onMeasure() called with 0x7fffffff for heightMeasureSpec

Question

I have a custom view that overrides onMeasure.

I see onMeasure() getting called twice, the first time with the heightMeasureSpec at 0x7fffffff - that doesn't seem to be a valid MeasureSpec value.

Then, it gets called again, that time with the proper value.

Here are the basic components, stripped down to the relevant parts:

The custom view:

public class CustomView extends ViewGroup implements SurfaceHolder.Callback {
    public CustomView(Context context, AttributeSet as) {
        super(context, as);

        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        inflater.inflate(R.layout.custom_view, this, true);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
        int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);

        setMeasuredDimension(width, height);
    }
}

The layout (again, stripped down to keep this as brief as possible):

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

And here is the layout that contains it:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

        <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        >        
            <CustomView
            android:id="@+id/custom_view"
            android:layout_width="@dimen/custom_size"
            android:layout_height="@dimen/custom_size"
            />
        </RelativeLayout>
    </ScrollView>
</LinearLayout>

Key observations here:

• The custom view has a fixed width and height (the custom size is 128dp).
• The view itself is inside a RelativeLayout.
• All of this is inside a ScrollView.

In this scenario, I get onMeasure called first with 0x40000100, 0x7fffffff, and then again with 0x40000100, 0x40000100, which is what I would have expected in the first place.

Maybe it's perfectly normal for onMeasure to be called with an invalid height first? I could ignore it, but I don't want to add any hacks here.

---

ANSWER: It's a bug in the operating system that has been fixed, documented here:

In platform version 17 and lower, RelativeLayout was affected by a measurement bug that could cause child views to be measured with incorrect MeasureSpec values. (See MeasureSpec.makeMeasureSpec for more details.) This was triggered when a RelativeLayout container was placed in a scrolling container, such as a ScrollView or HorizontalScrollView. If a custom view not equipped to properly measure with the MeasureSpec mode UNSPECIFIED was placed in a RelativeLayout, this would silently work anyway as RelativeLayout would pass a very large AT_MOST MeasureSpec instead.

I'm not going to post this as an answer, Snicolas has been nice enough to look at this so he deserves his accepted answer.

Answer 1

I used this small IDE one gist. And, as you can see, both values you received are in the mode EXACTLY. If we follow references implemenations of onMeasure most favored on StackOverFlow, and they both go in the same direction :

• https://stackoverflow.com/a/12267248/693752;
• https://stackoverflow.com/a/10339611/693752.

there is nothing else you have to do except passing them to setMeasureDimensions. You can only modify the measures received in the case they are not in the mode EXACTLY.

Am I missing something ?