Custom Square LinearLayout. How?

Question

I create my own class for the square layout:

public class SquareLayout extends LinearLayout{

    public SquareLayout(Context context) {
        super(contex         


        

Answer 1

// you forget to call super.onMeasure(widthMeasureSpec, widthMeasureSpec);

@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

    super.onMeasure(widthMeasureSpec, widthMeasureSpec);
    int width = MeasureSpec.getSize(widthMeasureSpec);
    int height = MeasureSpec.getSize(heightMeasureSpec);
    int size = width > height ? height : width;
    setMeasuredDimension(size, size);

}

// xml file

<com.example.testapplication.SquareLayout
    android:id="@+id/layout"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_gravity="center_horizontal"
    android:orientation="horizontal" >

    <ImageView
        android:id="@+id/cellImageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="2dp"
        android:adjustViewBounds="true"
        android:padding="2dp"
        android:scaleType="centerCrop"
        android:src="@drawable/ic_launcher" />

  </com.example.testapplication.SquareLayout> 

Answer 2

Edit:

The solution below has now been deprecated, as ConstraintLayout has become the new standard and provides this functionality.

Original Answer:

Turns out the Android team gave us the solution, but nobody knows about it! Check out these two classes from the Percent Support Library:

• PercentFrameLayout
• PercentRelativeLayout

If you want to impose the ratio of a view, you have to place it within one of these layouts. So in this case, you have to place a standard LinearLayout, not your subclass, within one of these layouts with the right aspect ratio. Example if you want to use a PercentFrameLayout:

<android.support.percent.PercentFrameLayout
         xmlns:android="http://schemas.android.com/apk/res/android"
         xmlns:app="http://schemas.android.com/apk/res-auto"
         android:layout_width="match_parent"
         android:layout_height="match_parent">
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         app:layout_aspectRatio="100%">
         <!-- Whatever subviews you want here -->
     </LinearLayout>
 </android.support.percent.PercentFrameLayout>

And there you go, all your views will be contained within a square linear layout!

don't forget to add the gradle dependency compile 'com.android.support:percent:23.3.0' Adjust the version number as required

Answer 3

I had problems calling setMeasuredDimension directly when applying the same technique to a RelativeLayout. I was unable to correctly align against the bottom edge. Changing to instead call up to super.onMeasure() with a new measure spec worked better.

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int width = MeasureSpec.getSize(widthMeasureSpec);
    int height = MeasureSpec.getSize(heightMeasureSpec);
    int size = Math.min(width, height);
    super.onMeasure(MeasureSpec.makeMeasureSpec(size, MeasureSpec.EXACTLY),
        MeasureSpec.makeMeasureSpec(size, MeasureSpec.EXACTLY));
  }