getSelectedItem Spinner 没有响应

Question

我有一个带有类别列表的 Spinner，它从 JSON 获取数据。我想做的是，当 所有类别 以外的项目被选中时，子类别的另一个微调器变得可见，并根据其类别加载来自 JSON 的数据。

以前我设法做到了，但在搁置几天并完成其他部分后，它不再有效了。

由于第一个加载到旋转器中的是 所有类别，它触发了 setOnItemSelectedListener() 并隐藏了 subcategorySpinner。如果选择了其他项目，subcategorySpinner 仍未显示。

代码逻辑有问题吗？请帮忙。

categorySpinner = (Spinner) rootView.findViewById(R.id.categorySpinner);
ArrayAdapter<String> adapter2 = new ArrayAdapter<String>(getActivity().getApplicationContext(), R.layout.spinner_item, categoryList);
adapter2.setDropDownViewResource(R.layout.spinner_dropdown_item);
categorySpinner.setAdapter(adapter2);

categorySpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
categoryString = categorySpinner.getSelectedItem().toString().replace(" ", "%20");
if (categorySpinner.getSelectedItem().toString().equals("All Category")) {
   Log.d("debug", "all category");
   subcategorySpinner.setVisibility(View.GONE);
} else {
   Log.d("debug", "other than all category");
   subcategorySpinner.setVisibility(View.VISIBLE);
   generateSubcategorySpinner(Config.GET_SUBCATEGORY_URL+"?category="+categoryString);
}
}


});

Answer 1

试试这个代码片段

Spinner dropdown = (Spinner) findViewById(R.id.type);
final String[] items = new String[]{"SELECT TYPE OF OFFER","PERCENTAGE", "AMOUNT", "ITEM"};
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,R.layout.spinner_item, items);
dropdown.setAdapter(adapter);
String selectedItem = dropdown.getSelectedItem().toString();

Answer 2

试试这个

categorySpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {


// On selecting a spinner item
         categoryString = parent.getItemAtPosition(position).toString().replace(" ", "%20");



if (categoryString.equals("All Category")) {
   Log.d("debug", "all category");
   subcategorySpinner.setVisibility(View.GONE);
} else {
   Log.d("debug", "other than all category");
   subcategorySpinner.setVisibility(View.VISIBLE);
   generateSubcategorySpinner(Config.GET_SUBCATEGORY_URL+"?category="+categoryString);
}
}

Answer 3

将您的代码更改为

categorySpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {


// On selecting a spinner item
categoryString = parent.getItemAtPosition(position).toString();
Log.d("debug", categoryString+"..."+position);

if (categoryString.equals("All Category")) {
   Log.d("debug", "all category");
   subcategorySpinner.setVisibility(View.GONE);
} else {
   Log.d("debug", "other than all category");
   subcategorySpinner.setVisibility(View.VISIBLE);

   categoryString = categoryString.replace(" ", "%20")
   generateSubcategorySpinner(Config.GET_SUBCATEGORY_URL+"?category="+categoryString);
}
}

Answer 4

你可以直接使用参数(position)

而不是， categoryString = parent.getItemAtPosition(position).toString();

你可以使用像， categoryString = position.toString();

Answer 5

好吧，我不太明白我在逻辑上做了什么，因为它看起来没什么不同，但这解决了它。哦好吧..我猜是什么漂浮在船上。

根据 H Raval 的建议，我将 if else 移动到一个方法中，现在它可以正常工作了。

categorySpinner = (Spinner) rootView.findViewById(R.id.categorySpinner);
                ArrayAdapter<String> adapter2 = new ArrayAdapter<String>(getActivity().getApplicationContext(), R.layout.spinner_item, categoryList);
                adapter2.setDropDownViewResource(R.layout.spinner_dropdown_item);
                categorySpinner.setAdapter(adapter2);
                String str = categorySpinner.getSelectedItem().toString();
                Log.d("debug", "str "+str);

                categorySpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                    @Override
                    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                        categoryString = parent.getItemAtPosition(position).toString();
                        Log.d("debug", categoryString+"..."+position);

                        subCategorySpinnerView(categoryString);
                    }
                });

private void subCategorySpinnerView(String categoryString) {

    if (categoryString.equals("All Category")) {
        Log.d("debug", "all category");
        subcategorySpinner.setVisibility(View.GONE);
    } else {
        Log.d("debug", "other than all category");
        subcategorySpinner.setVisibility(View.VISIBLE);

        categoryString = categoryString.replace(" ", "%20");
        generateSubcategorySpinner(Config.GET_SUBCATEGORY_URL+"?category="+categoryString);
    }

}

getSelectedItem Spinner 没有响应

No respond from getSelectedItem Spinner

android

android-spinner