当我从一个活动打开活动时遇到麻烦，当我按下手机的后退按钮时，应用程序崩溃了。在这里，我描述了活动和片段的所有细节。
FeedFragment.java
public class FeedFragment extends BaseFragment {
ListView lvFeeds;
TextView tvNoRecord;
public static Handler[] handler;
public static Runnable[] animateViewPager;
static Handler bannerHandler;
static Runnable bannerRunnable;
boolean stopSliding = false;
boolean isLastItemLoaded = false;
FeedAdapter feedAdapter;
ArrayList<FeedBean> feedList = new ArrayList<>();
int[] bannerImages = new int[]{
R.drawable.ic_feed_one,
R.drawable.ic_feed_two,
R.drawable.ic_feed_three,
R.drawable.ic_feed_four,
R.drawable.ic_feed_five
};
String articleId;
static int position = 0;
@SuppressLint("NewApi")
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_feed, container, false);
lvFeeds = (ListView) view.findViewById(R.id.lvFeeds);
tvNoRecord = (TextView) view.findViewById(R.id.tvNoRecord);
LayoutInflater mInflater = (LayoutInflater) getActivity()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
final View headerView = mInflater.inflate(R.layout.feed_banner_view, null);
CirclePageIndicator cpiBanner = (CirclePageIndicator) headerView.findViewById(R.id.indicators);
final JazzyViewPager vpFeedBanner = (JazzyViewPager) headerView.findViewById(R.id.vpFeeds);
vpFeedBanner.setTransitionEffect(JazzyViewPager.TransitionEffect.Accordion);
BannerAdapter pagerAdapter = new BannerAdapter(vpFeedBanner);
vpFeedBanner.setAdapter(pagerAdapter);
cpiBanner.setViewPager(vpFeedBanner);
cpiBanner.setCurrentItem(vpFeedBanner.getCurrentItem());
lvFeeds.addHeaderView(headerView);
listFeed();
bannerHandler = new Handler();
bannerRunnable = new Runnable() {
public void run() {
try {
if (position >= bannerImages.length - 1) {
vpFeedBanner.setCurrentItem(0);
} else {
vpFeedBanner.setCurrentItem(
vpFeedBanner.getCurrentItem() + 1, true);
}
bannerHandler.postDelayed(bannerRunnable, Constant.VP_ANIMATION_TIME);
} catch (Exception e) {
e.printStackTrace();
}
}
};
return view;
}
@Override
public void onResume() {
super.onResume();
try {
if (!feedList.isEmpty())
setAllSlidingAnimation(feedList.size());
bannerHandler.postDelayed(bannerRunnable, Constant.VP_ANIMATION_TIME);
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void onPause() {
super.onPause();
try {
if (bannerHandler != null) {
bannerHandler.removeCallbacks(bannerRunnable);
}
if (!feedList.isEmpty())
removeAllSlidingAnimation(feedList.size());
} catch (Exception e) {
e.printStackTrace();
}
}
class BannerAdapter extends PagerAdapter {
JazzyViewPager vpFloor;
LayoutInflater mInflater;
public BannerAdapter(JazzyViewPager viewPager) {
this.vpFloor = viewPager;
mInflater = (LayoutInflater) getActivity()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
class ViewHolder {
RoundedImageView ivFeed;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView(vpFloor.findViewFromObject(position));
}
@Override
public Object instantiateItem(ViewGroup container, final int position) {
final ViewHolder viewHolder = new ViewHolder();
View layout = mInflater.inflate(R.layout.row_feed_view_pager_banner, null);
viewHolder.ivFeed = (RoundedImageView) layout.findViewById(R.id.ivFeed);
try {
BaseActivity.setImageToBanner(getActivity(), bannerImages[position], viewHolder.ivFeed);
viewHolder.ivFeed.setImageDrawable(getResources().getDrawable(bannerImages[position]));
vpFloor.setObjectForPosition(layout, position);
container.addView(layout);
} catch (Exception e) {
e.printStackTrace();
}
return layout;
}
@Override
public int getCount() {
return bannerImages.length;
}
@Override
public boolean isViewFromObject(View view, Object object) {
if (view instanceof OutlineContainer) {
return ((OutlineContainer) view).getChildAt(0) == object;
} else {
return view == object;
}
}
}
void listFeed() {
BaseActivity.showLoader(getActivity());
JSONObject feedObj = null;
RequestQueue queue = Volley.newRequestQueue(getActivity());
final String serverRequest = Constant.WEB_SERVICE_LIST_FEED;
Log.e("", "ListFeed URL : " + serverRequest);
JsonObjectRequest jsObjRequest = new JsonObjectRequest(
com.android.volley.Request.Method.POST, serverRequest,
null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
Log.e("",
"ListFeed Response : " + response.toString());
JSONObject serverResponse = response
.getJSONObject(Constant.LIST_FEED_ACTION);
String Ws_Status = serverResponse.getString(Constant.TAG_STATUS);
String Ws_Message = serverResponse.getString(Constant.TAG_MESSAGE);
BaseActivity.hideLoader();
if (serverResponse.getString(Constant.TAG_STATUS)
.equalsIgnoreCase(Constant.TAG_STATUS_FAILURE)) {
} else {
feedList.clear();
JSONArray categoriesArray = serverResponse.getJSONArray(Constant.TAG_CATEGORIES);
int categoryLength = categoriesArray.length();
handler = new Handler[categoryLength + 1];
animateViewPager = new Runnable[categoryLength + 1];
for (int i = 0; i < categoriesArray.length(); i++) {
JSONObject categoriesObject = categoriesArray.getJSONObject(i);
FeedBean feedBean = new FeedBean();
feedBean.setId(categoriesObject.getString(Constant.TAG_ID));
feedBean.setName(categoriesObject.getString(Constant.TAG_NAME));
JSONArray articles = categoriesObject.getJSONArray(Constant.TAG_ARTICLES);
ArrayList<ArticleBean> articleList = new ArrayList<>();
for (int j = 0; j < articles.length(); j++) {
JSONObject articlesObject = articles.getJSONObject(j);
ArticleBean articleBean = new ArticleBean();
articleBean.setId(articlesObject.getString(Constant.TAG_ID));
articleBean.setTitle(articlesObject.getString(Constant.TAG_TITLE));
articleBean.setTimeLapsed(articlesObject.getString(Constant.TAG_TIME_LAPSED));
articleBean.setBody(articlesObject.getString(Constant.TAG_BODY));
articleBean.setArticleUrl(articlesObject.getString(Constant.TAG_ARTICLE_URL));
articleBean.setTags(articlesObject.getString(Constant.TAG_TAGS));
articleBean.setUserId(articlesObject.getString(Constant.TAG_USER_ID));
articleBean.setFeaturedImage(articlesObject.getString(Constant.TAG_FEATURED_IMAGE));
articleBean.setLikeCounter(articlesObject.getString(Constant.TAG_LIKE_COUNTER));
articleBean.setLocation(articlesObject.getString(Constant.TAG_LOCATION));
articleList.add(articleBean);
}
feedBean.articleBeanList = articleList;
int articleLength = articles.length();
feedBean.setArticleLength(articleLength);
feedList.add(feedBean);
}
feedAdapter = new FeedAdapter();
lvFeeds.setAdapter(feedAdapter);
removeAllSlidingAnimation(feedList.size());
setAllSlidingAnimation(feedList.size());
}
} catch (Exception e) {
BaseActivity.hideLoader();
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError e) {
BaseActivity.hideLoader();
e.printStackTrace();
}
});
jsObjRequest.setRetryPolicy(new DefaultRetryPolicy(Constant.WEB_SERVICE_TIME_OUT,
DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
queue.add(jsObjRequest);
}
void removeAllSlidingAnimation(int length) {
try {
for (int i = 0; i < length; i++) {
if (handler[i] != null) {
handler[i].removeCallbacks(animateViewPager[i]);
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
void setAllSlidingAnimation(int length) {
try {
for (int i = 0; i < length; i++) {
if (handler[i] != null) {
handler[i].postDelayed(animateViewPager[i], Constant.VP_ANIMATION_TIME);
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
public void runnable(final int size, final JazzyViewPager mViewPager, final int position) {
try {
handler[position] = new Handler();
animateViewPager[position] = new Runnable() {
public void run() {
if (!stopSliding) {
if (mViewPager.getCurrentItem() == size - 1) {
mViewPager.setCurrentItem(0);
} else {
mViewPager.setCurrentItem(
mViewPager.getCurrentItem() + 1, true);
}
try {
handler[position].postDelayed(animateViewPager[position], Constant.VP_ANIMATION_TIME);
} catch (NullPointerException e) {
e.printStackTrace();
}
}
}
};
} catch (Exception e) {
e.printStackTrace();
}
}
class FeedAdapter extends BaseAdapter {
private LayoutInflater inflater = null;
public FeedAdapter() {
inflater = (LayoutInflater) getActivity()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
return feedList.size();
}
@Override
public Object getItem(int position) {
return feedList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int i, View convertView, ViewGroup parent) {
View itemView = convertView;
ViewHolder viewHolder = null;
if (convertView == null) {
itemView = inflater.inflate(R.layout.row_feed, null);
viewHolder = new ViewHolder();
viewHolder.llFeed = (LinearLayout) itemView.findViewById(R.id.llFeed);
viewHolder.vpFeeds = (JazzyViewPager) itemView.findViewById(R.id.vpFeeds);
viewHolder.indicators = (CirclePageIndicator) itemView.findViewById(R.id.indicators);
viewHolder.tvFeedTitle = (TextView) itemView.findViewById(R.id.tvFeedTitle);
viewHolder.tvFeedSubTitle = (TextView) itemView.findViewById(R.id.tvFeedSubTitle);
viewHolder.tvFeedTime = (TextView) itemView.findViewById(R.id.tvFeedTime);
viewHolder.tvCategoryName = (TextView) itemView.findViewById(R.id.tvCategoryName);
viewHolder.vpFeeds.setTransitionEffect(JazzyViewPager.TransitionEffect.Accordion);
itemView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) itemView.getTag();
}
try {
FeedBean bean = feedList.get(i);
FeedPagerAdapter pagerAdapter = new FeedPagerAdapter(viewHolder.vpFeeds, viewHolder.tvFeedTitle, viewHolder.tvFeedSubTitle, viewHolder.tvFeedTime, bean, viewHolder.llFeed, viewHolder.indicators);
viewHolder.vpFeeds.setAdapter(pagerAdapter);
viewHolder.indicators.setViewPager(viewHolder.vpFeeds);
viewHolder.indicators.setCurrentItem(viewHolder.vpFeeds.getCurrentItem());
viewHolder.tvCategoryName.setText(bean.getName().toUpperCase().trim());
if (viewHolder.tvCategoryName.getText().toString().equalsIgnoreCase(Constant.CAT_FEATURED)) {
viewHolder.tvCategoryName.setBackgroundColor(getResources().getColor(R.color.color_feed_yellow));
} else if (viewHolder.tvCategoryName.getText().toString().equalsIgnoreCase(Constant.CAT_ORIGINAL)) {
viewHolder.tvCategoryName.setBackgroundColor(getResources().getColor(R.color.color_feed_purple));
} else if (viewHolder.tvCategoryName.getText().toString().equalsIgnoreCase(Constant.CAT_MUSIC)) {
viewHolder.tvCategoryName.setBackgroundColor(getResources().getColor(R.color.color_feed_pink));
} else if (viewHolder.tvCategoryName.getText().toString().equalsIgnoreCase(Constant.CAT_GIVE)) {
viewHolder.tvCategoryName.setBackgroundColor(getResources().getColor(R.color.color_feed_lightGreen));
} else if (viewHolder.tvCategoryName.getText().toString().equalsIgnoreCase(Constant.CAT_LIFESTYLE)) {
viewHolder.tvCategoryName.setBackgroundColor(getResources().getColor(R.color.color_feed_parrot));
} else if (viewHolder.tvCategoryName.getText().toString().equalsIgnoreCase(Constant.CAT_INSPIRATION)) {
viewHolder.tvCategoryName.setBackgroundColor(getResources().getColor(R.color.color_feed_lightRed));
} else if (viewHolder.tvCategoryName.getText().toString().equalsIgnoreCase(Constant.CAT_TECH)) {
viewHolder.tvCategoryName.setBackgroundColor(getResources().getColor(R.color.color_lightBlack));
} else if (viewHolder.tvCategoryName.getText().toString().equalsIgnoreCase(Constant.CAT_FASHION)) {
viewHolder.tvCategoryName.setBackgroundColor(getResources().getColor(R.color.color_feed_lightBlue));
} else {
viewHolder.tvCategoryName.setBackgroundColor(getResources().getColor(R.color.color_feed_pink));
}
runnable(bean.getArticleLength(), viewHolder.vpFeeds, i);
if (i != 0)
if ((i + 1) % 2 == 0) {
if (!isLastItemLoaded) {
removeAllSlidingAnimation(i);
setAllSlidingAnimation(i);
}
}
} catch (Exception e) {
e.printStackTrace();
}
return itemView;
}
class ViewHolder {
JazzyViewPager vpFeeds;
TextView tvFeedTitle, tvFeedSubTitle, tvFeedTime, tvCategoryName;
CirclePageIndicator indicators;
LinearLayout llFeed;
}
}
class FeedPagerAdapter extends PagerAdapter {
JazzyViewPager vpFloor;
private LayoutInflater mInflater;
TextView tvFeedTitle, tvFeedSubTitle, tvFeedTime;
FeedBean bean;
LinearLayout llFeed;
CirclePageIndicator indicators;
public FeedPagerAdapter(JazzyViewPager vpFloor, TextView tvFeedTitle, TextView tvFeedSubTitle, TextView tvFeedTime, FeedBean bean, LinearLayout llFeed, CirclePageIndicator indicators) {
this.vpFloor = vpFloor;
mInflater = (LayoutInflater) getActivity()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
this.tvFeedTitle = tvFeedTitle;
this.tvFeedTime = tvFeedTime;
this.tvFeedSubTitle = tvFeedSubTitle;
this.bean = bean;
this.llFeed = llFeed;
this.indicators = indicators;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView(vpFloor.findViewFromObject(position));
}
@Override
public Object instantiateItem(ViewGroup container, final int position) {
final ViewHolder viewHolder = new ViewHolder();
View layout = mInflater.inflate(R.layout.row_feed_view_pager, null);
viewHolder.ivFeed = (RoundedImageView) layout.findViewById(R.id.ivFeed);
try {
BaseActivity.setImageToView(getActivity(), bean.articleBeanList.get(position).getFeaturedImage(), viewHolder.ivFeed);
} catch (Exception e) {
e.printStackTrace();
}
llFeed.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
if (bean.articleBeanList.size() == 1) {
openDetailActivity(bean.articleBeanList.get(position).getId());
} else {
openDetailActivity(bean.articleBeanList.get(position).getId());
}
} catch (Exception e) {
e.printStackTrace();
}
}
});
vpFloor.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
try {
tvFeedTitle.setText(bean.articleBeanList.get(position).getTitle().toUpperCase());
tvFeedSubTitle.setText(bean.articleBeanList.get(position).getBody().toUpperCase());
tvFeedTime.setText(bean.articleBeanList.get(position).getTimeLapsed().toUpperCase());
articleId = bean.articleBeanList.get(position).getId();
indicators.setCurrentItem(position);
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
layout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
if (bean.articleBeanList.size() == 1) {
openDetailActivity(bean.articleBeanList.get(position).getId());
} else {
openDetailActivity(bean.articleBeanList.get(position).getId());
}
} catch (Exception e) {
}
}
});
try {
vpFloor.setObjectForPosition(layout, position);
tvFeedTitle.setText(bean.articleBeanList.get(vpFloor.getCurrentItem()).getTitle().toUpperCase());
tvFeedTitle.setText(bean.articleBeanList.get(vpFloor.getCurrentItem()).getTitle().toUpperCase());
tvFeedSubTitle.setText(bean.articleBeanList.get(vpFloor.getCurrentItem()).getBody().toUpperCase());
tvFeedTime.setText(bean.articleBeanList.get(vpFloor.getCurrentItem()).getTimeLapsed().toUpperCase());
articleId = bean.articleBeanList.get(vpFloor.getCurrentItem()).getId();
} catch (Exception e) {
e.printStackTrace();
}
container.addView(layout);
return layout;
}
class ViewHolder {
RoundedImageView ivFeed;
}
@Override
public int getCount() {
return bean.getArticleLength();
}
@Override
public boolean isViewFromObject(View view, Object obj) {
if (view instanceof OutlineContainer) {
return ((OutlineContainer) view).getChildAt(0) == obj;
} else {
return view == obj;
}
}
}
void openDetailActivity(String articleId) {
startActivity(new Intent(DashboardActivity.context, StoriesDetailsActivity.class).putExtra(Constant.TAG_ID, articleId));
}
}
logcat的
FATAL EXCEPTION: main
01-19 19:27:29.134 19925-19925/com.cultureapp E/AndroidRuntime: Process: com.cultureapp, PID: 19925
01-19 19:27:29.134 19925-19925/com.cultureapp E/AndroidRuntime: java.lang.IndexOutOfBoundsException: Invalid index 1, size is 1
01-19 19:27:29.134 19925-19925/com.cultureapp E/AndroidRuntime: at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
01-19 19:27:29.134 19925-19925/com.cultureapp E/AndroidRuntime: at java.util.ArrayList.get(ArrayList.java:308)
01-19 19:27:29.134 19925-19925/com.cultureapp E/AndroidRuntime: at android.widget.HeaderViewListAdapter.isEnabled(HeaderViewListAdapter.java:164)
答案 0 :(得分：1)
在你的代码中，你正在调用list.get（1），但列表大小为1.因此，你只能调用list.get（0）。您正试图触及不存在的对象。
答案 1 :(得分：0)
java.lang.IndexOutOfBoundsException表示：
你有一个ArrayList，它有1个元素，所以你只能得到位置0的元素。
但是在这里，你试图访问位置1的元素，这是不可能的，因为它不存在。
问题可能在这里：
@Override
public void onResume() {
super.onResume();
try {
if (!feedList.isEmpty())
setAllSlidingAnimation(feedList.size());
...
}
如果feedList的尺寸为1，您将尝试访问 SECOND 元素（第一个位于第0位，第二个位于位置1 == feedList.size() ）。