retrieve the call number in my android APP

I would like to get the number call when i receive a call in my app.I would like to retrieve it and store it somewhere.

public void onCallStateChanged(int state, String incomingNumber) {
    super.onCallStateChanged开发者_Python百科(state, incomingNumber);

.........

incomingNumber contains nothing.

Do you have the permissions?

Note that access to some telephony information is permission-protected. Your application won't receive updates for protected information unless it has the appropriate permissions declared in its manifest file. Where permissions apply, they are noted in the appropriate LISTEN_ flags.

http://developer.android.com/reference/android/telephony/PhoneStateListener.html

Include following permissions in your application manifest as a child of application.

<uses-permission android:name="android.permission.READ_PHONE_STATE" />

Also include a receiver in manifest

<!-- SAMPLE APPLICATION IS NAME OF OUR APPLICATION -->
<receiver android:name="SampleApplication" 
    android:enabled="true"
    android:exported="true"
    android:permission="">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
        <action android:name="android.intent.action.PHONE_STATE" />
    </intent-filter>

</receiver>

Create a class that extends android.telephony.PhoneStateListener and implement its onCallStateChanged

public class 
class MyPhoneStateListener extends PhoneStateListener
  {
      public void onCallStateChanged(int state, String incomingNumber)
      {
          Log.d("SampleApp","Incoming call from: "+incomingNumber);
      }
  }

Now in you onCreate() call TelephonyManager and add this class as listener:

TelephonyManager myTelManager = (TelephonyManager)getSystemService(TELEPHONY_SERVICE); 
MyPhoneStateListener myListner = new MyPhoneStateListener();
myTelManager.listen(myListner, PhoneStateListener.LISTEN_CALL_STATE);

You can check result in LogCat.

EDIT :Complete class which stores response in variable:

import android.app.Activity;
import android.os.Bundle;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;

public class SampleApp extends Activity{

private String incomingCallNumber="";
@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState); 
    setContentView(R.layout.rating);
    TelephonyManager myTelManager = 
(TelephonyManager)getSystemService(TELEPHONY_SERVICE); 
    MyPhoneStateListener myListner = new MyPhoneStateListener();
    myTelManager.listen(myListner, PhoneStateListener.LISTEN_CALL_STATE);


}
class MyPhoneStateListener extends PhoneStateListener
{
  public void onCallStateChanged(int state, String incomingNumber)
  {
     SampleApp.this.incomingCallNumber=incomingNumber;
  }
}

}