How to block incoming call when switch widget is on?

Question

I have an app in which I have placed a switch toggle button. The purpose of my app is that whenever the switch button is set to ON, all incoming calls should be blocked. I am able to block all calls but I am unable to block when the switch is set to ON.

I have created a class called MyClassReceiver that extends Broadcast Receiver, all the call blocking is done in this class. I have added receiver code in Manifest file that works perfectly.

This is the code I am using:-

MainActivity.java

package com.chinmay.smsender;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.media.AudioManager;
import android.os.Bundle;
import android.view.Menu;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.Switch;

public class MainActivity extends Activity {

public Switch mySwitch;
//private LinearLayout bgElement;
private AudioManager mAudio;
boolean switchChecked;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mySwitch = (Switch) findViewById(R.id.switch1);
    //bgElement = (LinearLayout) findViewById(R.id.container);
    mAudio = (AudioManager) getBaseContext().getSystemService(Context.AUDIO_SERVICE);

    mySwitch.setOnCheckedChangeListener(new OnCheckedChangeListener(){

        @Override
        public void onCheckedChanged(CompoundButton arg0, boolean isChecked) {
            if(isChecked) {
                mAudio.setRingerMode(AudioManager.RINGER_MODE_SILENT);
                broadcastIntent(true);
                //bgElement.setBackgroundColor(Color.GREEN);
            } else {
                mAudio.setRingerMode(AudioManager.RINGER_MODE_NORMAL);
                broadcastIntent(false);
                //bgElement.setBackgroundColor(Color.RED);
            } 
        }

    });
}

public void broadcastIntent(boolean isChecked) {
    Intent intent = new Intent();
    intent.setAction("com.chinmay.CUSTOM_INTENT");
    intent.putExtra("switchChecked", isChecked);
    sendBroadcast(intent);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}

MyClassReceiver.java

package com.chinmay.smsender;

import java.lang.reflect.Method;

import com.android.internal.telephony.ITelephony;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.telephony.TelephonyManager;
import android.widget.Toast;


public class MyClassReceiver extends BroadcastReceiver {
private ITelephony telephonyService;
Context context = null;
boolean isChecked;

@Override
public void onReceive(Context context, Intent intent) {

    TelephonyManager telephony = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);

    isChecked = intent.getExtras().getBoolean("switchChecked");

    if(isChecked) {
        Toast.makeText(context, "Blocking calls", Toast.LENGTH_LONG).show();

        if(intent.getStringExtra(TelephonyManager.EXTRA_STATE).equals(TelephonyManager.EXTRA_STATE_RINGING)) {
            //String incomingNumber = intent.getStringExtra(TelephonyManager.EXTRA_INCOMING_NUMBER);
            //Toast.makeText(context, "Call from: "+incomingNumber, Toast.LENGTH_LONG).show();

            try {
                   Class<?> c = Class.forName(telephony.getClass().getName());
                   Method m = c.getDeclaredMethod("getITelephony");
                   m.setAccessible(true);
                   telephonyService = (ITelephony) m.invoke(telephony);
                   //telephonyService.silenceRinger();
                   telephonyService.endCall();
            } catch (Exception e) {
                   e.printStackTrace();
            }

        }
    } else if(isChecked == false) {
        Toast.makeText(context, "Blocking calls off", 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)) {
        Toast.makeText(context, "Detected Call Hangup Event.", Toast.LENGTH_LONG).show();
    }*/
}

}

Android Manifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.chinmay.smsender"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="14"
    android:targetSdkVersion="19" />

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

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="com.chinmay.smsender.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.chinmay.smsender.MyClassReceiver">
        <intent-filter>
            <action android:name="android.intent.action.PHONE_STATE" />
            <action android:name="com.chinmay.CUSTOM_INTENT" />
        </intent-filter>
    </receiver>    
</application>

</manifest>

This is the error I get if I run this code

10-31 13:03:26.283: E/AndroidRuntime(759): FATAL EXCEPTION: main
10-31 13:03:26.283: E/AndroidRuntime(759): Process: com.chinmay.smsender, PID: 759
10-31 13:03:26.283: E/AndroidRuntime(759): java.lang.RuntimeException: Unable to start receiver com.chinmay.smsender.MyClassReceiver: java.lang.NullPointerException
10-31 13:03:26.283: E/AndroidRuntime(759):  at android.app.ActivityThread.handleReceiver(ActivityThread.java:2441)
10-31 13:03:26.283: E/AndroidRuntime(759):  at android.app.ActivityThread.access$1700(ActivityThread.java:139)
10-31 13:03:26.283: E/AndroidRuntime(759):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1286)
10-31 13:03:26.283: E/AndroidRuntime(759):  at android.os.Handler.dispatchMessage(Handler.java:102)
10-31 13:03:26.283: E/AndroidRuntime(759):  at android.os.Looper.loop(Looper.java:136)
10-31 13:03:26.283: E/AndroidRuntime(759):  at android.app.ActivityThread.main(ActivityThread.java:5086)
10-31 13:03:26.283: E/AndroidRuntime(759):  at java.lang.reflect.Method.invokeNative(Native Method)
10-31 13:03:26.283: E/AndroidRuntime(759):  at java.lang.reflect.Method.invoke(Method.java:515)
10-31 13:03:26.283: E/AndroidRuntime(759):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
10-31 13:03:26.283: E/AndroidRuntime(759):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
10-31 13:03:26.283: E/AndroidRuntime(759):  at dalvik.system.NativeStart.main(Native Method)
10-31 13:03:26.283: E/AndroidRuntime(759): Caused by: java.lang.NullPointerException
10-31 13:03:26.283: E/AndroidRuntime(759):  at com.chinmay.smsender.MyClassReceiver.onReceive(MyClassReceiver.java:49)
10-31 13:03:26.283: E/AndroidRuntime(759):  at android.app.ActivityThread.handleReceiver(ActivityThread.java:2434)
10-31 13:03:26.283: E/AndroidRuntime(759):  ... 10 more

I think that because I am sending 2 intents to MyClassReceiver, I am getting this error.

Please tell how can I get to know the state of switch button in MyClassReceiver itself and block every call if switch is on.

you are initializing context = null in class. just declare it in class and initilize in onreceive method it may work.. — M S Gadag, Oct 31 '14 at 11:49
@MSGadag I have no problem with Toast, I just want to get the boolean state of switch button in Broadcast Receiver class. — gegobyte, Oct 31 '14 at 13:01
I'm confused, why are you using broadcast receiver for this? You are within the same project, from one activity to a receiver. Does not appear to be necessary. Unless this was just sample you made to get point across. I would say just make your TelephoneHelper class with a method that handles it on switch changed. — Sam, Feb 15 '18 at 17:49

score 0 · Accepted Answer · edited May 23 '17 at 10:25

0

The boolean state of the switch widget can be accessed with the help of Shared Preferences. See the answer here:

How to get switch value in Android?

After getting the boolean state, we just have to check whether its true or not and if it is, then block call.

edited May 23 '17 at 10:25

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answered Nov 09 '14 at 07:41

gegobyte

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How to block incoming call when switch widget is on?

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