ListView具有多种item布局——实现微信对话列

       这篇文章的效果也是大家常见的，各种通讯应用的对话列表都是这种方式，像微信、whatsapp、易信、米聊等。我们这篇文章也权当为回忆，形成简单的笔记。这篇文章参考了2009年Google IO中的《TurboChargeYourUI-How to make your AndroidUI fast and efficient》和2010年Google IO中的《The World of List View》。像2009年Google IO的资料还是很前沿的，那会android开发资料很少，最重要的就是参考google发布的各种资料。

    在《TurboChargeYourUI-How to make your AndroidUI fast and efficient》介绍了怎样提高listview的性能，优化了listview的加载速度。这里的item使用的是单一布局，能够实现view的重用和回收，那么多种布局文件的怎么办呢，如果再使用上面的方法，view的重用会出现问题，Android使用的BaseAdapter提供了解决多种布局文件的重用方法。

1）重写 getViewTypeCount() – 该方法返回多少个不同的布局

2）重写 getItemViewType(int) – 根据position返回相应的Item

博主参加了2013博客之星评选，谢谢帮助，投票猛击：

http://vote.blog.csdn.net/blogstaritem/blogstar2013/xyz_lmn

/**
 * 比原来的多了getItemViewType和getViewTypeCount这两个方法，
 * 
 * */
public class ChatAdapter extends BaseAdapter {

	public static final String KEY = "key";
	public static final String VALUE = "value";

	public static final int VALUE_TIME_TIP = 0;// 7种不同的布局
	public static final int VALUE_LEFT_TEXT = 1;
	public static final int VALUE_LEFT_IMAGE = 2;
	public static final int VALUE_LEFT_AUDIO = 3;
	public static final int VALUE_RIGHT_TEXT = 4;
	public static final int VALUE_RIGHT_IMAGE = 5;
	public static final int VALUE_RIGHT_AUDIO = 6;
	private LayoutInflater mInflater;

	private List<Message> myList;

	public ChatAdapter(Context context, List<Message> myList) {
		this.myList = myList;

		mInflater = (LayoutInflater) context
				.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
	}

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

	@Override
	public Object getItem(int arg0) {
		return myList.get(arg0);
	}

	@Override
	public long getItemId(int arg0) {
		return arg0;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup arg2) {

		Message msg = myList.get(position);
		int type = getItemViewType(position);
		ViewHolderTime holderTime = null;
		ViewHolderRightText holderRightText = null;
		ViewHolderRightImg holderRightImg = null;
		ViewHolderRightAudio holderRightAudio = null;
		ViewHolderLeftText holderLeftText = null;
		ViewHolderLeftImg holderLeftImg = null;
		ViewHolderLeftAudio holderLeftAudio = null;
		
		if (convertView == null) {
			switch (type) {
			case VALUE_TIME_TIP:
				holderTime = new ViewHolderTime();
				convertView = mInflater.inflate(R.layout.list_item_time_tip,
						null);
				holderTime.tvTimeTip = (TextView) convertView
						.findViewById(R.id.tv_time_tip);
				holderTime.tvTimeTip.setText(msg.getValue());
				convertView.setTag(holderTime);
				break;
			// 左边
			case VALUE_LEFT_TEXT:
				holderLeftText = new ViewHolderLeftText();
				convertView = mInflater.inflate(R.layout.list_item_left_text,
						null);
				holderLeftText.ivLeftIcon = (ImageView) convertView
						.findViewById(R.id.iv_icon);
				holderLeftText.btnLeftText = (Button) convertView
						.findViewById(R.id.btn_left_text);
				holderLeftText.btnLeftText.setText(msg.getValue());
				convertView.setTag(holderLeftText);
				break;

			case VALUE_LEFT_IMAGE:
				holderLeftImg = new ViewHolderLeftImg();
				convertView = mInflater.inflate(R.layout.list_item_left_iamge,
						null);
				holderLeftImg.ivLeftIcon = (ImageView) convertView
						.findViewById(R.id.iv_icon);
				holderLeftImg.ivLeftImage = (ImageView) convertView
						.findViewById(R.id.iv_left_image);
				holderLeftImg.ivLeftImage.setImageResource(R.drawable.test);
				convertView.setTag(holderLeftImg);
				break;

			case VALUE_LEFT_AUDIO:
				holderLeftAudio = new ViewHolderLeftAudio();
				convertView = mInflater.inflate(R.layout.list_item_left_audio,
						null);
				holderLeftAudio.ivLeftIcon = (ImageView) convertView
						.findViewById(R.id.iv_icon);
				holderLeftAudio.btnLeftAudio = (Button) convertView
						.findViewById(R.id.btn_left_audio);
				holderLeftAudio.tvLeftAudioTime = (TextView) convertView
						.findViewById(R.id.tv_left_audio_time);
				holderLeftAudio.tvLeftAudioTime.setText(msg.getValue());
				convertView.setTag(holderLeftAudio);
				break;
			// 右边
			case VALUE_RIGHT_TEXT:
				holderRightText= new ViewHolderRightText();
				convertView = mInflater.inflate(R.layout.list_item_right_text,
						null);
				holderRightText.ivRightIcon = (ImageView) convertView
						.findViewById(R.id.iv_icon);
				holderRightText.btnRightText = (Button) convertView
						.findViewById(R.id.btn_right_text);
				holderRightText.btnRightText.setText(msg.getValue());
				convertView.setTag(holderRightText);
				break;

			case VALUE_RIGHT_IMAGE:
				holderRightImg= new ViewHolderRightImg();
				convertView = mInflater.inflate(R.layout.list_item_right_iamge,
						null);
				holderRightImg.ivRightIcon = (ImageView) convertView
						.findViewById(R.id.iv_icon);
				holderRightImg.ivRightImage = (ImageView) convertView
						.findViewById(R.id.iv_right_image);
				holderRightImg.ivRightImage.setImageResource(R.drawable.test);
				convertView.setTag(holderRightImg);
				break;

			case VALUE_RIGHT_AUDIO:
				holderRightAudio=new ViewHolderRightAudio();
				convertView = mInflater.inflate(R.layout.list_item_right_audio,
						null);
				holderRightAudio.ivRightIcon = (ImageView) convertView
						.findViewById(R.id.iv_icon);
				holderRightAudio.btnRightAudio = (Button) convertView
						.findViewById(R.id.btn_right_audio);
				holderRightAudio.tvRightAudioTime = (TextView) convertView
						.findViewById(R.id.tv_right_audio_time);
				holderRightAudio.tvRightAudioTime.setText(msg.getValue());
				convertView.setTag(holderRightAudio);
				break;

			default:
				break;
			}
			
		} else {
			Log.d("baseAdapter", "Adapter_:"+(convertView == null) );
			switch (type) {
			case VALUE_TIME_TIP:
				holderTime=(ViewHolderTime)convertView.getTag();
				holderTime.tvTimeTip.setText(msg.getValue());
				break;
			case VALUE_LEFT_TEXT:
				holderLeftText=(ViewHolderLeftText)convertView.getTag();
				holderLeftText.btnLeftText.setText(msg.getValue());
				break;
			case VALUE_LEFT_IMAGE:
				holderLeftImg=(ViewHolderLeftImg)convertView.getTag();
				holderLeftImg.ivLeftImage.setImageResource(R.drawable.test);
				break;
			case VALUE_LEFT_AUDIO:
				holderLeftAudio=(ViewHolderLeftAudio)convertView.getTag();
				holderLeftAudio.tvLeftAudioTime.setText(msg.getValue());
				break;
			case VALUE_RIGHT_TEXT:
				holderRightText=(ViewHolderRightText)convertView.getTag();
				holderRightText.btnRightText.setText(msg.getValue());
				break;
			case VALUE_RIGHT_IMAGE:
				holderRightImg=(ViewHolderRightImg)convertView.getTag();
				holderRightImg.ivRightImage.setImageResource(R.drawable.test);
				break;
			case VALUE_RIGHT_AUDIO:
				holderRightAudio=(ViewHolderRightAudio)convertView.getTag();
				holderRightAudio.tvRightAudioTime.setText(msg.getValue());
				break;

			default:
				break;
			}
			
			//holder = (ViewHolder) convertView.getTag();
		}
		return convertView;
	}

	/**
	 * 根据数据源的position返回需要显示的的layout的type
	 * 
	 * type的值必须从0开始
	 * 
	 * */
	@Override
	public int getItemViewType(int position) {

		Message msg = myList.get(position);
		int type = msg.getType();
		Log.e("TYPE:", "" + type);
		return type;
	}

	/**
	 * 返回所有的layout的数量
	 * 
	 * */
	@Override
	public int getViewTypeCount() {
		return 7;
	}

	class ViewHolderTime {
		private TextView tvTimeTip;// 时间
	}

	class ViewHolderRightText {
		private ImageView ivRightIcon;// 右边的头像
		private Button btnRightText;// 右边的文本
	}

	class ViewHolderRightImg {
		private ImageView ivRightIcon;// 右边的头像
		private ImageView ivRightImage;// 右边的图像
	}

	class ViewHolderRightAudio {
		private ImageView ivRightIcon;// 右边的头像
		private Button btnRightAudio;// 右边的声音
		private TextView tvRightAudioTime;// 右边的声音时间
	}

	class ViewHolderLeftText {
		private ImageView ivLeftIcon;// 左边的头像
		private Button btnLeftText;// 左边的文本
	}

	class ViewHolderLeftImg {
		private ImageView ivLeftIcon;// 左边的头像
		private ImageView ivLeftImage;// 左边的图像
	}

	class ViewHolderLeftAudio {
		private ImageView ivLeftIcon;// 左边的头像
		private Button btnLeftAudio;// 左边的声音
		private TextView tvLeftAudioTime;// 左边的声音时间
	}

}

分享两张微信、易信的图，你也可以做成这样子。

Demo下载，请猛击。