ContentProvider实现,如何将"Selection"和"SelectionArgs"转换为键值对？

Question

我正在实现一个ContentProvider,当我实现查询方法时,我遇到了一些困难.

public final Cursor query (Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)

如何获取键值参数对？

假设用户传递的内容类似于"a =？和b =？" 2,"hello"作为selectionArgs,我想获得一个HashMap {a:2,b:"hello"}.

Answer 1

这是一个程序,演示了您正在寻找的解决方案.仔细查看getHashmap()将选择字符串和选择参数作为参数的方法,并返回您要查找的内容的哈希映射.我以您的数据集为例.根据您的需求,它应该更接近您的解决方案.唯一需要注意的是,如果要在'='之外使用不同的逻辑比较,则需要修改正则表达式.如果它适合你,请告诉我

    public static void main(String[] args) {
        String sel = "a=? and b=?";
    String[] ags = new String[] { "2", "hello" };
        HashMap<String, String> result = getHashmap(sel, ags);

    Iterator it = result.entrySet().iterator();
    while (it.hasNext()) {
        Map.Entry pairs = (Map.Entry) it.next();
        System.out.println(pairs.getKey() + " = " + pairs.getValue());
        it.remove();
    }

}

public static HashMap<String, String> getHashmap(String selection,
        String[] selectionArgs) {
        HashMap<String, String> result = new HashMap<String, String>();

    Pattern pattern = Pattern.compile("[a-z]*(\\s)*=\\?",
    Pattern.CASE_INSENSITIVE);

    Matcher matcher = pattern.matcher(selection);

    int pos = 0;
    while (matcher.find()) {
        String[] selParts = matcher.group(0).split("=");
        result.put(selParts[0], selectionArgs[pos]);
    pos++;
    }

    return result;
}