i am new to Android and trying to understand the communication between apps.
I am trying to write 3 little apps which can communicate with each other. If you want to sent a message to everybody you just use an implicit broadcast.
implicit Intent intent.setAction("com.example.myChatMessage")
if you want to adress only 1 specifc receiver i did it with
explicite Intentintent.setComponent("com.example.test.android.broadcastreceiver.b",
"com.example.test.android.broadcastreceiver.b.myBroadcastReceiver")
this works, when the broadcast receiver is a seperate class and defined in the AndroidManifest.xml.
My Question: Is it possible to explicit adress a dynamicall registered broadcast receiver?
package com.example.test.android.broadcastreceiver.b;
public class MainActivity extends Activity {
private final IntentFilter intentfilter = new IntentFilter("com.example.myChatMessage");
private myBroadcastReceiver broadcastreceiver;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
broadcastreceiver = new myBroadcastReceiver();
registerReceiver(broadcastreceiver, intentfilter);
}
public static class myBroadcastReceiver extends BroadcastReceiver{
#Override
public void onReceive(Context context, Intent intent) {
String message = intent.getStringExtra("message");
Log.d("message", "B received: "+message);
}
}
}
It receives all implicit broadcasts but no explicit one - i don't know hot to adress it. Can you help me?
It does not appear possible to send an explicit intent to a dynamically registered broadcast receiver. Registering the receiver in AndroidManifest.xml is the only way.
If you dynamically register a BroadcastReceiver – by calling Context.registerReceiver() – you supply a BroadcastReceiver instance ... If you try to send an Intent to the receiver by naming the class of the BroadcastReceiver, it will never get delivered .. The Android system will not match the Intent you declared to the class of the BroadcastReceiver instance you registered.
Source: http://onemikro2nd.blogspot.com/2013/09/darker-corners-of-android.html
Related
the title says all, I need to change the variable of my service from a activity in my other app , what to finalize the service or not, this is possible?
I found the Message object , but I do not quite understand
The simplest solution would be to implement a BroadcastReceiver. Your Service listens for the Broadcast and the other App sends the Broadcast.
Example Reciever:
public class MyReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// Get bundle from intent and use it to set your Variable in your Service
}
}
Example Broadcaster (courtesy of Vogella):
Intent intent = new Intent();
intent.setAction("de.vogella.android.mybroadcast");
sendBroadcast(intent);
I'm trying to use a local broadcast receiver.
In order to do so I"ve done the next steps -
1) At an Activity, where Iwould like something to happen, I've created a class -
private class NewGroupReceiver extends BroadcastReceiver{
#Override
public void onReceive(Context context, Intent intent) {
Log.d("The group ", "GOT IN THE RECIVING");
Toast.makeText(this, "Working",Toast.LENGTH_SHORT).show();
}
}
2) At the same activity I've used the next code in order to create a receiver -
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
NewGroupReceiver receiver = new NewGroupReceiver();
//the intent filter will be action = "com.example.demo_service.action.SERVICE_FINISHED"
IntentFilter filter= new IntentFilter("com.example.apps.action.NEW_GROUP");
// register the receiver:
registerReceiver(receiver, filter);
}
3) At the a service class I've used the next code to know when something has happened-
Intent resultsIntent=new Intent("com.example.apps.action.NEW_GROUP");
LocalBroadcastManager localBroadcastManager =LocalBroadcastManager.getInstance(this);
localBroadcastManager.sendBroadcast(resultsIntent);
Now the problem is that when the thing I WOuld like to know has happen - I see the it's get into the code that I've used at step 3, but it doesen't seem to get into the BroadcastReceiver - the step 1 code.
Any idea what am I doing wrong here?
Thanks for any kind of help.
You are using the LocalBroadcastManager to send the request, but you register the receiver on the "global" Intent. You should either use LocalBroadcastManager to register the receiver or send the broadcast on the
application context:
Step 2
LocalBroadcastManager.getInstance(this).registerReceiver (receiver, filter);
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 new to android platform.please help me out how the Broadcast Receiver and Intent Filter behaves in android.please explain in simple line or with example.thanks in advance...
A broadcast receiver is a class in your Android project which is responsible to receive all intents, which are sent by other activities by using android.content.ContextWreapper.sendBroadcast(Intent intent)
In the manifest file of you receicving activity, you have to declare which is your broadcast receiver class, for example:
<receiver android:name="xyz.games.pacman.network.MessageListener">
<intent-filter>
<action android:name="xyz.games.pacman.controller.BROADCAST" />
</intent-filter>
</receiver>
As you can see, you also define the intent filter here, that is, which intents should be received by the broadcas receiver.
Then you have to define a class which extends BroadcastReceiver. This is the class you defined in the manifest file:
public class MessageListener extends BroadcastReceiver {
/* (non-Javadoc)
* #see android.content.BroadcastReceiver#onReceive(android.content.Context, android.content.Intent)
*/
#Override
public void onReceive(Context context, Intent intent) {
...
}
Here, all intents which are passed through the filter are received and you can access them using the parameter passed in the method call.
A BroadcastReceiver can be registered in two ways: dynamic or static. Static is nothing but declaring the action through an intent-filter in AndroidManifest.xml to register a new BroadcastReceiver class. Dynamic is registering the receiver from within another class. An intent-filter determines which action should be received.
To create a BroadcastReceiver, you have to extend the BroadcastReceiver class and override onReceive(Context,Intent) method. Here you can check the incoming intent with Intent.getAction() and execute code accordingly.
As a new class, static would be
public class Reciever1 extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
String str = intent.getAction();
if(str.equalsIgnoreCase("HELLO1")) {
Log.d("Abrar", "reciever....");
new Thread() {
public void run() {
Log.d("Abrar", "reciever....");
System.out.println("Abrar");
}
}.start();
}
or, if placed inside an existing class, it is called dynamically with
intentFilter = new IntentFilter();
intentFilter.addAction("HELLO1");
//---register the receiver---
registerReceiver(new Reciever1(), intentFilter);
BroadcastReceiver : 'Gateway' with which your app tells to Android OS that, your app is interested in receiving information.
Intent-Filter : Works with BroadcastReceiver and tells the 'What' information it is interested to receive in. For example, your app wants to receive information on Battery level.