Android实现聊天界面

本文实例为大家分享了Android实现聊天界面的具体代码,供大家参考,具体内容如下

文件目录

在app下的build.gradle中添加依赖库(RecyclerView)

apply plugin: 'com.android.application'

android {

compileSdkVersion 24

buildToolsVersion "26.0.1"

defaultConfig {

applicationId "com.example.uibestpractice"

minSdkVersion 15

targetSdkVersion 24

versionCode 1

versionName "1.0"

testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"

}

buildTypes {

release {

minifyEnabled false

proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguarrules.pro'

}

}

}

dependencies {

compile fileTree(dir: 'libs', include: ['*.jar'])

androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {

exclude group: 'com.android.support', module: 'support-annotations'

})

compile 'com.android.support:appcompat-v7:24.2.1'

compile 'com.android.support.constraint:constraint-layout:1.0.2'

compile 'com.android.support:recyclerview-v7:24.2.1'//添加RecyclerView依赖库

testCompile 'junit:junit:4.12'

}

编写主界面(activity_main.xml)

<?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="match_parent"

android:background="#d8e0d8">

<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>

  • 在主界面中放置的RecyclerView用于显示消息
  • EditText用于编辑消息
  • Button用于发送消息

定义消息的实体类Msg

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;

public Msg(String content,int type) {

this.content = content;

this.type = type;

}

public String getContent() {

return content;

}

public int getType() {

return type;

}

}

  • 用两个常量来表示消息的类型(接收的还是发送的)

编写RecyclerView的子布局(msg_item.xml)

<?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>

  • 将接收的消息居左对齐,发送的消息居右对齐

创建RecyclerView适配器类

package com.example.uibestpractice;

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;

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 rihgtMsg;

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);

rihgtMsg = (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.rightLayout.setVisibility(View.VISIBLE);

holder.leftLayout.setVisibility(View.GONE);

holder.rihgtMsg.setText(msg.getContent());

}

}

@Override

public int getItemCount() {

return mMsgList.size();

}

}

  • 定义了一个内部类ViewHolder,继承自RecyclerView.ViewHolder。ViewHolder的构造函数中传入一个View参数,这个参数通常是RecyclerView子项的最外层布局,这样我们就可以通过findViewById()方法来获取布局中的接收和发送消息布局的实例了。
  • MsgAdapter中也有一个构造函数,将要展示的数据源传进来复制给mMsgList。
  • MsgAdapter继承自RecyclerView.Adapter,必须重写onCreateViewHolder()、onBindViewHolder()、getItemCount()三个方法。
  • onCreateViewHolder()用于创建ViewHolder实例,在这个方法中将msg_item布局加载进来,然后创建一个ViewHolder实例,并把加载出来的布局传到构造函数中,返回实例。
  • onBindViewHolder()用于对RecyclerView子项的数据进行赋值。
  • getItemCount()获得RecyclerView有多少个子项

使用RecyclerView(修改MainActivity)

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();

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);

msgRecyclerView.scrollToPosition(msgList.size()-1);

inputText.setText("");

}

}

});

}

private void initMsgs() {

Msg msg1 = new Msg("Hello",Msg.TYPE_RECEIVED);

msgList.add(msg1);

Msg msg2 = new Msg("I'm John",Msg.TYPE_RECEIVED);

msgList.add(msg2);

Msg msg3 = new Msg("Hello",Msg.TYPE_SENT);

msgList.add(msg3);

}

}

onCreate()方法中先获得了RecyclerView的实例,然后创建了LinearLayoutManager对象,并把它设置到RecyclerView的实例中去。LayoutManager用于指定RecyclerView的布局方式,这里使用是线性布局的意思,可以实现ListView相同的效果。

设置了send按钮的响应事件,如果内容不为空则创建出一个新的Msg对象,并添加到msgList中去,之后调用了适配器的方法notifyItemInserted()来通知列表有新数据插入,这样新增的消息才能在RecyclerView中显示。接着调用RecyclerView的scrollToPosition()方法,将显示的数据定位到最后一行,最后清空输入栏。

效果图:

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。

以上是 Android实现聊天界面 的全部内容, 来源链接: utcz.com/p/240680.html

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