Whats wrong >?i cant do

Question

but something wrong,im new. My code

public class MainActivity extends AppCompatActivity {
    //kluci dla soedenenia
    public static final String APPI_ID = "----------------------";
    public static final String SECRET_KEY = "----------------";
    public static final String VERSION = "---";
    //moy log
    private static final String TAG = "myLogs";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //soedenil backendless
        Backendless.initApp(this, APPI_ID, SECRET_KEY, VERSION);

        Customer melinda = new Customer();
        melinda.setFirstName( "Melinda" );
        melinda.setLastName( "Grey" );
       Backendless.Persistence.of(Customer.class).save(melinda, new AsyncCallback<Customer>() {
           @Override
           public void handleResponse(Customer response) {

           }

           @Override
           public void handleFault(BackendlessFault fault) {

           }
       });
        System.out.println("Melinda's rate is "+melinda.getDiscountRatePercent()+"percent");
                melinda.setDiscountRatePercent( melinda.getDiscountRatePercent() + 2 );
        Backendless.Persistence.of(Customer.class).save(melinda, new AsyncCallback<Customer>() {
            @Override
            public void handleResponse(Customer customer) {

            }

            @Override
            public void handleFault(BackendlessFault fault) {

            }
        });
        Customer updatedMelinda = new Customer();
        updatedMelinda.setFirstName( "Melinda" );
        updatedMelinda.setLastName( "Grey" );

        updatedMelinda = Backendless.Persistence.of( Customer.class ).findById
                ( melinda.getID() );
        System.out.println("Now Melinda's discount rate is "+updatedMelinda.
                getDiscountRatePercent() +" percent.");

    }
        }

Customer class

public class Customer {
    private String lastName;
    private Integer discountRatePercent;
    private String firstName;
    public String getLastName()
    {
        return lastName;
    }
    public void setLastName( String lastName )
    {
        this.lastName = lastName;
    }
    public Integer getDiscountRatePercent()
    {
        return discountRatePercent;
    }
    public void setDiscountRatePercent( Integer discountRatePercent )
    {
        this.discountRatePercent = discountRatePercent;
    }
    public String getFirstName()
    {
        return firstName;
    }
    public void setFirstName( String firstName )
    {
        this.firstName = firstName;
    }
}

My java wrong

10-22 03:14:23.620 2774-2774/? E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.elvir.subdexample, PID: 2774 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.elvir.subdexample/com.example.elvir.subdexample.MainActivity}: java.lang.NullPointerException at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) at android.app.ActivityThread.access$800(ActivityThread.java:135) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5017) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.NullPointerException at com.example.elvir.subdexample.MainActivity.onCreate(MainActivity.java:40) at android.app.Activity.performCreate(Activity.java:5231) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) at android.app.ActivityThread.access$800(ActivityThread.java:135) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5017) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) at dalvik.system.NativeStart.main(Native Method)

melinda.setDiscountRatePercent( melinda.getDiscountRatePercent() + 2 ); — elik, Oct 22 '16 at 08:08
seems like this `melinda.getDiscountRatePercent()` is giving you null value or this line has some null value in it's fields — Pavneet_Singh, Oct 22 '16 at 08:14
at this `com.example.elvir.subdexample.MainActivity.onCreate(MainActivity.java:40)` line you have to look for null values — Pavneet_Singh, Oct 22 '16 at 08:18

score 1 · Answer 1 · answered Oct 22 '16 at 07:49

1

Try replacing

updatedMelinda = Backendless.Persistence.of( Customer.class ).findById
            ( updatedMelinda );

by

updatedMelinda = Backendless.Persistence.of( Customer.class ).findById
            ( melinda.getID() );

answered Oct 22 '16 at 07:49

Juan Felippo

224
2
9

1

full code would be more helpful. – Juan Felippo Oct 22 '16 at 07:50
Java screaming red "getID"i a – elik Oct 22 '16 at 07:54
i add full code – elik Oct 22 '16 at 07:54
1

There is a problem with your model and logic. Follow this example: https://github.com/Backendless/RestaurantToGo/blob/master/location_listing/src/main/java/com/backendless/samples/restaurant/entities/Restaurant.java. – Juan Felippo Oct 22 '16 at 08:55

Whats wrong >?i cant do

1 Answers1