Question

可以为不同的视图编写通用适配器吗？我对spinner和RecyclerView的通用适配器感兴趣。在我的项目中，我有RecyclerView和Spinner，我想为两者（Spinner和function checkForRepeatingDigits(N){ var arr = (''+N).split(''), result = arr.filter((elem, i) => arr.indexOf(elem) == i); return result.length != (''+N).length; } // Or function checkForRepeatingDigits(N){ return [...new Set((''+N).split(''))].length != (''+N).length; } console.log([1, 10, 11, 1010, 1981].map(checkForRepeatingDigits))）编写基础通用适配器你能救我吗？

Answer 1

是的，您可以为ListView / Spinner和RecyclerView

实施通用适配器

public static class CommonAdapter extends RecyclerView.Adapter<CommonAdapter.RecycleViewHolder>
            implements ListAdapter {


        private Context mContext;
        private List<String> data;

        public CommonAdapter(Context context, List<String> data) {
            mContext = context;
            this.data = data;
        }

        // Start of recycleview adapter
        @Override
        public RecycleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            return new RecycleViewHolder(new TextView(mContext));
        }

        @Override
        public void onBindViewHolder(RecycleViewHolder holder, int position) {
            holder.textView.setText(data.get(position));
        }

        @Override
        public int getItemCount() {
            return getCount();
        }

        public static class RecycleViewHolder extends RecyclerView.ViewHolder {

            public TextView textView;

            public RecycleViewHolder(View itemView) {
                super(itemView);
                textView = (TextView) itemView;
            }
        }

        // Implementation of list adapter(Spinner/ListView)
        @Override
        public boolean areAllItemsEnabled() {
            return true;
        }

        @Override
        public boolean isEnabled(int position) {
            return true;
        }

        @Override
        public void registerDataSetObserver(DataSetObserver observer) {

        }

        @Override
        public void unregisterDataSetObserver(DataSetObserver observer) {

        }

        @Override
        public int getCount() {
            return data.size();
        }

        @Override
        public String getItem(int position) {
            return data.get(position);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            SpinnerViewHolder holder;
            if (convertView == null) {
                convertView = new TextView(mContext);
                holder = new SpinnerViewHolder();
                holder.textView = (TextView) convertView;
                convertView.setTag(holder);
            } else {
                holder = (SpinnerViewHolder) convertView.getTag();
            }
            holder.textView.setText(getItem(position));
            return convertView;
        }

        @Override
        public int getViewTypeCount() {
            return 0;
        }

        @Override
        public boolean isEmpty() {
            return false;
        }

        public static class SpinnerViewHolder {
            public TextView textView;
        }

    }

这是执行此操作的基本思路，您可以更多地使用相同的适配器来为具有不同数据类型的所有不同ListView / RecyclerView使用相同的适配器。但到目前为止，我给出了组合适配器的基本概念。

适配器正在扩展RecyclerView.ViewHolder所需的RecyclerView，并且我正在ListAdapter / ListView所需的Spinner实施相同的课程

Answer 2

这是我的 androidx 的带有光标的示例。想法是为这两个都有一个通用的文本视图ID。您可以在 android.R.layout.simple_spinner_item 和 android.R.layout.simple_list_item_1 提供的xml文件中进行检查。

import android.database.Cursor;
import android.view.LayoutInflater;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

/**
 * Common adapter for cursor.
 */
public class CommonAdapter extends RecyclerView.Adapter<CommonAdapter.ViewHolder> {

        private Cursor mCursor;
        private boolean isSpinner;

        public CommonAdapter(boolean isSpinner){
            this.isSpinner = isSpinner;
        }

        @Override
        @NonNull
        public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            return new ViewHolder(parent, isSpinner);
        }

        @Override
        public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
            if (mCursor.moveToPosition(position)) {
                holder.mText.setText(mCursor.getString(
                        mCursor.getColumnIndexOrThrow(Data.COLUMN_ID)));
            }
        }

        @Override
        public int getItemCount() {
            return mCursor == null ? 0 : mCursor.getCount();
        }

        void setCursor(Cursor cursor) {
            mCursor = cursor;
            notifyDataSetChanged();
        }

        static class ViewHolder extends RecyclerView.ViewHolder {

            final TextView mText;

            ViewHolder(ViewGroup parent, boolean isSpinner) {
                super(LayoutInflater.from(parent.getContext()).inflate(
                        isSpinner?android.R.layout.simple_spinner_item:android.R.layout.simple_list_item_1
                        , parent, false));
                mText = itemView.findViewById(android.R.id.text1);
            }

        }

}

用于微调器和recyclerView的通用适配器

2 个答案: