.homeworkProvider", "class/#", CLASS_ITEM_REQUEST);
uriMatcher.addURI("org.dvc.homeworkreminder.homeworkProvider", "settings/#", SETTINGS_ITEM_REQUEST);

注意r中的小写字母homeworkreminder。感谢布鲁斯发现它！

最佳答案

设置匹配器时，您使用的是小写的“提醒”，但是实际的URI带有大写的“提醒”。