数据没有被添加到radiogroup的arraylist中？

Question

我想根据单选组的checkedId在ArrayList“arr”中添加数据。我有4个单选按钮“a0，a1，a2，a3”。所以如果我选择a1，数组列表应该加上rb2的值。在选择 a1 之后，如果我选择 a2，那么“arr”中的前一个值应该会更新（不会在第一个值之后添加）等等。任何帮助..

   rg.setOnCheckedChangeListener(new  RadioGroup.OnCheckedChangeListener() {
        public void onCheckedChanged(RadioGroup group, int checkedId) {

            ArrayList<String> arr = new ArrayList<String>();

            for (int i = 0; i <= mcq.size(); i++) {
                switch (checkedId) {
                    case R.id.a0:
                        // do operations specific to this selection

                        Toast.makeText(getApplication(),
                                rb1.getText(), Toast.LENGTH_SHORT).show();
                        break;

                    case R.id.a1:
                        // do operations specific to this selection

                        Toast.makeText(getApplication(),
                                rb2.getText(), Toast.LENGTH_SHORT).show();
                        break;

                    case R.id.a2:
                        // do operations specific to this selection

                        Toast.makeText(getApplication(),
                                rb3.getText(), Toast.LENGTH_SHORT).show();
                        break;
                    case R.id.a3:
                        // do operations specific to this selection

                        Toast.makeText(getApplication(),
                                rb4.getText(), Toast.LENGTH_SHORT).show();
                        break;

                }
                arr.add(String.valueOf(checkedId));
                Log.e("", String.valueOf(arr));
            }


        }
    });

Answer 1

您可以使用https://developer.android.com/reference/android/util/SparseArray.html

SparaseArray<Boolean> array = new SparseArray();
array.put(checkedId, rb.isChecked());

然后你可以像这样获取数组的所有选中元素：

for(int i = 0; i< sparseArray.size(); i++) {
   int id = sparseArray.keyAt(i);
   Boolean isChecked = sparseArray.get(id);
   if(isChecked) {
       log("Identifier " + id + " is checked");
   }
}