这个例子只是简单的实现了单机版的聊天功能，自己跟自己聊，啦啦~~
主要还是展示RecyclerView控件的使用吧~
参考我之前写的文章：
1、先添加一个关于聊天内容的Chat.java类：
package com.example.chenrui.common;
public class Chat {
private String targetUser;
private String content;
public Chat(String targetUser, String content) {
this.targetUser = targetUser;
this.content = content;
}
public String getTargetUser() {
return targetUser;
}
public void setTargetUser(String targetUser) {
this.targetUser = targetUser;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
}
Chat.java这个类有两个属性：聊天对象和聊天内容
2、添加一个RecyclerView控件子项chat_item.xml，这个是实现了聊天内容项的展示：
<?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"> <TextView
android:id="@+id/chatText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/chat"
android:gravity="center_vertical"
android:text="TextView" />
</LinearLayout>
3、添加RecyclerView控件的适配器ChatAdapter.java类：
package com.example.chenrui.app1; import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView; import com.example.chenrui.common.Chat; import java.util.List; public class ChatAdapter extends RecyclerView.Adapter<ChatAdapter.ViewHolder> { private List<Chat> chatList; public ChatAdapter(List<Chat> chatList) {
this.chatList = chatList;
} @NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.chat_item,viewGroup,false);
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
} @Override
public void onBindViewHolder(@NonNull ViewHolder viewHolder, int i) {
Chat chat = chatList.get(i);
viewHolder.chatText.setText(chat.getContent());
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(viewHolder.chatText.getLayoutParams());
if(chat.getTargetUser().equals("张三")) {
params.gravity = Gravity.LEFT;
} else {
params.gravity = Gravity.RIGHT;
}
viewHolder.chatText.setLayoutParams(params);
} @Override
public int getItemCount() {
return chatList.size();
} static class ViewHolder extends RecyclerView.ViewHolder { TextView chatText; public ViewHolder(@NonNull View itemView) {
super(itemView); chatText = itemView.findViewById(R.id.chatText);
}
}
}
上面的代码，设置的是，如果聊天对象是张三，就把聊天内容显示在列表的左侧，否则就显示在列表的右侧。这个是模拟自己和别人对话的展示效果
4、最后就是主Activity了
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"
tools:context=".MainActivity"> <android.support.v7.widget.RecyclerView
android:id="@+id/chatList"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@+id/linearLayout3"
app:layout_constraintTop_toTopOf="parent" /> <LinearLayout
android:id="@+id/linearLayout3"
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="@android:color/darker_gray"
android:orientation="horizontal"
app:layout_constraintBottom_toTopOf="@+id/linearLayout4"> <Spinner
android:id="@+id/targetUser"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1" /> <EditText
android:id="@+id/chatContent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="3"
android:inputType="textPersonName" />
</LinearLayout> <LinearLayout
android:id="@+id/linearLayout4"
android:layout_width="match_parent"
android:layout_height="50dp"
android:orientation="horizontal"
app:layout_constraintBottom_toBottomOf="parent"> <Button
android:id="@+id/chatSubmit"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="发言" />
</LinearLayout> </android.support.constraint.ConstraintLayout>
MainActivity.java
package com.example.chenrui.app1; import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner; import com.example.chenrui.common.Chat; import java.util.ArrayList;
import java.util.List; public class MainActivity extends AppCompatActivity { @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); final RecyclerView chatList = findViewById(R.id.chatList); final List<Chat> chatData = new ArrayList<Chat>();
final ChatAdapter chatAdapter = new ChatAdapter(chatData);
chatList.setAdapter(chatAdapter);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
chatList.setLayoutManager(layoutManager); final Spinner targetUser = findViewById(R.id.targetUser);
String[] data = {"张三","李四"};
ArrayAdapter<String> adapter = new ArrayAdapter<String> (this,R.layout.support_simple_spinner_dropdown_item,data);
targetUser.setAdapter(adapter); final EditText chatContent = findViewById(R.id.chatContent); Button chatSubmit = findViewById(R.id.chatSubmit);
chatSubmit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(!chatContent.getText().toString().equals("")) {
String user = targetUser.getSelectedItem().toString();
chatData.add(new Chat(user, chatContent.getText().toString())); chatAdapter.notifyItemInserted(chatData.size() - 1);
chatList.scrollToPosition(chatData.size() - 1);
chatContent.setText("");
}
}
});
}
}
显示效果：