Android Toolbar - Change height and width of Navigation Icon Programmatically

try this in AppCompatActivity

if(getSupportActionBar()!=null){
  getSupportActionBar().setDisplayHomeAsUpEnabled(true);
  getSupportActionBar().setHomeButtonEnabled(true);
}
toolbar.setNavigationOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) {
    getSupportFragmentManager().popBackStack();
  }});

in xml

<android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="90dp"
        android:background="#434343"
        android:elevation="4dp"
        android:minHeight="90dp"
        app:theme="@style/tool_bar_style" />

in styles.xml

    <style name="tool_bar_style">
    <item name="colorControlNormal">@color/white</item>
    <item name="android:textColor">@color/text_color_main</item>
    <item name="android:textColorPrimary">@color/text_color_main</item>
    <item name="android:textColorSecondary">@color/text_color_main</item>
    <item name="actionMenuTextColor">@color/text_color_main</item>
    <item name="android:textSize">@dimen/text_size_default</item>
    <item name="android:colorBackground">@color/toolbar_bg_color</item>
    <item name="android:listPreferredItemHeightSmall">@dimen/button_default_height</item>

</style>
<style name="Toolbar.TitleText" parent="TextAppearance.AppCompat.Widget.ActionBar.Title">">
    <item name="android:textSize">@dimen/text_size_big</item>
</style>

in dimens.xml

    <dimen name="text_size_big">14sp</dimen>
    <dimen name="text_size_default">22sp</dimen>
    <dimen name="button_default_height">90dp</dimen>

in colors

    <color name="text_color_main">@color/clean_white</color>
    <color name="toolbar_bg_color">#434343</color>

I did this way :

toolbar= (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
if(getSupportActionBar()!=null){
    Drawable drawable= getResources().getDrawable(R.drawable.ic_sync_white_36dp);
    Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
    Drawable newdrawable = new BitmapDrawable(getResources(), Bitmap.createScaledBitmap(bitmap, 250, 250, true));
    newdrawable.setColorFilter(Color.BLUE, PorterDuff.Mode.SRC_ATOP);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setHomeAsUpIndicator(newdrawable);

}

You can use calculate-dp-from-pixels-in-android-programmatically and converting-pixels-to-dp when creating scaled bitmap .

My Toolbar:

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

And screenshot :

Also another way is using custom layout in Toolbar like that:

<android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:minHeight="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" >
    <LinearLayout 
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="horizontal" android:layout_width="match_parent"
        android:background="@color/colorPrimary"
        android:id="@+id/custom_toolbar_layout"
        android:layout_height="wrap_content">

    <ImageView
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:tint="@android:color/holo_purple"
        android:id="@+id/imageView"
        android:gravity="center_vertical"
        android:src="@drawable/ic_clear_black_36dp" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:text="My Custom Toolbar"
        android:gravity="center_vertical"
        android:textSize="20sp"
        android:textColor="@android:color/white"
        android:layout_gravity="center_horizontal" />
    </LinearLayout>
</android.support.v7.widget.Toolbar>

If you want to access any View in Toolbar see @Aleksandar Stefanović's answer. And you can take a look at Material design guidelines for creating custom Toolbar

Then screenshot :

Icons from : Material Icons

If you're using an appcompat Toolbar, it actually behaves like a regular ViewGroup. So, you can access the Views inside of it, easily, like with any other ViewGroup.

For example, if you have an ImageView inside you toolbar, you can simply access it by:

        getSupportActionBar().getCustomView().findViewById(R.id.imageView)

From there, you just resize it as a regular ImageView.