学步园

list  view 在android UI 中起着很大的作用。 listview 要是书写不好会极大影响程序的性能。

这里有一个 项目实战 listview 例子。 关键是ListView 复杂UI 的实现。

最终的效果如：

package com.test.list;

import android.app.ListActivity;
import android.content.Context;
import android.os.Bundle;
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.TreeSet;

public class MultipleItemsList extends ListActivity {

    private MyCustomAdapter mAdapter;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mAdapter = new MyCustomAdapter();
        for (int i = 1; i < 50; i++) {
            mAdapter.addItem("item " + i);
            if (i % 4 == 0) {
                mAdapter.addSeparatorItem("separator " + i);
            }
        }
        setListAdapter(mAdapter);
    }

    private class MyCustomAdapter extends BaseAdapter {

        private static final int TYPE_ITEM = 0;
        private static final int TYPE_SEPARATOR = 1;
        private static final int TYPE_MAX_COUNT = TYPE_SEPARATOR + 1;

        private ArrayList<String> mData = new ArrayList<String>();
        private LayoutInflater mInflater;

        private TreeSet<Integer> mSeparatorsSet = new TreeSet<Integer>();

        public MyCustomAdapter() {
            mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        }

        public void addItem(final String item) {
            mData.add(item);
            notifyDataSetChanged();
        }

        public void addSeparatorItem(final String item) {
            mData.add(item);
            // save separator position
            mSeparatorsSet.add(mData.size() - 1);
            notifyDataSetChanged();
        }

        @Override
        public int getItemViewType(int position) {
            return mSeparatorsSet.contains(position) ? TYPE_SEPARATOR : TYPE_ITEM;
        }

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

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

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

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder holder = null;
            int type = getItemViewType(position);
            System.out.println("getView " + position + " " + convertView + " type = " + type);
            if (convertView == null) {
                holder = new ViewHolder();
                switch (type) {
                    case TYPE_ITEM:
                        convertView = mInflater.inflate(R.layout.item1, null);
                        holder.textView = (TextView)convertView.findViewById(R.id.text);
                        break;
                    case TYPE_SEPARATOR:
                        convertView = mInflater.inflate(R.layout.item2, null);
                        holder.textView = (TextView)convertView.findViewById(R.id.textSeparator);
                        break;
                }
                convertView.setTag(holder);
            } else {
                holder = (ViewHolder)convertView.getTag();
            }
            holder.textView.setText(mData.get(position));
            return convertView;
        }

    }

    public static class ViewHolder {
        public TextView textView;
    }
}

两个xml UI配置文件：

1： item1.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
	xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_height="wrap_content"
	android:layout_width="fill_parent">
	<!-- android:gravity="center_vertical" -->
	<TextView
		android:id="@+id/text"
		android:layout_height="50dp"
		android:gravity="center"
		android:text="text"
		android:visibility="visible"
		android:layout_width="fill_parent"
		android:textColor="#FF000000"
		android:background="#FFFFFFFF" />
</LinearLayout>

2: item2.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
	xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_height="wrap_content"
	android:layout_width="fill_parent">
	<TextView
		android:id="@+id/textSeparator"
		android:layout_height="wrap_content"
		android:gravity="center_vertical"
		android:text="text"
		android:visibility="visible"
		android:layout_width="fill_parent"
		android:textColor="#FFFFFFFF"
		android:background="#FFFF0000" />
</LinearLayout>

原文地址：

http://android.amberfog.com/?p=296