编写简单的聊天界面

来源：互联网发布：windows上类似imovie 编辑：程序博客网时间：2024/05/17 00:00

MainActivity

public class MainActivity extends AppCompatActivity {    private List<Msg> 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);        //初始化数据        initMsgs();        //获取控件实例        inputText = (EditText) findViewById(R.id.input_text);        send = (Button) findViewById(R.id.send);        msgRecyclerView = (RecyclerView) findViewById(R.id.msg_recycler_view);        //定义一个线性布局对象        LinearLayoutManager layoutManager = new LinearLayoutManager(this);        //将线性布局对象设置在滚动控件中        msgRecyclerView.setLayoutManager(layoutManager);        //将适配器与数据关联        adapter = new MsgAdapter(msgList);        //将适配器设置在控件中        msgRecyclerView.setAdapter(adapter);        /*        * 监听Send按钮        * 获取TextView中的内容        * 如果TextView中的内容不为空        * 1.将内容与消息类型传入实体类的构造函数        * 2.将消息添加到masList集合中        * 3.通知列表有新的数据加入        * 4.将控件位置定在最后一个        * 5.将TextView内容置空        * */        send.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                String content = inputText.getText().toString();                if(!"".equals(content)) {                    Msg msg = new Msg(content, Msg.TYPE_SENT);                    msgList.add(msg);                    adapter.notifyItemInserted(msgList.size() - 1);                    msgRecyclerView.scrollToPosition(msgList.size() - 1);                    inputText.setText("");                }            }        });    }    private void initMsgs() {        Msg msg1 = new Msg("Hello guy.", Msg.TYPE_SENT);        msgList.add(msg1);        Msg msg2 = new Msg("hello. who is that?" ,Msg.TYPE_RECEIVED);        msgList.add(msg2);        Msg msg3 = new Msg("This is Tom, Nice taking to you", Msg.TYPE_RECEIVED);        msgList.add(msg3);    }}

MsgAdapter

//泛型指定为MsgAdapter.ViewHolder，是MsgAdapter中的类public class MsgAdapter extends RecyclerView.Adapter<MsgAdapter.ViewHolder> {    private List<Msg> mMsgList;    //外部类继承自RecyclerView.Adapter，内部类继承自RecyclerView.ViewHolder    static class ViewHolder extends RecyclerView.ViewHolder {        //定义控件对象        LinearLayout leftLayout;        LinearLayout rightLayout;        TextView leftMsg;        TextView rightMsg;        public ViewHolder(View itemView) {            super(itemView);            //获取控件实例            leftLayout =  itemView.findViewById(R.id.left_layout);            rightLayout =  itemView.findViewById(R.id.right_layout);            leftMsg =  itemView.findViewById(R.id.left_msg);            rightMsg =  itemView.findViewById(R.id.right_msg);        }    }    public MsgAdapter(List<Msg> mMsgList) {        this.mMsgList = mMsgList;    }    //获取ViewHolder实例    @Override    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.msg_item,                 parent, false);        //view通常是RecyclerView子项最外层布局，传到ViewHolder中，可获取控件实例        return new ViewHolder(view);    }    //子项滚进屏幕时执行，用于设置数据    @Override    public void onBindViewHolder(ViewHolder holder, int position) {        Msg msg = mMsgList.get(position);        //如果是收到信息，显示左边图片和文字，隐藏右边，反之。        if(msg.getType() == Msg.TYPE_RECEIVED) {            holder.leftLayout.setVisibility(View.VISIBLE);            holder.rightLayout.setVisibility(View.GONE);            holder.leftMsg.setText(msg.getContent());        } else if (msg.getType() == Msg.TYPE_SENT) {            holder.rightLayout.setVisibility(View.VISIBLE);            holder.leftLayout.setVisibility(View.GONE);            holder.rightMsg.setText(msg.getContent());        }    }    @Override    public int getItemCount() {        return mMsgList.size();    }}

实体类Msg

public class Msg {    public static final int TYPE_RECEIVED = 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 String getContent() {        return content;    }    public int getType() {        return type;    }}

主布局activity_main

<LinearLayout    xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:background="#d8e0e8">    <android.support.v7.widget.RecyclerView        android:id="@+id/msg_recycler_view"        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/send"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="Send"/>    </LinearLayout></LinearLayout>

RecyclerView布局msg_item

<LinearLayout    xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:padding="10dp">    <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"            android:textColor="#121212"/>    </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>

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