I want to ask a question.
I have make a button that starts and stops a background service.
I make a class SmsReceiver which reads an incoming sms.
So i want when the service is start to call the the Sms BroadcastReceiver.
Any ideas or any other idea how to read an sms with background service?
If you already have the SmsReceiver working fine,all you need to do is register it from the Service.To do that you need to override the Service's onCreate().
Your Service should look something like this:
public class SmsService extends Service
{
private SmsReceiver receiver; //global so we can unregister it when the time comes.
public void onCreate ()
{
super.onCreate ();//call to super
//make a new intent filter so that all incoming SMS get to you as well
IntentFilter smsFilter = new IntentFilter("android.provider.Telephony.SMS_RECEIVED");
receiver = new SmsReceiver(); //make a new SmsReceiver
registerReceiver(receiver, smsFilter); //register the Receiver
}
public void onDestroy ()
{
unregisterReceiver (receiver); //unregisters the Receiver if Service is killed
super.onDestroy();
}
}
In the manifest, be sure to include the necessary SMS permissions and remember to also declare the Service in the manifest.
<service android:name=".SmsService" >
</service>
Related
Hi i am trying to understand Broadcast Receiver , i went through many sample codes , but still have some doubts. I wanted to know when we have to extend the Broadcast Receiver class and when should we use registerReceiver() method and when should we create object for BroadcastReceiver. In some programs i came across registerReceiver methods being used but without extending the Broadcast Receiver class. I also wanted to know how the onReceive method gets called.
Which approach should be used when?
here is the registerReceiver method:
registerReceiver(new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
switch (getResultCode()) {
........
}
}
}, new IntentFilter(SENT));
Object being created for BroadcastReceiver:
private BroadcastReceiver intentReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
.................
}
};
Android has intent action for broadcast receiver. BroadCast receiver will be trigger when it listen any action which registered within it.
Now we will take one example :
That we need to listen the action of "whenever any bluetooth device connect to our device". For that android has it fix action android.bluetooth.BluetoothDevice.ACTION_ACL_CONNECTED
So you can get it via manifest & registration also
BY Manifest Registration:
Put this in your manifest
<receiver android:name="MyBTReceiver">
<intent-filter>
<action android:name="android.bluetooth.BluetoothDevice.ACTION_ACL_CONNECTED" />
</intent-filter>
</receiver>
Create MyBTReceiver.class
public class MyBTReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("android.bluetooth.BluetoothDevice.ACTION_ACL_CONNECTED")){
Log.d(TAG,"Bluetooth connect");
}
}
}
That was the simplest broadcast Receiver.
Now,
if you are only interested in receiving a broadcast while you are running, it is better to use registerReceiver(). You can also register it within your existing class file. you also need to unregister it onDestroy().
here, you dont need any broadcast registration in manifest except activity registration
For example
public class MainActivity extends Activity {
IntentFilter filter1;
#Override
public void onCreate() {
filter1 = new IntentFilter("android.bluetooth.BluetoothDevice.ACTION_ACL_CONNECTED");
registerReceiver(myReceiver, filter1);
}
//The BroadcastReceiver that listens for bluetooth broadcasts
private final BroadcastReceiver myReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equalsIgnoreCase("android.bluetooth.BluetoothDevice.ACTION_ACL_CONNECTED")) {
Log.d(TAG,"Bluetooth connect");
}
}
};
#Override
public void onDestroy() {
unregisterReceiver(myReceiver);
}
}
In both cases BroadcastReceiver will be extended. In your second example you create so called anonymous class. New class has no specific name, that is why it's called so. Anyway this new class extends BroadcastReceiver and overrides onReceive() method.
Now back to your question. There are two kinds of receivers - statically and dynamically defined ones.
If you declare your receiver in AndroidManifest file, then it is statically defined. In this case you need to refer to a class implementing BroadcastReceiver by name. As you can see, you cannot use an anonymous class, because the last has no name. You have to explicitly implement a receiver. It's worth to mention, that in this case you do not use registerReceiver() method. Android does it for you automatically.
If you declare receivers dynamically (for instance in activity's onResume() method), then you can use anonymous class for that. To register a receiver you call registerReceiver() method. You can also use a named class too. Both options are valid in this case.
Hope this explains the difference.
In both case you are creating object.But in first case there is not any reference for
the receiver object so it can not be unregistered later but second one has so it can be
unregistered after registering object using below methods:
registerReceiver(intentReceiver );
unregisterReceiver(intentReceiver );
I have a class that extends BroadcastReceiver that reads new sms
public class SmsReceiver extends BroadcastReceiver
{
// reading sms
// I want to send the sms text to my main activity
}
And have another class in the same app that is my main Activity.
So when I receive new sms, I want to send its content to my main Activity that is already running and display it.
How can I do that?
I would be thankful for some code samples :)
i can suggest you two possibilities
send new broadcasts from this receiver to a new receiver which is registered inside your activity
register this receiver inside your activity and reduce the hassle
i guess option two is more suitable
this is how you may register a broadcast receiver inside your activity class:
IntentFilter filter = new IntentFilter();
public void onResume(){
filter.addAction("action_string_1");
filter.addAction("action_string_2");
registerReceiver(receiver, filter);
}
public void onPause(){
unregisterReceiver(receiver);
}
BroadcastReceiver receiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if(action.equals("action_string_1")){
//do something here
}
else if(action.equals("action_string_2")){
//do somethign here
}
}
};
I am working on an application which uses internet on every Activity. I am checking the connection onCreate of every Activity. But if n/w(Internet) is gone in between how can i know. is there any Method which can notify whenever the Network has gone during Application.
in each Activity class you can add this broadcast receiver in the onReceive method you can interact with the activity this is an example
public class MyActivity extends Activity {
private BroadcastReceiver receiver = new BroadcastReceiver() {
#Override
public void onReceive(...) {
...
}
});
public void onResume() {
super.onResume();
IntentFilter filter = new IntentFilter();
filter.addAction("android.net.conn.CONNECTIVITY_CHANGE");
this.registerReceiver(this.receiver, filter);
}
public void onPause() {
super.onPause();
this.unregisterReceiver(this.receiver);
}
}
this way the receiver is instantiated when the class is created (could also do in onCreate). Then in the onResume/onPause I handle registering and unregistering the receiver. Then in the reciever's onReceive method I do whatever is necessary to make the activity react the way I want to when it receives the broadcast.
There is a CONNECTIVITY_CHANGE broadcast which you can listen to get the updates about the connection. Here are some more details http://groups.google.com/group/android-developers/browse_thread/thread/ce1c3ed3e39a0c81
I am writing an alarm code and using a broadcast receiver. I am able to receive the broadcast receiver. but now I want to come back to the calling activity and update the UI of my activity. I am not able to this.
I used the following code in my activity but it is never executing that code.
private BroadcastReceiver myBroadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(context, "I am back!!", Toast.LENGTH_LONG).show();
}
};
#Override
protected void onPause()
{
super.onPause();
unregisterReceiver(myBroadcastReceiver);
}
#Override
protected void onResume()
{
super.onResume();
IntentFilter intentFilter = new IntentFilter("com.test.Main");
registerReceiver(myBroadcastReceiver, intentFilter);
}
in the manifest file I have included the following, here gotAlarm is the broadcast receiver file
<receiver android:name=".gotAlarm"
android:enabled="true">
</receiver>
gotAlarm file is one which gets called from the pending intent of the alarm set
public class gotAlarm extends BroadcastReceiver {
public void onReceive(Context context, Intent intent){
Toast.makeText(context, "Wake Up!!", Toast.LENGTH_LONG).show();
}
}
May be I am missing something very basic.
please help.
Two things:
If you dynamically register the receiver via Context.registerReceiver() then you won't receive broadcasts when Activity is paused (or stopped or not-running). If you need to receive broadcasts even when Activity is paused then create a top-level BroadcastReceiver class (as opposed to your inner class) and use <receiver> to register it.
BroadcastReceiver lifecycle docs state that BroadcastReceiver object is alive only during processing of onReceive(). You can not do any async tasks like showing dialogs, etc.. In your case (Activities might not be running and you receive a broadcast) you should use NotificationManager to notify user something happened.
I have dropped this way and I am starting a new activity on receiving broadcast. And I am sending information data from calling activity to broadcast and from broadcast to next activity. This has served the purpose.
Did you register your BroadcastReceiver (you can do this in the 'onResume'-method of your Activity)? Also, you should unregister your BroadcastReceiver in the 'onPause'-method.
I have an activity, it needs to response to a broadcast event.
Since an activity can not be a broadcast receiver at the same time,
I made a broadcast receiver.
My question is: how can I notify the activity from the broadcast receiver?
I believe this is a common situation, so is there a design pattern for this?
The broadcast is the notification. :) If you want to say, start an activity or a service, etc., based on a received broadcast then you need a standalone broadcast receiver and you put that in your manifest file. However, if you want your activity itself to respond to broadcasts then you create an instance of a broadcast receiver in your activity and register it there.
The pattern I use is:
public class MyActivity extends Activity {
private BroadcastReceiver receiver = new BroadcastReceiver() {
#Override
public void onReceive(...) {
...
}
});
public void onResume() {
super.onResume();
IntentFilter filter = new IntentFilter();
filter.addAction(BROADCAST_ACTION);
this.registerReceiver(this.receiver, filter);
}
public void onPause() {
super.onPause();
this.unregisterReceiver(this.receiver);
}
}
So, this way the receiver is instantiated when the class is created (could also do in onCreate). Then in the onResume/onPause I handle registering and unregistering the receiver. Then in the reciever's onReceive method I do whatever is necessary to make the activity react the way I want to when it receives the broadcast.