android - TabLayoutMediator 不保留 TabItem 属性

Question

我有一个使用 ViewPager2 和 TabLayout 和预设 TabItems 的简单设置:

...

        <com.google.android.material.tabs.TabLayout
            android:id="@+id/tabs"
            android:layout_width="0dp"
            android:layout_height="64dp"
            app:tabTextColor="@color/c0696D7"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toEndOf="@+id/palettesToggle"
            app:layout_constraintTop_toTopOf="parent"
            app:tabBackground="@color/cEEEEEE"
            app:tabIndicatorColor="@color/cFFFFFF"
            app:tabGravity="fill"
            app:tabUnboundedRipple="true"
            app:tabIconTint="@color/palettes_icon_tint"
            app:tabIndicatorGravity="stretch"
            app:tabMode="fixed">

            <com.google.android.material.tabs.TabItem android:icon="@drawable/palettes_layers" />

            <com.google.android.material.tabs.TabItem android:icon="@drawable/palettes_view" />

            <com.google.android.material.tabs.TabItem android:icon="@drawable/palettes_properties" />

            <com.google.android.material.tabs.TabItem android:icon="@drawable/palettes_blocks" />

            <com.google.android.material.tabs.TabItem android:icon="@drawable/palettes_blocks" />

            <com.google.android.material.tabs.TabItem android:icon="@drawable/palettes_settings" />

        </com.google.android.material.tabs.TabLayout>

        <androidx.viewpager2.widget.ViewPager2
            android:id="@+id/viewPager"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/tabs" />

...

以及以下接线代码:

TabLayoutMediator(tabs, viewPager) { tab, position ->

        }.attach()

以下设置忽略了 TabItem图标属性，我看到空选项卡。看来 TabLayoutMediator完全覆盖定义的 xml 属性，我必须将这些属性重置为 TabConfigurationStrategy 的一部分打回来。
我错过了什么吗？

Answer 1

方法TabLayoutMediator.attach() calls the method tabLayout.removeAllTabs();其中删除所有标签 然后再次添加标签。

另请查看 official doc :

When creating an instance of this class, you must supply an implementation of TabLayoutMediator.TabConfigurationStrategy in which you set the text of the tab, and/or perform any styling of the tabs that you require.

就像是:

new TabLayoutMediator(tabs, viewpager, new TabLayoutMediator.TabConfigurationStrategy() {
      @Override public void onConfigureTab(@NonNull TabLayout.Tab tab, int position) {
        //Configure your tabs...
        tab.setText(...);
        tab.setIcon(...);
      }
    }).attach();

或者:

 TabLayoutMediator(tabs, viewpager,
    TabLayoutMediator.TabConfigurationStrategy { tab, position ->
        //Configure tabs..
        when (position) {
            0 -> { tab.text = "..."}
            1 -> { tab.text = "..."}
        }
    }).attach()