ClassCastException：android.widget.RelativeLayout $ LayoutParams无法强制转换为android.widget.FrameLayout $ LayoutParams

Question

all,my situalation is that: activity contains viewpager, viewpager contains a few of fragments, and the main function of the fragment is playing video,and there are many functions about video,containing zooming the video,narrowing the video and so on.But when I trigger the function of zooming the video,the exception accurs:

java.lang.ClassCastException: android.widget.RelativeLayout$LayoutParams   
cannot be cast to android.widget.FrameLayout$LayoutParams

But when I use FrameLayout.LayoutParams,the exception also accurs,like this:

java.lang.ClassCastException: android.widget.FrameLayout$LayoutParams cannot    
be cast to android.widget.RelativeLayout$LayoutParams

And the xml of root view of the fragment is:

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout
    android:id="@+id/header_wrapper"
    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="@dimen/player_height">


    <RelativeLayout
        android:id="@+id/view_holder"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_centerInParent="true">

        <com.baidu.cyberplayer.core.BVideoView
            android:id="@+id/video_view"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" />
    </RelativeLayout>

    <RelativeLayout
        android:id="@+id/controlbar"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical">

        <Button
            android:id="@+id/play_btn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:layout_gravity="center_vertical"
            android:background="@drawable/play_btn_style" />

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_marginBottom="15dp"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/time_current"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center_horizontal"
                android:paddingLeft="4dip"
                android:paddingRight="4dip"
                android:paddingTop="4dip"
                android:text="00:00"
                android:textColor="@color/play_time"
                android:textSize="14sp"
                android:textStyle="bold" />

            <SeekBar
                android:id="@+id/media_progress"
                style="?android:attr/progressBarStyleHorizontal"
                android:layout_width="0dip"
                android:layout_height="30dip"
                android:layout_weight="1" />

            <TextView
                android:id="@+id/time_total"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center_horizontal"
                android:paddingLeft="4dip"
                android:paddingRight="4dip"
                android:paddingTop="4dip"
                android:text="00:00"
                android:textColor="@color/play_time"
                android:textSize="14sp"
                android:textStyle="bold" />

            <Button
                android:id="@+id/zoom_btn"
                android:layout_width="40dp"
                android:layout_height="40dp"
                android:background="@drawable/screensize_zoomout_button" />
        </LinearLayout>
    </RelativeLayout>

    <RelativeLayout
        android:id="@+id/VideoAction"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true">

        <ImageView
            android:id="@+id/detailPic"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            android:adjustViewBounds="false"
            android:contentDescription="@null"
            android:scaleType="fitXY"
            android:src="@drawable/big_bg" />

        <ImageButton
            android:id="@+id/pre_play_button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:background="#00000000"
            android:contentDescription="@null"
            android:src="@drawable/play_btn_style"
            android:visibility="invisible" />

        <com.basv.gifmoviewview.widget.GifMovieView
            android:id="@+id/loading_gif"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            app:gif="@drawable/big_loading" />
    </RelativeLayout>
</RelativeLayout>

The code of function that zoom the video is:

    RelativeLayout.LayoutParams param = new RelativeLayout.LayoutParams(
            Screen.getScreenWidth(getActivity().getWindowManager()),
            Screen.getScreenHeight(getActivity().getWindowManager()));
    mHeaderWrapper.setLayoutParams(param);
    mVV.setLayoutParams(param);
    mZoomButton.setBackgroundResource(R.drawable.screensize_zoomin_button);
    mCurrentScape = OrientationHelper.LANDSCAPE;

I think the exception accurs at the position of the code above:

    RelativeLayout.LayoutParams param = new  RelativeLayout.LayoutParams(
    Screen.getScreenWidth(getActivity().getWindowManager()),
    Screen.getScreenHeight(getActivity().getWindowManager()));

I want to realize the function: zoom and narrow the video,that,make the video in fragment full screen in activity and can make the video shrink.

Or,Which kind of LayoutParams should I use?

As you know,the question occurs that "mHeaderWrapper.setLayoutParams(param);",and I use the method "mHeaderWrapper.getParent" to know the parent of the layout mHeaderWrapper ,it is

" android.support.v4.app.NoSaveStateFrameLayout ",

but there is no android.support.v4.app.NoSaveStateFrameLayout.LayoutParams,how to handle with it?

Thank you!

Answer 1

How to deal with the ClassCastException

1) Be careful when trying to cast an object of a class into another class. Ensure that the new type belongs to one of its parent classes.

2) You can prevent the ClassCastException by using Generics, because Generics provide compile time checks and can be used to develop type-safe applications.

Refrence link

http://examples.javacodegeeks.com/java-basics/exceptions/java-lang-classcastexception-how-to-solve-class-cast-exception/

in Your case

may b im wrong but i think you should use framelayout ..

Answer 2

I think exception happens when you set layoutparams to mheaderwrapper. What's its parent?

Answer 3

Try changing

RelativeLayout.LayoutParams param = new  RelativeLayout.LayoutParams(
    Screen.getScreenWidth(getActivity().getWindowManager()),
    Screen.getScreenHeight(getActivity().getWindowManager()));

to

FrameLayout.LayoutParams param = new  FrameLayout.LayoutParams(
    Screen.getScreenWidth(getActivity().getWindowManager()),
    Screen.getScreenHeight(getActivity().getWindowManager()));