ListView实现聊天列表之处理不同数据项

    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。

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"?> 
<relativelayout xmlns:android="http://schemas.android.com/apk/res/android" 
  android:layout_width="match_parent" 
  android:layout_height="wrap_content" 
  android:padding="6dp" > 
 
  <imageview 
    android:id="@+id/iv_chatleftitem_avatar" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:background="#dd00f0" 
    android:src="@drawable/ic_launcher" /> 
 
  <textview 
    android:id="@+id/tv_chatleftitem_content" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textsize="16sp" 
    android:padding="16dp" 
    android:layout_torightof="@id/iv_chatleftitem_avatar" 
    android:background="@drawable/qfav_list_bubble_nor" 
    android:layout_marginright="64dp" 
    android:gravity="center_vertical" /> 
 
</relativelayout> 

item_chat_right.xml

<?xml version="1.0" encoding="utf-8"?> 
<relativelayout xmlns:android="http://schemas.android.com/apk/res/android" 
  android:layout_width="match_parent" 
  android:layout_height="wrap_content" 
  android:padding="6dp" > 
   
  <imageview 
    android:id="@+id/iv_chatrightitem_avatar" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignparentright="true" 
    android:background="#ddf000" 
    android:src="@drawable/ic_launcher" /> 
   
  <textview 
    android:id="@+id/tv_chatrightitem_content" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textsize="16sp" 
    android:padding="16dp" 
    android:layout_toleftof="@id/iv_chatrightitem_avatar" 
    android:background="@drawable/skin_aio_user_bubble_pressed" 
    android:layout_marginleft="64dp" 
    android:gravity="center_vertical" /> 
   
</relativelayout> 

activity_chat.xml

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android" 
  xmlns:tools="http://schemas.android.com/tools" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  tools:context="${relativepackage}.${activityclass}" > 
 
  <listview 
    android:id="@+id/lv_content" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:scrollbars="none" 
    android:divider="@null" 
    android:listselector="@android:color/transparent" > 
  </listview> 
 
</relativelayout> 

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 list<chatitembean> mdatas; 
  private layoutinflater minflater; 
   
  public chatlvadapter(context context, list<chatitembean> 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 list<chatitembean> mdatas ; 
  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>(); 
    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。