title: Android Relative layout button crashes app
body: <p>I'm making an app, now i want to make a button with an image and some text on it. 
  But every time I click the button my app crashes, android studio does compile however. </p>
  
  <p>This is how i my xml code to make the layout of the screen. </p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;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"&gt;
  
      &lt;RelativeLayout
          android:id="@+id/buttonStartTest"
          style="@android:style/Widget.Button"
          app:layout_constraintEnd_toEndOf="parent"
          app:layout_constraintHorizontal_bias="0.0"
          app:layout_constraintStart_toStartOf="parent"
          app:layout_constraintTop_toTopOf="parent"
          tools:ignore="MissingConstraints"&gt;
  
          &lt;ImageView... /&gt;
  
          &lt;TextView.../&gt;
      &lt;/RelativeLayout&gt;
  
  &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>
  
  <p>java code: </p>
  
  <pre><code>package com.example.user.ballbounceapp;
  
  import android.annotation.SuppressLint;
  import android.app.Activity;
  import android.support.v7.app.AppCompatActivity;
  import android.content.Intent;
  import android.os.Bundle;
  import android.view.View;
  import android.widget.Button;
  import android.widget.RelativeLayout;
  
  public class MainActivity extends AppCompatActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
  
      RelativeLayout StartTest = findViewById(R.id.buttonStartTest);
      StartTest.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
              TestActivity();
          }
      });
  }
  
  public void TestActivity(){
      Intent intent = new Intent(MainActivity.this,TestActivity.class);
      startActivity(intent);
  }
  
  };
  </code></pre>