Android片段：屏幕方向更改时崩溃

时间：2013-05-12 09:33:39

标签： android fragment android-fragmentactivity

我的片段存在问题。当屏幕方向改变时，我得到一个空指针异常。这是我的片段代码：

公共类PageFragment扩展Fragment {

 private WeatherCondition data;

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

      // fragment not when container null
      if (container == null) {
         return null;
      }
      // inflate view from layout
      return inflateLayout(inflater, container);
   }

 private View  inflateLayout(LayoutInflater inflater,ViewGroup container) {

      View view = (LinearLayout)inflater.inflate(R.layout.layout_pager,container,false);

      TextView tv = (TextView) view.findViewById(R.id.ora_data);
      tv.setText(data.getSunrise()+"-"+data.getSunset());
      tv=(TextView) view.findViewById(R.id.condizioni_data);
      tv.setText(data.getWeather());
      tv=(TextView) view.findViewById(R.id.windDirection_data);
      tv.setText(data.getWindDirection());
      tv=(TextView) view.findViewById(R.id.windDegree_data);
      tv.setText((Double.toString(data.getWindDegree())));
      tv=(TextView) view.findViewById(R.id.windSpeed_data);
      tv.setText((Double.toString(data.getWindSpeed())));
      tv=(TextView) view.findViewById(R.id.temperatura_data);
      tv.setText(Double.toString(data.getTemperatureC())+" C");
      tv=(TextView) view.findViewById(R.id.umidita_data);
      tv.setText(data.getHumidity()+"%");
      tv=(TextView) view.findViewById(R.id.pressione_data);
      tv.setText(data.getPressure()+" hPa");
      return view;

}

public void setData(WeatherCondition cond) {
    data=cond;
}

}

和调用片段的活动：

public class DetailedMeteo extends SherlockFragmentActivity{
    // list contains fragments to instantiate in the viewpager
    List<PageFragment> fragments = new Vector<PageFragment>();
    // page adapter between fragment list and view pager
    private PagerAdapter mPagerAdapter;
    // view pager
    private ViewPager mPager;

String index;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_detailedmeteo);
    index=getIntent().getStringExtra("indice");
}

@Override
protected void onResume(){
    super.onResume();
    retrieveData(index);
}

private void retrieveData(String i) {

    ArrayList<WeatherCondition> datiOrari=GetData.getGeoDetailedMeteo(i,getApplicationContext());

    for(WeatherCondition cond:datiOrari){
         // creating fragments and adding to list
          PageFragment pg=(PageFragment) Fragment.instantiate(this,PageFragment.class.getName());
          pg.setData(cond);
          fragments.add(pg);
    }

    // creating adapter and linking to view pager
    this.mPagerAdapter = new PagerAdapter(super.getSupportFragmentManager(),fragments);
    mPager = (ViewPager) super.findViewById(R.id.pager);
    mPager.setAdapter(this.mPagerAdapter);

}

}

这里有我的logcat输出：

05-12 11:21:48.695: E/AndroidRuntime(30302): FATAL EXCEPTION: main
05-12 11:21:48.695: E/AndroidRuntime(30302): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.freemeteo/com.meteo.freemeteo.DetailedMeteo}: java.lang.NullPointerException
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3692)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.app.ActivityThread.access$700(ActivityThread.java:141)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1240)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.os.Handler.dispatchMessage(Handler.java:99)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.os.Looper.loop(Looper.java:137)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.app.ActivityThread.main(ActivityThread.java:5041)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at java.lang.reflect.Method.invokeNative(Native Method)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at java.lang.reflect.Method.invoke(Method.java:511)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at dalvik.system.NativeStart.main(Native Method)
05-12 11:21:48.695: E/AndroidRuntime(30302): Caused by: java.lang.NullPointerException
05-12 11:21:48.695: E/AndroidRuntime(30302):    at com.meteo.fragments.PageFragment.inflateLayout(PageFragment.java:33)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at com.meteo.fragments.PageFragment.onCreateView(PageFragment.java:25)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:870)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1080)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:1810)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:501)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1164)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.app.Activity.performStart(Activity.java:5114)
05-12 11:21:48.695: E/AndroidRuntime(30302):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2153)
05-12 11:21:48.695: E/AndroidRuntime(30302):    ... 12 more

这是layout_pager.xml：

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
       android:layout_width="fill_parent"
       android:layout_height="fill_parent"
       android:background="@drawable/background"
       android:gravity="center_horizontal|center_vertical"
       android:orientation="vertical" >
   <ScrollView
       android:layout_width="wrap_content"
       android:layout_height="wrap_content" >
    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/gradient"
        android:orientation="vertical" 
        android:padding="10dp">
    <TextView
        android:id="@+id/ora"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/ora"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
       <TextView
        android:id="@+id/ora_data"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/condizioni_data"
        android:layout_alignParentRight="true"
        android:text="15-17"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
     <TextView
        android:layout_below="@id/ora"
        android:id="@+id/condizioni"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/meteo"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
     <TextView
        android:layout_below="@id/condizioni"
        android:id="@+id/temperatura"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/temperatura"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
     <TextView
        android:layout_below="@id/temperatura"
        android:id="@+id/umidita"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/umidita"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
     <TextView
        android:layout_below="@id/umidita"
        android:id="@+id/pressione"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/pressione"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
     <TextView
        android:layout_below="@id/pressione"
        android:id="@+id/windSpeed"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/vento"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
     <TextView
        android:layout_below="@id/windSpeed"
        android:id="@+id/windDegree"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/ventoGradi"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    <TextView
        android:layout_below="@id/windDegree"
        android:id="@+id/windDirection"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/windDirection"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    <TextView
        android:id="@+id/condizioni_data"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/temperatura_data"
        android:layout_alignParentRight="true"
        android:text="beloo bello"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    <TextView
        android:id="@+id/temperatura_data"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/umidita"
        android:layout_alignParentRight="true"
        android:text="15-17"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    <TextView
        android:id="@+id/umidita_data"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/temperatura_data"
        android:text="70%"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    <TextView
        android:id="@+id/pressione_data"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/pressione"
        android:layout_alignBottom="@+id/pressione"
        android:layout_alignParentRight="true"
        android:text="1024"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    <TextView
        android:id="@+id/windSpeed_data"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/pressione_data"
        android:text="100kmh"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    <TextView
        android:id="@+id/windDegree_data"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/windSpeed"
        android:text="270"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    <TextView
        android:id="@+id/windDirection_data"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:text="SW-E"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    </RelativeLayout>
    </ScrollView>
    </LinearLayout>

有人知道我哪里错吗？

3 个答案:

答案 0 :(得分：3)

尽量不要使用容器，也就是改变它：

View view = (LinearLayout)inflater.inflate(R.layout.layout_pager,container,false);

为此：

View view = (LinearLayout)inflater.inflate(R.layout.layout_pager,null,false);

它应该有用。

答案 1 :(得分：0)

尝试删除这些

  if (container == null) {
     return null;
  }

答案 2 :(得分：0)

将此添加到您的清单文件中，该文件使用Fragment 

 android:configChanges="orientation|screenSize"
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