java.lang.NumberFormatException：无效的int：“”（正在解析）

Question

The listed error occurs to this: (just a basic calorie calculator- enter #s in it updates the TextView of calorieTotal)((It might be better served with a button?))

public class MainActivity extends ActionBarActivity {
EditText breakfastCals;
EditText lunchCals;
EditText dinnerCals;
EditText otherCals;
EditText burnedCals;
TextView calorieTotal;

int n1=0;
int n2=0;
int n3=0;
int n4=0;
int n5=0;
int total=0;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    breakfastCals = (EditText) findViewById(R.id.breakfastCals);
    n1= Integer.parseInt(breakfastCals.getText().toString());

    lunchCals = (EditText) findViewById(R.id.lunchCals);
    n2= Integer.parseInt(lunchCals.getText().toString());

    dinnerCals = (EditText) findViewById(R.id.dinnerCals);
    n3= Integer.parseInt(dinnerCals.getText().toString());

    otherCals = (EditText) findViewById(R.id.otherCals);
    n4= Integer.parseInt(otherCals.getText().toString());

    burnedCals = (EditText) findViewById(R.id.burnedCals);
    n5= Integer.parseInt(burnedCals.getText().toString());

    total=((1500-n1-n2-n3-n4)+n5);
    calorieTotal= (TextView) findViewById(R.id.calorieTotal);
    calorieTotal.setText(Integer.toString(total));

}

Answer 1

make your editText as a numberic, to avoid invalid input and accept only numbers

add android:inputType="number" at the xml attributes.

<EditText
android:id="@+id/myNumber"
android:digits="0123456789."
android:inputType="numberDecimal"
/>

Answer 2

in your layout xml, add given code to all edittext, in which you want only number

android:digits="0123456789"

it will allows your edittext for only number, so NumberFormatException will not occur.

Answer 3

Before parsing into integer add a condition whether value is empty or not

if(TextUtils.isEmpty(breakfastCals.getText().toString()) {
n1=0;
}else{

n1= Integer.parseInt(breakfastCals.getText().toString()); 
}

Do this for all edittext