android.widget.LinearLayout$LayoutParams cannot be cast to android.widget.RelativeLayout$LayoutPara

 <LinearLayout
            android:id="@+id/ll_card"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical" >

            <ImageView
                android:id="@+id/iv_move"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:background="@drawable/blue_line" />

            
        </LinearLayout>

上面是布局文件，我要早代码中重新设置ImageView的宽度，用以下方法：

LayoutParams layoutParams = (LayoutParams) iv_move.getLayoutParams();
layoutParams.width = move_width;
iv_move.setLayoutParams(layoutParams);

运行的时候会报错： Caused by: java.lang.ClassCastException:android.widget.LinearLayout$LayoutParams cannot be cast to android.widget.Re

解决方法：ImageView是LinearLayout的子控件，它的LayoutParams 应该是LinearLayout给他的。所以应该是LinearLayout.LayoutParam 。

代码改成：

LinearLayout.LayoutParams layoutParams = (LinearLayout.LayoutParams) iv_move.getLayoutParams();
layoutParams.width = move_width;
iv_move.setLayoutParams(layoutParams);