Android开发ListView实现聊天列表之处理不同数据项

释放双眼,带上耳机,听听看~!

 

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="https://js.aizhan.com/develop/android/@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="https://js.aizhan.com/develop/android/@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);
}
}

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