Findviewbyid(r.id.badd) Error

I am trying to learn android app development and I am very much at the beginning. Can some one please tell me what am I doing wrong here? In my MainActivity.java I get errors on ad

Solution 1:

Change this

 <Button
android:layout-width="250dp"

to

<Button
android:layout_width="250dp"// _

Same for the textview and buttons.

If you have errors in your resource files R. java will not be generated leading to errors

Solution 2:

save you xml and recheck :) it will be solved for sure if u have given the same id names.

Solution 3:

  <Button
    android:layout-width="250dp"
    android:layout_height="wrap_content"
    android:onClick="Add one"
    android:text="Add one"
    android:layout_gravity="center"
    android:textSize="20dp"
    android:id="@+id/bAdd" />

<Button
    android:layout-width="250dp"
    android:layout_height="wrap_content"
    android:onClick="Add one"
    android:text="Subtract one"
    android:layout_gravity="center"
    android:textSize="20dp"
    android:id="@+id/bSub" />

There is a - in the layout_width attribute.

Secondly, i would like to bring your attention to the onClick attribute.You have defined onClick function by the name : - Add one.

You cannot have a space in a function name.

Solution 4:

I faced the same problem, to resolve this please do below :

a) Save the activity_main.xml file. b) If you are still facing the issue, just delete R.java file in "gen" directory.

Solution 5:

I had the same issue and figured it out. Change tvDisplay to whatever you named it on the xml file.

Mine worked when I did this: display = (TextView)findViewById(R.id.textView1);