未创建Android-Tab项
我正在学习如何做标签布局的教程。我不知道我在下面的代码中做了什么,它没有输出标签。当应用程序运行时,我看不到选项卡项。其他一切都可以未创建Android-Tab项,android,tabs,Android,Tabs,我正在学习如何做标签布局的教程。我不知道我在下面的代码中做了什么,它没有输出标签。当应用程序运行时,我看不到选项卡项。其他一切都可以 <android.support.design.widget.TabLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/tabs"> </a
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tabs">
</android.support.design.widget.TabLayout>
<view
android:layout_height="match_parent"
class="android.support.v4.view.ViewPager"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_marginTop="48dp"/>
</android.support.design.widget.CoordinatorLayout>
Acitvity
public class dashboard extends AppCompatActivity {
TabLayout tabs;
ViewPager container;
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dashboard);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
tabs = (TabLayout) findViewById(R.id.tabs);
tabs.setupWithViewPager(container);
tabs.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener(){
@Override
public void onTabSelected(TabLayout.Tab tab) {
container.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
container.setCurrentItem(tab.getPosition());
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
container.setCurrentItem(tab.getPosition());
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_dashboard, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
public PlaceholderFragment() {
}
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_dashboard, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.section_label);
textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
private String fragments [] = {"Completed", "In Progress"};
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
switch(position){
case 0:
return new dashboard_completed();
case 1:
return new dashboard_in_progress();
default:
return null;
}
}
@Override
public int getCount() {
return fragments.length;
}
@Override
public CharSequence getPageTitle(int position) {
return fragments[position];
}
}
}
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tabs">
</android.support.design.widget.TabLayout>
<view
android:layout_height="match_parent"
class="android.support.v4.view.ViewPager"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_marginTop="48dp"/>
</android.support.design.widget.CoordinatorLayout>
仪表板正在进行中
public class dashboard_in_progress extends Fragment {
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.dashboard_in_progress, container, false);
}
}
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tabs">
</android.support.design.widget.TabLayout>
<view
android:layout_height="match_parent"
class="android.support.v4.view.ViewPager"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_marginTop="48dp"/>
</android.support.design.widget.CoordinatorLayout>
仪表板\u已完成
public class dashboard_completed extends Fragment {
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.dashboard_completed, container, false);
}
}
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tabs">
</android.support.design.widget.TabLayout>
<view
android:layout_height="match_parent"
class="android.support.v4.view.ViewPager"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_marginTop="48dp"/>
</android.support.design.widget.CoordinatorLayout>
XML
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tabs">
</android.support.design.widget.TabLayout>
<view
android:layout_height="match_parent"
class="android.support.v4.view.ViewPager"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_marginTop="48dp"/>
</android.support.design.widget.CoordinatorLayout>
没有可显示的选项卡。使用以下命令:
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tabs">
</android.support.design.widget.TabLayout>
<view
android:layout_height="match_parent"
class="android.support.v4.view.ViewPager"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_marginTop="48dp"/>
</android.support.design.widget.CoordinatorLayout>
tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
这是你的问题
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tabs">
</android.support.design.widget.TabLayout>
<view
android:layout_height="match_parent"
class="android.support.v4.view.ViewPager"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_marginTop="48dp"/>
</android.support.design.widget.CoordinatorLayout>
ViewPager container;
...
private ViewPager mViewPager;
...
tabs.setupWithViewPager(container);
您正在声明两个ViewPager
s,但您只初始化了一个,并尝试使用空值设置TabLayout
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tabs">
</android.support.design.widget.TabLayout>
<view
android:layout_height="match_parent"
class="android.support.v4.view.ViewPager"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_marginTop="48dp"/>
</android.support.design.widget.CoordinatorLayout>
卸下ViewPager容器代码>声明,并将设置调用更改为:
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tabs">
</android.support.design.widget.TabLayout>
<view
android:layout_height="match_parent"
class="android.support.v4.view.ViewPager"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_marginTop="48dp"/>
</android.support.design.widget.CoordinatorLayout>
tabs.setupWithViewPager(mViewPager);
此外,您不需要自己在表格布局
上设置OnTabSelectedListener
。setupWithViewPager()
方法将为您处理此问题。代码看起来正常。您能否发布相应布局的XML代码,可能错误在您的XML代码中?是否有可能选项卡在那里,但它们没有文本?请同时发布SectionsPagerAdapter
的代码。dashboard_completed()是什么代码>和仪表板正在进行()
你最需要在onCraete()中添加选项卡。选项卡。setupWithViewPager(容器)
-选项卡应该来自PagerAdapter
,而不是手动添加。哦,天哪,你是我的英雄谢谢兄弟,我从过去8个小时就开始尝试了。嘿,没问题。直到我复制/粘贴您的代码以自己运行它时,我才看到它。如果将nullViewPager
传递给TabLayout
会引发异常,那么很容易发现,但这就是生活。干杯
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tabs">
</android.support.design.widget.TabLayout>
<view
android:layout_height="match_parent"
class="android.support.v4.view.ViewPager"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_marginTop="48dp"/>
</android.support.design.widget.CoordinatorLayout>