ActionBar标签 - 固定和可滚动？

<!-- XML Layout -->
<android.support.v7.widget.Toolbar
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/colorPrimary"
    android:minHeight="?attr/actionBarSize"
    app:layout_scrollFlags="scroll|enterAlways"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
    app:title="Toolbar">

    <TextView
        android:id="@+id/toolbar_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Toolbar Title"
        android:textSize="16sp"
        android:textColor="@android:color/white"
        android:layout_gravity="center" />

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

<!-- XML Layout -->
<android.support.v7.widget.Toolbar
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/colorPrimary"
    android:minHeight="?attr/actionBarSize"
    app:layout_scrollFlags="scroll|enterAlways"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
    app:title="Toolbar">

    <TextView
        android:id="@+id/toolbar_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Toolbar Title"
        android:textSize="16sp"
        android:textColor="@android:color/white"
        android:layout_gravity="center" />

    <android.support.v4.view.ViewPager
        android:id="@+id/pager"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="56dp"
        android:background="@android:color/white" />

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

// Activity
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        // Set the toolbar title
        toolbar.setTitle("Fixed or Scrollable ActionBar");
    }
}

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.v7