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。