How to insert button to navigation toolbar

Question

I added ImageButton to ToolBar. It appears in Android Studio but when application launchs on device it doesn't appear. Please, help if you can! Thank you before help!

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 
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">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay">

        <ImageButton
            android:id="@+id/home_button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/ic_home"
            android:layout_marginLeft="330dp"
            android:visibility="visible"/>

    </android.support.v7.widget.Toolbar>

</android.support.design.widget.AppBarLayout>

<include layout="@layout/content_main" />

</android.support.design.widget.CoordinatorLayout>

Answer 1

Use like this, If ImageButton is the single widget on the toolbar, you don't need to set margin, it will automatically be placed at left

 <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?actionBarSize"
        android:layout_alignParentTop="true"
        android:background="@color/colorPrimary"
        android:gravity="top"
        app:titleTextColor="@color/white">




        <ImageView
            android:id="@+id/iv_add"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="right"
            android:background="?attr/selectableItemBackgroundBorderless"
            android:clickable="true"
            android:contentDescription="TODO"
            android:focusable="true"
            android:padding="20dp"
            android:src="@mipmap/add"
            android:visibility="visible" />

    </android.support.v7.widget.Toolbar>