编写精美的UI聊天界面

效果图：

GIF.gif

1、导入Recyclerview依赖

dependencies {

compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:25.3.1'
compile 'com.android.support:recyclerview-v7:25.3.1'
testCompile 'junit:junit:4.12'

}

2、编写主界面 activity_main.xml中代码 :

< 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="#d8e9e8">



   

    

     

界面中放了一个RecyclerView用于显示聊天的消息内容

EditText用于输入消息

Button发送消息

3、定义消息实体类 新建Msg 代码如下:

public class Msg {
public static final int TYPE_RECEIVEO = 0;
public static final int TYPE_SENT = 1;
private String content;
private int type;

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

public static int getTypeReceiveo() {
    return TYPE_RECEIVEO;
}

public static int getTypeSent() {
    return TYPE_SENT;
}

public String getContent() {
    return content;
}

public void setContent(String content) {
    this.content = content;
}

public int getType() {
    return type;
}

public void setType(int type) {
    this.type = type;
}}

msg类中两个字段，content表示消息内容，type表示消息类型。消息类型有两个值可选择，TYPE_RECEUVED表示收到的消息，TYPE_SENT表示发送出去的消息

4、编写RecyclerView子项布局，新建msg_item.xml ：

xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="10dp">

这里我们让收到消息居左对齐，发送消息居右对其

5、创建RecyclerView适配器类，新建MsgAdapter :

public class MsgAdapter extends RecyclerView.Adapter {
private List mMsgList;

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

    public 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);
    }
}

public MsgAdapter(List msgList) {
    mMsgList = 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 = mMsgList.get(position);
    if (msg.getType() == Msg.TYPE_RECEIVEO) {
        //如果是收到的消息 ，则显示左边的消息布局,将右边的消息布局隐藏
        holder.leftLayout.setVisibility(View.VISIBLE);
        holder.rightLayout.setVisibility(View.GONE);
        holder.leftMsg.setText(msg.getContent());
    } else if (msg.getType() == Msg.TYPE_SENT) {
        //如果是发出的消息,则显示右边的消息不就，将左边的消息布局隐藏
        holder.rightLayout.setVisibility(View.VISIBLE);
        holder.leftLayout.setVisibility(View.GONE);
        holder.rightMsg.setText(msg.getContent());
    }
}

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

在onBindViewHolder()方法中对消息类型判断，如果这条消息是收到的，则显示左边。如果这条消息是发出的，则显示在右边消息布局。

6 、最后 MainActivity 中的代码，来为RecyclerView初始化数据，并给发送按钮添加监听事件 :

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

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initMsg();

    //findViewById
    inputText = (EditText) findViewById(R.id.input_text);
    send = (Button) findViewById(R.id.send);
    msgRecyclerView = (RecyclerView) findViewById(R.id.recycle_view);

    LinearLayoutManager layoutManager = new LinearLayoutManager(this);
    msgRecyclerView.setLayoutManager(layoutManager);
    adapter = new MsgAdapter(msgList);
    msgRecyclerView.setAdapter(adapter);
    send.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String content = inputText.getText().toString();
            if (!"".equals(content)) {
                Msg msg = new Msg(content, Msg.TYPE_SENT);
                msgList.add(msg);
                //当有新消息是刷新ListView中的显示
                adapter.notifyItemInserted(msgList.size() - 1);
                //将ListView定位到最后一行
                msgRecyclerView.scrollToPosition(msgList.size() - 1);
                //清空输入框内容
                inputText.setText("");
            }
        }
    });
}

//初始化数据用于在RecyclerView中显示
private void initMsg() {
    Msg msg1 = new Msg("Hello tututu.", Msg.TYPE_RECEIVEO);
    msgList.add(msg1);
    Msg msg2 = new Msg("What are you 弄啥嘞.", Msg.TYPE_SENT);
    msgList.add(msg2);
    Msg msg3 = new Msg("Guess what ？？", Msg.TYPE_RECEIVEO);
    msgList.add(msg3);
    Msg msg4 = new Msg("Rats ， screw you", Msg.TYPE_SENT);
    msgList.add(msg4);
    Msg msg5 = new Msg("FFFUK", Msg.TYPE_RECEIVEO);
    msgList.add(msg5);
    Msg msg6 = new Msg("1", Msg.TYPE_SENT);
    msgList.add(msg6);
    Msg msg7 = new Msg("2", Msg.TYPE_RECEIVEO);
    msgList.add(msg7);
    Msg msg8 = new Msg("3", Msg.TYPE_SENT);
    msgList.add(msg8);
    Msg msg9 = new Msg("QWER", Msg.TYPE_RECEIVEO);
    msgList.add(msg9);
    Msg msg10 = new Msg("DF", Msg.TYPE_SENT);
    msgList.add(msg10);
    Msg msg11 = new Msg("碧池", Msg.TYPE_RECEIVEO);
    msgList.add(msg11);

}  }

到这里我们的工作就都完成了。

Demo链接：https://github.com/15503737504/Liaotian