修复Viewpager Android视图

Question

我有一个带有选项卡式viewpager的Android应用程序，可以看到正在运行的应用程序的图像截图

http://i.stack.imgur.com/zhlKF.png

问题是我看到的是空白页面，而不是片段类引用的xml布局。写Viewpager支持的XML文件的正确方法是什么？这是XML布局代码first1.xml

<RelativeLayout 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">


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="HOLA MUNDO"/>

</RelativeLayout>

Frag1.java

package com.example.aliencomputing.kakamila;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class Frag1 extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.first1, container, false);
        return view;
    }
}

Frag2.java

package com.example.aliencomputing.kakamila;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class Frag2 extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.first2, container, false);
        return view;
    }
}

Frag3.java

package com.example.aliencomputing.kakamila;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class Frag3 extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.first3, container, false);
        return view;
    }
}

这是主要活动代码MainActivity.java

package com.example.aliencomputing.kakamila;

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



public class MainActivity extends FragmentActivity {

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

        ViewPager viewPager = (ViewPager) findViewById(R.id.pager);

        viewPager.setAdapter(new ViewPagerAdapter(getSupportFragmentManager()));

    }

}

和ViewPagerAdapter.java

package com.example.aliencomputing.kakamila;

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


public class ViewPagerAdapter extends FragmentPagerAdapter {

    final int PAGE_COUNT = 3;
    //TAB TITLES
    private String tabtitles[]=new String[] {"Tab1", "Tab2", "Tab3"};
    Context context;

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

    @Override
    public int getCount() {
        return PAGE_COUNT;
    }

    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
                Frag1 frag1 = new Frag1();
                return frag1;
            case 1:
                Frag2 frag2 = new Frag2();
                return frag2;

            case 2:
                Frag3 frag3 = new Frag3();
                return frag3;
        }
        return null;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return tabtitles[position];
    }
}

Answer 1

从您发布的activity_main中获取：您需要在viewpager之外的一个视图组，并且需要使pagertabstrip换行内容的高度高。

您发布的Java代码对我来说是正确的。

Answer 2

您的activity_main布局错误，请尝试以下操作：

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

  <android.support.v4.view.PagerTabStrip 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:layout_gravity="top"
      /> 

</android.support.v4.view.ViewPager>

您原来的主要错误是： android:layout_height="match_parent"