android - TabLayout 删除不必要的滚动

Question

我遇到了 android TabLayout 的棘手问题

import android.support.design.widget.TabLayout;

当我选择左侧最前面的选项卡，然后向右滚动选项卡并选择右侧最前面的选项卡时，TabLayout 首先再次显示左侧选项卡，然后滚动到右侧的选定选项卡。这是我的设置代码

    void setupTabs(ViewPager viewPager, TabLayout tabLayout) {
       ProductsPagerAdapter adapter = new ProductsPagerAdapter(getChildFragmentManager(), rootCategory.getChildCategories());
       viewPager.setAdapter(adapter);
       tabLayout.setupWithViewPager(viewPager);

       setStartingSelection(viewPager, adapter);


   }

    private void setStartingSelection(ViewPager viewPager, ProductsPagerAdapter adapter) {
        for(int i = 0 ; i < adapter.getCount(); i++){
            String title = (String) adapter.getPageTitle(i);
            if(title.equals(selectedCategory.getName())){
                viewPager.setCurrentItem(i);
                break;
            }
        }
    }

和布局

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="match_parent"
    android:orientation="vertical">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@color/toolbar_color"
            app:navigationIcon="@drawable/ic_back_white"
            app:title="@string/title_transport"
            app:titleTextColor="@color/title_color"/>


        <android.support.design.widget.TabLayout
            android:id="@+id/tab_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:tabMode="scrollable"
            app:tabTextColor="@color/white"
            app:tabIndicatorColor="@color/tab_indicator"
            app:tabGravity="fill"/>

    </android.support.design.widget.AppBarLayout>

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="0px"
        android:layout_weight="1"
        android:background="@android:color/white" />

</LinearLayout>

Answer 1

你可以试试这段代码

    tabLayout.setupWithViewPager(viewPager);
    // little hack to prevent unnecessary tab scrolling
    tabLayout.clearOnTabSelectedListeners();
    tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
        @Override
        public void onTabSelected(TabLayout.Tab tab) {
            viewPager.setCurrentItem(tab.getPosition(), false);
        }

        @Override
        public void onTabUnselected(TabLayout.Tab tab) { }

        @Override
        public void onTabReselected(TabLayout.Tab tab) { }
    });

或者你也可以直接在最后一行这样做

tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(viewPager) {
    @Override
    public void onTabSelected(TabLayout.Tab tab) {
        viewPager.setCurrentItem(tab.getPosition(), false);
    }
});