动态微调器-如果选择了一个项目，则将其从其他微调器中隐藏-onItemSelected 中的getDropdownView？

Question

所以我已经开始在 Java 中创建动态微调器，但我现在有点不知所措。 我知道这是一个常见问题，但是如何隐藏当前在微调器中选择的项目？ 我尝试通过字符串的 ArrayList 和 ArrayAdapters 删除项目，但我注意到一旦从列表中删除，选择也不再引用到列表项（因为它不再存在）。 我遇到了对 getDropDownView 视图的改编，它隐藏/禁用了项目列表中的第一个条目，而它仍保留在列表中（链接：http://pastebin.com/92BZvrkT）。 我现在想使用这个适配器来获取所选项目的位置，然后将其隐藏在其他 3 个微调器中。 我有 4 个微调器，它们都有相同的 ArrayList 作为它们的资源，并且每个都有自己的适配器，我用来更新数组。现在，如果我想使用链接中给出的这段代码（更具体地说），我该怎么办：

public View getDropDownView(int position, View convertView, ViewGroup parent)
    {
        View v = null;

        // If this is the initial dummy entry, make it hidden
        if (position == 0) {
            TextView tv = new TextView(getContext());
            tv.setHeight(0);
            tv.setVisibility(View.GONE);
            v = tv;
        }
        else {
            // Pass convertView as null to prevent reuse of special case views
            v = super.getDropDownView(position, null, parent);
        }

        // Hide scroll bar because it appears sometimes unnecessarily, this does not prevent scrolling
        parent.setVerticalScrollBarEnabled(false);
        return v;
    }
};

在我的 onItemSelectedListener 中，它看起来像：

public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    boolean countertest = false;
    switch(parent.getId())
    {
         case R.id.spinner_1:
            //there used to be the removal from the list and adding to it, until I've noticed my fatal mistake (removal of selected item)
            //I want to add the upper method, getDropDownView here somewhere, so I can control which item gets hidden
            break;
         case R.id.spinner_2:
            //... same here
            break;
    }

Answer 1

我有几个微调器显示相同的元素列表（或不同的列表但共享一些元素）。当在微调器中选择一个元素时，它将隐藏在其余微调器的下拉列表中。该解决方案与 Ravi 的https://stackoverflow.com/a/32351061/3031089 非常相似，但适用于处理复杂对象列表（不仅仅是字符串）。我还有一个选定对象的数组，并检查一个元素是否在这个数组中以确定在下拉列表中显示或隐藏它：

public class MyAdapter extends ArrayAdapter<MyObject> {

    private Context mContext;
    private int resId;

    MyAdapter(Context context, int resource, List<MyObject> objects) {
        super(context, resource, objects);
        mContext = context;
        resId = resource;
    }

    private class MyHolder {
        TextView myTextView;
        ImageView myImageView;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        MyHolder myHolder;
        MyObject myObject = getItem(position);
        if (convertView == null) {
            LayoutInflater mInflater = (LayoutInflater) mContext.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
            convertView = mInflater.inflate(resId, parent, false);
            myHolder = new MyHolder();
            myHolder.myTextView = (TextView) convertView.findViewById(R.id.myTextView);
            myHolder.myImageView = (ImageView) convertView.findViewById(R.id.myImageView);
            convertView.setTag(myHolder);
        }
        else
            myHolder = (MyHolder) convertView.getTag();
        myHolder.myTextView.setText(myObject.name);
        myHolder.myImageView.setImageBitmap(myObject.picture);
        return convertView;
    }

    @Override
    public View getDropDownView(int position, View convertView, ViewGroup parent) {
        MyHolder myHolder;
        MyObject myObject = getItem(position);
        if (mustHide(myObject))
            return new View(parent.getContext());
        if (convertView == null) {
            LayoutInflater mInflater = (LayoutInflater) mContext.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
            convertView = mInflater.inflate(resId, parent, false);
            myHolder = new MyHolder();
            myHolder.myTextView = (TextView) convertView.findViewById(R.id.myTextView);
            myHolder.myImageView = (ImageView) convertView.findViewById(R.id.myImageView);
            convertView.setTag(myHolder);
        }
        else
            myHolder = (MyHolder) convertView.getTag();
    // The next if loop is necessary because previously hidden elements have null tag
        if (myHolder == null) {
            LayoutInflater mInflater = (LayoutInflater) mContext.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
            convertView = mInflater.inflate(resId, parent, false);
            myHolder = new MyHolder();
            myHolder.myTextView = (TextView) convertView.findViewById(R.id.myTextView);
            myHolder.myImageView = (ImageView) convertView.findViewById(R.id.myImageView);
            convertView.setTag(myHolder);
        }
        myHolder.myTextView.setText(myObject.name);
        myHolder.myImageView.setImageBitmap(myObject.picture);
        return convertView;
    }

    private boolean mustHide(MyObject myObject) {
        // Check if an object is in the array of selected items
        // If so, return true; else return false
    }

}

最后，在 OnItemSelectedListener 更新您的选定对象数组：

public class IngItemSelectedListener implements AdapterView.OnItemSelectedListener {

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    // Update your list of selected objects 
    // and call notifyDataSetChanged() at all your spinners
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }

}