如何检测数组列表为空或空或包含android

Question

我需要检查我的ArrayList是null还是Empty或者Conatins是否有任何特殊字符？ ArrayList调试映像。

if(!lotNumArrList.contains(null)&&lotNumArrList!=null&&!lotNumArrList.isEmpty()){
        {
        }
}

Answer 1

试试这个：

 boolean hasSpecialChar = false;
            if (lotNumArrList != null && lotNumArrList.size() > 0) {
                for (int i = 0; i < lotNumArrList.size(); i++) {
                    String value = lotNumArrList.get(i).trim();
                    if (value.length() > 0 && value.contains(",")) {
                        hasSpecialChar = true;
                        break;
                    }
                }
            }

Answer 2

  if (lotNumArrList.size()>0){
            boolean isNull = false;
            for (int i = 0;i>lotNumArrList.size();i++){
                String itemValue = lotNumArrList.get(i).trim();
                if (itemValue==null||itemValue.equalsIgnoreCase("")||itemValue.length()==0){
                    isNull = true;
                    break;
                }else {
                    isNull = false;
                }

            }
            if (!isNull) {
                mDBHelper.getWritableDatabase();
                mDBHelper.updateFIQTY(fiGoods, fiQty,fiUnWgt,totWgt); mDBHelper.closeDatabase(); 
            }
        }

Answer 3

Pattern p = Pattern.compile("[^a-zA-Z]");
if(lotNumArrList!=null && !lotNumArrList.isEmpty() && !p.matcher(string).find()){

}

Answer 4

尚未测试。试试它是否有效。

if (lotNumArrList == null || lotNumArrList.size == 0){
    // your code here if null or empty
} else {
    String pattern = "[^a-zA-Z0-9]"; // you can change this one on what you want to have in your string

    for (String s : list)
            if(s.matches(pattern)){
            // your code here if found special characters
            }
}

Answer 5

假设您的ArrayList是ArrayList，请尝试以下代码

FilePath

希望它有所帮助！

Answer 6

尝试以下代码：

  Pattern p = Pattern.compile("[^a-z0-9 ]", Pattern.CASE_INSENSITIVE);
    boolean hasSpecialChar = false;
                if (lotNumArrList != null && lotNumArrList.size() > 0) {
                    for (int i = 0; i < lotNumArrList.size(); i++) {
                        String str = lotNumArrList.get(i).trim();
                        Matcher m = p.matcher(str);
                        boolean b = m.find();
                        if (b) {
                            hasSpecialChar = true;
                            break;
                        }
                    } 
}