I'm on a activity with a textview and in the background is AlarmReceiver running with a 10min time trigger.
The activity has a method which I want to call by the trigger. The method sets a new value to the textview. But by calling it from the trigger I can not use "findViewById". I get a NullPointerException at this point. I also tried to setContentView when its called by the trigger but also here I get an NullPointerException
This it the Code:
ValuesActivity:
public void setSyncValue(Context context, boolean fromSyncService, String value){
try {
if(fromSyncService){
setContentView(R.layout.activity_values);
}
...
try{
...
TextView lastSyncTV = (TextView) findViewById(R.id.last_sync_label);
lastSyncTV.setText(value);
...
} catch (Exception ex) {
....
}
} catch (Exception ex) {
....
}
}
AlarmReceiver
#Override
public void onReceive(Context context, Intent intent) {
try {
Intent i = new Intent(context, SyncService.class);
context.startService(i);
}catch (Exception ex){
.....
}
}
SyncService
//runns every 10min
#Override
protected void onHandleIntent(Intent intent) {
try {
...
ValuesActivity valuesActivity = new ValuesActivity();
valuesActivity.setSyncValue(....)
....
}
.....
}
actually you can't create an activity by creating an instance of that, you must run an activity by Intents. in your case if an activity is already in foreground and visible to user you must start activity with a FLAG_ACTIVITY_CLEAR_TOP flag. that send new intent to your current visible activity. to do this you can use this code:
context.startActivity(new Intent(this,ValuesActivity.class).putExtras(bundle).addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP));
in this way if activity already visible to user then android instead of recreating activity just send a new intent to method onNewIntent and you must override this method in your ValuesActivity to receive new intent sent by your service. something like this:
public void onNewIntent(Intent intent){
String value = intent.getStringExtra(/*your key*/);
lastSyncTV.setText(value);
}
if you want to check activity visibility you can add static property in your activity public static boolean isVisible = false; and toggle it true in onResume of your activity and toggle to false in onPause method.
then before startActivity just check if(ValuesActivity.isVisible).
Inside your
#Override
public void onReceive(Context context, Intent intent)
use
Intent intent = new Intent("alaram_received");
context.sendBroadcast(intent);
Inside your mainactivity first register the broadcast
IntentFilter intentFilter = new IntentFilter("alaram_received");
registerReceiver(alarm_receiver,intentFilter);
and then call your method in here:
BroadcastReceiver alarm_receiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
// your logic here
Log.i("alarm_received","success");
}
};
Related
I have a serious issue about passing data from BroadcastReceiver to an Activity. Let see my issue carefully. I have a class PhoneStateReceiver extends BroadcastReceiver that used to received an incoming phone.
public class PhoneStateReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
try {
System.out.println("Receiver start");
String state = intent.getStringExtra(TelephonyManager.EXTRA_STATE);
String incomingNumber = intent.getStringExtra(TelephonyManager.EXTRA_INCOMING_NUMBER);
if(state.equals(TelephonyManager.EXTRA_STATE_RINGING)){
}
}
catch (Exception e){
e.printStackTrace();
}
}
}
The incoming phone will be sent to an Activity, called ReceiverActivity. The ReceiverActivity receives the incoming phone and sends it to a server via a socket connection. The socket connection is initialized in the onCreate function. I googled and found server way to pass the data from BroadcastReceiver to an Activity. The common way is that send data via putExtra function and call startActivity. However, the way will call the onCreate again and then connect the socket, draw the UI again. Thus, it is not helpful in my case.
In my goal, If the phone receives an incoming call, it will send the incoming call to the ReceiverActivity. The ReceiverActivity receives the message and calls the send function. Which is the best way to do it? Thank you
The common way to pass data from a BroadcastReceiver to a ReceiverActivity that I used as follows
In PhoneStateReceiver class :
Intent intent_phonenum = new Intent(context, ReceiverActivity.class);
intent_phonenum.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent_phonenum.putExtra("phone_num", incomingNumber);
context.startActivity(intent_phonenum);
In ReceiverActivity class :
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
connect_socket();
Intent intent = getIntent();
phone_num = intent.getStringExtra("phone_num");
send(phone_num);
}
Simple without any third party libs.
Make sure BroadcastReceiver must be registered and also unregistered on OnPause().
You have to do two thing
Register a receiver in you activity like below.
public class MainActivity extends Activity {
Context context;
BroadcastReceiver updateUIReciver;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
context = this;
IntentFilter filter = new IntentFilter();
filter.addAction("service.to.activity.transfer");
updateUIReciver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
//UI update here
if (intent != null)
Toast.makeText(context, intent.getStringExtra("number").toString(), Toast.LENGTH_LONG).show();
}
};
registerReceiver(updateUIReciver, filter);
}
}
Now in you service
public class PhoneStateReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
try {
System.out.println("Receiver start");
String state = intent.getStringExtra(TelephonyManager.EXTRA_STATE);
String incomingNumber = intent.getStringExtra(TelephonyManager.EXTRA_INCOMING_NUMBER);
if (state.equals(TelephonyManager.EXTRA_STATE_RINGING)) {
Intent local = new Intent();
local.setAction("service.to.activity.transfer");
local.putExtra("number", incomingNumber);
context.sendBroadcast(local);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
There is a very simple design pattern you can use here to ease communication between your classes and also decouple your code: publisher/subscriber. My favorite library for this is EventBus:
First, add to your build.gradle file:
compile 'org.greenrobot:eventbus:3.0.0'
Then, create a simple POJO - Plain Old Java Object like this:
public class OnReceiverEvent{
private String phoneNumber;
public OnReceiverEvent(String phone){
this.phoneNumber = phone;
}
public String getPhoneNumber(){
return phoneNumber;
}
}
Next, by making your Receiver class a publisher, and your Activity a subscriber, you should be able to easily pass the information to your activity like this:
//inside your PhoneStateReceiver class when you want to pass info
EventBus.getDefault().post(new OnReceiverEvent(phoneNumber));
Next, inside your activity, simply do this:
//onStart
#Override
public void onStart(){
super.onStart();
EventBus.getDefault().register(this);
}
//onStop
#Override
public void onStop(){
super.onStop();
EventBus.getDefault().unregister(this);
}
Finally, handle the posted data i.e phoneNumber value:
#Subscribe
public void onPhoneNumberReceived(OnReceiverEvent event){
//get the phone number value here and do something with it
String phoneNumber = event.getPhoneNumber();
//display or something?
}
UPDATE
If you have another Event that you want this activity to subscribe to, simply create a method like you did in the first one using the #Subscribe annotation.
#Subscribe
public void onSomeOtherEvent(EventClassName event){
//get the variables here as usual;
}
This is the easiest way to pass the data from your receiver to your activity without having to worry about starting the activity over and over!
I hope this helps and good luck!
So I understand you don't want to recreate your Activity everytime.
In your Intent changing this flag will help you :
intent_phonenum.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
In Intent class if you read method summary of FLAG_ACTIVITY_CLEAR_TOP:
If set, and the activity being launched is already running in the
current task, then instead of launching a new instance of that activity,
all of the other activities on top of it will be closed and this Intent
will be delivered to the (now on top) old activity as a new Intent. (you can read more ...)
In this case: If your app is running and you have an Activity instance then Intent will not recreate your Activity. But assume that your app is in closed state and when BroadcastReceiver triggered, the Intent will create new Activity because you don't have instance of that Activity.
#Edit :
You can specify special Intent like that in your BroadcastReceiver:
public void onReceive(Context context, Intent intent) {
Bundle extras = intent.getExtras();
Intent i = new Intent("mycustombroadcast");
i.putExtra("phone_num", incomingNumber);
context.sendBroadcast(i);
}
Then in your Activity inside onCreate() register receiver like that :
BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
Bundle bundle = intent.getExtras();
int incoming_number= bundle.getInt("phone_num");
Log.e("incoming number", "" + incoming_number);
}
};
//then register receiver like that :
registerReceiver(broadcastReceiver, new IntentFilter("mycustombroadcast"));
You can unregister Receiver in onDestroy() : unregisterReceiver(broadcastReceiver);
Also another way is overriding onNewIntent() in your Activity:
#Override
protected void onNewIntent(Intent intent) {
//your intent is here, you can do sth.
super.onNewIntent(intent);
}
I have application that use audio device of the phone, I want my activity to be finish when any call come to my device
This is the code
public class PhoneStateReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context mContext, Intent intent) {
if (intent.getAction().equals("android.intent.action.PHONE_STATE")) {
if (intent.getStringExtra(TelephonyManager.EXTRA_STATE).equals(
TelephonyManager.EXTRA_STATE_RINGING)) {
// Send local broadcast to set pin code in the dialog
Intent broadcast = new Intent();
broadcast.setAction(ThurayaConstants.INCOMING_CALL);
mContext.sendBroadcast(broadcast);
}
}
}
}
I have added this class to listen to global receiver in the manifest file to detect when any call come to my device.
and in my fragment I register the following receiver
private BroadcastReceiver mIncomingCallReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
getActivity().finish();
}
};
The problem that my activity is not closed , can any one help here ???
I have 1 activity that I would like to start at different times with different variables from a Broadcast Receiver.
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (action.equalsIgnoreCase("tv.abcd.v4.ORIGINAL_VIDEO_SCENE")){
channelName = intent.getExtras().getString("com.abcd.Channel");
JSONObject json = new JSONObject(intent.getExtras().getString("com.abcd.Data"));
String incomingScene = json.getString("url");
scene.putExtra("channel", channelName);
scene.putExtra("url", incomingScene);
scene.addFlags(Intent.FLAG_FROM_BACKGROUND);
scene.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
scene.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(scene);
}
I have the code to start the activity via Intent and in the activity receiver the extras to make data appear.
Intent intent = getIntent();
sceneUrl = intent.getStringExtra("url");
Log.d("Image.incomingscene.url",sceneUrl);
channelName = intent.getStringExtra("channel");
Log.d("Image.incomingSceneAvatar",networkAvatar);
image = (ImageView)findViewById(R.id.imageView1);
image.setScaleType(ScaleType.FIT_CENTER);
progressBar = (ProgressBar)findViewById(R.id.progressBar1);
Picasso.with(this).load(sceneUrl).skipMemoryCache().fit().into(image, new EmptyCallback() {
});
Now after that I want to start the same activity again from the Broadcast Reciever with different data. So i want the previous activity to get out the way and allow this new instance to start up.
How to accomplish this feat?
register another broadcast receiver from the activity. Then, when you want to kill it, send a broadcast message from the broadcast receiver that you mentioned .
In your broadcastReceiver do something like the following :
public static final String CLOSE_Activity= "com.mypackage.closeactivity";
and in yopr OnReceive method do like the following :
#Override
public void onReceive(Context context, Intent intent) {
System.out.println("HIT OUTGOING");
Intent i = new Intent();
i.setAction(CLOSE_Activity);
context.sendBroadcast(i);
}
then in your activity craete a receviver and register it in the onResume method and unregeister it in the onPause method , like the following :
private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(RECEIVER_Class.CLOSE_Activity)) {
finish();
}
}
}
activity onResume method :
#Override
public void onResume() {
registerReceiver(broadcastReceiver, new IntentFilter(RECEIVER_Class.CLOSE_Activity));
}
activity onPause method :
#Override
public void onPause() {
super.onPause();
unregisterReceiver(receiver);
}
Please give me some feedback
Hope that helps .
I have a service that listens for (ON_BATTERY_CHANGE), then onReceive service sends a Broadcast to My MainActivity. The problem is that I somehow can't get them from service to my main activity. Code: Main Activity:
public class MainActivity extends Activity
private BroadcastReceiver batteryReceiverService;
private TextView text2;
....
protected void onCreate(Bundle savedInstanceState) {
text2=(TextView)findViewById(R.id.TV_text2);
batteryReceiverService = new BroadcastReceiver(){
#Override
public void onReceive(Context context, Intent intent) {
text2.setText("left: "+intent.getStringExtra("H")+" hours "+intent.getStringExtra("M")+" minute(s)");
Log.e("text2","text2 HHH " +intent.getStringExtra("H")); //log shows 0
Log.e("text2","text2 MMM " +intent.getStringExtra("H")); // log shows 0
}
};
registerReceiver(batteryReceiverService, new IntentFilter(UltimateBatterySaverService.BROADCAST_ACTION));
....
#Override
protected void onDestroy() {
unregisterReceiver(batteryReceiverService);
super.onDestroy();
}
Service:
public class UltimateBatterySaverService extends Service {
private Intent intent;
static final String BROADCAST_ACTION = "lt.whitegroup.ultimatebatterysaver";
private BroadcastReceiver batteryLevelReceiver;
....
public void onCreate() {
super.onCreate();
intent = new Intent(BROADCAST_ACTION);
}
#Override
public void onDestroy() {
unregisterReceiver(batteryLevelReceiver);
super.onDestroy();
}
IntentFilter batteryLevelFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
batteryLevelReceiver = new BroadcastReceiver(){
#Override
public void onReceive(Context context, Intent intent){
// Receiving data, calculating and etc
averageChargingH=timeAllInHours;
averageChargingM=timeAllInMinutes;
// to put extras and send broadcast
does();
......
public void does(){
String strLong = Long.toString(averageChargingH);
String strLong2 = Long.toString(averageChargingM);
Log.e("cccccc","strLong h "+strLong); // getting good value not 0(everything ok)
Log.e("cccccc","strLong2 m"+strLong2); // getting good value not 0(everything ok)
intent.putExtra("H", strLong);
intent.putExtra("M", strLong2);
sendBroadcast(intent);
}
Any ideas why my information is not transfered correctly?
The does() method seems to be using variables in the same scope as onReceive so I'm guessing that the intent variable in does() is actually the Intent passed in from onReceive.
Try adding some logging before sending the broadcast to check if the action of the intent is correct, or simply create the broadcast intent in the onReceive method and name it intent2.
I'm having two activities which are displayed side by side on one screen through a fragment for each activity. I want to send a String when I click a button on one of the activity, and then the other activity should retrieve the String I sent.
I know that it's possible to do that with the classic way setString() and getString() methods. But I'm wondering, could it be accomplished with putExtra() and getExtra() without opening the targeted activity on a new screen?
You can have both activity's intent as global variable and try using putExtra() from one activity and then getExtra() by another activity.
For Example,
public class activityOne extends Activity
{
public static Intent intent = null;
#Override
protected synchronized final void onCreate(final Bundle savedInstanceState)
{
intent = getIntent();
}
}
public class activityTwo extends Activity
{
public static Intent intent = null;
#Override
protected synchronized final void onCreate(final Bundle savedInstanceState)
{
intent = getIntent();
}
}
Now wherever you want you can access their intent like activityOne.intent,activityTwo.intent followed by null check
You can send the intent as a broadcast and have the receiving fragment register to that broadcast on its start (and unregister on its destroy).
Sending fragment:
Intent intent= new Intent(PARAM_TRANSFER);
intent.putExtra(key, extra);
sendBroadcast(intent);
Receiving fragment:
register:
IntentFilter intentFilter = new IntentFilter(PARAM_TRANSFER);
registerReceiver(mReceiver, intentFilter);
unregister:
try {
unregisterReceiver(mReceiver);
} catch (Exception e) {}
getting the param:
private class MyReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
intent.getExtra(key);
}
}