[英]Checking if string contains only allowed characters
I want to check if my string contains only allowed character. 我想检查我的字符串是否仅包含允许的字符。 Matcher works properly, but when I input something like this "123A" app crashes.
匹配器正常工作,但是当我输入类似“ 123A”的应用程序时崩溃。 For only letters it work properly(error).
仅字母可以正常工作(错误)。 How can I do that?
我怎样才能做到这一点?
My code: 我的代码:
pattern = Pattern.compile("[0-9]");
matcher = pattern.matcher(stNumber);
if(matcher.find())
else
error
This is my logcat error: 这是我的logcat错误:
03-07 21:49:50.917 1891-1891/com.converter_numeralsystem.app E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.converter_numeralsystem.app, PID: 1891
java.lang.NumberFormatException: Invalid long: "112a"
at java.lang.Long.invalidLong(Long.java:124)
at java.lang.Long.parse(Long.java:361)
at java.lang.Long.parseLong(Long.java:352)
at java.lang.Long.parseLong(Long.java:318)
at com.converter_numeralsystem.app.MainActivity.calculate(MainActivity.java:121)
at com.converter_numeralsystem.app.MainActivity.onClick(MainActivity.java:246)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
If you want to allow only numbers, you should use a regular expression to match the whole string (add +
to check for at least one digit). 如果只允许数字,则应使用正则表达式来匹配整个字符串(添加
+
检查至少一位数字)。 Also, use matches()
method instead of find()
to match the whole input string (your problem is that find()
finds the first match and then doesn't try to match the rest): 另外,使用
matches()
方法而不是find()
来匹配整个输入字符串(您的问题是find()
找到第一个匹配项,然后不尝试匹配其余匹配项):
pattern = Pattern.compile("[0-9]+");
matcher = pattern.matcher(stNumber);
if(matcher.matches())
else
error
Try 尝试
pattern = Pattern.compile("[0-9]+");
Or 要么
pattern = Pattern.compile("\\d+");
Also use 也使用
if(matcher.match())
Instead of 代替
if(matcher.find())
如果您有只想引入数字的编辑文本,则可以将此属性添加到xml文件中的编辑文本中:
android:digits="0123456789"
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