Question

基本上我想在可绘制资源之间切换，我无法弄清楚我将如何去做。我在一个If语句中写了所有内容，但它太长而且凌乱，而且它没有按照我想要的方式执行，因为如果输入错误的字母它就不会停止。

我要做的是，如果用户输入一个字母，背景将更改为之后的下一个字母，例如，如果用户输入A，则背景将更改为B，依此类推。它现在可以工作，但是错误的是如果用户在字母A上并且用户错误地输入字母P，则背景将切换到Q而不是告诉用户他们错了。

我确实有这个代码作为其他而不仅仅是If语句，但我想我今天会改变它。任何人都可以解释我如何将这个If语句放入案例陈述中吗？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

使用以下

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语句转换成switch case：

你也可以拥有可绘制阵列，然后你也不需要使用开关盒：

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

然后设置颜色

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

Answer 2

 switch (words.getText().toString().charAt(0)) {
   case 'A': 
    gestureViewer.setBackgroundResource(R.drawable.lettersb);

   break;

   case 'B' : 
    gestureViewer.setBackgroundResource(R.drawable.lettersc);

   break;

Learn Java for Android Development: Java Syntax

Answer 3

  private void set( i) {            

   switch(i) {      
    case 1:
        words.getText().toString().equalsIgnoreCase("A")) {
        gestureViewer.setBackgroundResource(R.drawable.lettersf);
        break;
    case 2:
        words.getText().toString().equalsIgnoreCase("B")) {
        gestureViewer.setBackgroundResource(R.drawable.lettersf);
        break;
       .
       .......
     }
 }

Answer 4

这可能是一种更好的方法

char current = words.getText().toString().charAt(0));
char next    = ( (ch-'A') + 1 ) % 26 + 'A';
gestureViewer.setBackgroundResource(R.drawable.getLetter( next ));

接下来是字母表中的[循环]下一个字符。

祝你好运

在图片之间切换案例

4 个答案: