java使用Android创建强大的密码生成器

Question

因此，我正在构建一个应用程序，根据用户的规格生成一个强大的密码。UI的规范部分看起来像this

以下是Main活动的onCreate。java类。我尝试创建一些逻辑，比如当选中某个单选按钮时if语句，以及每当选中复选框时向字符串变量添加允许的字符。视图对象都是全局的，但我不知道如何在用户设置的字符限制内，使用每个允许的字符中的至少一个创建随机字符串

以下是代码：

private static int MAX_LENGTH;

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

        capitalLetter = (CheckBox) findViewById(R.id.capital_letter);
        lowercaseLetter = (CheckBox) findViewById(R.id.lowercase_letter);
        numbers = (CheckBox) findViewById(R.id.numbers);
        symbols = (CheckBox) findViewById(R.id.symbols);

        passGroup = (RadioGroup) findViewById(R.id.passRadioGroup);

        sizeFour = (RadioButton) findViewById(R.id.size_four);
        sizeEight = (RadioButton) findViewById(R.id.size_eight);
        sizeTwelve = (RadioButton) findViewById(R.id.size_twelve);
        sizeSixteen = (RadioButton) findViewById(R.id.size_sixteen);

        passHint = (EditText) findViewById(R.id.passwordHint);

        passShow = (TextView) findViewById(R.id.passwordDisplay);

        passGenerate = (Button) findViewById(R.id.passwordGenerate);
        passClear = (Button) findViewById(R.id.passwordClear);

        String allowedCharacters = "";

        // Determines the types of characters permitted when a check box is checked.
        if (capitalLetter.isChecked()) {allowedCharacters += "ABCDEFGHIJKLMNOPQRSTUVWXYZ";}
        if (lowercaseLetter.isChecked()) {allowedCharacters += "abcdefghijklmnopqrstuvwxyz";}
        if (numbers.isChecked()) {allowedCharacters += "0123456789";}
        if (symbols.isChecked()) {allowedCharacters += "!@#$%^&*()_-+=<>?/{}~|";}

        //Determines the length of the string based on which radio button the user has selected.
        int checkedRadioButtonId = passGroup.getCheckedRadioButtonId();

        if (checkedRadioButtonId == 1) {MAX_LENGTH = 4;}
        if (checkedRadioButtonId == 2) {MAX_LENGTH = 8;}
        if (checkedRadioButtonId == 3) {MAX_LENGTH = 12;}
        if (checkedRadioButtonId == 4) {MAX_LENGTH = 16;}
    }

Answer 1

关于生成随机字符串的基本思想：

private static final String ALLOWED_CHARACTERS ="0123456789qwertyuiopasdfghjklzxcvbnm";

private static String getRandomString(final int sizeOfPasswordString){
  final Random random=new Random();
  final StringBuilder sb=new StringBuilder(sizeOfPasswordString);
  
  for(int i=0;i<sizeOfRandomString;++i){
      sb.append(ALLOWED_CHARACTERS.charAt(random.nextInt(ALLOWED_CHARACTERS.length())));
    
  }
  return sb.toString();
}

Answer 2

检查以下答案：

private static final String NUMBERS = "0123456789";
private static final String UPPER_ALPHABETS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
private static final String LOWER_ALPHABETS = "abcdefghijklmnopqrstuvwxyz";
private static final String SPECIALCHARACTERS = "@#$%&*";
CheckBox chkCapital, chkSmall, chkNumber, chkSpec;
Button btnSUbmit;
int MAX_CHAR = 0;
private RadioGroup radioGroup;
private RadioButton radiobtnm;

private static String getRandomPasswordCharacters(int pos) {
    Random randomNum = new Random();
    StringBuilder randomChar = new StringBuilder();
    switch (pos) {
        case 0:
            randomChar.append(NUMBERS.charAt(randomNum.nextInt(NUMBERS.length() - 1)));
            break;
        case 1:
            randomChar.append(UPPER_ALPHABETS.charAt(randomNum.nextInt(UPPER_ALPHABETS.length() - 1)));
            break;
        case 2:
            randomChar.append(SPECIALCHARACTERS.charAt(randomNum.nextInt(SPECIALCHARACTERS.length() - 1)));
            break;
        case 3:
            randomChar.append(LOWER_ALPHABETS.charAt(randomNum.nextInt(LOWER_ALPHABETS.length() - 1)));
            break;
    }
    return randomChar.toString();

}

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

    chkCapital = (CheckBox) findViewById(R.id.checkBox1);
    chkSmall = (CheckBox) findViewById(R.id.checkBox2);
    chkNumber = (CheckBox) findViewById(R.id.checkBox3);
    chkSpec = (CheckBox) findViewById(R.id.checkBox4);


    radioGroup = (RadioGroup) findViewById(R.id.radioGroup);
    btnSUbmit = (Button) findViewById(R.id.btnSUbmit);

    btnSUbmit.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            StringBuilder password = new StringBuilder();
            ArrayList<Integer> passSel = new ArrayList<Integer>();
            int selectedId = radioGroup.getCheckedRadioButtonId();

            radiobtnm = (RadioButton) findViewById(selectedId);

            MAX_CHAR = Integer.parseInt(radiobtnm.getText().toString());

            // when  UPPER CASE selected
            if (chkCapital.isChecked())
                passSel.add(1);

            // when  LOWER CASE selected
            if (chkSmall.isChecked())
                passSel.add(3);

            // when  Number  selected
            if (chkNumber.isChecked())
                passSel.add(0);

            // when  Special selected
            if (chkSpec.isChecked())
                passSel.add(2);

            for (int i = 1; i <= MAX_CHAR; ) {

                if (passSel.contains(0) && i <= MAX_CHAR) {
                    password.append(getRandomPasswordCharacters(0));
                    i++;
                }
                if (passSel.contains(1) && i <= MAX_CHAR) {
                    password.append(getRandomPasswordCharacters(1));
                    i++;
                }
                if (passSel.contains(2) && i <= MAX_CHAR) {
                    password.append(getRandomPasswordCharacters(2));
                    i++;
                }
                if (passSel.contains(3) && i <= MAX_CHAR) {
                    password.append(getRandomPasswordCharacters(3));
                    i++;
                }
            }
            Log.e("!_@@:your password is :> > ", password + "");
        }
    });
}