Android如何实现可多次点击按钮？解决按钮仅单次点击问题

开发学习用Android应用时，遇到按钮点击一次后，二次点击界面无明显变化的问题，相关代码如下：

XML布局代码 #

<Button
    android:id="@+id/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="50dp"
    android:width="200dp"
    android:height="80dp"
    android:shadowColor="@color/red"
    android:text="@string/button"
    android:textColor="@color/black"
    android:textSize="20sp"
    android:visibility="visible"
    app:cornerRadius="100dp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/text"
    app:rippleColor="@color/red"
    app:strokeColor="@color/red"
    tools:ignore="TextContrastCheck" />

Java点击事件代码 #

buttonGenerate.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        passwordText.setText(generate());
    }
});

generate方法代码 #

private String generate () {
Random random = new Random();
int character;
while (password.length() < 16) {
character = random.nextInt(76);
password += characters[character];
}
return password;
}

相关成员变量 #

private final String[] characters = {
"A" , "B" , "C" , "D" , "E" , "F" , "G" , "H",
"I" , "J" , "K" , "L" , "M" , "N" , "O" , "P" , "Q" , "R" , "S" , "T" ,
"U" , "V" , "W" , "X" , "Y" , "Z", "a" , "b" , "c" , "d" , "e" , "f" , "g" , "h",
"i" , "j" , "k" , "l" , "m" , "n" , "o" , "p" , "q" , "r" , "s" , "t" ,"u" , "v" , "w" , "x" , "y" , "z", "0" , "1" , "2" , "3" , "4" , "5" , "6" ,
"7" , "8" , "9", "!" , "#" , "'" , "+" , "%" , "(" , ")" , "&" ,
"=" , "?" , "*" , "-" , "$" , "{" , "}" };
private String password = "";

问题原因 #

按钮本身可正常点击，但类成员变量password在第一次调用generate()后长度已达到16，后续点击调用generate()时，while (password.length() < 16)条件不成立，直接返回原有字符串，导致界面显示无变化，看起来像按钮无法二次点击。

解决方案 #

修改generate()方法，确保每次调用都生成新密码，两种可行方案：

方案1：使用局部变量（推荐）

将password改为方法内的局部变量，每次调用方法时重新初始化：

private String generate () {
    String password = "";
    Random random = new Random();
    int character;
    while (password.length() < 16) {
        character = random.nextInt(76);
        password += characters[character];
    }
    return password;
}

方案2：重置成员变量

每次生成密码前，将类成员password重置为空：

private String generate () {
    password = "";
    Random random = new Random();
    int character;
    while (password.length() < 16) {
        character = random.nextInt(76);
        password += characters[character];
    }
    return password;
}

两种方案都能保证每次点击按钮时，生成全新的16位密码，界面会同步更新。

内容的提问来源于stack exchange，提问作者Orhan Gazi BARAK