CODEWITHSUNDEEP
javaandroidtelephonymanager
user960573
user960573

Reputation: 51

Android telephony API does not return cellsignalstrength on 4G phone

I am trying to retrieve cell signal strength and display on my 4G based phone. My phone build is LND-AL30 8.0.0.203 (C675). Does it mean that I have android ver 8 with api level 30? If so, which Api can I use to get signal strength?

Problem: When the application is launched and when location information is DISABLED, then application runs fine but retrieves zero length of cellInfo objects (tm.getAllCellInfo). So, i am unable to get signal strength at all.

Whereas If I turn on location information on my phone, the application crashes with exception: No virtual method cellInfo.getCellSignalStrength. Can you please suggest how to overcome this problem and retrieve cell signal strength?

Below is the android sdk versions that I am using.

build.gradle

android {
compileSdk 31

defaultConfig {
    applicationId "com.example.mobilenetworkinfo"
    minSdk 31
    targetSdk 31
    versionCode 1
    versionName "1.0"

    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}

buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
    }
}
compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}
}

Manifest.xml file with required permissions:

uses-permission android:name="android.permission.READ_PHONE_STATE" 
uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" 
uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" 
uses-permission android:name="android.permission.INTERNET"

And MainActivity.java file:

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.telephony.*;


public class MainActivity extends AppCompatActivity {
private final int REQUEST_READ_PHONE_STATE=1;
private final int REQUEST_ACCESS_COARSE_LOCATION=2;
private final int REQUEST_ACCESS_FINE_LOCATION=3;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Log.i("onCreate", "added hello from onCreate");

}


@SuppressLint({"NewApi", "MissingPermission"})
@TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR2)
public void sendMessage(View view) {
  

    int permissionCheck = ContextCompat.checkSelfPermission(this, 
     Manifest.permission.READ_PHONE_STATE);

    if (permissionCheck != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[] 
    {Manifest.permission.READ_PHONE_STATE}, REQUEST_READ_PHONE_STATE);
     } else {
        //TODO
     }
    int permissionCheck2 = ContextCompat.checkSelfPermission(this, 
    Manifest.permission.ACCESS_COARSE_LOCATION);

    if (permissionCheck2 != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[] 
    {Manifest.permission.ACCESS_COARSE_LOCATION}, REQUEST_ACCESS_COARSE_LOCATION);
    } else {
        //TODO
    }

    int permissionCheck3 = ContextCompat.checkSelfPermission(this, 
     Manifest.permission.ACCESS_FINE_LOCATION);

    if (permissionCheck3 != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[] 
    {Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_ACCESS_FINE_LOCATION);
     } else {
        //TODO
    }

    Intent intent = new Intent(this, DisplayMessageActivity.class);

    TelephonyManager tm = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);

    intent.putExtra("IMEI", tm.getImei());
    intent.putExtra("SIM serial number", tm.getSimSerialNumber());
    Integer i=0;
    for( CellInfo cellInfo: tm.getAllCellInfo()) {
    //for( i =1; i <= 6;i++){
        i++;
        

 intent.putExtra("cellSignalStrength"+i.toString(),
 cellInfo.getCellSignalStrength().getDbm()+"");

    }
    intent.putExtra("CELLCOUNT", i+"");
    Log.i("First", "added hello and count is " + i.toString());
    startActivity(intent);


}

@SuppressLint({"MissingPermission", "NewApi"})
@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] 
 grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    switch (requestCode) {
        case REQUEST_READ_PHONE_STATE:
            if ((grantResults.length > 0) && (grantResults[0] == 
  PackageManager.PERMISSION_GRANTED)) {
            }
            break;

        default:
            break;
    }
 }


}

Upvotes: 1

Views: 719

Answers (1)

Gabe Sechan
Gabe Sechan

Reputation: 93559

You're compiling with SDK level 18. getSignalStrength was just added in API 30. You need to set your target SDK version to at least 30 (and run it on a device at least 30) to compile. You'd probably want to make the minSDK version 30 as well, or you'll need to check the API level before calling it.

Upvotes: 1

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