SMS Messaging in Android(一)_Android

SMS Messaging in Android(1)

可以安全的说，在过去的近20年里卖的每一款移动电话都拥有SMS消息功能。事实上，SMS消息是移动手机中一个杀手级的应用程序，它为移动运营商创造了稳定的收入源。理解如何在你的应用程序中使用SMS消息能帮助你产生灵感来创建下一个杀手级程序。

在这篇文章里，我将一览如何在你的Android应用程序中发送和接收SMS消息。对Android开发者来说，有个好消息是你不需要一款真实的设备来测试SMS消息——免费的Android模拟器提供这一功能。

发送SMS消息

开始，先启动Eclipse并创建一个新的Android工程。命名工程如图1所示。

图1 使用Eclipse创建一个新的Android工程

Android使用一种基于权限的策略，应用程序所需的所有权限需要在AndroidManifest.xml文件中指定。通过这样做，当应用程序安装后，用户就能清楚地知晓应用程序需要哪些特定的访问权限。举个例子，发送SMS消息会引起用户的额外费用，在AndroidManifest.xml文件中指明SMS权限能让用户决定应用程序是否安装。

在AndroidManifest.xml文件中，添加两个权限——SEND_SMS和RECEIVE_SMS：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
????? package="net.learn2develop.SMSMessaging"
????? android:versionCode="1"
????? android:versionName="1.0.0">
??? <application android:icon="@drawable/icon" android:label="@string/app_name">
??????? <activity android:name=".SMS"
????????????????? android:label="@string/app_name">
??????????? <intent-filter>
??????????????? <action android:name="android.intent.action.MAIN" />
??????????????? <category android:name="android.intent.category.LAUNCHER" />
??????????? </intent-filter>
??????? </activity>
??? </application>
??? <uses-permission android:name="android.permission.SEND_SMS">
??? </uses-permission>
??? <uses-permission android:name="android.permission.RECEIVE_SMS">
??? </uses-permission>
</manifest>

在res/layout文件夹下的main.xml文件中添加以下代码，这样，用户可以输入电话号码和要发送的消息：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
??? android:orientation="vertical"
??? android:layout_width="fill_parent"
??? android:layout_height="fill_parent"
??? >
??? <TextView?
??????? android:layout_width="fill_parent"
??????? android:layout_height="wrap_content"
??????? android:text="Enter the phone number of recipient"
??????? />????
??? <EditText
??????? android:id="@+id/txtPhoneNo"?
??????? android:layout_width="fill_parent"
??????? android:layout_height="wrap_content"???????
??????? />
??? <TextView?
??????? android:layout_width="fill_parent"
??????? android:layout_height="wrap_content"????????
??????? android:text="Message"
??????? />????
??? <EditText
??????? android:id="@+id/txtMessage"?
??????? android:layout_width="fill_parent"
??????? android:layout_height="150px"
??????? android:gravity="top"????????
??????? />?????????
??? <Button
??????? android:id="@+id/btnSendSMS"?
??????? android:layout_width="fill_parent"
??????? android:layout_height="wrap_content"
??????? android:text="Send SMS"
??????? />???
</LinearLayout>

上面的代码创建的UI如图2所示。

图2 创建发送SMS消息的UI

接下来，在SMS Activity中，我们连接Button View，这样当用户点击它时，我们可以检查接收者的电话号码和输入的消息，然后使用sendSMS函数来发送消息。

package net.learn2develop.SMSMessaging;
?
import android.app.Activity;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.gsm.SmsManager;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
?
public class SMS extends Activity
{
??? Button btnSendSMS;
??? EditText txtPhoneNo;
??? EditText txtMessage;
?
??? /** Called when the activity is first created. */
??? @Override
??? public void onCreate(Bundle savedInstanceState)
??? {
??????? super.onCreate(savedInstanceState);
??????? setContentView(R.layout.main);???????
?
??????? btnSendSMS = (Button) findViewById(R.id.btnSendSMS);
??????? txtPhoneNo = (EditText) findViewById(R.id.txtPhoneNo);
??????? txtMessage = (EditText) findViewById(R.id.txtMessage);
?
??????? btnSendSMS.setOnClickListener(new View.OnClickListener()
??????? {
??????????? public void onClick(View v)
??????????? {???????????????
??????????????? String phoneNo = txtPhoneNo.getText().toString();
??????????????? String message = txtMessage.getText().toString();????????????????
??????????????? if (phoneNo.length()>0 && message.length()>0)???????????????
??????????????????? sendSMS(phoneNo, message);???????????????
??????????????? else
??????????????????? Toast.makeText(getBaseContext(),
??????????????????????? "Please enter both phone number and message.",
??????????????????????? Toast.LENGTH_SHORT).show();
??????????? }
??????? });???????
??? }???
}

sendSMS函数定义如下：

public class SMS extends Activity
{
??? //...
?
??? /** Called when the activity is first created. */
??? @Override
??? public void onCreate(Bundle savedInstanceState)
??? {
??????? //...
??? }
?
??? //---sends an SMS message to another device---
??? private void sendSMS(String phoneNumber, String message)
??? {???????
??????? PendingIntent pi = PendingIntent.getActivity(this, 0,
??????????? new Intent(this, SMS.class), 0);???????????????
??????? SmsManager sms = SmsManager.getDefault();
??????? sms.sendTextMessage(phoneNumber, null, message, pi, null);???????
??? }???
}

为了发送一个SMS消息，你需要使用SmsManager类。不同于其它的类，你不需要直接实例化这个类；取而代之的是调用getDefault()静态方法来获取一个SmsManager对象。sendTextMessage()方法发送SMS消息和一个PendingIntent。PendingIntent对象用于在以后的时间识别触发的目标。例如，发送消息后，你可以使用PendingIntent对象来显示其它的Activity。在这里，PendingIntent对象（pi）简单指向相同的Activity（SMS.java），所以，当SMS发送后，什么事情也不会发生。

如果你需要监视SMS消息的发送过程状况，你可以使用两个PendingIntent对象以及两个BroadcastReceiver对象，像这样：

??? //---sends an SMS message to another device---
??? private void sendSMS(String phoneNumber, String message)
??? {???????
??????? String SENT = "SMS_SENT";
??????? String DELIVERED = "SMS_DELIVERED";
?
??????? PendingIntent sentPI = PendingIntent.getBroadcast(this, 0,
??????????? new Intent(SENT), 0);
?
??????? PendingIntent deliveredPI = PendingIntent.getBroadcast(this, 0,
??????????? new Intent(DELIVERED), 0);
?
??????? //---when the SMS has been sent---
??????? registerReceiver(new BroadcastReceiver(){
??????????? @Override
??????????? public void onReceive(Context arg0, Intent arg1) {
??????????????? switch (getResultCode())
??????????????? {
??????????????????? case Activity.RESULT_OK:
??????????????????????? Toast.makeText(getBaseContext(), "SMS sent",
??????????????????????????????? Toast.LENGTH_SHORT).show();
??????????????????????? break;
??????????????????? case SmsManager.RESULT_ERROR_GENERIC_FAILURE:
??????????????????????? Toast.makeText(getBaseContext(), "Generic failure",
??????????????????????????????? Toast.LENGTH_SHORT).show();
??????????????????????? break;
??????????????????? case SmsManager.RESULT_ERROR_NO_SERVICE:
??????????????????????? Toast.makeText(getBaseContext(), "No service",
??????????????????????????????? Toast.LENGTH_SHORT).show();
??????????????????????? break;
??????????????????? case SmsManager.RESULT_ERROR_NULL_PDU:
??????????????????????? Toast.makeText(getBaseContext(), "Null PDU",
??????????????????????????????? Toast.LENGTH_SHORT).show();
??????????????????????? break;
??????????????????? case SmsManager.RESULT_ERROR_RADIO_OFF:
??????????????????????? Toast.makeText(getBaseContext(), "Radio off",
??????????????????????????????? Toast.LENGTH_SHORT).show();
??????????????????????? break;
??????????????? }
??????????? }
??????? }, new IntentFilter(SENT));
?
??????? //---when the SMS has been delivered---
??????? registerReceiver(new BroadcastReceiver(){
??????????? @Override
??????????? public void onReceive(Context arg0, Intent arg1) {
??????????????? switch (getResultCode())
??????????????? {
??????????????????? case Activity.RESULT_OK:
??????????????????????? Toast.makeText(getBaseContext(), "SMS delivered",
??????????????????????????????? Toast.LENGTH_SHORT).show();
??????????????????????? break;
??????????????????? case Activity.RESULT_CANCELED:
??????????????????????? Toast.makeText(getBaseContext(), "SMS not delivered",
??????????????????????????????? Toast.LENGTH_SHORT).show();
??????????????????????? break;???????????????????????
??????????????? }
??????????? }
??????? }, new IntentFilter(DELIVERED));???????
?
??????? SmsManager sms = SmsManager.getDefault();
??????? sms.sendTextMessage(phoneNumber, null, message, sentPI, deliveredPI);???????
??? }

上面的代码使用一个PendingIntent对象（sendPI）来监视发送过程。当SMS消息发送后，第一个BroadcastReceiver的onReceive事件会触发。在这里你可以检查发送过程的状态。第二个PendingIntent对象（deliveredPI）监视传送过程。当SMS消息成功送达时会触发第二个BroadcastReceiver的onReceive事件。

现在，你可以按下F11来测试应用程序了。为了从一个模拟器实例发送SMS消息到另一个实例，进入SDK的Tools文件夹并运行Emulator.exe来简单启动另一个Android模拟器实例。

图3 发送SMS消息

图3演示了如何从一个模拟器发送SMS消息到另一个模拟器；使用目标模拟器的端口号（显示在窗口的左上角）作为它的电话号码。当SMS发送成功时，它会显示一个“SMS sent”消息。当它成功送达时，它会显示一个“SMS delivered”消息。注意，使用模拟器进行测试时，当SMS成功送达时，“SMS delivered”消息不会显示；它仅在真机上工作。

图4显示了接收模拟器中SMS消息接收后的样子。消息一开始显示在通知条上（屏幕的上方）。往下拖拽通知条，显示出接收到的消息。查看完整的消息，点击那个消息。

图4 Android模拟器接收SMS消息

如果你不想触及发送SMS消息的所有麻烦，你可以使用一个Intent对象来帮助你发送SMS消息。下面的代码就演示了如何引发内建的SMS程序来帮助你发送SMS消息：

??????? Intent sendIntent = new Intent(Intent.ACTION_VIEW);
??????? sendIntent.putExtra("sms_body", "Content of the SMS goes here...");
??????? sendIntent.setType("vnd.android-dir/mms-sms");
??????? startActivity(sendIntent);

图5显示了内建的SMS应用程序发送SMS消息。

图5 引发内建的SMS程序

接收SMS消息

除了可以程序化的发送SMS消息，你还可以使用一个BroadcastReceiver对象来拦截新的SMS消息。

想看如何在Android应用程序中接收SMS消息的话，可以在AndroidManifest.xml文件中添加<receiver>元素，这样，新来的SMS消息就能被SmsReceiver类拦截：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
????? package="net.learn2develop.SMSMessaging"
????? android:versionCode="1"
????? android:versionName="1.0.0">
??? <application android:icon="@drawable/icon" android:label="@string/app_name">
??????? <activity android:name=".SMS"
????????????????? android:label="@string/app_name">
??????????? <intent-filter>
??????????????? <action android:name="android.intent.action.MAIN" />
??????????????? <category android:name="android.intent.category.LAUNCHER" />
??????????? </intent-filter>
??????? </activity>???????
?
??????? <receiver android:name=".SmsReceiver">
??????????? <intent-filter>
??????????????? <action android:name=
??????????????????? "android.provider.Telephony.SMS_RECEIVED" />
??????????? </intent-filter>
??????? </receiver>
?
??? </application>
??? <uses-permission android:name="android.permission.SEND_SMS">
??? </uses-permission>
??? <uses-permission android:name="android.permission.RECEIVE_SMS">
??? </uses-permission>
</manifest>

添加一个新的类文件并命名为SmsReceiver.java（如图6）。

图6 添加SmsReceiver.java文件到工程中

在SmsReceiver类中，扩展BroadcastReceiver类，并重写onReceive方法：

package net.learn2develop.SMSMessaging;
?
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
?
public class SmsReceiver extends BroadcastReceiver
{
[email protected]
????????public void onReceive(Context context, Intent intent)
?????? {????????
????????}
}

当SMS消息接收后，onReceive()方法会触发。SMS消息附着在Intent对象上（onReceive方法的第二个参数，intent）的Bundle对象里。消息以PDU格式储存在一个对象数组里。要提取每个消息，可以使用SmsMessage类的createFromPdu（）静态方法。然后，使用Toast类显示SMS消息：

package net.learn2develop.SMSMessaging;
?
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.gsm.SmsMessage;
import android.widget.Toast;
?
public class SmsReceiver extends BroadcastReceiver
{
??? @Override
??? public void onReceive(Context context, Intent intent)
??? {
??????? //---get the SMS message passed in---
??????? Bundle bundle = intent.getExtras();???????
??????? SmsMessage[] msgs = null;
??????? String str = "";???????????
??????? if (bundle != null)
??????? {
??????????? //---retrieve the SMS message received---
??????????? Object[] pdus = (Object[]) bundle.get("pdus");
??????????? msgs = new SmsMessage[pdus.length];???????????
??????????? for (int i=0; i<msgs.length; i++){
??????????????? msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);???????????????
??????????????? str += "SMS from " + msgs[i].getOriginatingAddress();????????????????????
??????????????? str += " :";
??????????????? str += msgs[i].getMessageBody().toString();
??????????????? str += "\n";???????
??????????? }
??????????? //---display the new SMS message---
??????????? Toast.makeText(context, str, Toast.LENGTH_SHORT).show();
??????? }????????????????????????
??? }
}