Question

I want to add an Image in an existing Layout. I create the Image with this code snippet:
http://www.inter-fuser.com/2009/12/android-reflections-with-bitmaps.html

This class creates a ImageView with the right image. I want to add the Image in this layout:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

    <include
        android:id="@+id/actionbar_back"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        layout="@layout/actionbar_back" />

    <LinearLayout
        android:id="@+id/ll_ueberschrift"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@color/gray" 
        android:gravity="center"
        android:layout_below="@id/actionbar_back" >

        <TextView
            android:id="@+id/tv_ueberschrift"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Java" 
            android:layout_gravity="right" 
            android:textSize="30sp" />       
    </LinearLayout>


        <!--  ListRow Left sied Thumbnail image -->

    <LinearLayout
        android:id="@+id/ll_thumbnail" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="3dip"      
        android:layout_alignParentLeft="true"
        android:layout_marginRight="5dip"
        android:layout_marginTop="20dp"
        android:layout_below="@id/ll_ueberschrift" >

        <ImageView
            android:id="@+id/iv_objekt"
            android:contentDescription="@string/description"
            android:layout_width="120sp"
            android:layout_height="120sp"
            android:paddingLeft="5dp" />
    </LinearLayout>
<RelativeLayout>

Now I try to add the Image to the existing ImageView:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

   ...

   //Create an Image view and add our bitmap with reflection to it
   ImageView imageView = new ImageView(this);
   imageView.setImageBitmap(bitmapWithReflection);
   imageView.setPadding(5, 5, 5, 5);

    View linearLayout =  findViewById(R.id.ll_picture_and_reflection);
    ((LinearLayout) linearLayout).addView(imageView);
    setContentView(R.layout.objekt_einzeln); 
}

But I just a get “NullPointerException”.

Any suggestion what to do or what is incorrect?
Thank a lot

EDIT: I meant “View linearLayout = findViewById(R.id.iv_objekt);”

Answer 1

You are doing setContentView after you are trying to reference the LinearLayout. Do this:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.objekt_einzeln); 

   //Create an Image view and add our bitmap with reflection to it
   ImageView imageView = new ImageView(this);
   imageView.setImageBitmap(bitmapWithReflection);
   imageView.setPadding(5, 5, 5, 5);

    View linearLayout =  findViewById(R.id.ll_picture_and_reflection);
    ((LinearLayout) linearLayout).addView(imageView);

}

But even then you are referencing a LinearLayout which is not in that XML you provided.

Make sure you do setContentView first, then make sure the LinearLayout is actually in the layout you provide in setContentView