为什么两边view加了margin，会导致左侧滑出的view比右侧滑出的view要小

[LinTaoAndroid]

<com.demo.widget.SwipeMenuLayout 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="wrap_content"
app:contentView="@+id/contentView"
app:leftMenuView="@+id/leftView"
app:rightMenuView="@+id/rightView">

<LinearLayout
    android:id="@+id/leftView"
    android:layout_width="160dp"
    android:layout_height="match_parent"
    android:layout_marginRight="10dp"
    android:background="@drawable/notification_open_shape"
    android:gravity="center">

    <TextView
        android:id="@+id/leftTextView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clickable="true"
        android:gravity="center"
        android:text="@string/okay_notification_open"
        android:textColor="@color/panel_notification_open_text_color"
        android:textSize="18sp" />

</LinearLayout>

<LinearLayout
    android:id="@+id/contentView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/notification_row_background" />

<LinearLayout
    android:id="@+id/rightView"
    android:layout_width="160dp"
    android:layout_height="match_parent"
    android:layout_marginLeft="10dp"
    android:background="@drawable/notification_delete_shape"
    android:gravity="center">

    <TextView
        android:id="@+id/rightTextView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clickable="true"
        android:gravity="center"
        android:text="@string/keyguard_password_delete"
        android:textColor="@color/panel_notification_open_text_color"
        android:textSize="18sp" />

</LinearLayout>

</com.demo.widget.SwipeMenuLayout>