how to create triangle gap on cardview?

how can I create a triangle gap on the bottom of a cardview like this in android studio?

You can use the TriangleEdgeTreatment included in the Material Components Library.

Just use a simple layout like:

    <com.google.android.material.card.MaterialCardView
        android:id="@+id/card"
        .../>

then apply the TriangleEdgeTreatment on the bottom edge:

    MaterialCardView cardView = findViewById(R.id.card);
    cardView.setShapeAppearanceModel(cardView.getShapeAppearanceModel().toBuilder()
            .setBottomEdge(new TriangleEdgeTreatment(40.f, true))
            .build());