java.lang.NumberFormatException: Invalid int: "" : Error

Question

I am doing some calculation but unable to parse a string into int or even in float.I searched for solution and i read it somewhere there must be a empty string but i checked my editText using

log.v("Valuee",e1.getText().toString());

and its print the values prove that string is not empty.. What i am missing ?

Here is logcat

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.farrukh.bmi/com.example.farrukh.bmi.Main2Activity}: java.lang.NumberFormatException: Invalid int: "" 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.NumberFormatException: Invalid int: "" at java.lang.Integer.invalidInt(Integer.java:137) at java.lang.Integer.parseInt(Integer.java:358) at java.lang.Integer.parseInt(Integer.java:331) at com.example.farrukh.bmi.Main2Activity.onCreate(Main2Activity.java:31) 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) 

Here is MainActivity.java

 public class Main2Activity extends AppCompatActivity {

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main2);

          final   Button b = (Button) findViewById(R.id.button);
          final   EditText e1 = (EditText) findViewById(R.id.editText2);
          final   TextView text = (TextView) findViewById(R.id.textView4);
          final  String height = e1.getText().toString();


          final int a = Integer.parseInt(height); //got error while parsing

     b.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {


                 //   Log.v("EditText",e1.getText().toString());

                }
            });


        }


    }

Here is activity.xml

<Button
        android:layout_width="132dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="50dp"
         android:layout_gravity="center_horizontal"
        android:text="CLICK"
        android:clickable="true"
        android:id="@+id/button"/>

<EditText
        android:layout_width="120dp"
        android:layout_height="wrap_content"
        android:inputType="number"
        android:ems="10"
        android:id="@+id/editText2"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="20dp"
        android:gravity="center" />


    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:id="@+id/textView4"
        android:layout_gravity="center_horizontal"
        android:gravity="center"
        android:layout_marginTop="20dp"
        android:textColor="#3b9ff0" />

Answer 1

put these lines inside onClick()

final  String height = e1.getText().toString();
final int a = Integer.parseInt(height);

You are fetching value of e1 in onCreate(), while you want it when user click on button

Also need to check whether height is having any value or not, check Stuluske's answer for this