【Android】17.0 UI開發（八）——利用RecyclerView列表控件實現精美的聊天界面

1.0 首先新建一個項目，名叫：UIBestPractice，目錄以下：

 

2.0 這裏須要先準備兩張圖片，放在app\src\main\res\drawable-xhdpi目錄下。

這裏圖片名稱已經制做成爲Nine-Patch圖片，本來的名字沒有「.9」字樣。在目錄下鼠標選中圖片，右擊，選擇「」便可進入Nine-Patch圖片編輯環境，

      

 

將可見是以下的畫面,鼠標點擊就會在邊上添加黑色線條，意味着該線條所對應的邊是容許變形的，按住shift鍵再點擊，便可取消黑邊，並且鼠標只有停在圖片的四條邊才能夠操做，纔會出現黑邊，鼠標也纔會變成成爲雙箭頭圖案：

能夠看到右側是拉伸時的形狀預覽。

保存便可，自動生成相同名字的後綴名爲「.9.png」的圖片。

 

3.0 在主活動界面設置佈局，activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#ffffff" tools:context=".MainActivity">

    <android.support.v7.widget.RecyclerView android:id="@+id/msg_recycler_view" android:layout_width="match_parent" android:layout_height="0dp" app:layout_constraintBottom_toTopOf="@+id/linear" app:layout_constraintEnd_toEndOf="@+id/linear" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_weight="1" />

    <LinearLayout android:id="@+id/linear" android:layout_width="match_parent" android:layout_height="wrap_content" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.0" app:layout_constraintStart_toStartOf="parent">

        <EditText android:id="@+id/input_text" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_weight="1" android:hint="在這裏鍵入內容" android:maxLines="2" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toLeftOf="@+id/send"/>

        <Button android:id="@+id/send" android:layout_width="wrap_content" android:layout_height="wrap_content" android:baselineAligned="false" android:text="發送" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintLeft_toRightOf="@+id/input_text"/>

    </LinearLayout>

</android.support.constraint.ConstraintLayout>

 

效果以下：

 

4.0 設置聊天適配器Msg.java：

package com.example.uibestpractice; public class Msg { public static final int TYPE_RECEIVED = 0; public static final int TYPE_SENT = 1; private String content; private int type; // content 消息的內容 // type 消息的類型 // TYPE_RECEIVED 表示這是一條收到的信息 // TYPE_SENT 表示這是一條發出的信息
    public Msg(String content,int type){ this.content =content; this.type = type; } public String getContent(){ return content; } public int getType(){ return type; } }

 

5.0 MsgAdapter.java

package com.example.uibestpractice; import android.support.v7.widget.RecyclerView; import android.view.LayoutInflater; import android.view.ViewGroup; import android.widget.LinearLayout; import android.widget.TextView; import android.view.View; import java.util.List; public class MsgAdapter extends RecyclerView.Adapter<MsgAdapter.ViewHolder> { private List<Msg> 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<Msg> msgList){ mMsgList =msgList; } @Override public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) { View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.msg_item,viewGroup,false); return new ViewHolder(view); } @Override public void onBindViewHolder(ViewHolder viewHolder, int i) { Msg msg = mMsgList.get(i); if (msg.getType() == Msg.TYPE_RECEIVED){ //若是是收到的信息，則顯示在左邊的消息佈局，將右邊的消息佈局隱藏
 viewHolder.leftLayout.setVisibility(View.VISIBLE); viewHolder.rightLayout.setVisibility(View.GONE); viewHolder.leftMsg.setText(msg.getContent()); }else if (msg.getType() == Msg.TYPE_SENT){ //若是是發出的信息，則顯示在右邊的消息佈局，將左邊的消息佈局隱藏
 viewHolder.leftLayout.setVisibility(View.GONE); viewHolder.rightLayout.setVisibility(View.VISIBLE); viewHolder.rightMsg.setText(msg.getContent()); } } @Override public int getItemCount() { return mMsgList.size(); } }

 

6.0 針對聊天顯示進行佈局設置，msg_item.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" 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:background="@drawable/juxingqipao_left" android:gravity="left" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent">

        <TextView android:id="@+id/left_msg" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="left" />
    </LinearLayout>

    <LinearLayout android:id="@+id/right_layout" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@drawable/juxingqipao_right" android:gravity="right" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintTop_toTopOf="parent">


    <TextView android:id="@+id/right_msg" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="right" />
    </LinearLayout>
</android.support.constraint.ConstraintLayout>

 

 

7.0 主函數 ：MainActivity.java

package com.example.uibestpractice; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.RecyclerView; import android.view.View; import android.widget.Button; import android.widget.EditText; import java.util.ArrayList; import java.util.List; 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); initMsgs();//初始化數據
        inputText = (EditText) findViewById(R.id.input_text); send = (Button) findViewById(R.id.send); msgRecyclerView = (RecyclerView) findViewById(R.id.msg_recycler_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); adapter.notifyItemInserted(msgList.size() - 1); //當有新消息時，刷新RecyclerView中的顯示
                    msgRecyclerView.scrollToPosition(msgList.size() - 1); //將RecyclerView定位到最後一行
                    inputText.setText("");//清空輸入框中的內容
 } } }); } private void initMsgs() { Msg msg1 = new Msg("你好，張三", Msg.TYPE_RECEIVED); msgList.add(msg1); Msg msg2 = new Msg("你好，請問你是？", Msg.TYPE_SENT); msgList.add(msg2); Msg msg3 = new Msg("我是tuituitui的小仙女一隻，很高興認識你啊！", Msg.TYPE_RECEIVED); msgList.add(msg3); } }

 

 

8.0 運行效果(真機)以下: