在 FragmentPagerAdapter 的帮助下将选项卡添加到 ActionBar

Question

我是 Android UI 设计的新手，我正在开发带有两个选项卡的选项卡 UI

请帮我解决..

谢谢

这是我的 MainActivity 代码

import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBarActivity;

public class MainSwipeActivity  extends ActionBarActivity implements ActionBar.TabListener {

private ViewPager viewPager;
private TabsPagerAdapter mAdapter;
private ActionBar actionBar;
// Tab titles
private String[] tabs = { "One", "Two", "Three" };
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_swipe);
    //////////
    viewPager = (ViewPager) findViewById(R.id.pager);
    actionBar = getActionBar();
    mAdapter = new TabsPagerAdapter(getSupportFragmentManager());

    viewPager.setAdapter(mAdapter);
actionBar.setHomeButtonEnabled(false);
  actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Adding Tabs
    for (String tab_name : tabs) {
        actionBar.addTab(actionBar.newTab().setText(tab_name)
                .setTabListener(this));
    }


    viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

        @Override
        public void onPageSelected(int position) {
            // on changing the page
            // make respected tab selected
            actionBar.setSelectedNavigationItem(position);
        }

        @Override
        public void onPageScrolled(int arg0, float arg1, int arg2) {
        }

        @Override
        public void onPageScrollStateChanged(int arg0) {
        }
    });

}///////////////////


@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
    viewPager.setCurrentItem(tab.getPosition());
}

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

}

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

}

}

有这样的布局

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

我有 2 个片段，即一和二其中包含简单的 UI 元素

我的 FragmentPagerAdapter class 包含以下代码

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
public class TabsPagerAdapter extends FragmentPagerAdapter {
    public TabsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int index) {

        switch (index) {
            case 0:
                // Top Rated fragment activity
                return new One();
            case 1:
                // Games fragment activity
                return new Two();
            case 2:
                // Movies fragment activity
                return new One();
        }

        return new One();
    }

    @Override
    public int getCount() {
        // get item count - equal to number of tabs
        return 3;
    }

}

Logcat 包含

3160-3160/envoyone.ak.ace.sampleer E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: envoyone.ak.ace.sampleer, PID: 3160
    java.lang.RuntimeException: Unable to start activity ComponentInfo{envoyone.ak.ace.sampleer/envoyone.ak.ace.sampleer.MainSwipeActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ActionBar.setHomeButtonEnabled(boolean)' on a null object reference
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access0(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ActionBar.setHomeButtonEnabled(boolean)' on a null object reference
            at envoyone.ak.ace.sampleer.MainSwipeActivity.onCreate(MainSwipeActivity.java:41)
            at android.app.Activity.performCreate(Activity.java:5937)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access0(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
04-02 17:34:17.522    3160-3172/envoyone.ak.ace.sampleer I/art﹕ Background sticky concurrent mark sweep GC freed 3145(284KB) AllocSpace objects, 0(0B) LOS objects, 33% free, 757KB/1135KB, paused 3.061ms total 194.971ms
04-02 17:34:34.300    3160-3160/envoyone.ak.ace.sampleer I/Process﹕ Sending signal. PID: 3160 SIG: 9

将 actionbar= getactionbar(); 替换为 actionBar = getSupportActionBar(); 之后，我的日志变成了这样

  Process: envoyone.ak.ace.sampleer, PID: 3332
    java.lang.ClassCastException: envoyone.ak.ace.sampleer.MainSwipeActivity@d2bd257 must implement OnFragmentInteractionListener
            at envoyone.ak.ace.sampleer.One.onAttach(One.java:84)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:905)
            at android.support.v4.app.FragmentManagerImpl.performPendingDeferredStart(FragmentManager.java:844)
            at android.support.v4.app.Fragment.setUserVisibleHint(Fragment.java:859)
            at android.support.v4.app.FragmentPagerAdapter.setPrimaryItem(FragmentPagerAdapter.java:130)
            at android.support.v4.view.ViewPager.populate(ViewPager.java:1071)
            at android.support.v4.view.ViewPager.populate(ViewPager.java:919)
            at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1441)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
            at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
            at android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:453)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
            at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
            at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
            at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
            at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
            at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
            at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2560)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2001)
            at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1166)
            at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1372)
            at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054)
            at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5779)
            at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
            at android.view.Choreographer.doCallbacks(Choreographer.java:580)
            at android.view.Choreographer.doFrame(Choreographer.java:550)
            at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
04-02 18:03:57.438    3332-3344/envoyone.ak.ace.sampleer I/art﹕ Background partial concurrent mark sweep GC freed 744(142KB) AllocSpace objects, 0(0B) LOS objects, 53% free, 896KB/1920KB, paused 34.582ms total 117.072ms

这里是One.Line84相关的代码

 @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            mListener = (OnFragmentInteractionListener) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                    + " must implement OnFragmentInteractionListener");
        }
    }

Answer 1

你好原来是我在AndroidStudio

新建一个Fragment时自动生成的方法之间发生冲突导致的错误

我通过删除自动化方法并仅保留

解决了这个问题

public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState){
}

这是唯一需要的功能。

我遵循了此处提到的步骤 [http://www.androidhive.info/2013/10/android-tab-layout-with-swipeable-views-1/][1]

感谢大家的帮助。

在 FragmentPagerAdapter 的帮助下将选项卡添加到 ActionBar

Adding Tabs to ActionBar with help of FragmentPagerAdapter

android

android-layout

android-fragments

android-activity