Question

我有一个问题我做对了但是在我的程序中，标签的滑动无法正常显示任何页面。

主要Activity.java

public class MainActivity extends FragmentActivity implements TabListener {
ViewPager vp;
 ActionBar actionbar;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    vp=(ViewPager)findViewById(R.id.pager);
    vp.setAdapter(new MyAdapter(getSupportFragmentManager()));
    actionbar=getActionBar();
    actionbar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
    ActionBar.Tab tab1=actionbar.newTab();
    tab1.setText("MP3");
    tab1.setTabListener(this);
    ActionBar.Tab tab2=actionbar.newTab();      
    tab2.setText("MP4");
    tab2.setTabListener(this);
    actionbar.addTab(tab1);
    actionbar.addTab(tab2);
}
@Override
public void onTabReselected(Tab arg0, FragmentTransaction arg1) {
Log.d("Gul",   "OntabReselected"+"postion"+arg0.getPosition()+"name"+arg0.getText());
}
@Override
public void onTabSelected(Tab arg0, FragmentTransaction arg1) {
    Log.d("Gul", "onTabSelected"+"postion"+arg0.getPosition()+"name"+arg0.getText());

}
@Override
public void onTabUnselected(Tab arg0, FragmentTransaction arg1) {
    Log.d("Gul", "onTabUnselected"+"postion"+arg0.getPosition()+"name"+arg0.getText());

}
}

 class MyAdapter extends FragmentPagerAdapter{

public MyAdapter(FragmentManager fm) {
    super(fm);
    // TODO Auto-generated constructor stub
}

@Override
public Fragment getItem(int arg0) {
    // TODO Auto-generated method stub
    Fragment f=null;
    if(arg0==0){
        f=new Mp3list();
    }
    else{
        f=new Mp4list();
    }
    return null;
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    return 2;
}

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.view.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
 />

我知道有一个问题，但我找不到它，当我点击标签时，它们仍无法正常工作？ mp3list和mp4list是两个片段类。

Answer 1

由于Google引入了android支持设计库，所以只需这样做：

将以下依赖项添加到gradle

compile 'com.android.support:appcompat-v7:22.2.0'

compile 'com.android.support:design:22.2.0'

修改MainActivity，如下所示：

import android.os.Bundle;  
import android.support.design.widget.TabLayout;  
import android.support.v4.app.Fragment;  
import android.support.v4.app.FragmentManager;  
import android.support.v4.app.FragmentPagerAdapter;  
import android.support.v4.view.ViewPager;  
import android.support.v7.app.AppCompatActivity;  
import android.support.v7.widget.Toolbar;  
import android.view.Menu;  
import android.view.MenuItem;

import java.util.ArrayList;  
import java.util.List;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
    if (viewPager != null) {
        setupViewPager(viewPager);
    }

    TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(viewPager);
}

private void setupViewPager(ViewPager viewPager) {
    // create an adapter
    Adapter adapter = new Adapter(getSupportFragmentManager());

    // add your fragments to the adapter
    adapter.addFragment(new Mp3list() , "MP3");
    adapter.addFragment(new Mp4list() , "MP4");

    // set the adapter to the ViewPager
    viewPager.setAdapter(adapter);
}


// adapter class
class Adapter extends FragmentPagerAdapter {
    private final List<Fragment> mFragments = new ArrayList<>();
    private final List<String> mFragmentTitles = new ArrayList<>();

    public Adapter(FragmentManager fm) {
        super(fm);
    }

    public void addFragment(Fragment fragment, String title) {
        mFragments.add(fragment);
        mFragmentTitles.add(title);
    }

    @Override
    public Fragment getItem(int position) {
        return mFragments.get(position);
    }

    @Override
    public int getCount() {
        return mFragments.size();
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return mFragmentTitles.get(position);
    }
}
}

最后将您的activity_main.xml布局更改为：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<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/ThemeOverlay.AppCompat.Light" />

<android.support.design.widget.TabLayout
    android:id="@+id/tabs"
    android:background="?attr/colorPrimary"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:tabMode="scrollable" />
    <!-- tabMode can be scrollable or fixedß -->

<android.support.v4.view.ViewPager
    android:id="@+id/viewpager"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

</LinearLayout>

如何进行滑动视图导航？

1 个答案: