java - 无法为 tabLayout 添加选项卡

Question

我无法将新选项卡添加到 tabLayout。

XML 文件

<RelativeLayout
android:id="@+id/main_layout"
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"
tools:context="com.dailam103.messagetimer.MainActivity">
<android.support.design.widget.TabLayout
    android:id="@+id/tabs"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:tabMode="fixed"
    app:tabGravity="fill"/>

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
</android.support.v4.view.ViewPager>
</RelativeLayout>

MainActivity.java

package com.dailam103.messagetimer;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.support.design.widget.TabLayout;
public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
    tabLayout.addTab(tabLayout.newTab().setTag(1).setText("Tab 1"));
    final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
    final TabAdapter adapter = new TabAdapter(getSupportFragmentManager(), tabLayout.getTabCount());
    viewPager.setAdapter(adapter);
    viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
    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) {
        }
    });

}
}

错误位于

tabLayout.addTab(tabLayout.newTab().setTag(1).setText("选项卡 1"));

请问为什么我无法将选项卡添加到 tabLayout？

Answer 1

您不需要像这样编写很长的代码。

 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) {
        }
    });

只需添加tabLayout.setupWithViewPager(viewPager);

• 或可用于从任何地方设置 tablayout 的代码。

  public class ViewPagerBean {
  ViewPager viewPager;
  TabLayout tabLayout;
  ArrayList<TabBean> tabTitleList;
  
  
  public ViewPager getViewPager() {
      return viewPager;
  }
  
  public void setViewPager(ViewPager viewPager) {
      this.viewPager = viewPager;
  }
  
  public TabLayout getTabLayout() {
      return tabLayout;
  }
  
  public void setTabLayout(TabLayout tabLayout) {
      this.tabLayout = tabLayout;
  }
  
  public ArrayList<TabBean> getTabTitleList() {
      return tabTitleList;
  }
  
  public void setTabTitleList(ArrayList<TabBean> tabTitleList) {
      this.tabTitleList = tabTitleList;
  }
  }
  
  public class TabBean {
  int icon;
  int title;
  BaseFragment baseFragment;
  
  public TabBean(int icon, int title, BaseFragment baseFragment) {
  this.icon = icon;
  this.title = title;
  this.baseFragment = baseFragment;
  }
  
  public int getIcon() {
  return icon;
  }
  
  public void setIcon(int icon) {
  this.icon = icon;
  }
  
  public int getTitle() {
  return title;
  }
  
  public void setTitle(int title) {
  this.title = title;
  }
  
  public BaseFragment getBaseFragment() {
  return baseFragment;
  }
  
  public void setBaseFragment(BaseFragment baseFragment) {
  this.baseFragment = baseFragment;
  }
  }
  

• 我的所有 fragment 都扩展了BaseFragment。如果您在 Activity 中需要 tablayout，只需将 BaseFragment 替换为您的 BaseActivity 类即可。

  private TabLayout tabLayout;
  private ViewPager viewPagerImage;
  
  tabLayout = (TabLayout) fragmentView.findViewById(R.id.tabLayoutDefault);
  viewPagerImage = (ViewPager) fragmentView.findViewById(R.id.homeViewPager);
  

• 将此代码写入您的 BaseFragment 或 BaseActivity 类中。

  public void setViewPager(ViewPagerBean viewPagerBean) {
  ViewPager viewPager = viewPagerBean.getViewPager();
  TabLayout tabLayout = viewPagerBean.getTabLayout();
  FragmentManager fragmentManager = getFragmentManager();
  PagerAdapter adapterMyEvents = new PagerAdapter(fragmentManager, 
  viewPagerBean.getTabTitleList());
  viewPager.setAdapter(adapterMyEvents);
  tabLayout.setupWithViewPager(viewPager);
  viewPager.setCurrentItem(0);
  setCustomTabView(viewPagerBean);
  }
  
  private void setCustomTabView(ViewPagerBean pagerBean) {
  for (int i = 0; i < pagerBean.getTabLayout().getTabCount(); i++) {
  TabLayout.Tab tab = pagerBean.getTabLayout().getTabAt(i);
  LinearLayout linearLayout = (LinearLayout) LayoutInflater.from(getActivity()).inflate(R.layout.tab_custom_layout, pagerBean.getTabLayout(), false);
  TextView tabTextView = (TextView) linearLayout.findViewById(R.id.tab_title);
  ImageView ivTabLeftIcon = (ImageView) linearLayout.findViewById(R.id.ivTabLeftIcon);
  TabBean tabBean = pagerBean.getTabTitleList().get(i);
  
  if (tabBean.getTitle() != 0)
      tabTextView.setText(tabBean.getTitle());
  if (tabBean.getIcon() != 0)
      ivTabLeftIcon.setImageResource(tabBean.getIcon());
  if (tab != null) {
      tab.setCustomView(linearLayout);
  }
  }
  }
  
  
  
  
  private class PagerAdapter extends FragmentStatePagerAdapter {
  
  private ArrayList<TabBean> arrayList;
  
  public PagerAdapter(FragmentManager fm, ArrayList<TabBean> mTitles) {
  super(fm);
  this.arrayList = mTitles;
  }
  
  @Override
  public Fragment getItem(int position) {
  return arrayList.get(position).getBaseFragment();
  }
  
  
  @Override
  public CharSequence getPageTitle(int position) {
  return getString(arrayList.get(position).getTitle());
  }
  
  
  @Override
  public int getCount() {
  return arrayList.size();
  }
  }
  

• 这样就可以轻松使用

          public ArrayList<TabBean> getUserHomeTabFragmentList() {
          ArrayList<TabBean> arrayList = new ArrayList<>();
  
          FragmentHomeLunchList fragmentMenuLunch = new FragmentHomeLunchList();
          FragmentHomeDinnerList fragmentMenuDinner = new 
          FragmentHomeDinnerList();
  
          arrayList.add(new TabBean(R.drawable.ic_lunch, R.string.lunch, fragmentMenuLunch));
          arrayList.add(new TabBean(R.drawable.ic_dinner, R.string.dinner, fragmentMenuDinner));
  
          return arrayList;
          }
  
          private void setPagerAdapterWithTabLayout() {
          ArrayList<TabBean> tabsList = UtilProject.getInstance().getList();
          ViewPagerBean viewPagerBean = new ViewPagerBean();
          viewPagerBean.setTabLayout(tabLayout);
          viewPagerBean.setTabTitleList(tabsList);
          viewPagerBean.setViewPager(viewPagerBottom);
          setViewPager(viewPagerBean);
          viewPagerBottom.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
          @Override
          public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
  
          }
  
          @Override
          public void onPageSelected(int position) {
  
          }
  
          @Override
          public void onPageScrollStateChanged(int state) {
  
          }
          });
          }