Android(安卓)聊天界面对话

转载请注明出处：http://blog.csdn.net/htwhtw123/article/details/77510010
实现Android 聊天界面对话，可以设计成接受到的消息在左显示，发送的消息右边显示。使用RecyclerView实现，主要思路是：在子项布局中同时设置左边和右边的TextView，选择性的让TextView可见或不可见。源码见github:点击跳转。下面是在 Androidd 8.0模拟器运行的效果。

1.导入RecyclerView:
ctr+al+shift+s:打开Project Structure对话框，点击Dependencies标签->点击右边的加号->点击libray dependence->在搜索框输入recyclerview->回车->双击选中下图所示项

2.添加图片，设置图片的拉伸方式：自己找一个一个对话框图片->复制到drawable目录下->右击图片文件->create 9 patch file …->弄成如下的样子->把原图片删除。左右各一个，可以在选择图片时，将图片水平旋转，就有了对称的另一张图。例如下面的communicate_left.9.png

3.设置RecyclerVeiw的子布局:
item_layout.xml中的代码：

<?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:layout_marginTop="20dp"    android:orientation="vertical">    <TextView        android:id="@+id/leftTv"        android:textSize="25sp"        android:text="左边发出:\n右边你好"        android:paddingRight="5dp"        android:paddingLeft="10dp"        android:paddingTop="5dp"        android:paddingBottom="5dp"        android:background="@drawable/communicate_left"        android:layout_width="wrap_content"        android:layout_height="wrap_content"/>    <TextView        android:id="@+id/rightTv"        android:text="右边发出:\n左边你好"        android:paddingRight="10dp"        android:paddingLeft="5dp"        android:paddingTop="5dp"        android:paddingBottom="5dp"        android:background="@drawable/communicate_right"        android:textSize="25sp"        android:gravity="right"        android:layout_marginRight="2dp"        android:layout_width="wrap_content"        android:layout_gravity="right"        android:layout_height="wrap_content"/>LinearLayout>

4.ItemAdpter适配器代码:

package com.xingyi.chatui;import android.content.Context;import android.support.v7.widget.RecyclerView;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;import java.util.ArrayList;import java.util.List;public class ItemAdapter extends RecyclerView.Adapter.MyViewHolder> {    List list;    Context context;    int leftOrRight;    public ItemAdapter( Context context) {        this.context = context;        list=new ArrayList<>();    }    @Override    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        MyViewHolder holder = new MyViewHolder(LayoutInflater.from(                context).inflate(R.layout.item_layout, parent,                false));        return holder;    }    @Override    public void onBindViewHolder(MyViewHolder holder,  int position) {        if(leftOrRight==MainActivity.LEFT){            holder.tvLeft.setVisibility(View.VISIBLE);            holder.tvRight.setVisibility(View.GONE);            holder.tvLeft.setText(list.get(position));        }else if(leftOrRight==MainActivity.RIGHT){            holder.tvLeft.setVisibility(View.GONE);            holder.tvRight.setVisibility(View.VISIBLE);            holder.tvRight.setText(list.get(position));        }    }    //添加子项    public void addItem(String str,int leftOrRight) {        this.leftOrRight=leftOrRight;        list.add(str);        notifyItemInserted(list.size()-1);    }    @Override    public int getItemCount() {        return list.size();    }    class MyViewHolder extends RecyclerView.ViewHolder {        TextView tvLeft,tvRight;        public MyViewHolder(View itemView) {            super(itemView);            tvLeft = (TextView) itemView.findViewById(R.id.leftTv);            tvRight = (TextView) itemView.findViewById(R.id.rightTv);        }    }}

5.主活动的布局activity_main：

<?xml version="1.0" encoding="utf-8"?><LinearLayout    xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.xingyi.test.MainActivity"    android:orientation="vertical">    <LinearLayout        android:gravity="center"        android:layout_width="match_parent"        android:layout_height="wrap_content">        <Button            android:onClick="leftClick"            android:text="左边发送"            android:layout_width="wrap_content"            android:layout_height="wrap_content"/>        <Button            android:onClick="rightClick"            android:layout_marginLeft="29dp"            android:text="右边发送"            android:layout_width="wrap_content"            android:layout_height="wrap_content"/>    LinearLayout>    <android.support.v7.widget.RecyclerView        android:id="@+id/rv"        android:layout_width="match_parent"        android:layout_height="match_parent"/>LinearLayout>

6.MainActivity
这里需要注意的是，Recyclerview的导入语句，选择：
import android.support.v7.widget.RecyclerView;

package com.xingyi.chatui;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;public class MainActivity extends AppCompatActivity {    RecyclerView recyclerView;    ItemAdapter itemAdapter;    final  static int LEFT=1;    final  static int RIGHT=2;    int i=0;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();    }    private void initView(){        recyclerView= (RecyclerView) findViewById(R.id.rv);        recyclerView.setLayoutManager(new LinearLayoutManager(this));        itemAdapter=new ItemAdapter(this);        recyclerView.setAdapter(itemAdapter);    }    public void leftClick(View v){        //第一个参数指定发出内容，第二参数指定发出的是左还是右        itemAdapter.addItem("左边发出:\n右边你好"+i,LEFT);        recyclerView.smoothScrollToPosition(i);//移动到指定位置        i++;    }    public void rightClick(View v){        //第一个参数指定发出内容，第二参数指定发出的是左还是右        itemAdapter.addItem("右边发出:\n左边你好"+i,RIGHT);        recyclerView.smoothScrollToPosition(i);//移动到指定位置        i++;    }}

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