urimatcher不使用预填充的数据库

Question

//内容提供程序代码

private PantryDbHelper dbHelper;

private static final int PANTRY = 1;
private static final int INFO = 5;

公共静态最终字符串授权=“com.battlestarMathematica.stayfresh.pantryprovider”；

//path to db
public static final String URL = "content://" + AUTHORITY;
public static final Uri CONTENT_URI = Uri.parse(URL);
public static final Uri CONTENT_URI_PANTRY = Uri.withAppendedPath(CONTENT_URI,"pantry");
public static final Uri CONTENT_URI_INFO = Uri.withAppendedPath(CONTENT_URI,"info");

static final UriMatcher uriMatcher;

static {
    uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
    uriMatcher.addURI(AUTHORITY,"info",INFO);
    uriMatcher.addURI(AUTHORITY, "pantry", PANTRY);
}

public Cursor query(@NonNull Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder){
    SQLiteDatabase db = dbHelper.getReadableDatabase();

    SQLiteQueryBuilder builder = new SQLiteQueryBuilder();
        switch (uriMatcher.match(uri)) {
            case PANTRY:
                builder.setTables(PantryContract.PANTRY_TABLE_NAME);
                break;
            case INFO:
                builder.setTables("info");
            default:
                throw new IllegalArgumentException("Unsupported URI " + uri);
        }

//游标加载程序代码

public Loader<Cursor> onCreateLoader(int id, Bundle args){
    return new CursorLoader(
            //context
            this,
            //content URI
            PantryContentProvider.CONTENT_URI_INFO,
            //columns to return
            new String[] {"_id","itemname"},
            //selection
            null,
            //selection args
            null,
            //sort order
            "itemname");
}

Answer 1

您的代码中只是缺少一个break语句。

urimatcher匹配，switch语句跳转到case info:，但由于没有中断；也执行default:大小写。

尝试替换这个

        case INFO:
            builder.setTables("info");
        default:
            throw new IllegalArgumentException("Unsupported URI " + uri);

        case INFO:
            builder.setTables("info");
            break;
        default:
            throw new IllegalArgumentException("Unsupported URI " + uri);