I'd like to know:
how the android OS detect a incoming call(number) and displays the contact name and gives us a option to attend the call.
What happens inside the OS when the "END CALL BUTTON" is tapped.
When I searched regarding this I am getting only the Classes and methods to create my own app. Requesting for the explanation.
In Android it is possible to detect call events using the built-in TelephonyManager API.TelephonyManager class provides access to information about the telephony services on the device.
Example :
Create a new class called MyCallReceiver
package com.example;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.telephony.TelephonyManager;
import android.widget.Toast;
public class MyCallReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getStringExtra(TelephonyManager.EXTRA_STATE).equals(TelephonyManager.EXTRA_STATE_RINGING)) {
// This code will execute when the phone has an incoming call
// get the phone number
String incomingNumber = intent.getStringExtra(TelephonyManager.EXTRA_INCOMING_NUMBER);
Toast.makeText(context, "Call from:" +incomingNumber, Toast.LENGTH_LONG).show();
} else if (intent.getStringExtra(TelephonyManager.EXTRA_STATE).equals(
TelephonyManager.EXTRA_STATE_IDLE)
|| intent.getStringExtra(TelephonyManager.EXTRA_STATE).equals(
TelephonyManager.EXTRA_STATE_OFFHOOK)) {
// This code will execute when the call is disconnected
Toast.makeText(context, "Detected call hangup event", Toast.LENGTH_LONG).show();
}
}
}
BroadcastReceiver class that will monitor the phone state and whenever there is a change in phone state, the onReceive() method of the BroadcastReceiver will be called.
Add the READ_PHONE_STATE permission in your AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name="com.example.MyCallReceiver" >
<intent-filter>
<action android:name="android.intent.action.PHONE_STATE" />
</intent-filter>
</receiver>
</application>
</manifest>
Check this for references : BroadcastReceiver
Related
I want to run broadcastreceiver without stoping and i dont know how.
I do not know if there is service runs all the time...
Thnaks!
You don't need to start/stop a BroadcastReceiver. Its not your background running service. All you need is to register or unregister it for your application. Once registered, its always ON.
When some specific event occur, system notifies(broadcast) all registered applications about the event. all registered apps receives this as an Intent. Also, you can send your own broadcast.
for more, see this
Simple Example:
in my manifest, I'm including a permission and a receiver
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android.receivercall"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="10" />
<uses-permission android:name="android.permission.READ_PHONE_STATE"/>
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<receiver android:name=".Main">
<intent-filter >
<action android:name="android.intent.action.PHONE_STATE"/>
</intent-filter>
</receiver>
<activity android:name=".TelServices">
<intent-filter >
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>
Now, my receiver, Main.java
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.telephony.TelephonyManager;
import android.widget.Toast;
public class Main extends BroadcastReceiver {
String number,state;
#Override
public void onReceive(Context context, Intent intent) {
state=intent.getStringExtra(TelephonyManager.EXTRA_STATE);
if(state.equals(TelephonyManager.EXTRA_STATE_RINGING)){
number=intent.getStringExtra(TelephonyManager.EXTRA_INCOMING_NUMBER);
Toast.makeText(context, "Call from : "+number, Toast.LENGTH_LONG).show();
}
else if(state.equals(TelephonyManager.EXTRA_STATE_IDLE))
Toast.makeText(context, "Call ended", Toast.LENGTH_LONG).show();
else
Toast.makeText(context, intent.getAction(), Toast.LENGTH_LONG).show();
}
}
Here, when I install this app, I'm registering a Broadcastreceiver through manifest. And the Toast will appear every time a call comes/ends.
we have an application which will record the right date&time when user trigger an event.
we don't want user to change the date&time to a passed time.
How to disable date&setting on Android system level?
Even if you could find some hack to do this, this is not something you want to do. A better solution would be to listen for the ACTION_TIMEZONE_CHANGED, ACTION_TIME_CHANGED, and ACTION_DATE_CHANGED events and then change your previous time accordingly. This is actually very easy to do, I can provide sample code if you need help.
TimeChanged.java
package com.example.stackoverflow17462606;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class TimeChanged extends BroadcastReceiver {
public TimeChanged() {
}
#Override
public void onReceive(Context context, Intent intent) {
// Do whatever changes you need here
// you can check the updated time using Calendar c = Calendar.getInstance();
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.stackoverflow17462606"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="7"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<receiver
android:name="com.example.stackoverflow17462606.TimeChanged"
android:enabled="true"
android:exported="true" >
<intent-filter>
<action android:name="android.intent.action.TIMEZONE_CHANGED"/>
<action android:name="android.intent.action.TIME_SET"/>
<action android:name="android.intent.action.DATE_CHANGED"/>
</intent-filter>
</receiver>
</application>
</manifest>
Please remember that this will only fire if you've launched your app once on the device (to prevent apps from running themselves once their installed)
i'm having trouble with the auto-start feature of my APP.
I've searched trhough the forums, seen many suggestions, none seems to work and I don't know why.
Here's the BootUpReciver.java
package com.???.???;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import android.widget.Toast;
public class BootUpReciver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if ("android.intent.action.BOOT_COMPLETED".equals(intent.getAction())) {
//Intent pushIntent = new Intent(context, BackgroundService.class);
//context.startService(pushIntent);
Toast.makeText(context, "Device Booted", Toast.LENGTH_LONG).show();
Log.d("TAG","Device Booted");
}
}
}
And here's my Manifest file
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.???.???"
android:versionCode="1"
android:versionName="1.0" >
<uses-permission android:name="android.permission.VIBRATE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="17" />
<application
android:theme="#android:style/Theme.Holo"
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<receiver android:name=".BootUpReciver">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
<activity
android:name="com.???.???.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
When i restart my phone i don't even see the Toast, why? what should i do? I need to auto-start to get some sharedprefs and write a value to a file every boot.
Thanks.
While testing I found that If I show toast in onReceive then it is not showing. But if I start an activity in onReceive then it is working. So you can also check this. Start an activity or service and perform your task there.
I am building an android app which once installed helps automating some of my home controls. As the first simple feature of the app, i want the phone to toast me with welcome message whenever i enter my home.
I thought i could implement this by putting in a BroadCastReceiver with action name "android.net.wifi.WIFI_STATE_CHANGED" and i assumed, whenever a new network is available, the broadcast receiver will be notified and i could check the SSID to see if i have arrived home.
Manifest file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.myfirstapp"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.myfirstapp.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver
android:name="com.example.myfirstapp.WifiNetworksAvailableBroadcastReceiver"
android:enabled="true" >
<intent-filter>
<action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
</intent-filter>
</receiver>
<activity
android:name="com.example.myfirstapp.WifiTester"
android:label="#string/title_activity_wifi_tester" >
</activity>
</application>
</manifest>
My WifiNetworksAvailableBroadcastReceiver looks like:
public class WifiNetworksAvailableBroadcastReceiver extends BroadcastReceiver {
protected static final String TAG = "MyApp";
#Override
public void onReceive(Context context, Intent intent) {
WifiManager mMgr = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
Log.i(TAG, "------");
for(final ScanResult result:mMgr.getScanResults()) {
if(result.SSID.equals("<MY_HOME_WIFI_SSID>")) {
Toast.makeText(context, "Welcome home", Toast.LENGTH_LONG).show();
}
}
Log.i(TAG, "======");
}
}
Now with the app installed. I enter my home but i do not get the toast. I tried running the app in the background but still i did not get the toast. Could anyone give an direction? Is my approach correct?
Try to change the receiver with the event SCAN_RESULTS_AVAILABLE_ACTION.
Your receiver will be called every time a new wifi scan has been done, then you can check if your SSID is present in the list of available ones calling getScanResults() and eventually show the toast.
PS.
Have you registered your receiver?
I have been working on an app to respond to received SMS messages (before you complain, I know this has been asked A LOT, but believe me, I can't get it to work at all, and I've tried searching for hours). I've got my manifest set up like so:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.csbctech.notiscreen"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.RECEIVE_SMS"/>
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<activity
android:name=".NotiScreenActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name="NotiScreenSmsReceiver" android:process=":remote">
<intent-filter>
<action android:name="android.provider.Telephony.SMS_RECEIVED"/>
</intent-filter>
</receiver>
</application>
</manifest>
And my receiver class looks like this:
package com.csbctech.notiscreen;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.CountDownTimer;
import android.os.PowerManager;
import android.util.Log;
public class NotiScreenSmsReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
Log.w("NotiScreen", "Got SMS");
}
}
But the "NotiScreenSmsReceiver" class never gets called. I've tried several different examples, and I can't for the life of me get the receiver class to get called...I've even tried removing the uses-permission, and I don't even get an error message about not having permissions. What could be wrong? Oh please help me, you're my only hope!
Are you running this on a phone with a custom SMS app such as GOSMS? I've heard that some of those programs will stop the broadcast so that they can create their own notifications and stop the stock ones.
Change
<receiver android:name="NotiScreenSmsReceiver" android:process=":remote">
to
<receiver android:name=".NotiScreenSmsReceiver" android:process=":remote">