Get Signal Strength - GSM and CDMA

MainActivity.java

package com.example.sample_phonesignalstrength;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.telephony.PhoneStateListener;
import android.telephony.SignalStrength;
import android.telephony.TelephonyManager;
import android.widget.TextView;

public class MainActivity extends Activity {
 private TextView textView1;
 private TelephonyManager mTelephonyManager;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  
  textView1 = (TextView) this.findViewById(R.id.textView1);
  
  mTelephonyManager = (TelephonyManager) this.getSystemService(Context.TELEPHONY_SERVICE);
  mTelephonyManager.listen(new MyPhoneStateListener(), PhoneStateListener.LISTEN_SIGNAL_STRENGTHS);
 } 
 private class MyPhoneStateListener extends PhoneStateListener{
  @Override
  public void onSignalStrengthsChanged(SignalStrength signalStrength) {
   super.onSignalStrengthsChanged(signalStrength);
   if(mTelephonyManager.getPhoneType() == TelephonyManager.PHONE_TYPE_GSM){
    textView1.setText("GSM Strength"+signalStrength.getGsmSignalStrength());
   }
   else if(mTelephonyManager.getPhoneType() == TelephonyManager.PHONE_TYPE_CDMA){
    textView1.setText("CDMA Strength"+signalStrength.getCdmaDbm()+" dBm");
   }
   else{
    textView1.setText("Unknown PhoneType: "+mTelephonyManager.getPhoneType());
   }
  }
 }

}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="TextView"
        android:textSize="30sp" />

</RelativeLayout>