Android如何强制检查给定字符串是否为字母数字

import java.util.regex.Pattern;

public class MainActivity extends AppCompatActivity {
    private static final String REGEX_ALPHANUMERIC = "^[a-zA-Z0-9]+$";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        String inputString = "abc123";

        boolean isAlphanumeric = checkAlphanumeric(inputString);
        if (isAlphanumeric) {
            Toast.makeText(this, "The input string is alphanumeric.", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(this, "The input string is not alphanumeric.", Toast.LENGTH_SHORT).show();
        }
    }

    private boolean checkAlphanumeric(String inputString) {
        Pattern pattern = Pattern.compile(REGEX_ALPHANUMERIC);
        return pattern.matcher(inputString).matches();
    }
}