使用RecyclerView来完成聊天对话框

聊天记录信息类，该类中2个成员变量聊天内容content和信息来源type

public class Msg
{
public static final int TYPE_RECEIVE = 0;
public static final int TYPE_SEND = 1;
private String content;
private int type;

public Msg(String content, int type)
{
this.content = content;
this.type = type;
}

public String getContent()
{
return content;
}

public int getType()
{
return type;
}
}

定义一个适配器用于RecyclerView数据适配，根据信息来源不同，选择性显示聊天记录信息

/**
* Created by Xiongxl on 2016/12/20.
*/
public class MsgAdapter extends RecyclerView.Adapter<MsgAdapter.ViewHolder>
{
List<Msg> msgList;

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.msg_item, parent, false);
return new ViewHolder(view);
}

@Override
public void onBindViewHolder(ViewHolder holder, int position)
{
Msg msg = msgList.get(position);
if (msg.getType() == Msg.TYPE_RECEIVE)
{
holder.leftLayout.setVisibility(View.VISIBLE);
holder.rightLayout.setVisibility(View.GONE);
holder.leftMsg.setText(msg.getContent());
} else if (msg.getType() == Msg.TYPE_SEND)
{
holder.rightLayout.setVisibility(View.VISIBLE);

f079
holder.leftLayout.setVisibility(View.GONE);
holder.rightMsg.setText(msg.getContent());
}
}

public MsgAdapter(List<Msg> msgs)
{
this.msgList = msgs;
}

@Override
public int getItemCount()
{
return msgList.size();
}

static class ViewHolder extends RecyclerView.ViewHolder
{
LinearLayout leftLayout;
LinearLayout rightLayout;
TextView leftMsg;
TextView rightMsg;

ViewHolder(View view)
{
super(view);
leftLayout = (LinearLayout) view.findViewById(R.id.left_layout);
rightLayout = (LinearLayout) view.findViewById(R.id.right_layout);
leftMsg = (TextView) view.findViewById(R.id.left_msg);
rightMsg = (TextView) view.findViewById(R.id.right_msg);
}
}
}

recyclerView项目内容的布局文件，包含一个左边的聊天记录和右边的聊天记录

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">

<LinearLayout
android:id="@+id/left_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="left"
android:background="@drawable/left">

<TextView
android:id="@+id/left_msg"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_margin="10dp"/>
</LinearLayout>

<LinearLayout
android:id="@+id/right_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:background="@drawable/right">

<TextView
android:id="@+id/right_msg"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_margin="10dp"/>
</LinearLayout>
</LinearLayout>

项目的布局文件，布局文件中有一个recyclerView、EditText和一个Button用于信息发送触发事件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="#d8e0e8">

<android.support.v7.widget.RecyclerView
android:id="@+id/msg_recyclerView"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">

<EditText
android:id="@+id/input_text"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:hint="Type something here"
android:maxLines="2"/>

<Button
android:id="@+id/btnSend"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Send"/>
</LinearLayout>

</LinearLayout>

MainActivity活动内的代码代码如下

public class MainActivity extends AppCompatActivity
{
List<Msg> msgList = new ArrayList<>();
EditText inputText;
Button btnSend;
RecyclerView recyclerView;
private MsgAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initMsg();
btnSend = (Button) this.findViewById(R.id.btnSend);
inputText = (EditText) this.findViewById(R.id.input_text);
recyclerView = (RecyclerView) this.findViewById(R.id.msg_recyclerView);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(linearLayoutManager);
adapter = new MsgAdapter(msgList);
recyclerView.setAdapter(adapter);
btnSend.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View view)
{
String content = inputText.getText().toString().trim();
if (!content.equals(""))
{
msgList.add(new Msg(content, Msg.TYPE_SEND));
adapter.notifyItemInserted(msgList.size() - 1);
recyclerView.scrollToPosition(msgList.size() - 1);
inputText.setText("");
}
}
});
}

private void initMsg()
{
Msg msg1 = new Msg("hello sealong", Msg.TYPE_RECEIVE);
msgList.add(msg1);
Msg msg2 = new Msg("hello peipei", Msg.TYPE_SEND);
msgList.add(msg2);
Msg msg = new Msg("What are you doing", Msg.TYPE_RECEIVE);
msgList.add(msg);
}
}

数据集更改后，通知适配器有更改，并且将RecyclerView的滚动条滑到最后一个元素

adapter.notifyItemInserted(msgList.size() - 1);
recyclerView.scrollToPosition(msgList.size() - 1);