Null pointer exception when calling measure on inflated layout

Question

So I have a layout that is a separate file, so I inflate it. Then I change my text views and image in my layout, and call measure, but I get a null pointer when I try to measure the layout. I cannot for the life of me figure out why this is. I'm trying to convert the layout to a bitmap eventually.

View inflatedView  = ((Activity)getContext()).getLayoutInflater().inflate(R.layout.my_layout, null);

inflatedView.measure(getWidth(), getHeight());
inflatedView.layout(0, 0, inflatedView.getMeasuredWidth(),inflatedView.getMeasuredHeight());
Bitmap viewAsImage = Bitmap.createBitmap(inflatedView.getWidth(), inflatedView.getHeight(), Bitmap.Config.ARGB_8888);
Canvas viewCanvas = new Canvas(viewAsImage);

Here is the XML

<RelativeLayout  xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" android:layout_gravity="bottom"
    android:id="@+id/my_layout"
    android:background="@color/transparent_black">
    <ImageView android:id="@+id/image_left"
        android:layout_width="48dip" android:layout_height="48dip"
        android:layout_centerVertical="true" android:layout_alignParentLeft="true"
        android:scaleType="fitXY" android:maxWidth="48dip" android:maxHeight="48dip"
        android:padding="5dip" />
    <ImageView android:id="@+id/image_right"
        android:layout_width="wrap_content" android:layout_height="wrap_content"
        android:layout_marginRight="20dip" android:src="@drawable/arrow"
        android:layout_centerVertical="true" android:scaleType="fitXY"
        android:maxWidth="48dip" android:maxHeight="48dip"
        android:layout_alignParentRight="true" />
    <TextView android:paddingLeft="4dip" android:paddingRight="1dip"
        android:layout_width="wrap_content"         android:layout_height="wrap_content"
        android:layout_toRightOf="@id/image_left"
        android:layout_toLeftOf="@id/image_right"       android:id="@+id/some_name"
        android:maxLines="1" android:ellipsize="end" android:textSize="20sp"
        android:textColor="@color/white"
                    android:layout_centerVertical="true"
        android:textStyle="normal" />
</RelativeLayout>

At the measure() line, it throws a null pointer, and I have verified that getWidth and getHeight are giving legitimate values.

Any ideas?

Thanks!

Answer 1

measure() throws Null Pointer Exception because when you inflate you layout it won't read layout height width properties.

Just add this line before calling view.measure() depending upon type of layout you are using

v.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));

public Bitmap getBitmapFromView(RelativeLayout v) {         v.setLayoutParams(new LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT));         v.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));         v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());         Bitmap b = Bitmap.createBitmap(v.getMeasuredWidth(), v.getMeasuredHeight(), Bitmap.Config.ARGB_8888);          Canvas c = new Canvas(b);         v.draw(c);         return b;     } 

Answer 2

The top level RelativeLayout seems to freak out on measure without boundaries. Set explicit boundaries on the inflated view before calling measure:

v.setLayoutParams(new ViewGroup.LayoutParams(0,0));

Answer 3

Inflater does not extract layout_width and layout_height attributes when you don't assign its parent as an argument in inflate method, so try to set LayoutParams with specified width and height and then call measure.