Question

I’m doing the following within a Java class, NOT from within an Activity.

LinearLayout buttonLayout = (LinearLayout) parentContext.getLayoutInflater().inflate(R.layout.app_dialog, null);
Button btnSignIn = (Button) parentContext.findViewById(R.id.BTN_ID_SIGN_IN);
Button btnCancel = (Button) parentContext.findViewById(R.id.BTN_ID_CANCEL);
btnSignIn.setOnClickListener(new OnClickListener(){
    public void onClick(View v) { ... }});

Layout xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/footer" android:layout_width="fill_parent"
    android:layout_height="wrap_content" android:orientation="horizontal"
    android:layout_alignParentBottom="true" style="@android:style/ButtonBar" >

    <Button android:id="@+id/BTN_ID_SIGN_IN" android:layout_width="wrap_content"
        android:layout_height="wrap_content" android:layout_weight="1"
        android:text="@string/em_btn_signin" />

    <Button android:id="@+id/BTN_ID_CANCEL" android:layout_width="wrap_content"
        android:layout_height="wrap_content" android:layout_weight="1"
        android:text="@string/em_btn_cancel" />
</LinearLayout>

The last line is throwing an NPE. When I try my code without an onClickListener, the buttons show up perfectly (though obv nothing happens when I tap them). Why won’t it let me set anything to the button?

Answer 1

Try this:

Button btnSignIn = (Button) buttonLayout.findViewById(R.id.BTN_ID_SIGN_IN);
Button btnCancel = (Button) buttonLayout.findViewById(R.id.BTN_ID_CANCEL);
btnSignIn.setOnClickListener(new OnClickListener(){
    public void onClick(View v) { ... }});