The idea is simple, use java expressions in layout params like layout_left="view1.right+10dp". It is helpful when LinearLayout and RelativeLayout is not enough for you.

<TextView
	app:layout_left="icon.right+10dp"
	app:layout_right="100%-14dp"
	app:layout_centerY="icon.centerY"
	android:layout_height="wrap_content"
	.../>

Try the sample apk: FlexLayout.apk

Add dependencies in your build.gradle:

	dependencies {
	    compile 'com.github.mmin18:flexlayout:1.1.0'
	}

Or if you are using Eclipse, just copy FlexLayout.java and attrs.xml to your project.

Remember the app:layout_width is different from android:layout_width
xmlns:app="http://schemas.android.com/apk/res-auto"

<Button
	app:layout_left="10%"
	app:layout_right="10%"
	app:centerY="50%"
	android:layout_height="wrap_content"
	../>

or

<Button
	app:layout_width="80%"
	app:centerX="50%"
	app:centerY="50%"
	android:layout_height="wrap_content"
	../>

Reference previous view using prev, next view using next

<View
	app:layout_left="prev.right"
	app:layout_right="next.left"
	app:layout_top="prev.top"
	app:layout_bottom="next.bottom" />

Reference a specific view using view's id

<View
	app:layout_left="view1.right"
	app:layout_right="android:text1.left"
	app:layout_top="view1.top"
	app:layout_bottom="android:text1.bottom" />

You can also use parent to reference the FlexLayout and this to reference the child view itself. Use screen to reference screen size. (screen, parent, this only support width and height property.)

view.visible: view.getVisibility() == View.VISIBLE

view.gone: view.getVisibility() == View.GONE

view.tag: view.getTag(). Use View.setTag() to set a Number or Boolean and call View.requestLayout() to trigger layout. Types other than Number and Boolean returns 0.

The syntax is the same as Java or C. Numbers can have units like 10dp, 15sp

(parent.height-view1.centerY)/2
100%-80dp
max(view1.right, view2.right)
screen.width<screen.height ? 64dp : 48dp
view1.visible && view2.visible ? max(view1.bottom, view2.bottom) : 0px

Operators (Order in precedence)

Functions