HashMap到ListView

Question

我有HashMap,我怎么能把它放在ListView中？哪个适配器需要使用？

    public void showCinemas(HashMap<String, String> cinemas)
{
    ...//What?
    list.setAdapter(adapter);
}

Answer 1

制作简单的适配器类:

MyAdapter.java

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.Map;

public class MyAdapter extends BaseAdapter {
    private final ArrayList mData;

    public MyAdapter(Map<String, String> map) {
        mData = new ArrayList();
        mData.addAll(map.entrySet());
    }

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

    @Override
    public Map.Entry<String, String> getItem(int position) {
        return (Map.Entry) mData.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO implement you own logic with ID
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        final View result;

        if (convertView == null) {
            result = LayoutInflater.from(parent.getContext()).inflate(R.layout.my_adapter_item, parent, false);
        } else {
            result = convertView;
        }

        Map.Entry<String, String> item = getItem(position);

        // TODO replace findViewById by ViewHolder
        ((TextView) result.findViewById(android.R.id.text1)).setText(item.getKey());
        ((TextView) result.findViewById(android.R.id.text2)).setText(item.getValue());

        return result;
    }
}

布局/ my_adapter_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        >

    <TextView
            android:id="@android:id/text1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            />

    <TextView
            android:id="@android:id/text2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            />
</LinearLayout>

你的代码:

public void showCinemas(HashMap<String, String> cinemas) {
    MyAdapter adapter = new MyAdapter(cinemas);
    list.setAdapter(adapter);
}

Answer 2

HashMap由2个Collection(或更好的1个Collection和1个Set)组成,所以扩展ArrayAdapter是不可能的.但是你可以轻松获得Map.Entry的Collection(或更好的Set),并将其转换为List:

从:

Map<String, Object> map = new HashMap<String, Object>();

至:

List<Map.Entry<String, Object>> list = new ArrayList(map.entrySet());

所以我使用像这样的派生ArrayAdapter:

class HashMapArrayAdapter extends ArrayAdapter {

        private static class ViewHolder {
            TextView tV1;
            TextView tV2;
        }

        public HashMapArrayAdapter(Context context, int textViewResourceId, List<Map.Entry<String, Object>> objects) {
            super(context, textViewResourceId, objects);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            ViewHolder viewHolder;

            if (convertView == null) {
                convertView = LayoutInflater.from(getContext()).inflate(android.R.layout.simple_list_item_2, parent, false);
                viewHolder = new ViewHolder();
                viewHolder.tV1 = (TextView) convertView.findViewById(android.R.id.text1);
                viewHolder.tV2 = (TextView) convertView.findViewById(android.R.id.text2);
                convertView.setTag(viewHolder);
            } else
                viewHolder = (ViewHolder) convertView.getTag();

            Map.Entry<String, Object> entry = (Map.Entry<String, Object>) this.getItem(position);

            viewHolder.tV1.setText(entry.getKey());
            viewHolder.tV2.setText(entry.getValue().toString());
            return convertView;
        }

然后创建适配器:

 ArrayAdapter adapter = new HashMapArrayAdapter(this.getActivity(), android.R.layout.simple_list_item_2, new ArrayList(map.entrySet()));