Question

I have 2 edittext fields where it needs the item name (String) and the quantity (Integer). If user enters nothing on both fields or if even just one field is empty, I want to show a toast saying “please enter item” or “please enter quantity”. It creates and error. Here is the snippet below:

 public void onClick(DialogInterface dialog, int id) {

                        String item = itemET.getText().toString();
                        int quantity = Integer.parseInt(quantityET.getText().toString());
                        if(itemET.equals("")){
                            Toast t =Toast.makeText(GroceryList.this, "Please enter item", 5000);
                            t.show();   
                            }
                            if(quantityET.equals("")){
                            Toast t =Toast.makeText(GroceryList.this, "Please enter quantity or enter 0 if none", 5000);
                            t.show();
                            }

And here is the error in logcat:

09-19 10:01:51.766: E/AndroidRuntime(527): FATAL EXCEPTION: main
09-19 10:01:51.766: E/AndroidRuntime(527): java.lang.NumberFormatException: unable to parse '' as integer
09-19 10:01:51.766: E/AndroidRuntime(527):  at java.lang.Integer.parseInt(Integer.java:362)
09-19 10:01:51.766: E/AndroidRuntime(527):  at java.lang.Integer.parseInt(Integer.java:332)
09-19 10:01:51.766: E/AndroidRuntime(527):  at com.mexican.recipes.GroceryList$1$1.onClick(GroceryList.java:60)
09-19 10:01:51.766: E/AndroidRuntime(527):  at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:159)
09-19 10:01:51.766: E/AndroidRuntime(527):  at android.os.Handler.dispatchMessage(Handler.java:99)
 09-19 10:01:51.766: E/AndroidRuntime(527):     at android.os.Looper.loop(Looper.java:123)
 09-19 10:01:51.766: E/AndroidRuntime(527):     at android.app.ActivityThread.main(ActivityThread.java:3683)
 09-19 10:01:51.766: E/AndroidRuntime(527):     at java.lang.reflect.Method.invokeNative(Native Method)
 09-19 10:01:51.766: E/AndroidRuntime(527):     at java.lang.reflect.Method.invoke(Method.java:507)
 09-19 10:01:51.766: E/AndroidRuntime(527):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
 09-19 10:01:51.766: E/AndroidRuntime(527):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
 09-19 10:01:51.766: E/AndroidRuntime(527):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

There’s two seperate problems in this code: calling parseInt on an empty string is going to raise an exception (the error you’re seeing), and you’re doing a .equals comparison on the EditText object itself, not on the string contained inside. Do the following:

public void onClick(DialogInterface dialog, int id) {

   String itemString = itemET.getText().toString();
   String quantityString = quantityET.getText().toString();
   int quantity;

   if(itemString.equals(""))
   {
      Toast t =Toast.makeText(GroceryList.this, "Please enter item", 5000);
      t.show();   
   }

   if(quantityString.equals("")){
      Toast t =Toast.makeText(GroceryList.this, "Please enter quantity or enter 0 if none", 5000);
      t.show();
   }
   else {
      quantity = Integer.parseInt(quantityString);
   }
}

This will still crash if you supply something which isn’t a number (for example, if you typed ‘a’ into the box), but it should be able to handle nothing being entered.