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通常我们用惯的ListView每一项的布局都是相同的,只是控件所绑定的数据不同。但单单只是如此并不能满足我们某些特殊需求,比如我们常见的QQ、微信的聊天列表,除了有左右之分外,内容更是有很大区别,有文字、语音、图片、视频等等,他们真的是ListView可以实现的吗?答案是肯定的,只要我们做一下类型区别即可。
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实现效果如下所示:
大家不要在意布局,这里为了方便就随意了。大家可以看到,这里有两种布局,一种头像在左,一种头像在右,虽然这是一种简单的情况,但我们只需要了解其中的原理,再复杂的情况都可以迎刃而解。
我们只要将每一种布局划为一种类型进行区分,根据我们所区分的类型在我们自定义的Adapter中加载不同布局即可,代码如下所示:
if (bean.getType() == 1) { convertView = mInflater.inflate(R.layout.item_chat_left, null); holder.mIvAvatar = (ImageView) convertView.findViewById(R.id.iv_chatLeftItem_avatar); holder.mTvContent = (TextView) convertView.findViewById(R.id.tv_chatLeftItem_content); } else if (bean.getType() == 2) { convertView = mInflater.inflate(R.layout.item_chat_right, null); holder.mIvAvatar = (ImageView) convertView.findViewById(R.id.iv_chatRightItem_avatar); holder.mTvContent = (TextView) convertView.findViewById(R.id.tv_chatRightItem_content); }
是不是发现很简单,最后,我再将所有代码一同贴出来。
item_chat_left.xml
<?xml version="1.0" encoding="utf-8"?>
item_chat_right.xml
<?xml version="1.0" encoding="utf-8"?>
activity_chat.xml
ChatItemBean.java
import android.graphics.Bitmap; public class ChatItemBean { private int type; private String content; private Bitmap avatar; public int getType() { return type; } public void setType(int type) { this.type = type; } public String getContent() { return content; } public void setContent(String content) { this.content = content; } public Bitmap getAvatar() { return avatar; } public void setAvatar(Bitmap avatar) { this.avatar = avatar; } }
ChatLVAdapter.java
import java.util.List; import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.TextView; public class ChatLVAdapter extends BaseAdapter { private ListmDatas; private LayoutInflater mInflater; public ChatLVAdapter(Context context, List datas) { this.mInflater = LayoutInflater.from(context); this.mDatas = datas; } @Override public int getCount() { return mDatas.size(); } @Override public Object getItem(int position) { return mDatas.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = null; ChatItemBean bean = mDatas.get(position); if (convertView == null) { holder = new ViewHolder(); if (bean.getType() == 1) { convertView = mInflater.inflate(R.layout.item_chat_left, null); holder.mIvAvatar = (ImageView) convertView.findViewById(R.id.iv_chatLeftItem_avatar); holder.mTvContent = (TextView) convertView.findViewById(R.id.tv_chatLeftItem_content); } else if (bean.getType() == 2) { convertView = mInflater.inflate(R.layout.item_chat_right, null); holder.mIvAvatar = (ImageView) convertView.findViewById(R.id.iv_chatRightItem_avatar); holder.mTvContent = (TextView) convertView.findViewById(R.id.tv_chatRightItem_content); } convertView.setTag(holder); } else { // 通过tag找到缓存的布局 holder = (ViewHolder) convertView.getTag(); } holder.mIvAvatar.setImageBitmap(bean.getAvatar()); holder.mTvContent.setText(bean.getContent()); return convertView; } public final class ViewHolder { public ImageView mIvAvatar; public TextView mTvContent; }
ChatActivity.java
import java.util.ArrayList; import java.util.List; import android.app.Activity; import android.graphics.BitmapFactory; import android.os.Bundle; import android.widget.ListView; public class ChatActivity extends Activity { private ListView mLv; private ListmDatas ; private ChatLVAdapter mAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_chat); mLv = (ListView) findViewById(R.id.lv_content); initData(); mAdapter = new ChatLVAdapter(this, mDatas); mLv.setAdapter(mAdapter); } private void initData() { mDatas = new ArrayList (); ChatItemBean chat1 = new ChatItemBean(); chat1.setType(1); chat1.setContent("早啊!"); chat1.setAvatar(BitmapFactory.decodeResource(getResources(), R.drawable.ic_item1)); mDatas.add(chat1); ChatItemBean chat2 = new ChatItemBean(); chat2.setType(2); chat2.setContent("早!一大早找我有啥事?"); chat2.setAvatar(BitmapFactory.decodeResource(getResources(), R.drawable.ic_item2)); mDatas.add(chat2); ChatItemBean chat3 = new ChatItemBean(); chat3.setType(1); chat3.setContent("没事就不能找你谈情说爱吗?也没什么事,看你有没有在撸代码。"); chat3.setAvatar(BitmapFactory.decodeResource(getResources(), R.drawable.ic_item1)); mDatas.add(chat3); ChatItemBean chat4 = new ChatItemBean(); chat4.setType(2); chat4.setContent("算了吧,别找我!我害怕。"); chat4.setAvatar(BitmapFactory.decodeResource(getResources(), R.drawable.ic_item2)); mDatas.add(chat4); ChatItemBean chat5 = new ChatItemBean(); chat5.setType(2); chat5.setContent("都被代码撸惨了,我哪敢一早起来找虐。"); chat5.setAvatar(BitmapFactory.decodeResource(getResources(), R.drawable.ic_item2)); mDatas.add(chat5); } }
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持创新互联。