在CollapsingToolbarLayout中折叠状态下未显示后退按钮

Question

我有一个CollapsingToolbarLayout它在展开状态下显示后退按钮,但没有显示在折叠状态.

我试过setNavigationIcon()了,Toolbar但它设置了扩展状态.

这是布局

<android.support.design.widget.CoordinatorLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="250dp"
    android:fitsSystemWindows="true">

    <android.support.design.widget.CollapsingToolbarLayout
        android:id="@+id/user_collapsing_toolbar"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        app:contentScrim="@color/colorAccent"
        app:layout_scrollFlags="scroll|exitUntilCollapsed">

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            android:scaleType="centerCrop"
            android:src="@drawable/tbt_logo"
            app:layout_collapseMode="parallax" />

        <android.support.v7.widget.Toolbar
            android:id="@+id/user_toolbar"
            android:layout_width="match_parent"
            android:layout_height="?android:attr/actionBarSize"
            app:titleTextColor="@android:color/white"/>
    </android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>

<android.support.v4.widget.NestedScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <include layout="@layout/pen_point_item_layout" />
        <include layout="@layout/pen_point_item_layout" />
    </LinearLayout>
</android.support.v4.widget.NestedScrollView>

Java的:

toolbar = (Toolbar) findViewById(R.id.user_toolbar);
    toolbar.setNavigationIcon(R.drawable.ic_back);
    setSupportActionBar(toolbar);

    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setDisplayShowTitleEnabled(true);
    collapsingToolbar = (CollapsingToolbarLayout) findViewById(R.id.user_collapsing_toolbar);
    collapsingToolbar.setTitle("Profile");
    collapsingToolbar.setCollapsedTitleTextColor(Color.WHITE);
    collapsingToolbar.setExpandedTitleColor(Color.WHITE);

我该怎么办？

Answer 1

将layout_collapseMode添加到工具栏.

app:layout_collapseMode="pin"