title: reduce left margin of navigation icon of toolbar in android
body: <p>as i'm new to android i set back button in my toolbar, i want to reduce its padding/margin from left how can i do that??
  thanks in adwance.</p>
  
  <p>this is my design code</p>
  
  <pre><code>&lt;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"&gt;
  &lt;TextView
  android:id="@+id/tripidtoolbar"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_gravity="left"
  android:text="name"
  android:textColor="#ffffff"
  android:textSize="18sp"
  android:textStyle="bold"
  /&gt;
  &lt;TextView
  android:id="@+id/dayNotoolbar"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_gravity="right"
  android:textColor="#ffffff"
  android:layout_marginRight="10dp"
  android:text="day"
  android:textAllCaps="true"
  android:textSize="18sp"
  android:textStyle="bold"
  /&gt;
  &lt;/android.support.v7.widget.Toolbar&gt;
  </code></pre>
  
  <p>this is how i manually set back button</p>
  
  <pre><code>protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_vouchers_details);
  Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
  toolbar.setNavigationIcon(R.drawable.arrowbackwhite);
  toolbar.setNavigationOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
  onBackPressed();
  }
  });
  setSupportActionBar(toolbar);
  </code></pre>
  
  <p>this is my <strong>screen</strong>(back button havin left margin)<br>
  <img src="https://i.stack.imgur.com/uzUzo.png"/></p>