v-if有两个条件

Question

我有以下代码，即使<a target="_blank" class="has-text-link" v-if="doc.acceptance_letter!=null || doc.acceptance_letter!= '' " :href="doc.acceptance_letter" > view </a>

，v-if始终显示为true

doc.acceptance_letter

我想在 <android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:id="@+id/coordinatorlayout" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/colorWhite" > <android.support.design.widget.AppBarLayout android:id="@+id/apSelectedLine" android:layout_width="match_parent" android:layout_height="350dp" android:background="@color/colorWhite"> <android.support.design.widget.CollapsingToolbarLayout android:id="@+id/collapsing_container" android:layout_width="match_parent" android:layout_height="match_parent" android:minHeight="250dp" app:layout_scrollFlags="scroll|exitUntilCollapsed"> <fragment xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/map" android:name="com.google.android.gms.maps.SupportMapFragment" android:layout_width="match_parent" android:layout_height="match_parent" app:layout_collapseMode="parallax" /> <android.support.v7.widget.CardView android:id="@+id/cvStep2Loading" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_margin="0dp" android:background="@color/colorWhite" android:backgroundTint="@color/colorWhite" android:minWidth="100dp" android:minHeight="40dp" android:visibility="gone" app:cardBackgroundColor="@color/colorWhite" app:cardCornerRadius="8dp" app:cardElevation="16dp"> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <ProgressBar android:id="@+id/pbStep2Loading" style="?android:attr/progressBarStyleHorizontal" android:layout_width="32dp" android:layout_height="32dp" android:layout_marginStart="8dp" android:layout_marginLeft="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:layout_marginRight="8dp" android:layout_marginBottom="8dp" android:background="@drawable/circle_shape" android:indeterminate="false" android:max="100" android:padding="4dp" android:progress="0" android:progressDrawable="@drawable/circular_progress" /> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginStart="8dp" android:layout_marginLeft="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:layout_marginRight="8dp" android:layout_marginBottom="8dp" android:gravity="center" android:text="loading.." android:textColor="@color/grey" /> </LinearLayout> </android.support.v7.widget.CardView> </android.support.design.widget.CollapsingToolbarLayout> </android.support.design.widget.AppBarLayout> <android.support.v4.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:id="@+id/nsBusesAndStops" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/colorWhite" android:fillViewport="false" app:layout_behavior="@string/appbar_scrolling_view_behavior"> <android.support.constraint.ConstraintLayout android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/llNestSelectedLine" android:visibility="visible"> <me.relex.circleindicator.CircleIndicator android:id="@+id/indicator" android:layout_width="match_parent" android:layout_height="8dp" android:layout_marginTop="8dp" android:layout_marginBottom="8dp" android:background="@color/colorWhite" android:backgroundTint="@color/colorWhite" app:ci_drawable_unselected="@drawable/unselected_grey_circle" app:ci_drawable="@drawable/selected_black_circle" app:layout_constraintTop_toTopOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintStart_toStartOf="parent"/> <android.support.v4.view.ViewPager android:id="@+id/vpSelectedLine" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/colorWhite" app:layout_constraintTop_toBottomOf="@id/indicator" app:layout_constraintRight_toRightOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintBottom_toTopOf="@id/rvStops" > </android.support.v4.view.ViewPager> <android.support.v7.widget.RecyclerView android:id="@+id/rvStops" android:layout_width="match_parent" android:layout_height="wrap_content" android:background="@color/colorWhite" android:backgroundTint="@color/colorWhite" android:nestedScrollingEnabled="false" app:layout_constraintTop_toBottomOf="@id/vpSelectedLine" app:layout_constraintRight_toRightOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintBottom_toBottomOf="parent" /> </android.support.constraint.ConstraintLayout> </android.support.v4.widget.NestedScrollView> </android.support.design.widget.CoordinatorLayout> 为空或为空时隐藏此锚标记。 谁能告诉我我做错了什么？

Answer 1

您的代码将始终显示，因为它始终不同于null或''（一个变量不能同时具有两个值）。正如评论所建议的那样，您只需选中v-if="doc.acceptance_letter即可将其隐藏在任何虚假值中，或者执行v-if="doc.acceptance_letter != null && doc.acceptance_letter != ''

<a 
  target="_blank"
  class="has-text-link"
  v-if="doc.acceptance_letter
  :href="doc.acceptance_letter"  
>
  view
</a>

Answer 2

当doc.acceptance_letter不为空且不为空时，必须使用&&代替||来显示标签。

<a 
  target="_blank"
  class="has-text-link"
  v-if="doc.acceptance_letter!=null && doc.acceptance_letter!= '' "
  :href="doc.acceptance_letter">
  view
</a> 

Answer 3

缺少'='

v-if="doc.acceptance_letter!== null || doc.acceptance_letter!== '' "