[英]Collapsing Toolbar and Fragment
I have an app that is laid out like this, the mainactivity hosts 2 tabs with accompanied fragments, the first fragment has a recycler view that works, I'm trying to add the parallax effect as the person scrolls up or down, wasn't sure if I should add it to the fragment's xml or the mainactivity's xml, I added it to the mainactivity's xml and included the fragment as my recyclerview, needless to say that the parallax didn't work and now the app doesn't open and I get a NullPointerException now but I didn't touch the code.Please point me in the correct direction. 我有一个像这样布局的应用程序,mainactivity托管2个标签,附带片段,第一个片段有一个有效的回收器视图,我试图添加视差效果,因为人向上或向下滚动,不是确定我是否应该将它添加到片段的xml或mainactivity的xml中,我将它添加到mainactivity的xml并将片段作为我的recyclerview包含,不用说视差不起作用,现在应用程序无法打开,我现在得到一个NullPointerException,但我没有碰到代码。请指出我正确的方向。
XML Below XML下面
frag1.xml frag1.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/my_recycler_view"
android:scrollbars="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
MainActivity.xml MainActivity.xml
<android.support.design.widget.CoordinatorLayout
android:id="@+id/main_layout"
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_height="100dp"
android:layout_width="match_parent"
android:fitsSystemWindows="true"
>
<android.support.design.widget.CollapsingToolbarLayout
app:layout_scrollFlags="scroll|exitUntilCollapsed"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<ImageView
android:layout_height="match_parent"
android:layout_width="match_parent"
app:layout_collapseMode="parallax"
/>
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:background="@color/ColorPrimary"
android:elevation="6dp"
android:minHeight="?attr/actionBarSize"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
app:layout_collapseMode="pin"/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<android.support.design.widget.TabLayout
android:id="@+id/tab_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/toolbar"
android:background="?attr/colorPrimary"
android:elevation="6dp"
android:minHeight="?attr/actionBarSize"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:layout_scrollFlags="enterAlways"
/>
<android.support.v4.view.ViewPager
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:layout_below="@id/tab_layout"
app:layout_behavior="@string/appbar_scrolling_view_behavior"/>
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>
crash log excerpt 崩溃日志摘录
07-08 19:43:54.671 2264-2264/com.example.dimple.test E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.dimple.test, PID: 2264
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView$LayoutManager.onMeasure(android.support.v7.widget.RecyclerView$Recycler, android.support.v7.widget.RecyclerView$State, int, int)' on a null object reference
at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:1764)
at android.view.View.measure(View.java:17430)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:727)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:463)
at android.view.View.measure(View.java:17430)
Full log can be found here http://pastebin.com/4cPGTx2z 完整的日志可以在http://pastebin.com/4cPGTx2z找到
You want to set something up like this: 你想设置这样的东西:
<android.support.design.widget.CoordinatorLayout>
<android.support.design.widget.AppBarLayout>
<android.support.design.widget.CollapsingToolbarLayout
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<ImageView
app:layout_collapseMode="parallax"/>
<android.support.v7.widget.Toolbar />
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<LinearLayout
app:layout_behavior="@string/appbar_scrolling_view_behavior" >
<android.support.design.widget.TabLayout />
<android.support.v4.view.ViewPager />
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>
This will give you a parallax effect with Fragments
inside the ViewPager
. 这将使您在ViewPager
使用Fragments
获得视差效果。
Make sure you add the: 确保添加:
android:fitsSystemWindows="true" 机器人:fitsSystemWindows = “真”
Attribute to both AppBarLayout
and CollapsingToolbarLayout
, and this attribute to the Toolbar
: AppBarLayout
和CollapsingToolbarLayout
属性,以及Toolbar
此属性:
app:layout_collapseMode="pin" 应用程式:layout_collapseMode = “销”
If you want to add another Fragment
you can add a FrameLayout
like so: 如果你想添加另一个Fragment
你可以像这样添加一个FrameLayout
:
<android.support.design.widget.CoordinatorLayout>
<android.support.design.widget.AppBarLayout>
<!-- CollapsingToolbarLayout -->
</android.support.design.widget.AppBarLayout>
<LinearLayout >
<android.support.design.widget.TabLayout />
<android.support.v4.view.ViewPager />
</LinearLayout>
<FrameLayout />
</android.support.design.widget.CoordinatorLayout>
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