java - 在图片之间切换大小写

Question

基本上我想在可绘制资源之间切换，但我不知道该怎么做。我把它全部写在一个 If 语句中，但是它太长太乱而且它没有按照我想要的方式执行，因为如果他们输入错误的字母它不会停止。

我想做的是，如果用户输入一个字母，背景将变为下一个字母，例如，如果用户输入 A，背景将变为 B，依此类推。它现在确实可以工作，但是错误的是，如果用户在字母 A 上并且用户错误地输入了字母 P，背景将切换到 Q 而不是告诉用户他们错了。

我确实将此代码作为 else if 而不是 If 语句，但我只是想我今天会更改它。谁能解释一下我如何将这个 If 语句放入 case 语句中？谢谢你的帮助

             if (words.getText().toString().equalsIgnoreCase("A")) {

                gestureViewer.setBackgroundResource(R.drawable.lettersb);

            } else {
             onDestroy();
            } 
             if (words.getText().toString().equalsIgnoreCase("B")) {
                gestureViewer.setBackgroundResource(R.drawable.lettersc);
            } else {
            }
             if (words.getText().toString().equalsIgnoreCase("C")) {
                gestureViewer.setBackgroundResource(R.drawable.lettersd);
            } else {
            }
             if (words.getText().toString().equalsIgnoreCase("D")) {
                    gestureViewer.setBackgroundResource(R.drawable.letterse);
            } else {
            }
             if 
                (words.getText().toString().equalsIgnoreCase("E")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersf);
            } else {
            }
                if (words.getText().toString().equalsIgnoreCase("F")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersg);

            } else {
            }
                if (words.getText().toString().equalsIgnoreCase("G")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersh);
            }else {
            }
                if (words.getText().toString().equalsIgnoreCase("H")) {

                    gestureViewer.setBackgroundResource(R.drawable.lettersi);
            }else {
            }
                if (words.getText().toString().equalsIgnoreCase("I")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersj);
            } else {
            }
                if (words.getText().toString().equalsIgnoreCase("J")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersk);
            }else {
            }
                if (words.getText().toString().equalsIgnoreCase("K")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersl);
            }else {
            }
                if (words.getText().toString().equalsIgnoreCase("L")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersm);
            }else {
            }
                if (words.getText().toString().equalsIgnoreCase("M")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersn);
            }else {
            }
                if (words.getText().toString().equalsIgnoreCase("N")) {
                    gestureViewer.setBackgroundResource(R.drawable.letterso);
            }else {
            }
                if (words.getText().toString().equalsIgnoreCase("O")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersp);
            }else {
            }
                if (words.getText().toString().equalsIgnoreCase("P")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersq);
            }else {
            }
                if (words.getText().toString().equalsIgnoreCase("Q")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersr);
            } else {
            }
                if (words.getText().toString().equalsIgnoreCase("R")) {
                    gestureViewer.setBackgroundResource(R.drawable.letterss);
            } else  {
                    }

                if (words.getText().toString().equalsIgnoreCase("S")) {

                    gestureViewer.setBackgroundResource(R.drawable.letterst);
            }else {

            }

                if (words.getText().toString().equalsIgnoreCase("T")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersu);
            }else {

            }

                if (words.getText().toString().equalsIgnoreCase("U")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersv);
            }else {

            }
                if (words.getText().toString().equalsIgnoreCase("V")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersw);
            }else {

            }
                if (words.getText().toString().equalsIgnoreCase("W")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersx);
            }else {

            }
                if (words.getText().toString().equalsIgnoreCase("X")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersy);
            }else {

            }
                if (words.getText().toString().equalsIgnoreCase("Y")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersz);
            }else {

            }
                if (words.getText().toString().equalsIgnoreCase("Z")) {
                    gestureViewer.setBackgroundResource(R.drawable.lettersa);

            } else {

            }
         }
         public void beforeTextChanged(CharSequence s, int start, int count, int after){

         }
         public void afterTextChanged(Editable s) {


         } 
});

    }

Answer 1

使用跟随

char ch=words.getText().toString().charAt(0));

    switch(ch-'A')
    {
      case 0:
           //A;
           break;
      case 1:
           //B;
           break;
    .....
    }

通过这个你可以将 if 语句转换为 switch case:

你也可以有 drawable 数组，那么你也不需要使用 switch case:

int[] arr=new int[]{R.id.drawable_A, .......};

那么设置颜色就是

char ch=words.getText().toString().charAt(0));
int index=ch-'A';
view.setBackgroundResource(index);