İstisna yöntemi başarısız oldu

Question

Bir app-to-app uygulaması android uygulaması Daha önce kod ve bazı istisnalar ile bazı sorunları vardı, şimdi, iyi, ama son bir istisna karşısında.

03-24 20:45:49.789 25058-25058/com.example.abhinav123.sinch2 E/AndroidRuntime: FATAL EXCEPTION: main 
                      Process: com.example.abhinav123.sinch2, PID: 25058 
                      Theme: themes:{} 
                      java.lang.NullPointerException: Attempt to invoke interface method 'void com.sinch.android.rtc.calling.Call.addCallListener(com.sinch.android.rtc.calling.CallListener)' on a null object reference 
                       at com.example.abhinav123.sinch2.CallActivity$1.onClick(CallActivity.java:49) 
                       at android.view.View.performClick(View.java:5204) 
                       at android.view.View$PerformClick.run(View.java:21158) 
                       at android.os.Handler.handleCallback(Handler.java:739) 
                       at android.os.Handler.dispatchMessage(Handler.java:95) 
                       at android.os.Looper.loop(Looper.java:148) 
                       at android.app.ActivityThread.main(ActivityThread.java:5461) 
                       at java.lang.reflect.Method.invoke(Native Method) 
                       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

49 çizgidir: Uygulamanın çağrı aktivite için , İşte benim kod

public class CallActivity extends AppCompatActivity { 
private com.sinch.android.rtc.calling.Call call; 
private TextView callState; 
private Button button; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.call); 
    TextView callState = (TextView) findViewById(R.id.callState); 
    Intent intent = getIntent(); 
    String callerId = intent.getStringExtra("callerId"); 
    final String recipientId = intent.getStringExtra("recipientId"); 
    final SinchClient sinchClient = Sinch.getSinchClientBuilder() 
      .context(this) 
      .userId(""+callerId) 
      .applicationKey("c6a1ec06-3f48-4e2d-980c-021ea6d2c8ca") 
      .applicationSecret("pH2/AwzRJkmFS2M3kQ1XcA==") 
      .environmentHost("sandbox.sinch.com") 
      .build(); 
    sinchClient.setSupportCalling(true); 
    sinchClient.startListeningOnActiveConnection(); 
    sinchClient.start(); 
    sinchClient.getCallClient().addCallClientListener(new SinchCallClientListener()); 
    button = (Button) findViewById(R.id.button); 
    button.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View view) { 
      call.addCallListener(new SinchCallListener()); 
      if (call == null) { 
       call = sinchClient.getCallClient().callUser(recipientId); 
       button.setText("Hang Up"); 
      } else { 
       call.hangup(); 

      } // make a call! 
     } 
    }); 
} 
private class SinchCallListener implements CallListener { 

    @Override 
    public void onCallProgressing(com.sinch.android.rtc.calling.Call progressingCall) { 
     callState.setText("ringing"); 
    } 

    @Override 
    public void onCallEstablished(com.sinch.android.rtc.calling.Call establishedCall) { 
     callState.setText("connected"); 
     setVolumeControlStream(AudioManager.STREAM_VOICE_CALL); 
    } 

    @Override 
    public void onCallEnded(com.sinch.android.rtc.calling.Call endedCall) { 
     callState.setText(""); 
     call = null; 
     button.setText("Call"); 
     setVolumeControlStream(AudioManager.USE_DEFAULT_STREAM_TYPE); 
    } 

    @Override 
    public void onShouldSendPushNotification(com.sinch.android.rtc.calling.Call call, List<PushPair>pushPairs) { 

    } 
} 

private class SinchCallClientListener implements com.sinch.android.rtc.calling.CallClientListener { 
    @Override 
    public void onIncomingCall(com.sinch.android.rtc.calling.CallClient callClient, com.sinch.android.rtc.calling.Call incomingCall) { 
     call = incomingCall; 
     call.answer(); 
     call.addCallListener(new SinchCallListener()); 
     button.setText("Hang Up"); 
    } 
} 

}

logcat diyor olduğunu call.addCallListener (yeni SinchCallListener());

yardım lütfen .. Sadece burada call ilan ettiler

Answer 1

: private com.sinch.android.rtc.calling.Call call;

Ama bunu kullanmadan önce, bunu başlatılmadı var.