代碼設置view的寬高注意細節

 <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>

 

上面是佈局文件，我要早代碼中從新設置ImageView的寬度，用如下方法：

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

 

運行的時候會報錯： Caused by: java.lang.ClassCastException:android.widget.LinearLayout$LayoutParams cannot be cast to android.widget.Re

 

解決方法：ImageView是LinearLayout的子控件，它的LayoutParams 應該是LinearLayout給他的。因此應該是LinearLayout.LayoutParam 。

代碼改爲：

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