生成“随机键盘”的代码如下：

1. MakeNumBtn: function () {
2. function getRandomArrayElements(arr, count) {
3. var shuffled = arr.slice(0), i = arr.length, min = i - count, temp, index;
4. while (i-- > min) {
5. index = Math.floor((i + 1) * Math.random());
6. temp = shuffled[index];
7. shuffled[index] = shuffled[i];
8. shuffled[i] = temp;
9. }
10. return shuffled.slice(min);
11. }
12.  
13. if (op === "+") {
14. ans = A + B;
15. } else if (op === "-") {
16. ans = A - B;
17. } else if (op === "×") {
18. ans = A * B;
19. } else if (op === "÷") {
20. ans = A / B;
21. }
22. var nums = '0123456789'
23. var arrAns = [];
24.  
25. var temp = ans.toString().split('');
26. for (var i = 0; i < temp.length; i++) {
27. if (arrAns.indexOf(temp[i]) == -1) {
28. arrAns.push(temp[i]);
29. }
30. nums = nums.replace(temp[i], '');
31. }
32. arrAns = getRandomArrayElements(arrAns.concat(getRandomArrayElements(nums.split(''), 4 - arrAns.length)), 4);
33. this.setData({ btn1: arrAns[0] });
34. this.setData({ btn2: arrAns[1] });
35. this.setData({ btn3: arrAns[2] });
36. this.setData({ btn4: arrAns[3] });
37. },

对于英文键盘跟上边差不多，在“单词拼写”小程序中，沿用上述解决方法，只不过把0-9数字换成了a-zA-Z加上英文“'”和"-"，由于英文单词长度都比较长，无法一次全部输入，采用的是变通的方法，每次键盘显示需要当前输入的字母，输入后显示下个字母的键盘。具体界面如下图：

主要代码如下：

1. MakeInputBtn: function () {
2. if (this.data.mEnglish.length == this.data.inputValue.length) {
3. return;
4. }
5.  
6. function getRandomArrayElements(arr, count) {
7. var shuffled = arr.slice(0), i = arr.length, min = i - count, temp, index;
8. while (i-- > min) {
9. index = Math.floor((i + 1) * Math.random());
10. temp = shuffled[index];
11. shuffled[index] = shuffled[i];
12. shuffled[i] = temp;
13. }
14. return shuffled.slice(min);
15. }
16. var letters = "abcdefghijklmnopqrstuvwxyz'- ABCDEFGHIJKLMNOPQRSTUVWXYZ"
17. var arrAns = [];
18.  
19. var currentLetter = this.data.mEnglish[this.data.inputValue.length];
20. //console.log(currentLetter);
21. if (currentLetter) {
22. var temp = currentLetter.toString().split('');
23. for (var i = 0; i < temp.length; i++) {
24. if (arrAns.indexOf(temp[i]) == -1) {
25. arrAns.push(temp[i]);
26. }
27. letters = letters.replace(temp[i], '');
28. }
29. arrAns = getRandomArrayElements(arrAns.concat(getRandomArrayElements(letters.split(''), 4 - arrAns.length)), 4);
30. this.setData({ btn1: arrAns[0] });
31. this.setData({ btn2: arrAns[1] });
32. this.setData({ btn3: arrAns[2] });
33. this.setData({ btn4: arrAns[3] });