Develop Reference

Detect Call On Hold

I wanted to know if there is any definitive way to know if the call is put on hold by the receiver on the receiver side only.
Now I checked the Telephony documentation, and this shows that there are three states for a call :
CALL_STATE_IDLE: When no call activity is there
CALL_STATE_RINGING: When a new call is ringing and waiting to be taken up.
CALL_STATE_OFFHOOK: At least one call exists that is dialing, active, or on hold, and no calls are ringing or waiting.
Here lies the problem, OFFHOOK takes the active and hold state as one. There seems to be no way to distinguish between them.
But an interesting observation I made was that dialler recieves a notification when the call is retrieved from hold, that means there exists some way to know the difference. Hence, I would be obliged if you assist me in finding that way.

It looks like the current Telephony APIs doen't let you read the precise call state.
In this commit, however
https://github.com/android/platform_frameworks_base/commit/c5ac15a3e11c03951e269b243674858411204b67
You can see a proposal for a precise call state monitoring.
https://android-review.googlesource.com/#/c/60660/
Here you can see that at Feb 13 5:26 AM this "Change has been successfully merged into the git repository."
This means that sooner or later we'll see it in a future Android release.

How to know the status of call on android programatically

I have an app that has to perform certain actions after phone call is ended.
like in my application after every call i should save the call time, duration and write it to text file for further processing. Main problem here is how do I know that call is just ended.
I have checked Telephony manager like
TelephonyManager.CALL_STATE_RINGING
TelephonyManager.CALL_STATE_OFFHOOK
But I am still unable to achieve this task. Any help please.

Check out BroadcastReceiver. And here is a nice tutorial on how to catch changes in the phone state.

How do I know who ended the call in Android - User or Remote User?

I want to specifically know who ended the call. I have setup a broadcast receiver for
"android.intent.action.PHONE_STATE"
When I detect a transition from Off hook to idle, I know the call has ended. But how do I know who ended the call?
Thanks a ton!

I'm afraid there's presently no way to determine if the user pressed "end call" or if the other end (or ends, in a group call) terminated. The only workaround I can suggest is monitoring the other states to observe if the phone state ringing was encountered. In such a case, you could assume the user is making the phone call as opposed to receiving it.
Bear in mind that there are other problems related to PHONE_STATE, such as handling multiple calls simultaneously.
In retrospect, I'm not entirely sure what you mean with "who". As for other apps ending the call: there is no official API to end phone calls; only through reflection can an app invoke the TelephonyService's endCall() function. Here, too, it is not possible to determine if the call was terminated through user interaction or not.

Show my activity instead of standard screen for incoming call

I'm developing an application for android 2.3.3. It contains a few EditView's to show an information for an incoming call: country, current time, phone number... I know how to get and show that information. The problem I faced is that I don't know how to show my activity instead of the standard screen for incoming calls.
Now it shows the information after the incoming calls.
How to do it?

It's not possible. According to the PhoneApp the intent used to start the InCallScreen is bound to the phoneapp, you have no chance to intercept this. So the screen will be shown every time.
What you may try to do is to be notified by the TelephonyManager when the phone goes into the CALL_STATE_RINGING state and then paint your UI just over the InCallScreen. It may be possible to do so but you woudn't be able to offhook the call (unsure, but I don't think so) from your UI. Also the state is not set immediately when the InCallScreen pops up, it's delayed by some milliseconds.

Take a look at the questions about showing popups over the incoming call screen:
Popup over incoming-call screen
android incoming call screen
If it isn't enough to show a popup over the incoming call UI, then you could make your popup cover the whole screen to hide it. At that point you'll need a way to accept the incoming call without showing the default incoming call screen (which you are now covering). A quick search found this answer that suggests a workaround to accept the incoming call. I'm not sure offhand if there is an official API to do it.

It's impossible to remove the default UI of the incoming call in android, unless you modify the Android OS codings. But instead you can use your own custom UI activity over the default one. It's attained by using the Thread concept(to make the custom designed UI come-over the default one)!!

How to differentiate between a missed call and an refuse to answer?

I am designing an application in which I need to differentiate between a call rejected by the receiver (by pressing the dialing button) with the one not answered and is disconnected by the one who is dialing. is there anything that makes a differentiation since both of these come under the missed call category in Android?

You are lacking some details; please advise.
Are you referring to the Call Log provider android.provider.CallLog.Calls? There are only 3 call types defined. Can you provide the data of all the fields for such a Call Log entry?
The only other way (we know of) to tell is to watch the Phone State (via IntentReceiver) and track the transitions yourself. Most likely, a transition of Ringing to Idle would indicate the call was refused instead of answered, in which case it would transition Ringing to Offhook.