I have an Android application which uses C2DM services (aka push).
I have a separate class which implements the registration process and which receives the data (and extends BroadcastReceiver).
I want to communicate this data to the activity which currently is in the foreground. The activity currently in the foreground may differ depending on user action.
What's the best way to communicate in between the receiver and the current activity?
Thanks.
I solved this problem by sending out a new broadcast from the C2DMReceiver class, which looked something like this.
The C2DMReceiver class:
public class C2DMReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals("com.google.android.c2dm.intent.REGISTRATION")) {
handleRegistration(context, intent);
} else if (intent.getAction().equals("com.google.android.c2dm.intent.RECEIVE")) {
handleMessage(context, intent);
}
}
private void handleRegistration(Context context, Intent intent) {
// handle registration
}
private void handleMessage(Context context, Intent intent) {
Intent i = new Intent("push");
i.putExtras(intent);
// context.sendOrderedBroadcast(i, null);
context.sendBroadcast(i);
}
}
Another class I called PushReceiver. This is the class that will extend BroadcastReceiver and receive the broadcast sent by C2DMReceiver.
public class PushReceiver extends BroadcastReceiver {
public PushReceiver() {
}
#Override
public void onReceive(Context context, Intent intent) {
// do stuff
abortBroadcast();
}
public static class PushFilter extends IntentFilter {
private static final int DEFAULT_PUSH_PRIORITY = 1;
public PushFilter() {
this(DEFAULT_PUSH_PRIORITY);
}
public PushFilter(int priority) {
super("push");
setPriority(priority);
}
}
}
And the activity class, in this case called MyActivity. This should work well if you are using a base activity class that all other activities extend. That way every activity registers the receiver. By doing the register/unregister in onResume/onPause, you should be able to guarantee that only the current activity receives the broadcast. If not, you can send an ordered broadcast from C2DMReceiver and use priority in the PushFilter.
public class MyActivity extends Activity {
private PushReceiver pushReceiver;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// your onCreate method
pushReceiver = new PushReceiver();
}
public void onResume() {
super.onResume();
// your onResume method
registerReceiver(pushReceiver, new PushReceiver.PushFilter());
}
public void onPause() {
super.onPause();
// your onPause method
unregisterReceiver(pushReceiver);
}
}
In my case, I wrote the PushReceiver constructor to take a View and then "did stuff" with the view in the onReceive method. Without knowing more about what your trying to do, I can't elaborate on this, but hopefully this can provide a decent template to work from.
Related
I have a broadcast receiver that gets triggered on geofencing events and either "clocks in" or "clocks out" with the server. If my application's "Attendance" activity is already open I would like it to display the clocking status change but I don't want the Broadcast Receiver to start the activity if it's not open - in other words display the change "live" while the activity is open only.
The way I imagine doing this is with the Broadcast Receiver sending an Intent to the activity but name "startActivity()" doesn't sound encouraging unless there are any special flags I can pass to prevent starting an Activity that isn't already open - I can't seem to find any.
The other option would be to constantly poll the value while the activity is open but it doesn't seem optimal so I would only use it if there wasn't another way and I can't think of a reason why it couldn't be possible with Intents.
There are several different ways to accomplish the same task. One is registering a listener like the following example:
MainActivity
public class MainActivity extends AppCompatActivity
{
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Receiver.setOnReceiveListener(new Receiver.OnReceiveListener() {
public void onReceive(Context Context, Intent intent)
{
//Do something.
}
});
}
#Override
protected void onDestroy()
{
super.onDestroy();
Receiver.setOnReceiveListener(null);
}
}
Receiver
public class Receiver extends BroadcastReceiver
{
private static OnReceiveListener static_listener;
public static abstract interface OnReceiveListener
{
public void onReceive(Context context, Intent intent);
}
public static void setOnReceiveListener(OnReceiveListener listener)
{
static_listener = listener;
}
#Override
public final void onReceive(Context context, Intent intent)
{
if(static_listener != null) {
static_listener.onReceive(context, intent);
}
}
}
Just have your BroadcastReceiver send a broadcast Intent. Your Activity should register a listener from this broadcast Intent and if it gets triggered, it can update the UI.
Here's an example:
Declare a private member variable in your Activity:
private BroadcastReceiver receiver;
In Activity.onCreate(), register the BroadcastReceiver:
IntentFilter filter = new IntentFilter();
filter.addAction("my.package.name.CLOCK_STATUS_CHANGE");
receiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
// Here you can update the UI ...
}
};
registerReceiver(receiver, filter);
And in onDestroy() you can unregister it (probably not necessary, but cleaner):
if (receiver != null) {
unregisterReceiver(receiver);
receiver = null;
}
In your BroadcastReceiver that detects the geofencing event, you should create and send a broadcast Intent:
Intent broadcastIntent = new Intent("my.package.name.CLOCK_STATUS_CHANGE");
sendBroadcast(broadcastIntent);
I have a function in activity I want to run this function with broadcastreceiver. How can I make this?
public class Myclass extends BroadcastReceiver{
#Override
public void onReceive(Context context, Intent intent) {
}
}
This is my broadcastreceiver class I want to run function which is in my activty please tell me with some code how to do this.
If the method you want to execute needs your activity instance, then you can register the broadcast receiver inside your activity, so it can access your activity's state and functions.
In your Activity "onCreate" method:
final IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("Your Intent action here");
intentFilter.addAction("Another action you want to receive");
final BroadcastReceiver myReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
theFunctionYouWantToExecute();
}
};
registerReceiver(myReceiver, intentFilter);
And in your "onDestroy" method:
unregisterReceiver(myReceiver);
Keep in mind that in this case your broadcast receiver has full access to your activity state, BUT it's lifecycle will be conditioned to the activity lifecycle.
Another option you have is to declare your activity method as static, so you can execute it in any part of your application.
You can declare an interface in Myclass and implement it in your MainActivity
public class Myclass extends BroadcastReceiver{
public interface MyClassInterface {
void onMyClassReceive();
}
private MyClassInterface mListener;
public Myclass(MyClassInterface mMyClassInterface) {
mListener = mMyClassInterface;
}
#Override
public void onReceive(Context context, Intent intent) {
mListener.onMyClassReceive();
}
}
Then in your MainActivity:
public class MainActivity implements Myclass.MyClassInterface {
private mMyClass Myclass = new Myclass(this);
#Override
public void onMyClassReceive() {
// Do stuff when Myclass.onMyClassReceive() is called,
// which will be called when Myclass.onReceive() is called.
}
}
You are almost there. Just create your method in the Activity and using Activity's instance call that method. Remember that your method inside your Activity should be not private.
public class Myclass extends BroadcastReceiver{
#Override
public void onReceive(Context context, Intent intent) {
new YourActivity().yourFunction();
}
}
If you want to create a static method inside your Activity then
public class Myclass extends BroadcastReceiver{
#Override
public void onReceive(Context context, Intent intent) {
YourActivity.yourFunction();
}
}
To trigger the Broadcast, you have to pass an Intent. If you want to trigger it from any Activity then
Intent intent = new Intent();
this.sendBroadcast(intent);
If you want to trigger the Broadcast from a Fragment then
Intent intent = new Intent();
getActivity().sendBroadcast(intent);
I know it's quote naif, but you could call a static method in your activity.
In your activity you declare the method like this:
public static <return_type> yourMethod(<input_objs>){
....
Your code
....
}
In the receiver you can use this function just calling:
YourActivityClass.yourMethod(<input_objs>);
I hope it helped.
How could I know if an activity is the top of stack? I thought about using onResume/onPause, but this is not exactly, as it would fail once the app goes to background.
The fact is that I'm sending a broadcast receiver that is received for all activities (I have a BaseActivity that is extended by all activities and that registers to the broadcast). So, only the activity that is at the top of the stack must react to the broadcast. If I use the isResumed() then it would work always but when the app goes to background. Any idea?
Thanks in advance!
in base activity you register the broadcast Receiver and in receiver function you call one abstract function which one is implemented by all child activities.
The activity which is on top will automatically receive that function call.
Edit sample code:
public abstract class BaseActivity extends AppCompatActivity {
private static final String NOTIFICATION_ARRIVED = "arrived";
public abstract void receivedFunction(Intent intent);
private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
displayToast(" received in Base");
receivedFunction(intent);
}
};
public void displayToast(String s) {
Toast.makeText(this,s,Toast.LENGTH_SHORT).show();
}
#Override
public void onResume() {
super.onResume();
registerReceiver(mMessageReceiver, new IntentFilter(BaseActivity.NOTIFICATION_ARRIVED));
}
#Override
public void onPause() {
super.onPause();
unregisterReceiver(mMessageReceiver);
}
}
public class MainActivity extends BaseActivity {
#Override
public void receivedFunction(Intent intent) {
displayToast(" received in child");
}
// do whetever you want . if you ovveride onpause and onResume then call super as well
}
or any other child
public class MainActivity2 extends BaseActivity {
#Override
public void receivedFunction(Intent intent) {
displayToast(" received in child");
}
// do whetever you want . if you ovveride onpause and onResume then call super as well
}
// to broadcast
Intent intent = new Intent(BaseActivity.NOTIFICATION_ARRIVED);
sendBroadcast(intent);
Well, I have a service, I have an Activity. They communicate via messages (It must communicate with messages so don't tell me about Intents or other things, please).
I receive a Bundle from the Service, all ok.
Now with the Bundle i've received I want to do something. I want to call a method from "SomeClass", but I can't, because I'm inside of "IncomingHandler" class.
What's the best way to call SomeClass from inside IncomingHandler?
Thanks in advance
class SomeClass implements ServiceConnection {
class IncomingHandler extends Handler {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MyService.MS_GET_SOMETHING:
Bundle received=msg.getData();
...
If you really want the activity to be calling methods on the service, its time to learn about AIDL, which allows an Activity to make function calls on a bound service via an RPC mechanism. Documentation found here.
I have implemented the feature (Service calls method in activity) like this:
Service sends a broadcast-message.
Activity has a local nested broadcastreceiver that can call a method in the parent activity.
public class MainActivity extends Activity {
private BroadcastReceiver myReceiver = null;
class _RemoteTimeTrackerReceiver extends BroadcastReceiver {
#Override
public void onReceive (Context context, Intent intent) {
// call method in activity
reloadGui();
}
}
#Override
public void onResume() {
super.onResume();
if (myReceiver == null)
{
myReceiver = new _RemoteTimeTrackerReceiver();
IntentFilter filter = new IntentFilter(Global.REFRESH_GUI);
registerReceiver(myReceiver, filter);
}
reloadGui();
}
#Override
public void onPause() {
if (myReceiver != null)
{
unregisterReceiver(myReceiver);
myReceiver = null;
}
super.onPause();
}
void reloadGui() {}
I need some way to detect when the network connection has been lost.
So a switch between mobile and wifi doesn't really matter it's just to detect at runtime when the connection has been lost.
I now have found some code which works fine for me.
public class ConnectivityReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Log.d(ConnectivityReceiver.class.getSimpleName(), "action: "
+ intent.getAction());
}
}
I want to check inside the onReceive() method wheter or not a connection is still available or not.
The thing is, that I want to show a message to the user, if it has been lost. So what's the best way of passing back to my Activity, that the connection has been lost?
If you want to track network connection state only when activity is on screen you can place your ConnectivityReceiver as inner nested class in Activity. In this case you should register it in onResume method and unregister it in onPause. It will look like this:
public class MyActivity extends Activity {
private class ConnectivityReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Log.d(ConnectivityReceiver.class.getSimpleName(), "action: "
+ intent.getAction());
}
}
private final BroadcastReceiver receiver = new ConnectivityReceiver();
#Override
protected void onPause() {
super.onPause();
unregisterReceiver(receiver);
}
#Override
protected void onResume() {
super.onResume();
IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(receiver, filter);
}
}
You can have an inner Class which extends BroadcastReceiver and you can dynamically register it. From the innterclass(precisely onRecieve() method) you can access your Activity.