Java 致命异常:主应用程序在一段时间后崩溃
很长一段时间以来,我都面临着将xml解析成片段导航选项卡的问题。当我运行我的项目时,它会出现2-4秒,不查看我的listview(空白片段),然后崩溃。我认为onPostExecute方法有问题。我能求你帮忙吗 日志:Java 致命异常:主应用程序在一段时间后崩溃,java,android,android-asynctask,Java,Android,Android Asynctask,很长一段时间以来,我都面临着将xml解析成片段导航选项卡的问题。当我运行我的项目时,它会出现2-4秒,不查看我的listview(空白片段),然后崩溃。我认为onPostExecute方法有问题。我能求你帮忙吗 日志: E/AndroidRuntime(473): FATAL EXCEPTION: main E/AndroidRuntime(473): java.lang.NullPointerException E/AndroidRuntime(473): at android.widget
E/AndroidRuntime(473): FATAL EXCEPTION: main
E/AndroidRuntime(473): java.lang.NullPointerException
E/AndroidRuntime(473): at android.widget.ArrayAdapter.init(ArrayAdapter.java:271)
12-12 15:53:59.730: E/AndroidRuntime(473): at android.widget.ArrayAdapter.<init>(ArrayAdapter.java:150)
E/AndroidRuntime(473): at com.example.premierleague.clubsAdapter.<init>(clubsAdapter.java:37)
E/AndroidRuntime(473): at com.example.premierleague.Fragment1$ClubsDownloadTask.onPostExecute(Fragment1.java:113)
E/AndroidRuntime(473): at com.example.premierleague.Fragment1$ClubsDownloadTask.onPostExecute(Fragment1.java:1)
E/AndroidRuntime(473): at android.os.AsyncTask.finish(AsyncTask.java:417)
E/AndroidRuntime(473): at android.os.AsyncTask.access$300(AsyncTask.java:127)
12-12 15:53:59.730: E/AndroidRuntime(473): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
E/AndroidRuntime(473): at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime(473): at android.os.Looper.loop(Looper.java:123)
E/AndroidRuntime(473): at android.app.ActivityThread.main(ActivityThread.java:4627)
E/AndroidRuntime(473): at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(473): at java.lang.reflect.Method.invoke(Method.java:521)
E/AndroidRuntime(473): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
E/AndroidRuntime(473): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
E/AndroidRuntime(473): at dalvik.system.NativeStart.main(Native Method)
E/AndroidRuntime(473):致命异常:main
E/AndroidRuntime(473):java.lang.NullPointerException
E/AndroidRuntime(473):位于android.widget.ArrayAdapter.init(ArrayAdapter.java:271)
12-12 15:53:59.730:E/AndroidRuntime(473):在android.widget.ArrayAdapter.(ArrayAdapter.java:150)
E/AndroidRuntime(473):在com.example.premireleague.clubsAdapter.(clubsAdapter.java:37)
E/AndroidRuntime(473):位于com.example.premierage.Fragment1$ClubsDownloadTask.onPostExecute(Fragment1.java:113)
E/AndroidRuntime(473):位于com.example.premierage.Fragment1$ClubsDownloadTask.onPostExecute(Fragment1.java:1)
E/AndroidRuntime(473):位于android.os.AsyncTask.finish(AsyncTask.java:417)
E/AndroidRuntime(473):位于android.os.AsyncTask.access$300(AsyncTask.java:127)
12-12 15:53:59.730:E/AndroidRuntime(473):位于android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
E/AndroidRuntime(473):位于android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime(473):位于android.os.Looper.loop(Looper.java:123)
E/AndroidRuntime(473):位于android.app.ActivityThread.main(ActivityThread.java:4627)
E/AndroidRuntime(473):位于java.lang.reflect.Method.Invokenactive(本机方法)
E/AndroidRuntime(473):位于java.lang.reflect.Method.invoke(Method.java:521)
E/AndroidRuntime(473):位于com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
E/AndroidRuntime(473):位于com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
E/AndroidRuntime(473):位于dalvik.system.NativeStart.main(本机方法)
Fragment1.java
public class Fragment1 extends Fragment {
MainActivity activity = new MainActivity();
private clubsAdapter mAdapter;
private ListView clubs;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_1, container, false);
Log.i("PremierLeague", "OnCreateView()");
clubs = (ListView)rootView.findViewById(R.id.clubsList);
clubs.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// TODO Auto-generated method stub
}
});
if(isNetworkAvailable()){
Log.i("PremierLeague", "starting download Task");
ClubsDownloadTask download = new ClubsDownloadTask();
download.execute();
}else{
mAdapter = new clubsAdapter(getActivity().getApplicationContext(), -1,
ClubsXmlPullParser.getItemsFromFile(getActivity()));
clubs.setAdapter(mAdapter);
}
return super.onCreateView(inflater, container, savedInstanceState);
}
//Helper method to determine if Internet connection is available.
private boolean isNetworkAvailable() {
ConnectivityManager connectivityManager
= (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
return activeNetworkInfo != null;
}
private class ClubsDownloadTask extends AsyncTask<Void, Void, Void>{
private clubsAdapter mAdapter;
private List<LeagueClub> clubs;
Fragment1 ctx;
Context context = getActivity();
private Context mContext;
@Override
protected Void doInBackground(Void... arg0) {
try {
Downloader.DownloadFromUrl("http://dl.dropboxusercontent.com/s/h2qc41k2yy3c1ir/clubs.xml", getActivity().openFileOutput("clubs.xml", Context.MODE_PRIVATE));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Void result){
mAdapter = new clubsAdapter(mContext, -1, ClubsXmlPullParser.getItemsFromFile(getActivity()));
((ListView) clubs).setAdapter(mAdapter);
Log.i("PremierLeague", "adapter size = "+ mAdapter.getCount());
}
}
}
公共类Fragment1扩展了Fragment{
MainActivity活动=新的MainActivity();
私人俱乐部适配器;
私人ListView俱乐部;
@凌驾
创建视图上的公共视图(布局、充气机、视图组容器、,
Bundle savedInstanceState){
视图根视图=充气机。充气(R.layout.fragment_1,容器,错误);
Log.i(“英超联赛”、“OnCreateView()”);
clubs=(ListView)rootView.findViewById(R.id.clubsList);
clubs.setOnItemClickListener(新的OnItemClickListener(){
@凌驾
公共链接(AdapterView arg0、视图arg1、内部arg2、,
长arg3){
//TODO自动生成的方法存根
}
});
if(isNetworkAvailable()){
Log.i(“英超联赛”,“开始下载任务”);
ClubsDownloadTask download=新建ClubsDownloadTask();
下载.execute();
}否则{
mAdapter=newclubsadapter(getActivity().getApplicationContext(),-1,
ClubsXmlPullParser.getItemsFromFile(getActivity());
俱乐部。setAdapter(mAdapter);
}
返回super.onCreateView(充气机、容器、savedInstanceState);
}
//确定Internet连接是否可用的帮助器方法。
专用布尔值isNetworkAvailable(){
连接管理器连接管理器
=(ConnectivityManager)getActivity().getSystemService(Context.CONNECTIVITY_服务);
NetworkInfo activeNetworkInfo=connectivityManager.getActiveNetworkInfo();
返回activeNetworkInfo!=null;
}
私有类ClubsDownloadTask扩展了AsyncTask{
私人俱乐部适配器;
私人名单俱乐部;
片段1-ctx;
Context=getActivity();
私有上下文;
@凌驾
受保护的Void doInBackground(Void…arg0){
试一试{
Downloader.DownloadFromUrl(“http://dl.dropboxusercontent.com/s/h2qc41k2yy3c1ir/clubs.xml,getActivity().openFileOutput(“clubs.xml”,Context.MODE_PRIVATE));
}catch(filenotfounde异常){
e、 printStackTrace();
}
捕获(IOE异常){
//TODO自动生成的捕捉块
e、 printStackTrace();
}
返回null;
}
受保护的void onPostExecute(void结果){
mAdapter=newclubsadapter(mContext,-1,ClubsXmlPullParser.getItemsFromFile(getActivity());
((ListView)clubs.setAdapter(mAdapter);
Log.i(“英超联赛”,“适配器大小=“+mAdapter.getCount());
}
}
}
自定义适配器
public class clubsAdapter extends ArrayAdapter<LeagueClub> {
ImageLoader imageLoader;
DisplayImageOptions options;
@SuppressWarnings("deprecation")
public clubsAdapter(Context class1, int textViewResourceId, List<LeagueClub> clubs) {
super(class1, textViewResourceId, clubs);
//Setup the ImageLoader, we'll use this to display our images
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(class1).build();
imageLoader = ImageLoader.getInstance();
imageLoader.init(config);
//Setup options for ImageLoader so it will handle caching for us.
options = new DisplayImageOptions.Builder()
.cacheInMemory()
.cacheOnDisc()
.build();
}
// TODO Auto-generated constructor stu
/*
* (non-Javadoc)
* @see android.widget.ArrayAdapter#getView(int, android.view.View, android.view.ViewGroup)
*
* This method is responsible for creating row views out of a StackSite object that can be put
* into our ListView
*/
@Override
public View getView(int pos, View convertView, ViewGroup parent){
RelativeLayout row = (RelativeLayout)convertView;
Log.i("PremierLeague", "getView pos = " + pos);
if(null == row){
//No recycled View, we have to inflate one.
LayoutInflater inflater = (LayoutInflater)parent.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = (RelativeLayout)inflater.inflate(R.layout.row_site, null);
}
//Get our View References
final ImageView clubLogo = (ImageView)row.findViewById(R.id.clubLogo);
TextView nameTxt = (TextView)row.findViewById(R.id.nameTxt);
TextView aboutTxt = (TextView)row.findViewById(R.id.aboutTxt);
TextView stadiumTxt = (TextView)row.findViewById(R.id.stadiumTxt);
final ProgressBar indicator = (ProgressBar)row.findViewById(R.id.progress);
//Initially we want the progress indicator visible, and the image invisible
indicator.setVisibility(View.VISIBLE);
clubLogo.setVisibility(View.INVISIBLE);
//Setup a listener we can use to switch from the loading indicator to the Image once it's ready
ImageLoadingListener listener = new ImageLoadingListener(){
@Override
public void onLoadingStarted(String arg0, View arg1) {
// TODO Auto-generated method stub
}
@Override
public void onLoadingCancelled(String arg0, View arg1) {
// TODO Auto-generated method stub
}
@Override
public void onLoadingComplete(String arg0, View arg1, Bitmap arg2) {
indicator.setVisibility(View.INVISIBLE);
clubLogo.setVisibility(View.VISIBLE);
}
@Override
public void onLoadingFailed(String arg0, View view, FailReason arg2) {
indicator.setVisibility(View.INVISIBLE);
ImageView imageView = (ImageView) view.findViewById(R.id.clubLogo);
imageView.setVisibility(View.VISIBLE);
}
};
//Load the image and use our options so caching is handled.
imageLoader.displayImage(getItem(pos).getLogo(), clubLogo,options, listener);
//Set the relevant text in our TextViews
nameTxt.setText(getItem(pos).getName());
aboutTxt.setText(getItem(pos).getAbout());
stadiumTxt.setText(getItem(pos).getStadium());
return row;
}
}
公共类ClubAdapter扩展了ArrayAdapter{
图像加载器;
显示图像选项;
@抑制警告(“弃用”)
公共俱乐部适配器(上下文类1,int textViewResourceId,列出俱乐部){
超级(class1,textViewResourceId,clubs);
//设置ImageLoader,我们将使用它来显示图像
ImageLoaderConfiguration config=newImageLoaderConfiguration.Builder(class1.build();
imageLoader=imageLoader.getInstance();
init(config);
//ImageLoader的设置选项,以便它为我们处理缓存。
选项=新建DisplayImageOptions.Builder()
.cacheInMemory()
.cacheOnDisc()
.build();
}
//TODO自动生成构造函数stu
/*
*(非Javadoc)
*@see android.widget.ArrayAdapter#getView(int,android.view.view,android.view.ViewGroup)
*
*此方法负责从可以放置的StackSite对象中创建行视图
*进入我们的列表视图
*/
@凌驾
公共视图getView(int pos、视图转换视图、视图组父视图){
RelativeLayout行=(RelativeLayout)convertView;
Log.i(“英超联赛”、“getView pos=“+pos”);
如果(空==行){
//没有循环视图,我们必须对其进行充气。
LayoutFlater充气器=(LayoutFlater)parent.getContext().getSystemService(Context.LAYOUT\u充气器\u服务);
行=(RelativeLayout)充气器。充气(R.layout.row_站点,空);
}
//获取我们的视图引用
最终ImageView clubLogo=(ImageView)row.findViewById(R.id.clubLogo);
TextView nameTxt=(TextView)row.findViewById(R.id.nameTxt);
正文
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_1, container, false);
Log.i("PremierLeague", "OnCreateView()");
clubs = (ListView)rootView.findViewById(R.id.clubsList);
clubs.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// TODO Auto-generated method stub
}
});
return rootView;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if(isNetworkAvailable()){
Log.i("PremierLeague", "starting download Task");
ClubsDownloadTask download = new ClubsDownloadTask();
download.execute();
}else{
mAdapter = new clubsAdapter(getActivity().getApplicationContext(), -1,
ClubsXmlPullParser.getItemsFromFile(getActivity()));
clubs.setAdapter(mAdapter);
}
}
ListView clubs = (ListView) getView().findViewById(R.id.clubsList);