How to create EditText with rounded corners?

Just to add to the other answers, I found that the simplest solution to achieve the rounded corners was to set the following as a background to your Edittext.

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

    <solid android:color="@android:color/white"/>
    <corners android:radius="8dp"/>

</shape>

With the Material Components Library you can use the MaterialShapeDrawable to draw custom shapes.

With a EditText you can do:

    <EditText
        android:id="@+id/edittext"
        ../>

Then create a MaterialShapeDrawable:

float radius = getResources().getDimension(R.dimen.default_corner_radius);

EditText editText = findViewById(R.id.edittext);
//Apply the rounded corners 
ShapeAppearanceModel shapeAppearanceModel = new ShapeAppearanceModel()
                .toBuilder()
                .setAllCorners(CornerFamily.ROUNDED,radius)
                .build();

MaterialShapeDrawable shapeDrawable = 
            new MaterialShapeDrawable(shapeAppearanceModel);
//Apply a background color
shapeDrawable.setFillColor(ContextCompat.getColorStateList(this,R.color.white));
//Apply a stroke
shapeDrawable.setStroke(2.0f, ContextCompat.getColor(this,R.color.colorAccent));

ViewCompat.setBackground(editText,shapeDrawable);

It requires the version 1.1.0 of the library.