Viewpager見えない

Question

ここ主活動レイアウトXML

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="wrap_content" 
    android:layout_height="fill_parent"> 

    <LinearLayout 
     android:id="@+id/left" 
     android:layout_width="100dp" 
     android:layout_height="fill_parent" 
     android:layout_alignParentLeft="true" 
     android:background="@color/red" 
     android:orientation="horizontal" > 
    </LinearLayout> 

    <android.support.v4.view.ViewPager 
     xmlns:tools="http://schemas.android.com/tools" 
     android:id="@+id/pager" 
     android:layout_width="0dip" 
     android:layout_height="fill_parent" 
     android:layout_toLeftOf="@+id/left" 
     android:layout_toRightOf="@+id/right" 
     tools:context=".MainActivity" /> 

    <LinearLayout 
     android:id="@+id/right" 
     android:layout_width="100dp" 
     android:layout_height="fill_parent" 
     android:layout_alignParentRight="true" 
     android:background="@color/red" 
     android:orientation="horizontal" > 
    </LinearLayout> 

</RelativeLayout> 

フラグメントレイアウトXMLである：

<?xml version="1.0" encoding="utf-8"?>  
<LinearLayout 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" android:orientation="horizontal" 
     tools:context=".DummySectionFragment" android:background="@color/gray"> 

     <TextView 
      android:id="@+id/section_label" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" /> 

    </LinearLayout> 

主な活動：

package com.example.androidtest; 

import android.app.ActionBar; 
import android.app.FragmentTransaction; 
import android.os.Bundle; 
import android.support.v4.app.FragmentActivity; 
import android.support.v4.view.ViewPager; 
import android.view.Menu; 

public class MainActivity extends FragmentActivity implements 
     ActionBar.TabListener { 

    /** 
    * The {@link android.support.v4.view.PagerAdapter} that will provide 
    * fragments for each of the sections. We use a 
    * {@link android.support.v4.app.FragmentPagerAdapter} derivative, which 
    * will keep every loaded fragment in memory. If this becomes too memory 
    * intensive, it may be best to switch to a 
    * {@link android.support.v4.app.FragmentStatePagerAdapter}. 
    */ 
    SectionsPagerAdapter mSectionsPagerAdapter; 

    /** 
    * The {@link ViewPager} that will host the section contents. 
    */ 
    ViewPager mViewPager; 

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

     // Set up the action bar. 
     final ActionBar actionBar = getActionBar(); 
     actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); 

     // Create the adapter that will return a fragment for each of the three 
     // primary sections of the app. 
     mSectionsPagerAdapter = new SectionsPagerAdapter(
       getSupportFragmentManager(), getApplicationContext()); 

     // Set up the ViewPager with the sections adapter. 
     mViewPager = (ViewPager) findViewById(R.id.pager); 
     mViewPager.setAdapter(mSectionsPagerAdapter); 

     // When swiping between different sections, select the corresponding 
     // tab. We can also use ActionBar.Tab#select() to do this if we have 
     // a reference to the Tab. 
     mViewPager 
       .setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() { 
        @Override 
        public void onPageSelected(int position) { 
         actionBar.setSelectedNavigationItem(position); 
        } 
       }); 

     // For each of the sections in the app, add a tab to the action bar. 
     for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) { 
      // Create a tab with text corresponding to the page title defined by 
      // the adapter. Also specify this Activity object, which implements 
      // the TabListener interface, as the callback (listener) for when 
      // this tab is selected. 
      actionBar.addTab(actionBar.newTab() 
        .setText(mSectionsPagerAdapter.getPageTitle(i)) 
        .setTabListener(this)); 
     } 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.main, menu); 
     return true; 
    } 

    @Override 
    public void onTabSelected(ActionBar.Tab tab, 
      FragmentTransaction fragmentTransaction) { 
     // When the given tab is selected, switch to the corresponding page in 
     // the ViewPager. 
     mViewPager.setCurrentItem(tab.getPosition()); 
    } 

    @Override 
    public void onTabUnselected(ActionBar.Tab tab, 
      FragmentTransaction fragmentTransaction) { 
    } 

    @Override 
    public void onTabReselected(ActionBar.Tab tab, 
      FragmentTransaction fragmentTransaction) { 
    } 
} 

フラグメント：

package com.example.androidtest; 

import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.util.Log; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.view.ViewGroup.LayoutParams; 
import android.widget.TextView; 

/** 
* A dummy fragment representing a section of the app, but that simply 
* displays dummy text. 
*/ 
public class DummySectionFragment extends Fragment { 
    /** 
    * The fragment argument representing the section number for this 
    * fragment. 
    */ 
    public static final String ARG_SECTION_NUMBER = "section_number"; 

    public DummySectionFragment() { 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
      Bundle savedInstanceState) { 
     View rootView = inflater.inflate(R.layout.fragment_main_dummy, 
       container, false); 
     TextView dummyTextView = (TextView) rootView 
       .findViewById(R.id.section_label); 
     dummyTextView.setText(Integer.toString(getArguments().getInt(
       ARG_SECTION_NUMBER))); 
     return rootView; 
    } 
} 

ページャアダプタ：予想

package com.example.androidtest; 

import java.util.Locale; 

import android.content.Context; 
import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentManager; 
import android.support.v4.app.FragmentPagerAdapter; 


/** 
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to 
* one of the sections/tabs/pages. 
*/ 
public class SectionsPagerAdapter extends FragmentPagerAdapter { 

    private Context context; 

    public SectionsPagerAdapter(FragmentManager fm, Context context) { 
     super(fm); 
     this.context = context; 
    } 

    @Override 
    public Fragment getItem(int position) { 
     // getItem is called to instantiate the fragment for the given page. 
     // Return a DummySectionFragment (defined as a static inner class 
     // below) with the page number as its lone argument. 
     Fragment fragment = new DummySectionFragment(); 
     Bundle args = new Bundle(); 
     args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1); 
     fragment.setArguments(args); 
     return fragment; 
    } 

    @Override 
    public int getCount() { 
     // Show 3 total pages. 
     return 3; 
    } 

    @Override 
    public CharSequence getPageTitle(int position) { 
     Locale l = Locale.getDefault(); 
     switch (position) { 
     case 0: 
      return context.getString(R.string.title_section1).toUpperCase(l); 
     case 1: 
      return context.getString(R.string.title_section2).toUpperCase(l); 
     case 2: 
      return context.getString(R.string.title_section3).toUpperCase(l); 
     } 
     return null; 
    } 
} 

：両サイドに2つの赤いバー。中央のViewPager。

何が起こっているのですか？両側に2つの赤いバーがあります。真ん中に空白。

質問：なぜですか？

EDIT：

私はこの作業を取得するために、以下に主な活動のレイアウトXMLを変更しました。

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="wrap_content" 
    android:layout_height="fill_parent"> 

    <LinearLayout 
     android:id="@+id/left" 
     android:layout_width="100dp" 
     android:layout_height="fill_parent" 
     android:layout_alignParentLeft="true" 
     android:background="@color/red" 
     android:orientation="horizontal" > 
    </LinearLayout> 

    <android.support.v4.view.ViewPager 
     xmlns:tools="http://schemas.android.com/tools" 
     android:id="@+id/pager" 
     android:layout_width="fill_parent" 
     android:layout_height="fill_parent" 
     tools:context=".MainActivity" android:layout_toRightOf="@+id/left"/> 

    <LinearLayout 
     android:id="@+id/right" 
     android:layout_width="100dp" 
     android:layout_height="fill_parent" 
     android:layout_alignParentRight="true" 
     android:background="@color/red" 
     android:orientation="horizontal" > 
    </LinearLayout> 

</RelativeLayout> 

唯一の変化は、私がandroid:layout_toRightOf="@+id/right"を取り除き、layout_width = "fill_parent" に変更されます。 Fill_parent私は理解します。なぜ他のものを取り除くのが違いになるのでしょうか？

Answer 1

：代わりにRelativeLayoutの

1. 利用のLinearLayout水平方向であなたのmain.xmlため。
2. あなたのビューページャにandroid：layout_weight = "1"を追加します。

Answer 2

まあ、あなたのviewPagerの幅は：android:layout_width="0dip"です。真ん中に空白がありません。 android:layout_width="match_parent"に設定してみてください。この方法では、rightとleftの間のすべてのスペースが使用されます。あなたはmain.xmlに二つのことをしなければならない