Question

我一直试图让我的漂亮的基本地图应用程序与jfeinstein10的SlidingMenu一起使用，并且每次尝试获取地图时都会收到NullPointerException。在我尝试实现SlidingMenu之前它工作得很好，所以当我将MainActivity从Activity切换到来自jfeinstein10的SlidingMenuExample的BaseActivity时，我必须搞砸了。我的MainActivity＆＃39; onCreate看起来像这样< / p>

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null)
        mContent = getSupportFragmentManager().getFragment(savedInstanceState, "mContent");
    if (mContent == null)
        mContent = new MainView();


    setContentView(R.layout.content_frame);
    getSupportFragmentManager()
    .beginTransaction()
    .replace(R.id.content_frame, mContent).commit();

    setBehindContentView(R.layout.menu_frame);
    getSupportFragmentManager()
    .beginTransaction()
    .replace(R.id.menu_frame, new RandomList()).commit();
    getSlidingMenu().setTouchModeAbove(SlidingMenu.TOUCHMODE_FULLSCREEN);
    setSlidingActionBarEnabled(true);
    setUpMapIfNeeded();
    //testMap();
}
private void setUpMapIfNeeded(){
    if (map == null) {
        FragmentManager fmanager = getSupportFragmentManager();
        Fragment fragment = fmanager.findFragmentById(R.id.map);
        SupportMapFragment supportmapfragment = (SupportMapFragment) fragment;
        map = supportmapfragment.getMap();
        if (map != null) {
                map.setMapType(MapOptions.getMapType());
                map.getUiSettings().setAllGesturesEnabled(true); 
                map.setMyLocationEnabled(true);
                if(MapOptions.getCenterPoint() != null) {
                    map.moveCamera(CameraUpdateFactory.newLatLngZoom(MapOptions.getCenterPoint().getPosition(), 14));
        }
    }
}

Thiis调用MainView类，如下所示，

public class MainView extends SherlockFragment {

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.activity_main, container, false);
    }
}

我的MainActivity扩展了我在这里粘贴的BaseActivity，

public class BaseActivity extends SlidingFragmentActivity {

    private int mTitleRes;
    protected ListFragment mFrag;

    public BaseActivity(int titleRes){
        mTitleRes = titleRes;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setTitle(mTitleRes);

        setBehindContentView(R.layout.menu_frame);
        FragmentTransaction ft = this.getSupportFragmentManager().beginTransaction();
        mFrag = new RandomList();
        ft.replace(R.id.menu_frame, mFrag);
        ft.commit();

        final SlidingMenu sm = getSlidingMenu();
        sm.setShadowWidth(15);
        sm.setShadowDrawable(R.drawable.shadow);
        sm.setBehindOffset(60);
        sm.setFadeDegree(0.35f);
        sm.setTouchModeAbove(SlidingMenu.TOUCHMODE_FULLSCREEN);
        sm.setBehindCanvasTransformer(new CanvasTransformer(){
            @TargetApi(Build.VERSION_CODES.HONEYCOMB)
            @SuppressLint("NewApi")
            @Override
            public void transformCanvas(Canvas canvas, float percentOpen) {
                // TODO Auto-generated method stub
                boolean layer = percentOpen > 0.0f && percentOpen < 1.0f;
                int layerType = layer ? View.LAYER_TYPE_HARDWARE : View.LAYER_TYPE_NONE;

                if (layerType != sm.getContent().getLayerType()){
                    sm.getContent().setLayerType(layerType, null);
                    sm.getMenu().setLayerType(layerType, null);
                }
            }
        });

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setIcon(R.drawable.ic_launcher);

    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item){
        switch(item.getItemId()){
        case android.R.id.home:
            toggle();
            return true;
        }
        return onOptionsItemSelected(item);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu){
        getSupportMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

    public class BasePagerAdapter extends FragmentPagerAdapter{
        private List<Fragment> mFragments = new ArrayList<Fragment>();
        private ViewPager mPager;

        public BasePagerAdapter(FragmentManager fm, ViewPager vp){
            super(fm);
            mPager = vp;
            mPager.setAdapter(this);
            for (int i = 0; i < 3; i++){
                addTab(new RandomList());
            }
        }

        public void addTab(Fragment frag){
            mFragments.add(frag);
        }

        @Override
        public Fragment getItem(int position){
            return mFragments.get(position);
        }

        @Override
        public int getCount(){
            return mFragments.size();
        }
    }

}

我的activity_main的xml文件是

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <fragment
        android:id="@+id/map"
        android:name="com.google.android.gms.maps.SupportMapFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

最后，这是我在LogCat中遇到的错误。关于如何解决这个问题的任何想法？

03-26 16:13:54.427: E/AndroidRuntime(18720): FATAL EXCEPTION: main
03-26 16:13:54.427: E/AndroidRuntime(18720): Process: com.example.kennai, PID: 18720
03-26 16:13:54.427: E/AndroidRuntime(18720): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.kennai/com.example.kennai.MainActivity}: java.lang.NullPointerException
03-26 16:13:54.427: E/AndroidRuntime(18720):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at android.app.ActivityThread.access$800(ActivityThread.java:135)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at android.os.Handler.dispatchMessage(Handler.java:102)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at android.os.Looper.loop(Looper.java:136)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at android.app.ActivityThread.main(ActivityThread.java:5017)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at java.lang.reflect.Method.invokeNative(Native Method)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at java.lang.reflect.Method.invoke(Method.java:515)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at dalvik.system.NativeStart.main(Native Method)
03-26 16:13:54.427: E/AndroidRuntime(18720): Caused by: java.lang.NullPointerException
03-26 16:13:54.427: E/AndroidRuntime(18720):    at com.example.kennai.MainActivity.setUpMapIfNeeded(MainActivity.java:197)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at com.example.kennai.MainActivity.onCreate(MainActivity.java:74)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at android.app.Activity.performCreate(Activity.java:5231)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
03-26 16:13:54.427: E/AndroidRuntime(18720):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
03-26 16:13:54.427: E/AndroidRuntime(18720):    ... 11 more

谢谢，尼克

使用SlidingMenu的Android GoogleMap

0 个答案: