如何在 Android 中使用自定义正则表达式验证 EditText 输入？

Question

我是 android 开发和正则表达式的新手。我可以通过 EditText 检索用户的输入并检查它是否为空，如果它为空，则稍后显示错误消息，但我不确定如何使用自定义正则表达式进行检查。这是我的代码：

 myInput = (EditText) findViewById(R.id.myInput);
String myInput_Input_a = String.valueOf(myInput.getText());

//replace if input contains whiteSpace
String myInput_Input = myInput_Input_a.replace(" ","");


    if (myInput_Input.length()==0 || myInput_Input== null ){

               myInput.setError("Something is Missing! ");
     }else{//Input into databsae}

所以，我希望用户输入一个 5 字符长的字符串，其中前 2 个字母必须是数字，后 3 个字符必须是字符。那么我该如何实施呢？

Answer 1

根据正则表达式检查输入的通用模式：

String regexp = "\\d{2}\\D{3}"; //your regexp here

if (myInput_Input_a.matches(regexp)) {
    //It's valid
}

上面的实际正则表达式假设您实际上是指 2 个数字/数字（相同的东西）和 3 个非数字。相应调整。

正则表达式的变化：

"\\d{2}[a-zA-Z]{3}"; //makes sure the last three are constrained to a-z (allowing both upper and lower case)
"\\d{2}[a-z]{3}"; //makes sure the last three are constrained to a-z (allowing only lower case)
"\\d{2}[a-zåäöA-ZÅÄÖ]{3}"; //makes sure the last three are constrained to a-z and some other non US-ASCII characters (allowing both upper and lower case)
"\\d{2}\\p{IsAlphabetic}{3}" //last three can be any (unicode) alphabetic character not just in US-ASCII