<?xml version="1.0" encoding="utf-8"?> <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <TextView android:id="@+id/status" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="http://www.netkiller.cn" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintTop_toTopOf="parent" /> <Button android:id="@+id/record" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginStart="8dp" android:layout_marginBottom="1dp" android:onClick="onClick" android:text="Record" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintStart_toStartOf="parent" /> <Button android:id="@+id/play" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginEnd="8dp" android:layout_marginBottom="7dp" android:text="Play" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" /> </android.support.constraint.ConstraintLayout>