TabLayout 选项卡文本不显示
TabLayout tabs text not displaying
我在 Fragment
中使用 TabLayout
来显示三个固定选项卡,这些选项卡可以正常工作,但即使在我设置 app:tabTextColor
属性后它也不显示选项卡文本在布局中它仍然不可见。
NewFragment.java
public class NewFragment extends Fragment {
private RecyclerView mRecyclerView;
private RecyclerView.LayoutManager mLayoutManager;
private RecyclerView.Adapter mAdapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View inflatedView = inflater.inflate(R.layout.new_fragment, container, false);
TabLayout tabLayout = (TabLayout) inflatedView.findViewById(R.id.tabLayout);
tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
tabLayout.addTab(tabLayout.newTab().setText("Tab 3"));
final ViewPager viewPager = (ViewPager) inflatedView.findViewById(R.id.viewpager);
LinearLayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
mLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
viewPager.setAdapter(new PagerAdapter(getFragmentManager(), tabLayout.getTabCount()));
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setupWithViewPager(viewPager);
tabLayout.setTabMode(TabLayout.MODE_FIXED);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
return inflatedView;
}
public class PagerAdapter extends FragmentStatePagerAdapter {
int mNumOfTabs;
public PagerAdapter(FragmentManager fm, int NumOfTabs) {
super(fm);
this.mNumOfTabs = NumOfTabs;
}
@Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new FragmentTab();
case 1:
return new FragmentTab();
case 2:
return new FragmentTab();
default:
return null;
}
}
@Override
public int getCount() {
return mNumOfTabs;
}
}
}
newfragment.xml
<android.support.design.widget.AppBarLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".NewFragment">
<android.support.design.widget.TabLayout
android:id="@+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMode="fixed"
app:tabTextColor="#ffffff"
app:tabGravity="fill"
app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"/>
<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@android:color/white"/>
</android.support.design.widget.AppBarLayout>
问题是您在使用 addTab()
调用设置选项卡后调用 setupWithViewPager()
,有效地覆盖了它们。
来自 TabLayout
关于 setupWithViewPager()
的 documentation:
The tabs displayed in this
layout will be populated from the ViewPager
adapter's page titles.
如果您想将 TabLayout
与 ViewPager
一起使用,您应该在 PagerAdapter
中覆盖 getPageTitle()
(并删除 addTab()
调用,它们是多余的)。
例如:
public class ExamplePagerAdapter extends FragmentStatePagerAdapter {
// tab titles
private String[] tabTitles = new String[]{"Tab1", "Tab2", "Tab3"};
public ExamplePagerAdapter(FragmentManager fm) {
super(fm);
}
// overriding getPageTitle()
@Override
public CharSequence getPageTitle(int position) {
return tabTitles[position];
}
@Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new Tab1Fragment();
case 1:
return new Tab2Fragment();
case 2:
return new Tab3Fragment();
default:
throw new RuntimeException("Invalid tab position");
}
}
@Override
public int getCount() {
return tabTitles.length;
}
// ...
}
我在调用 tabs.setupWithViewPager(viewPager)
后为每个选项卡添加了选项卡文本和图标
viewPager.setAdapter(new MyViewAdapter(getSupportFragmentManager()));
TabLayout tabs=(TabLayout) findViewById(R.id.tabs);
tabs.setupWithViewPager(viewPager);
tabs.getTabAt(0).setIcon(R.drawable.icon1);
tabs.getTabAt(1).setIcon(R.drawable.icon2);
tabs.getTabAt(0).setText(getResources().getText(R.string.tab1));
tabs.getTabAt(1).setText(getResources().getText(R.string.tab2));
我想在 XML 中定义 TabItem 而不是以编程方式进行。正如您提到的,此 setupWithViewPager() 调用将选项卡项的文本和图标重置为空(它使用相同的选项卡对象,只是重置其内容)。我使用了您的方法,但使其更具可重用性。这是我的代码:
public class TabLayoutUtil {
public static void setupTabLayoutWithViewPager(TabLayout tabLayout, ViewPager viewPager) {
ArrayList<Pair<CharSequence, Drawable>> tabsContentCopy= new ArrayList<>();
for (int i = 0; i < tabLayout.getTabCount(); i++) {
TabLayout.Tab tab = tabLayout.getTabAt(i);
tabsContentCopy.add(new Pair<>(tab != null ? tab.getText() : null, tab != null ? tab.getIcon() : null));
}
tabLayout.setupWithViewPager(viewPager);
for (int i = 0; i < tabLayout.getTabCount(); i++) {
if (i<tabsContentCopy.size()) {
tabLayout.getTabAt(i).setText(tabsContentCopy.get(i).first);
tabLayout.getTabAt(i).setIcon(tabsContentCopy.get(i).second);
}
}
}
}
我正在使用 Kotlin 并花了一个小时来查找此代码的错误。
var viewPager: ViewPager = view.findViewById(R.id.viewPager)
...
adapter = TabAdapter(fragmentManager!!)
adapter.addFragment(Fragment1(), "Fragment 1")
adapter.addFragment(Fragment2(), "Fragment 2")
viewPager.adapter = adapter
tabLayout.setupWithViewPager(viewpager)
我可以毫无错误地编译它,但是选项卡标题不会显示,直到我意识到我分配给 tabLayout 的 viewpager 不是 viewPager(注意大写 'P')。它不会产生错误,因为 kotlin 会找到任何匹配的布局 ID,在这种情况下 "viewpager" 这是一个 ViewPager 但在另一个视图上。
我在 Fragment
中使用 TabLayout
来显示三个固定选项卡,这些选项卡可以正常工作,但即使在我设置 app:tabTextColor
属性后它也不显示选项卡文本在布局中它仍然不可见。
NewFragment.java
public class NewFragment extends Fragment {
private RecyclerView mRecyclerView;
private RecyclerView.LayoutManager mLayoutManager;
private RecyclerView.Adapter mAdapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View inflatedView = inflater.inflate(R.layout.new_fragment, container, false);
TabLayout tabLayout = (TabLayout) inflatedView.findViewById(R.id.tabLayout);
tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
tabLayout.addTab(tabLayout.newTab().setText("Tab 3"));
final ViewPager viewPager = (ViewPager) inflatedView.findViewById(R.id.viewpager);
LinearLayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
mLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
viewPager.setAdapter(new PagerAdapter(getFragmentManager(), tabLayout.getTabCount()));
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setupWithViewPager(viewPager);
tabLayout.setTabMode(TabLayout.MODE_FIXED);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
return inflatedView;
}
public class PagerAdapter extends FragmentStatePagerAdapter {
int mNumOfTabs;
public PagerAdapter(FragmentManager fm, int NumOfTabs) {
super(fm);
this.mNumOfTabs = NumOfTabs;
}
@Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new FragmentTab();
case 1:
return new FragmentTab();
case 2:
return new FragmentTab();
default:
return null;
}
}
@Override
public int getCount() {
return mNumOfTabs;
}
}
}
newfragment.xml
<android.support.design.widget.AppBarLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".NewFragment">
<android.support.design.widget.TabLayout
android:id="@+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMode="fixed"
app:tabTextColor="#ffffff"
app:tabGravity="fill"
app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"/>
<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@android:color/white"/>
</android.support.design.widget.AppBarLayout>
问题是您在使用 addTab()
调用设置选项卡后调用 setupWithViewPager()
,有效地覆盖了它们。
来自 TabLayout
关于 setupWithViewPager()
的 documentation:
The tabs displayed in this layout will be populated from the
ViewPager
adapter's page titles.
如果您想将 TabLayout
与 ViewPager
一起使用,您应该在 PagerAdapter
中覆盖 getPageTitle()
(并删除 addTab()
调用,它们是多余的)。
例如:
public class ExamplePagerAdapter extends FragmentStatePagerAdapter {
// tab titles
private String[] tabTitles = new String[]{"Tab1", "Tab2", "Tab3"};
public ExamplePagerAdapter(FragmentManager fm) {
super(fm);
}
// overriding getPageTitle()
@Override
public CharSequence getPageTitle(int position) {
return tabTitles[position];
}
@Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new Tab1Fragment();
case 1:
return new Tab2Fragment();
case 2:
return new Tab3Fragment();
default:
throw new RuntimeException("Invalid tab position");
}
}
@Override
public int getCount() {
return tabTitles.length;
}
// ...
}
我在调用 tabs.setupWithViewPager(viewPager)
viewPager.setAdapter(new MyViewAdapter(getSupportFragmentManager()));
TabLayout tabs=(TabLayout) findViewById(R.id.tabs);
tabs.setupWithViewPager(viewPager);
tabs.getTabAt(0).setIcon(R.drawable.icon1);
tabs.getTabAt(1).setIcon(R.drawable.icon2);
tabs.getTabAt(0).setText(getResources().getText(R.string.tab1));
tabs.getTabAt(1).setText(getResources().getText(R.string.tab2));
我想在 XML 中定义 TabItem 而不是以编程方式进行。正如您提到的,此 setupWithViewPager() 调用将选项卡项的文本和图标重置为空(它使用相同的选项卡对象,只是重置其内容)。我使用了您的方法,但使其更具可重用性。这是我的代码:
public class TabLayoutUtil {
public static void setupTabLayoutWithViewPager(TabLayout tabLayout, ViewPager viewPager) {
ArrayList<Pair<CharSequence, Drawable>> tabsContentCopy= new ArrayList<>();
for (int i = 0; i < tabLayout.getTabCount(); i++) {
TabLayout.Tab tab = tabLayout.getTabAt(i);
tabsContentCopy.add(new Pair<>(tab != null ? tab.getText() : null, tab != null ? tab.getIcon() : null));
}
tabLayout.setupWithViewPager(viewPager);
for (int i = 0; i < tabLayout.getTabCount(); i++) {
if (i<tabsContentCopy.size()) {
tabLayout.getTabAt(i).setText(tabsContentCopy.get(i).first);
tabLayout.getTabAt(i).setIcon(tabsContentCopy.get(i).second);
}
}
}
}
我正在使用 Kotlin 并花了一个小时来查找此代码的错误。
var viewPager: ViewPager = view.findViewById(R.id.viewPager)
...
adapter = TabAdapter(fragmentManager!!)
adapter.addFragment(Fragment1(), "Fragment 1")
adapter.addFragment(Fragment2(), "Fragment 2")
viewPager.adapter = adapter
tabLayout.setupWithViewPager(viewpager)
我可以毫无错误地编译它,但是选项卡标题不会显示,直到我意识到我分配给 tabLayout 的 viewpager 不是 viewPager(注意大写 'P')。它不会产生错误,因为 kotlin 会找到任何匹配的布局 ID,在这种情况下 "viewpager" 这是一个 ViewPager 但在另一个视图上。