Android null object reference on ProgressBar in dialog

I have the following code where I create a ProgressBar in a dialog:

final Dialog dialog = new Dialog(context);
dialog.setContentView(R.layout.wait_for_response_dialog);

final ProgressBar bar = (ProgressBar) findViewById(R.id.responseWaitBar);
final int[] i = {0};

bar.setProgress(i[0]);

And my layout of the ProressBar is the following in wait_for_response_dialog.xml:

<ProgressBar
        android:id="@+id/responseWaitBar"
        style="@android:style/Widget.ProgressBar.Horizontal"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true" />

But I get the following error for line bar.setProgress(i[0]);:

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ProgressBar.setProgress(int)' on a null object reference

Use dialog to init. the ProgressBar.

final Dialog dialog = new Dialog(context);
dialog.setContentView(R.layout.wait_for_response_dialog);

final ProgressBar bar = (ProgressBar)dialog.findViewById(R.id.responseWaitBar);
final int[] i = {0};

bar.setProgress(i[0]);

If your ProgressBar is inside your dialog you need to change the line

final ProgressBar bar = (ProgressBar) findViewById(R.id.responseWaitBar);

for this

final ProgressBar bar = (ProgressBar) dialog.findViewById(R.id.responseWaitBar);

Good luck!