android手机编程3.7

alltolove · 发表于 2017-10-1 10:12:03

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这个小案列非常简单，图片我就从网上随便找了一个，如果没有在布局文件里随便设置个背景颜色也行。首先在build.gradle里安装依赖，在dependencies标签下添加一行

compile 'com.android.support:recyclerview-v7:26.+'

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然后修改activity_main.xml文件

<?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:background="#d8e0e8"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="@+id/msg_recycleview"
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"
/>
<Button
android:id="@+id/send"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="send"/>
</LinearLayout>
</LinearLayout>

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然后再mainactivity.java旁边新建一个javabean的类

package com.example.xinwei.chartactivity;
/**
* Created by xinwei on 2017/10/1.
*/
public class Msg {
public static final int TYPE_RECEIVED = 0;
public static final int TYPE_SENT = 1;
private String content;
private int type;
public String getContent() {
return content;
}
public int getType() {
return type;
}
public Msg(String content, int type){
this.content=content;
this.type=type;
}
}

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在布局layout文件夹下新建msg_item.xml文件

<?xml version="1.0" encoding="utf-8"?>
<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/message_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="#fff"/>
</LinearLayout>
<LinearLayout
android:id="@+id/right_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:background="@drawable/message_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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然后创建适配器类，在mainactivity.java旁边新建个MsgAdapter.java文件

package com.example.xinwei.chartactivity;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
import java.util.List;
/**
* Created by xinwei on 2017/10/1.
*/
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 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_RECEIVED){
holder.leftLayout.setVisibility(View.VISIBLE);
holder.rightLayout.setVisibility(View.GONE);
holder.leftMsg.setText(msg.getContent());
}else if(msg.getType()==Msg.TYPE_SENT){
holder.leftLayout.setVisibility(View.GONE);
holder.rightLayout.setVisibility(View.VISIBLE);
holder.rightMsg.setText(msg.getContent());
}
}
@Override
public int getItemCount() {
return mMsgList.size();
}
}

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然后修改mainactivity.java中的代码

package com.example.xinwei.chartactivity;
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 msgRecycleView;
private MsgAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initMsgs();
inputText=(EditText)findViewById(R.id.input_text);
send=(Button)findViewById(R.id.send);
msgRecycleView=(RecyclerView)findViewById(R.id.msg_recycleview);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
msgRecycleView.setLayoutManager(layoutManager);
adapter=new MsgAdapter(msgList);
msgRecycleView.setAdapter(adapter);
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);
msgRecycleView.scrollToPosition(msgList.size()-1);
inputText.setText("");
}
}
});
}
private void initMsgs() {
Msg msg1 =new Msg("hello guy",Msg.TYPE_RECEIVED);
msgList.add(msg1);
Msg msg2 =new Msg("hello who is that",Msg.TYPE_SENT);
msgList.add(msg2);
Msg msg3 =new Msg("This is Tom.Nice talking to you",Msg.TYPE_RECEIVED);
msgList.add(msg3);
}
}

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最后最好准备两张图片修改文件名为msg_left.png和msg_right.png放进drawable目录,效果图：

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[学习笔记] android手机编程3.7

马上注册，结交更多好友，享用更多功能^_^

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