用sockets打造自己的Android聊天app（安卓篇）
16lz
2021-01-23
用sockets打造自己的Android聊天app（安卓篇）
翻译自http://www.androidhive.info/2014/10/android-building-group-chat-app-using-sockets-part-2/
在上一篇文章中我们介绍了web sockets，搭建好了web环境，这篇文章我们开始安卓app的开发。同web应用一样，有两个屏幕，第一个是输入名字，第二个就是显示和发送消息。OK，我们这次的开发环境依然是Eclipse IDE.
6 建立Android App
首先定义一下我们所用到的颜色res ⇒ values ⇒ colors.xml
<?xml version="1.0" encoding="utf-8"?><resources> <color name="actionbar">#3cb879color> <color name="body_background">#e8e8e8color> <color name="body_background_green">#82e783color> <color name="server_status_bar">#2b2b2bcolor> <color name="title_gray">#434343color> <color name="white">#ffffffcolor> <color name="bg_msg_you">#5eb964color> <color name="bg_msg_from">#e5e7ebcolor> <color name="msg_border_color">#a1a1a1color> <color name="bg_btn_join">#1e6258color> <color name="bg_msg_input">#e8e8e8color> <color name="text_msg_input">#626262color> <color name="lblFromName">#777777color>resources>再定义我们所用到的字符串res ⇒ values ⇒ strings.xml
<?xml version="1.0" encoding="utf-8"?><resources> <string name="app_name">WebMobileGroupChatstring> <string name="title">(Android WebSockets Chat App)string> <string name="author_name">By Ravi Tamadastring> <string name="author_url">www.androidhive.infostring> <string name="enter_name">Enter your namestring> <string name="btn_join">JOINstring> <string name="btn_send">Sendstring>resources>再增加样式文件res ⇒ values ⇒ styles.xml
<resources> <style name="ChatAppTheme" parent="@android:style/Theme.Holo.Light"> <item name="android:actionBarStyle">@style/MyActionBarTheme style> <style name="MyActionBarTheme" parent="@android:style/Widget.Holo.Light.ActionBar"> <item name="android:background">@color/actionbar - "android:titleTextStyle"
>@style/TitleTextStyle style> <style name="TitleTextStyle" parent="android:TextAppearance.Holo.Widget.ActionBar.Title"> <item name="android:textColor">@color/white style>resources>下面这个布局文件是第一个屏幕，让用户输入用户名：
<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/actionbar" android:orientation="vertical" > <ImageView android:id="@+id/imgLogo" android:layout_width="60dp" android:layout_height="60dp" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:layout_gravity="center_horizontal" android:layout_marginBottom="10dp" android:layout_marginTop="60dp" android:src="@drawable/ic_launcher" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/imgLogo" android:layout_centerHorizontal="true" android:layout_marginTop="15dp" android:text="@string/title" android:textColor="@color/white" android:textSize="13dp" /> <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_centerInParent="true" android:gravity="center_horizontal" android:orientation="vertical" android:padding="20dp" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="10dp" android:layout_marginTop="15dp" android:text="@string/enter_name" android:textColor="@color/white" android:textSize="18dp" /> <EditText android:id="@+id/name" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginBottom="10dp" android:layout_marginTop="10dp" android:background="@color/white" android:inputType="textCapWords" android:padding="10dp" /> <Button android:id="@+id/btnJoin" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="40dp" android:background="@color/bg_btn_join" android:paddingLeft="25dp" android:paddingRight="25dp" android:text="@string/btn_join" android:textColor="@color/white" /> LinearLayout> <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_marginBottom="20dp" android:gravity="center_horizontal" android:orientation="vertical" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/author_name" android:textColor="@color/white" android:textSize="12dp" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/author_url" android:textColor="@color/white" android:textSize="12dp" /> LinearLayout>RelativeLayout>下面是对应的Activity，很简单，就是传递数据
NameActivity.java
package info.androidhive.webgroupchat;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class NameActivity extends Activity { private Button btnJoin; private EditText txtName; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_name); btnJoin = (Button) findViewById(R.id.btnJoin); txtName = (EditText) findViewById(R.id.name); // Hiding the action bar getActionBar().hide(); btnJoin.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if (txtName.getText().toString().trim().length() > 0) { String name = txtName.getText().toString().trim(); Intent intent = new Intent(NameActivity.this, MainActivity.class); intent.putExtra("name", name); startActivity(intent); } else { Toast.makeText(getApplicationContext(), "Please enter your name", Toast.LENGTH_LONG).show(); } } }); }}不要忘记在清单文件中加上网络权限
在做完这些之后你的app应该是这样子
在实现sockets之前，我们还需要定义一些资源，用来显示聊天界面
下载background图片放到drawable目录下。
定义如下三个drawable文件，这些用作聊天的背景tile_bg.xml, bg_msg_from.xml and bg_msg_you.xml
tile_bg.xml<?xml version="1.0" encoding="utf-8"?><bitmap xmlns:android="http://schemas.android.com/apk/res/android" android:src="@drawable/bg_messages" android:tileMode="repeat" />bg_msg_from.xml<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <solid android:color="@color/bg_msg_from" > solid> <corners android:radius="5dp" > corners>shape>bg_msg_you.xml<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <solid android:color="@color/bg_msg_you" > solid> <corners android:radius="5dp" > corners>shape>然后我们在定义两个布局文件，分别是聊天的条目（自己的和别人的）
list_item_message_left.xml<?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:orientation="vertical" android:paddingBottom="5dp" android:paddingTop="5dp" android:paddingLeft="10dp"> <TextView android:id="@+id/lblMsgFrom" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="12dp" android:textColor="@color/lblFromName" android:textStyle="italic" android:padding="5dp"/> <TextView android:id="@+id/txtMsg" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="16dp" android:layout_marginRight="80dp" android:textColor="@color/title_gray" android:paddingLeft="10dp" android:paddingRight="10dp" android:paddingTop="5dp" android:paddingBottom="5dp" android:background="@drawable/bg_msg_from"/>LinearLayout>list_item_message_right.xml<?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:gravity="right" android:orientation="vertical" android:paddingBottom="5dp" android:paddingRight="10dp" android:paddingTop="5dp" > <TextView android:id="@+id/lblMsgFrom" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="5dp" android:textColor="@color/lblFromName" android:textSize="12dp" android:textStyle="italic" /> <TextView android:id="@+id/txtMsg" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="80dp" android:background="@drawable/bg_msg_you" android:paddingBottom="5dp" android:paddingLeft="10dp" android:paddingRight="10dp" android:paddingTop="5dp" android:textColor="@color/white" android:textSize="16dp" />LinearLayout>接下来的这个布局文件就是我们聊天的主界面
activity_main.xml<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" android:background="@drawable/tile_bg" android:orientation="vertical" > <ListView android:id="@+id/list_view_messages" android:layout_width="fill_parent" android:layout_height="0dp" android:layout_weight="1" android:background="@null" android:divider="@null" android:transcriptMode="alwaysScroll" android:stackFromBottom="true"> ListView> <LinearLayout android:id="@+id/llMsgCompose" android:layout_width="fill_parent" android:layout_height="wrap_content" android:background="@color/white" android:orientation="horizontal" android:weightSum="3" > <EditText android:id="@+id/inputMsg" android:layout_width="0dp" android:layout_height="fill_parent" android:layout_weight="2" android:background="@color/bg_msg_input" android:textColor="@color/text_msg_input" android:paddingLeft="6dp" android:paddingRight="6dp"/> <Button android:id="@+id/btnSend" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:background="@color/bg_btn_join" android:textColor="@color/white" android:text="@string/btn_send" /> LinearLayout>LinearLayout>接下来是两个帮助类，第一个Utils类有两个功能，第一个是存储Session id，第二个就是把消息转换成一个JSON字符串，如下
Utils.javapackage info.androidhive.webgroupchat.other;import org.json.JSONException;import org.json.JSONObject;import android.content.Context;import android.content.SharedPreferences;import android.content.SharedPreferences.Editor;public class Utils { private Context context; private SharedPreferences sharedPref; private static final String KEY_SHARED_PREF = "ANDROID_WEB_CHAT"; private static final int KEY_MODE_PRIVATE = 0; private static final String KEY_SESSION_ID = "sessionId", FLAG_MESSAGE = "message"; public Utils(Context context) { this.context = context; sharedPref = this.context.getSharedPreferences(KEY_SHARED_PREF, KEY_MODE_PRIVATE); } public void storeSessionId(String sessionId) { Editor editor = sharedPref.edit(); editor.putString(KEY_SESSION_ID, sessionId); editor.commit(); } public String getSessionId() { return sharedPref.getString(KEY_SESSION_ID, null); } public String getSendMessageJSON(String message) { String json = null; try { JSONObject jObj = new JSONObject(); jObj.put("flag", FLAG_MESSAGE); jObj.put("sessionId", getSessionId()); jObj.put("message", message); json = jObj.toString(); } catch (JSONException e) { e.printStackTrace(); } return json; }}下面是JavaBean对象
Message.javapackage info.androidhive.webgroupchat.other;public class Message { private String fromName, message; private boolean isSelf; public Message() { } public Message(String fromName, String message, boolean isSelf) { this.fromName = fromName; this.message = message; this.isSelf = isSelf; } public String getFromName() { return fromName; } public void setFromName(String fromName) { this.fromName = fromName; } public String getMessage() { return message; } public void setMessage(String message) { this.message = message; } public boolean isSelf() { return isSelf; } public void setSelf(boolean isSelf) { this.isSelf = isSelf; }}下面这个类是配置对象
WsConfig.javapackage info.androidhive.webgroupchat.other;public class WsConfig { public static final String URL_WEBSOCKET = "ws://192.168.0.102:8080/WebMobileGroupChatServer/chat?name=";}下面这个是ListView的适配器，主要就是判断是自己的消息还是别人的消息，在getView中分别填充
package info.androidhive.webgroupchat;import info.androidhive.webgroupchat.other.Message;import java.util.List;import android.annotation.SuppressLint;import android.app.Activity;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.TextView;public class MessagesListAdapter extends BaseAdapter { private Context context; private List messagesItems; public MessagesListAdapter(Context context, List navDrawerItems) { this.context = context; this.messagesItems = navDrawerItems; } @Override public int getCount() { return messagesItems.size(); } @Override public Object getItem(int position) { return messagesItems.get(position); } @Override public long getItemId(int position) { return position; } @SuppressLint("InflateParams") @Override public View getView(int position, View convertView, ViewGroup parent) { /** * The following list not implemented reusable list items as list items * are showing incorrect data Add the solution if you have one * */ Message m = messagesItems.get(position); LayoutInflater mInflater = (LayoutInflater) context .getSystemService(Activity.LAYOUT_INFLATER_SERVICE); // Identifying the message owner if (messagesItems.get(position).isSelf()) { // message belongs to you, so load the right aligned layout convertView = mInflater.inflate(R.layout.list_item_message_right, null); } else { // message belongs to other person, load the left aligned layout convertView = mInflater.inflate(R.layout.list_item_message_left, null); } TextView lblFrom = (TextView) convertView.findViewById(R.id.lblMsgFrom); TextView txtMsg = (TextView) convertView.findViewById(R.id.txtMsg); txtMsg.setText(m.getMessage()); lblFrom.setText(m.getFromName()); return convertView; }} 下载android websockets library，感谢 Koush大神
将下载的代码导入到eclipse中，并且在自己的项目中引用它
开始最重要的了。。。。
同js代码作为sockets客户端类似，WebSocketClient 也有一些回调函数，onConnect, onMessage and onDisconnect.
parseMessage() 函数用作解析从server中获得的Json字符串
在parseMessage()方法中，json的目的有flag表示
当新的消息收到时，要调用adapter.notifyDataSetChanged() 方法去更新列表
sendMessageToServer()发送到服务器
playBeep() 播放声音
package info.androidhive.webgroupchat;import info.androidhive.webgroupchat.other.Message;import info.androidhive.webgroupchat.other.Utils;import info.androidhive.webgroupchat.other.WsConfig;import java.net.URI;import java.net.URLEncoder;import java.util.ArrayList;import java.util.List;import java.util.Locale;import org.json.JSONException;import org.json.JSONObject;import android.app.Activity;import android.content.Intent;import android.media.Ringtone;import android.media.RingtoneManager;import android.net.Uri;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.ListView;import android.widget.Toast;import com.codebutler.android_websockets.WebSocketClient;public class MainActivity extends Activity { // LogCat tag private static final String TAG = MainActivity.class.getSimpleName(); private Button btnSend; private EditText inputMsg; private WebSocketClient client; // Chat messages list adapter private MessagesListAdapter adapter; private List listMessages; private ListView listViewMessages; private Utils utils; // Client name private String name = null; // JSON flags to identify the kind of JSON response private static final String TAG_SELF = "self", TAG_NEW = "new", TAG_MESSAGE = "message", TAG_EXIT = "exit"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); btnSend = (Button) findViewById(R.id.btnSend); inputMsg = (EditText) findViewById(R.id.inputMsg); listViewMessages = (ListView) findViewById(R.id.list_view_messages); utils = new Utils(getApplicationContext()); // 从上一个屏幕获取姓名 Intent i = getIntent(); name = i.getStringExtra("name"); btnSend.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // Sending message to web socket server sendMessageToServer(utils.getSendMessageJSON(inputMsg.getText() .toString())); // Clearing the input filed once message was sent inputMsg.setText(""); } }); listMessages = new ArrayList(); adapter = new MessagesListAdapter(this, listMessages); listViewMessages.setAdapter(adapter); /** * 创建web sockets客户端，有如下的回调函数 * */ client = new WebSocketClient(URI.create(WsConfig.URL_WEBSOCKET + URLEncoder.encode(name)), new WebSocketClient.Listener() { @Override public void onConnect() { } /** * 从服务端接受消息 * */ @Override public void onMessage(String message) { Log.d(TAG, String.format("Got string message! %s", message)); parseMessage(message); } @Override public void onMessage(byte[] data) { Log.d(TAG, String.format("Got binary message! %s", bytesToHex(data))); // Message will be in JSON format parseMessage(bytesToHex(data)); } /** * 连接中断 * */ @Override public void onDisconnect(int code, String reason) { String message = String.format(Locale.US, "Disconnected! Code: %d Reason: %s", code, reason); showToast(message); // clear the session id from shared preferences utils.storeSessionId(null); } @Override public void onError(Exception error) { Log.e(TAG, "Error! : " + error); showToast("Error! : " + error); } }, null); client.connect(); } /** * 发送消息 * */ private void sendMessageToServer(String message) { if (client != null && client.isConnected()) { client.send(message); } } /** * 解析从服务端收到的json 消息的目的由flag字段所指定，flag=self，消息属于指定的人， * new：新人加入 * 到对话中，message：新的消息，exit：退出 * * * * * */ private void parseMessage(final String msg) { try { JSONObject jObj = new JSONObject(msg); // JSON node 'flag' String flag = jObj.getString("flag"); // 如果是self，json中包含sessionId信息 if (flag.equalsIgnoreCase(TAG_SELF)) { String sessionId = jObj.getString("sessionId"); // Save the session id in shared preferences utils.storeSessionId(sessionId); Log.e(TAG, "Your session id: " + utils.getSessionId()); } else if (flag.equalsIgnoreCase(TAG_NEW)) { // If the flag is 'new', new person joined the room String name = jObj.getString("name"); String message = jObj.getString("message"); // number of people online String onlineCount = jObj.getString("onlineCount"); showToast(name + message + ". Currently " + onlineCount + " people online!"); } else if (flag.equalsIgnoreCase(TAG_MESSAGE)) { // if the flag is 'message', new message received String fromName = name; String message = jObj.getString("message"); String sessionId = jObj.getString("sessionId"); boolean isSelf = true; // Checking if the message was sent by you if (!sessionId.equals(utils.getSessionId())) { fromName = jObj.getString("name"); isSelf = false; } Message m = new Message(fromName, message, isSelf); // 把消息加入到arraylist中 appendMessage(m); } else if (flag.equalsIgnoreCase(TAG_EXIT)) { // If the flag is 'exit', somebody left the conversation String name = jObj.getString("name"); String message = jObj.getString("message"); showToast(name + message); } } catch (JSONException e) { e.printStackTrace(); } } @Override protected void onDestroy() { super.onDestroy(); if(client != null & client.isConnected()){ client.disconnect(); } } /** * 把消息放到listView里 * */ private void appendMessage(final Message m) { runOnUiThread(new Runnable() { @Override public void run() { listMessages.add(m); adapter.notifyDataSetChanged(); // Playing device's notification playBeep(); } }); } private void showToast(final String message) { runOnUiThread(new Runnable() { @Override public void run() { Toast.makeText(getApplicationContext(), message, Toast.LENGTH_LONG).show(); } }); } /** * 播放默认的通知声音 * */ public void playBeep() { try { Uri notification = RingtoneManager .getDefaultUri(RingtoneManager.TYPE_NOTIFICATION); Ringtone r = RingtoneManager.getRingtone(getApplicationContext(), notification); r.play(); } catch (Exception e) { e.printStackTrace(); } } final protected static char[] hexArray = "0123456789ABCDEF".toCharArray(); public static String bytesToHex(byte[] bytes) { char[] hexChars = new char[bytes.length * 2]; for (int j = 0; j < bytes.length; j++) { int v = bytes[j] & 0xFF; hexChars[j * 2] = hexArray[v >>> 4]; hexChars[j * 2 + 1] = hexArray[v & 0x0F]; } return new String(hexChars); }} 最终结果应该是这样的
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