Android：嘗試獲取AppBarLayout時應用程序崩潰LayoutParams

Question

我嘗試設置AppBarLayout參數時出現ClassCastException。下面是我的XML代碼

<android.support.design.widget.CoordinatorLayout 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" 
    android:fitsSystemWindows="true" 
    tools:context="com.example.testapp.ConsoleActivity"> 

    <android.support.design.widget.AppBarLayout 
     android:layout_width="match_parent" 
     android:layout_height="280dp" 
     android:theme="@style/AppTheme.AppBarOverlay" 
     android:id="@+id/app_bar_layout"> 

     <android.support.design.widget.CollapsingToolbarLayout 
      android:id="@+id/collapsing_toolbar" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      app:contentScrim="?attr/colorPrimary" 
      app:layout_scrollFlags="scroll|exitUntilCollapsed"> 

      <android.support.v4.view.ViewPager 
       android:layout_width="match_parent" 
       android:layout_height="220dp" 
       android:id="@+id/app_bar_account_cards_pager" 
       app:layout_collapseMode="parallax" 
       android:layout_marginTop="?attr/actionBarSize" /> 

      <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" 
       app:layout_collapseMode="pin" /> 

     </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" 
     android:clipToPadding="false" 
     android:id="@+id/nested_scroll_bar" 
     app:layout_behavior="@string/appbar_scrolling_view_behavior"> 

     <include layout="@layout/content_console" 
      android:layout_height="match_parent" 
      android:layout_width="match_parent"/> 

    </android.support.v4.widget.NestedScrollView> 



</android.support.design.widget.CoordinatorLayout> 

，我試圖讓使用AppBarLayoutParams的實例下面的Java代碼

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
AppBarLayout.LayoutParams p = (AppBarLayout.LayoutParams) toolbar.getLayoutParams(); 
p.setScrollFlags(0); 
toolbar.setLayoutParams(p); 

但我正在逐漸java.lang.ClassCastException: android.support.design.widget.CollapsingToolbarLayout$LayoutParams cannot be cast to android.support.design.widget.AppBarLayout$LayoutParams這條線AppBarLayout.LayoutParams p = (AppBarLayout.LayoutParams) toolbar.getLayoutParams();。我該如何解決這個問題？

Answer 1

您有

android.support.design.widget.CollapsingToolbarLayout.LayoutParams 

進行投射，而不是

android.support.design.widget.AppBarLayout.LayoutParams 

編輯：佈局PARAMS由視圖的immidiate父母提供

CollapsingToolbarLayout collapsingToolbar = (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar); 
AppBarLayout.LayoutParams p = (AppBarLayout.LayoutParams) collapsingToolbar.getLayoutParams(); 
p.setScrollFlags(0); 
collapsingToolbar.setLayoutParams(p);