java - 滑动选项卡时出错 - Android 应用程序

Question

我尝试开发一个 Android 应用程序 - Swipe Tabs，其中包含三个 fragment (A、B 和 C)。它与我的代码配合得很好。下一步我尝试在 fragment A 中添加 ListView 。

然后我尝试填充 Main Activity.java 文件中的 ListView 。我的错误来了。在我的 MainActivity.java 文件中，有两个类用作适配器。该错误全部与运行时有关，即我的应用程序已不幸停止!!!

以下是我使用的代码。

    package com.techcruise.swipe;


    import android.app.ActionBar;
    import android.app.ActionBar.Tab;
    import android.app.ActionBar.TabListener;
    import android.app.FragmentTransaction;
    import android.os.Bundle;
    import android.app.Fragment;
    import android.content.Context;
    import android.content.res.Resources;
    import android.support.v4.app.FragmentActivity;
    import android.support.v4.app.FragmentManager;
    import android.support.v4.app.FragmentPagerAdapter;
    import android.support.v4.view.ViewPager;
    import android.util.Log;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ArrayAdapter;
    import android.widget.ImageView;
    import android.widget.ListView;
    import android.widget.TextView;



    public class MainActivity extends FragmentActivity {

        ActionBar actionBar;
        ViewPager viewpager;
        ListView list;
        String[] titles;
        String[] descr;
        int[] images = {R.drawable.aavishkaar,R.drawable.addidas,R.drawable.addons_women,R.drawable.airtel,R.drawable.allen_solly,R.drawable.archies,R.drawable.arrow,R.drawable.basics_life,R.drawable.bata,R.drawable.beanstalk,R.drawable.biba,R.drawable.black_berrys,R.drawable.casio,R.drawable.citibank_atm,R.drawable.clarks,R.drawable.classic_polo,R.drawable.cocktail,R.drawable.crocodile,R.drawable.crusoe,R.drawable.csb_atm,R.drawable.cub_atm,R.drawable.dar_jewellery,R.drawable.derby,R.drawable.diva,R.drawable.druken,R.drawable.faces_canada,R.drawable.fashion_place,R.drawable.funskool,R.drawable.giny_jony,R.drawable.gocolors,R.drawable.green_gold_store,R.drawable.hidesign,R.drawable.home_centre,R.drawable.hp_world,R.drawable.indian_terrian,R.drawable.iob,R.drawable.isha_shop,R.drawable.jashn,R.drawable.jockey,R.drawable.kvb_atm,R.drawable.lavie,R.drawable.lawrence_mayo,R.drawable.lee,R.drawable.legends,R.drawable.levis,R.drawable.lifestyle,R.drawable.maybell,R.drawable.mehandi,R.drawable.methiyadi,R.drawable.mochi,R.drawable.mom_me,R.drawable.mufti,R.drawable.naturals_longue,R.drawable.new_indian_emporium,R.drawable.nike,R.drawable.nokia,R.drawable.odyssey,R.drawable.otto,R.drawable.pantaloons,R.drawable.pepe_jeans,R.drawable.peter_england,R.drawable.planet_sports,R.drawable.poorvika,R.drawable.propel_fitness,R.drawable.puma,R.drawable.queens_ethinic_trends,R.drawable.rathna_video_audio,R.drawable.relaince_footprint,R.drawable.relaince_trends,R.drawable.reynolds_write_site,R.drawable.rmkv_kids,R.drawable.rmkv,R.drawable.safari,R.drawable.samsonite,R.drawable.samsung_smart_phine_cafe,R.drawable.savithri_photo_house,R.drawable.sbi_atm,R.drawable.soch,R.drawable.sony_vaio,R.drawable.spar,R.drawable.spice_hotspot,R.drawable.sss_car_spa,R.drawable.sthri_elite,R.drawable.sting,R.drawable.the_chennai_mobiles,R.drawable.titan,R.drawable.united_colors,R.drawable.van_heusen,R.drawable.westside,R.drawable.woodland,R.drawable.wrangler,R.drawable.zimson};


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

            Resources res = getResources();
            titles= res.getStringArray(R.array.title);
            descr = res.getStringArray(R.array.desc);

            list = (ListView) findViewById(R.id.listView1);

          ivAdapter adapter = new ivAdapter(this,titles,images,descr);
       list.setAdapter(adapter);

            viewpager = (ViewPager) findViewById (R.id.pager);
            viewpager.setAdapter(new VineshAdapter(getSupportFragmentManager()));
            viewpager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

                @Override
                public void onPageSelected(int arg0) {
                    // TODO Auto-generated method stub
                    Log.d("techcruise","onPageSelected at "+" position "+arg0);
                }

                @Override
                public void onPageScrolled(int arg0, float arg1, int arg2) {
                    // TODO Auto-generated method stub
                    Log.d("techcruise","onPageScrolled at "+" position "+arg0+" from "+arg1+" with number of pixels="+arg2);
                }

                @Override
                public void onPageScrollStateChanged(int arg0) {
                    // TODO Auto-generated method stub
                    if(arg0==ViewPager.SCROLL_STATE_IDLE)
                    {
                        Log.d("techcruise", "onPageScrollStateChanged Idle");
                    }
                    if(arg0==ViewPager.SCROLL_STATE_DRAGGING)
                    {
                        Log.d("techcruise", "onPageScrollStateChanged Dragging");
                    }
                    if(arg0==ViewPager.SCROLL_STATE_SETTLING)
                    {
                        Log.d("techcruise", "onPageScrollStateChanged Settling");
                    }
                }
            });
}
}
class ivAdapter extends ArrayAdapter<String>
{
    Context context;
    int[] images;
    String[] mytitle;
    String[] mydescp;
    ivAdapter(Context c, String[] tittles, int[] imgs, String[] desc)
    {
        super(c, R.layout.single_row, R.id.listView1, tittles);
        this.context=c;
        this.images=imgs;
        this.mytitle= tittles;
        this.mydescp=desc;
    }
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        try 
        {   
        LayoutInflater inflator = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View row = inflator.inflate(R.layout.single_row, parent, false);
        ImageView myImage = (ImageView) row.findViewById(R.id.imageViewsr);
        TextView myText = (TextView) row.findViewById(R.id.textViewsr);
        TextView mydesc = (TextView) row.findViewById(R.id.textViewsr1);

        myImage.setImageResource(images[position]);
        myText.setText(mytitle[position]);
        mydesc.setText(mydescp[position]);

        return row;
        }
        catch (Exception ex)
        {
            return convertView;
        }
    }
}
class VineshAdapter extends FragmentPagerAdapter 
{

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

    @Override
    public android.support.v4.app.Fragment getItem(int arg0) {
        // TODO Auto-generated method stub
        android.support.v4.app.Fragment fragment=null;
        if(arg0==0)
        {
            fragment=new FragmentA();
        }
        if(arg0==1)
        {
            fragment =new FragmentB();
        }
        if(arg0==2)
        {
            fragment =new FragmentC();
        }
        return fragment;
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return 3;
    }
}

我的应用程序还有其他方法吗？？？需要帮助吗？？

以下是LogCAt:

03-13 11:58:56.186: D/ActivityThread(30403): hoder:android.app.IActivityManager$ContentProviderHolder@41d867c8,provider,holder.Provider:android.content.ContentProviderProxy@41d86f40
03-13 11:58:56.189: D/asset(30403): AssetManager-->addDefaultAssets CIP path not exsit!
03-13 11:58:56.192: D/Proxy(30403): setHttpRequestCheckHandler
03-13 11:58:56.193: D/dalvikvm(30403): open_cached_dex_file : /data/app/com.techcruise.swipe-2.apk /data/dalvik-cache/data@app@com.techcruise.swipe-2.apk@classes.dex
03-13 11:58:56.196: D/ActivityThread(30403): BIND_APPLICATION handled : 0 / AppBindData{appInfo=ApplicationInfo{41d84120 com.techcruise.swipe}}
03-13 11:58:56.341: D/AndroidRuntime(30403): Shutting down VM
03-13 11:58:56.341: W/dalvikvm(30403): threadid=1: thread exiting with uncaught exception (group=0x41a2fc98)
03-13 11:58:56.341: W/dalvikvm(30403): threadid=1: uncaught exception occurred
03-13 11:58:56.342: W/System.err(30403): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.techcruise.swipe/com.techcruise.swipe.MainActivity}: java.lang.NullPointerException
03-13 11:58:56.342: W/System.err(30403):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2338)
03-13 11:58:56.342: W/System.err(30403):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
03-13 11:58:56.343: W/System.err(30403):    at android.app.ActivityThread.access$800(ActivityThread.java:151)
03-13 11:58:56.343: W/System.err(30403):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
03-13 11:58:56.343: W/System.err(30403):    at android.os.Handler.dispatchMessage(Handler.java:110)
03-13 11:58:56.343: W/System.err(30403):    at android.os.Looper.loop(Looper.java:193)
03-13 11:58:56.343: W/System.err(30403):    at android.app.ActivityThread.main(ActivityThread.java:5292)
03-13 11:58:56.343: W/System.err(30403):    at java.lang.reflect.Method.invokeNative(Native Method)
03-13 11:58:56.343: W/System.err(30403):    at java.lang.reflect.Method.invoke(Method.java:515)
03-13 11:58:56.344: W/System.err(30403):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
03-13 11:58:56.344: W/System.err(30403):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
03-13 11:58:56.344: W/System.err(30403):    at dalvik.system.NativeStart.main(Native Method)
03-13 11:58:56.344: W/System.err(30403): Caused by: java.lang.NullPointerException
03-13 11:58:56.345: W/System.err(30403):    at com.techcruise.swipe.MainActivity.onCreate(MainActivity.java:49)
03-13 11:58:56.345: W/System.err(30403):    at android.app.Activity.performCreate(Activity.java:5264)
03-13 11:58:56.345: W/System.err(30403):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1088)
03-13 11:58:56.346: W/System.err(30403):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2302)
03-13 11:58:56.346: W/System.err(30403):    ... 11 more
03-13 11:58:56.346: W/dalvikvm(30403): threadid=1: calling UncaughtExceptionHandler
03-13 11:58:56.347: E/AndroidRuntime(30403): FATAL EXCEPTION: main
03-13 11:58:56.347: E/AndroidRuntime(30403): Process: com.techcruise.swipe, PID: 30403
03-13 11:58:56.347: E/AndroidRuntime(30403): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.techcruise.swipe/com.techcruise.swipe.MainActivity}: java.lang.NullPointerException
03-13 11:58:56.347: E/AndroidRuntime(30403):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2338)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at android.app.ActivityThread.access$800(ActivityThread.java:151)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at android.os.Handler.dispatchMessage(Handler.java:110)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at android.os.Looper.loop(Looper.java:193)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at android.app.ActivityThread.main(ActivityThread.java:5292)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at java.lang.reflect.Method.invokeNative(Native Method)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at java.lang.reflect.Method.invoke(Method.java:515)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at dalvik.system.NativeStart.main(Native Method)
03-13 11:58:56.347: E/AndroidRuntime(30403): Caused by: java.lang.NullPointerException
03-13 11:58:56.347: E/AndroidRuntime(30403):    at com.techcruise.swipe.MainActivity.onCreate(MainActivity.java:49)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at android.app.Activity.performCreate(Activity.java:5264)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1088)
03-13 11:58:56.347: E/AndroidRuntime(30403):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2302)
03-13 11:58:56.347: E/AndroidRuntime(30403):    ... 11 more

Answer 1

-嘿!维内什。您在“49”行遇到空指针异常，这可能是在 setadapter 检查您的“标题、图像、描述”是否为空，检查您获得的是什么为空。

-谢谢