My app is crashing when i try to retrieve imie number...here is my code

Question

Android Manifest

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

MainActivity.java

import android.content.Context;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.telephony.TelephonyManager;
    import android.view.View;
    import android.widget.Button;
    import android.widget.TextView;

    public class MainActivity extends AppCompatActivity {

        TextView tv;
        Button bn;
        String imei;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            tv = (TextView)findViewById(R.id.tvimei);
            bn = (Button)findViewById(R.id.button);

            TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
            imei = telephonyManager.getDeviceId();
            bn.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    tv.setText(imei);
                }
            });

        }
    }

I was trying to get imei number and display it on homepage for testing purpose but the app crashes as soon as I run it on the phone

Answer 1

Hi try to add permission if your device is marshmallow check the below code also

import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.telephony.TelephonyManager;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private static final int PERMISSION_REQUEST_CODE = 1;
    TextView tv;
    Button bn;
    String imei;

     private boolean checkPermission(){
    int result = ContextCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.READ_PHONE_STATE);

    if (result == PackageManager.PERMISSION_GRANTED){
        return true;
    } else {
        return false;
    }
}
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView)findViewById(R.id.tvimei);
        bn = (Button)findViewById(R.id.button);
        if(checkPermission()){
        Snackbar.make(view, "Permission already granted.", Snackbar.LENGTH_LONG).show();
        TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
        imei = telephonyManager.getDeviceId();
    }else{
        Snackbar.make(view,"Please give access to read your phone state.",Snackbar.LENGTH_LONG).show();
        requestPermission();
    }

        bn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                tv.setText(imei);
            }
        });

    }

     private void requestPermission() {
    if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.READ_PHONE_STATE)){

        Toast.makeText(getApplicationContext(),"Give permission to check whether internet is of or on.",Toast.LENGTH_LONG).show();

    } else {

        ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.READ_PHONE_STATE},PERMISSION_REQUEST_CODE);
    }
}
@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
    switch (requestCode) {
        case PERMISSION_REQUEST_CODE:
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                Snackbar.make(view,"Permission Granted, Now you can check network status.",Snackbar.LENGTH_LONG).show();

            } else {

                Snackbar.make(view,"Permission Denied, You cannot check networkstatus.",Snackbar.LENGTH_LONG).show();

            }
            break;

    }
}
}