My App keeps stopping

Here is my app register.class:

Login.class

public class login extends AppCompatActivity {  
  
    private EditText inputPhone;  
    private EditText inputPassword;  
  
    SQLiteOpenHelper dbhelper;  
    SQLiteDatabase db;  
    Cursor cursor;  
    private ProgressDialog progressDialog;  
  
    @Override  
 protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_login);  
        ActionBar ab = getSupportActionBar();  
        assert ab != null;  
        ab.hide();  
        inputPhone = (EditText)findViewById(R.id.phone);  
        inputPassword = (EditText)findViewById(R.id.password);  
        Button buttonSign = (Button) findViewById(R.id.buttonSignIn);  
        Button btnLinkToRegister = (Button) findViewById(R.id.btnLinkToRegisterScreen);
        dbhelper = new SQLiteDBHelper(this);  
        db = dbhelper.getReadableDatabase();  
  
        buttonSign.setOnClickListener(new View.OnClickListener() {  
            @Override  
 public void onClick(View v) {  
                String phone = inputPhone.getText().toString();  
                String pass = inputPassword.getText().toString();  
  
                cursor = db.rawQuery(String.format("SELECT *FROM  %s  WHERE %s =?  AND %s =? ", TABLE_NAME, COLUMN_MOBILE, COLUMN_PASSWORD),new String[] {phone,pass});  
                if (cursor != null && cursor.moveToFirst()) {  
                    if(cursor.getCount() > 0) {  
  
  
                        //Retrieving User FullName and Email after successfull login and passing to LoginSucessActivity  
 String _fphone = cursor.getString(cursor.getColumnIndex(COLUMN_MOBILE));  
                        String _pass= cursor.getString(cursor.getColumnIndex(COLUMN_PASSWORD));  
                        Toast.makeText(login.this, "Login Success", Toast.LENGTH_SHORT).show();  
                        Intent intent = new Intent(login.this,Bienvenue.class);  
                        intent.putExtra("mobile",_fphone);  
                        intent.putExtra("password",_pass);  
                        startActivity(intent);  
  
                        //Removing MainActivity[Login Screen] from the stack for preventing back button press.  
 finish();  
  
            }  
                }  
                else {  
  
                    //I am showing Alert Dialog Box here for alerting user about wrong credentials  
 final AlertDialog.Builder builder = new AlertDialog.Builder(login.this);  
                    builder.setTitle("Alert");  
                    builder.setMessage("Mobile  ou Password is wrong.");  
                    builder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {  
                        @Override  
 public void onClick(DialogInterface dialogInterface, int i) {  
  
                            dialogInterface.dismiss();  
  
                        }  
                    });  
  
                    AlertDialog dialog = builder.create();  
                    dialog.show();  
                    //-------Alert Dialog Code Snippet End Here  
 }  
            }
    });  
        btnLinkToRegister.setOnClickListener(new View.OnClickListener() {  
            @Override  
 public void onClick(View v) {  
                Intent intent = new Intent(login.this,register.class);  
                startActivity(intent);  
            }  
        });  
    }  

 

sir 

prhaps the error is comming from a google api 

here pl described details for a short area of coding .so one can understand well.