尝试连接stringArray / ViewPager后，我收到致命异常/空指针异常。我不确定到底出了什么问题（或者我是否应该对我在logcat中出现的Unexpected value from nativeGetEnabledTags: 0付出任何心思。
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12-18 10:49:11.602: W/Trace(19113): Unexpected value from nativeGetEnabledTags: 0
12-18 10:49:11.602: W/Trace(19113): Unexpected value from nativeGetEnabledTags: 0
12-18 10:49:11.603: W/Trace(19113): Unexpected value from nativeGetEnabledTags: 0
12-18 10:49:11.603: E/InputEventReceiver(19113): Exception dispatching input event.
12-18 10:49:11.603: E/MessageQueue-JNI(19113): Exception in MessageQueue callback: handleReceiveCallback
12-18 10:49:11.615: E/MessageQueue-JNI(19113): java.lang.NullPointerException
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at com.idg.omv.ui.phone.Home$2.onPageSelected(Home.java:116)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.support.v4.view.ViewPager.scrollToItem(ViewPager.java:567)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:551)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.support.v4.view.ViewPager.onTouchEvent(ViewPager.java:2015)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.View.dispatchTouchEvent(View.java:7255)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2235)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1932)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2241)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1946)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2241)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1946)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2241)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1946)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2241)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1946)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2241)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1946)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2241)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1946)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2241)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1946)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1968)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1420)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.app.Activity.dispatchTouchEvent(Activity.java:2441)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1916)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.View.dispatchPointerEvent(View.java:7435)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3610)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3538)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4790)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4750)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4902)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:179)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.os.MessageQueue.nativePollOnce(Native Method)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.os.MessageQueue.next(MessageQueue.java:125)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.os.Looper.loop(Looper.java:140)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at android.app.ActivityThread.main(ActivityThread.java:5297)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at java.lang.reflect.Method.invokeNative(Native Method)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at java.lang.reflect.Method.invoke(Method.java:511)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
12-18 10:49:11.615: E/MessageQueue-JNI(19113): at dalvik.system.NativeStart.main(Native Method)
12-18 10:49:11.615: D/AndroidRuntime(19113): Shutting down VM
12-18 10:49:11.615: W/dalvikvm(19113): threadid=1: thread exiting with uncaught exception (group=0x412ca9a8)
12-18 10:49:11.619: E/AndroidRuntime(19113): FATAL EXCEPTION: main
12-18 10:49:11.619: E/AndroidRuntime(19113): java.lang.NullPointerException
12-18 10:49:11.619: E/AndroidRuntime(19113): at com.idg.omv.ui.phone.Home$2.onPageSelected(Home.java:116)
12-18 10:49:11.619: E/AndroidRuntime(19113): at android.support.v4.view.ViewPager.scrollToItem(ViewPager.java:567)
12-18 10:49:11.619: E/AndroidRuntime(19113): at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:551)
12-18 10:49:11.619: E/AndroidRuntime(19113): at android.support.v4.view.ViewPager.onTouchEvent(ViewPager.java:2015)
第116行是.execute（）;这里：
new GetYouTubeUserVideosTask(responseHandler, playlist1)
.execute();
public class Home extends YouTubeBaseActivity implements
VideoClickListener {
private VideosListView listView;
private ActionBarDrawerToggle actionBarDrawerToggle;
public static final String API_KEY = "XXXXXXXXXXXXXXXXXXXXXXXXXX";
public static final String VIDEO_ID = "o7VVHhK9zf0";
private int mCurrentTabPosition = NO_CURRENT_POSITION;
private static final int NO_CURRENT_POSITION = -1;
private DrawerLayout drawerLayout;
private ListView drawerListView;
private String[] drawerListViewItems;
ScrollView mainScrollView;
Button fav_up_btn1;
Button fav_dwn_btn1;
String TAG = "DEBUG THIS";
String playlist = "eminemvevo";
Activity activity;
int imageArray[];
String[] stringArray;
String runPrevious = "No";
private OnPageChangeListener mPageChangeListener;
ImagePagerAdapter adapter = new ImagePagerAdapter();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home);
final ActionBar actionBar = getActionBar();
final ViewPager mPager = (ViewPager) findViewById(R.id.view_pager);
adapter.notifyDataSetChanged();
mPager.setAdapter(adapter);
actionBar.setCustomView(R.layout.actionbar_custom_view_home);
actionBar.setDisplayShowTitleEnabled(false);
actionBar.setDisplayShowCustomEnabled(true);
drawerListViewItems = getResources().getStringArray(R.array.items);
drawerListView = (ListView) findViewById(R.id.left_drawer);
drawerListView.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_listview_item, drawerListViewItems));
mPager.setOnPageChangeListener(mPageChangeListener);
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
actionBarDrawerToggle = new ActionBarDrawerToggle(this,
drawerLayout,
R.drawable.ic_drawer,
R.string.drawer_open,
R.string.drawer_close
);
drawerLayout.setDrawerListener(actionBarDrawerToggle);
getActionBar().setDisplayHomeAsUpEnabled(true);
_initMenu();
drawerLayout.setDrawerShadow(R.drawable.drawer_shadow,
GravityCompat.START);
listView = (VideosListView) findViewById(R.id.videosListView);
listView.setOnVideoClickListener(this);
new GetYouTubeUserVideosTask(responseHandler, playlist).execute();
mPager.setOnPageChangeListener(new OnPageChangeListener() {
@Override
public void onPageSelected(int pos) {
String playlist1 = stringArray[pos];
new GetYouTubeUserVideosTask(responseHandler, playlist1)
.execute();
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
@Override
public void onPageScrollStateChanged(int pos) {
}
});
mPageChangeListener = new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
onTabChanged(mPager.getAdapter(), mCurrentTabPosition, position);
position = mCurrentTabPosition;
int oldPos = mPager.getCurrentItem();
Log.d("PK", "Page selected");
if (position > oldPos) {
System.out.print(position);
// Moving to the right
String playlist = "TheMozARTGROUP";
new GetYouTubeUserVideosTask(responseHandler, playlist)
.execute();
} else if (position < oldPos) {
// Moving to the Left
System.out.print(position);
String playlist = "TheMozARTGROUP";
new GetYouTubeUserVideosTask(responseHandler, playlist)
.execute();
}
mPager.setOnPageChangeListener(mPageChangeListener);
}
private void onTabChanged(PagerAdapter adapter,
int mCurrentTabPosition, int position) {
Log.d("PK", "Tab changed");
// TODO Auto-generated method stub
}
};
}
private class MyActivityGetYouTubeUserVideosTask extends
GetYouTubeUserVideosTask {
public MyActivityGetYouTubeUserVideosTask(Handler replyTo,
String username) {
super(replyTo, username);
// TODO Auto-generated constructor stub
}
@Override
protected void onPostExecute(Void result) {
if (result != null) {
// TODO update your list data
adapter.notifyDataSetChanged();
}
}
}
private void _initMenu() {
// drawerListView.setOnItemClickListener(new DrawerItemClickListener());
}
Handler responseHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
populateListWithVideos(msg);
};
};
private void populateListWithVideos(Message msg) {
Library lib = (Library) msg.getData().get(
GetYouTubeUserVideosTask.LIBRARY);
listView.setVideos(lib.getVideos());
}
@Override
protected void onStop() {
responseHandler = null;
super.onStop();
}
@Override
public void onVideoClicked(Video video) {
Intent intent = new Intent(this, Player.class);
intent.putExtra("id", video.getId());
intent.putExtra("title", video.getTitle());
intent.putExtra("uploader", video.getUploader());
intent.putExtra("viewCount", video.getviewCount());
startActivity(intent);
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
actionBarDrawerToggle.onConfigurationChanged(newConfig);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (actionBarDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
return super.onOptionsItemSelected(item);
}
private class ImagePagerAdapter extends PagerAdapter implements
ViewPager.OnPageChangeListener {
public ImagePagerAdapter(Activity act, int[] mImages,
String[] stringArra) {
imageArray = mImages;
activity = act;
stringArray = stringArra;
}
public ImagePagerAdapter() {
super();
}
private int[] mImages = new int[] { R.drawable.selstation_up_btn,
R.drawable.classical_up_btn, R.drawable.country_up_btn,
R.drawable.dance_up_btn, R.drawable.hiphop_up_btn,
R.drawable.island_up_btn, R.drawable.latin_up_btn,
R.drawable.pop_up_btn, R.drawable.samba_up_btn };
private String[] stringArray = new String[] { "vevo",
"TheMozARTGROUP", "TimMcGrawVEVO", "TiestoVEVO",
"EminemVEVO" };
@Override
public int getCount() {
return mImages.length;
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == ((ImageView) object);
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
Context context = Home.this;
ImageView imageView = new ImageView(context);
imageView.setScaleType(ScaleType.FIT_XY);
imageView.setImageResource(mImages[position]);
((ViewPager) container).addView(imageView, 0);
return imageView;
}
public void destroyItem(ViewGroup container, int position, Object object) {
((ViewPager) container).removeView((ImageView) object);
}
private class DrawerItemClickListener implements
ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView parent, View view,
int position, long id) {
Log.d("pk", "onItemClick");
// Highlight the selected item, update the title, and close the
// drawer
// update selected item and title, then close the drawer
drawerListView.setItemChecked(position, true);
setTitle("......");
String text = "menu click... should be implemented";
// Toast.makeText(Home.this, text, Toast.LENGTH_LONG).show();
drawerLayout.closeDrawer(drawerListView);
}
}
@Override
public void onPageScrollStateChanged(int arg0) {
// TODO Auto-generated method stub
Log.d("pk", "onPageScrollStateChanged");
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
// TODO Auto-generated method stub
Log.d("pk", "onPageScrolled");
}
@Override
public void onPageSelected(int arg0) {
// TODO Auto-generated method stub
Log.d("pk", "onPageSelected");
}
}
}
答案 0 :(得分：1)
String[] stringArray; // is not initialized
和这个
private String[] stringArray = new String[] { "vevo",
"TheMozARTGROUP", "TimMcGrawVEVO", "TiestoVEVO",
"EminemVEVO" };
在ImageAdapter。可能是你想要将其移出ImageAdapter类
所以我相信playlist1为空。您还将playList声明为实例变量。
答案 1 :(得分：0)
你确定，第116行之后的行
mPager.setOnPageChangeListener(mPageChangeListener);
在这里正确吗？它似乎属于mPageChangeListener的定义，对我来说看起来很奇怪。