Question

在我的项目中，我通过ViewPager创建我的tabBar，如下所示：

MainActivity.java

mViewPager = (ViewPager) findViewById(R.id.content_main_viewpager);

        if ( mViewPager != null ) {
            final ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());

            adapter.addFragment( new LandingSearch(), "" );
            adapter.addFragment( new LandingWiki(), "" );
            adapter.addFragment( new LandingForum(), "" );

            mViewPager.setAdapter(adapter);
            mViewPager.setOffscreenPageLimit( 3 );

            final TabLayout tabs = (TabLayout) findViewById(R.id.content_main_tabs);

            if ( tabs != null ) {
                tabs.post(new Runnable() {
                    @Override
                    public void run() {
                        tabs.setupWithViewPager( mViewPager );
                        tabs.getTabAt(0).setIcon(R.drawable.ic_tab_search);
                        tabs.getTabAt(1).setIcon(R.drawable.ic_tab_favorite);
                        tabs.getTabAt(2).setIcon(R.drawable.ic_tab_forum);
                    }
                });

            }
        }

app_bar_main.xml

<?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"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:fitsSystemWindows="true"
tools:context="com.mathleaks.MainActivity">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" />

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

    <include layout="@layout/content_main" />

<com.mathleaks.ui.util.MainViewPager
    android:id="@+id/content_main_viewpager"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1"
    android:visibility="visible"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">


</com.mathleaks.ui.util.MainViewPager>

<android.support.design.widget.TabLayout
    android:id="@+id/content_main_tabs"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:tabMode="fixed"
    app:tabGravity="center"
    android:animateLayoutChanges="true"
    android:background="@color/background"
    app:background="@color/background"
    app:layout_scrollFlags="scroll|enterAlways" >

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

</LinearLayout>

现在，当应用程序中发生特殊事件时，我想在我的第二个tabBar片段（LandingWiki）中隐藏我的tabBar。到目前为止，我还没有成功。

final TabLayout tabs = (TabLayout)findViewById(R.id.content_main_tabs);
tabs.setVisibility(View.GONE);

结果：

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.design.widget.TabLayout.setVisibility(int)' on a null object reference

Answer 1

这可能是因为findViewById引用了片段而不是主要活动。

您可以执行以下操作：从片段中（在onActivityCreated事件之后）

final TabLayout tabs = (TabLayout)getActivity().findViewById(R.id.content_main_tabs);
tabs.setVisibility(View.GONE);

Android动态删除tabBar（隐藏）

1 个答案: