Question

I have the following layout in main.xml:

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

    <FrameLayout
        android:layout_width="125dp"
        android:layout_height="300dp"
        android:layout_gravity="center"
        android:padding="5dp"
        android:background="#FFFF00">

        <View
            android:id="@+id/placeholder"
            android:layout_width="fill_parent"
            android:layout_height="290dp"
            android:background="#FF0000" />

    </FrameLayout>

</FrameLayout>

And the following code in MainActivity.java:

public class MainActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        View view = findViewById(R.id.placeholder);

        MarginLayoutParams mlParams = (ViewGroup.MarginLayoutParams)view.getLayoutParams();
        mlParams.topMargin = 50;
        view.setLayoutParams(mlParams);
    }

}

The margin will be applied to the child’s view but it won’t affect the parent’s view size at all. I could “fix” this issue with the following line:

((View)view.getParent()).getLayoutParams().height += 50;

But how can I do that without explicitly changing the parent’s `height? Is this possible or it doesn’t make much sense?

Answer 1

If you want the inner FrameLayout to grow with the child size, you have to set it’s height to wrap_content.

If you give it a fixed height, as you did here, nothing will change that. It will keep the fixed size, no matter to what size/margins you adjust the children. Which means you have to adjust the parent size manually as well if you want to avoid wrap_content (as you already said).

And just by the way: The root viewgroup, where your content gets placed is always a FrameLayout. Which means that you create a FrameLayout in a FrameLayout in a FrameLayout. 🙂 That might deepen the view hierachy unneccessary, depending on if you got other views in here. A deep hierachy is bad for performance, keep it flat if you can. Maybe have a look at the <merge /> tag.