Java 为什么我不能将此JSON对象传递给另一个活动
我正在使用截取从Json获取新闻条目。在MainActivity中，我成功地获取并解析了json，因此我对此没有问题。 现在，每个新闻项目都包含一个标题和新闻摘录。我想要的是，每次点击新闻摘录时，它都会启动另一个名为“新闻详细信息”的活动， 在启动过程中，单击的新闻摘录的“ID”（一个json对象）将被发送到NewsDetails 在新闻详情中，我将连接“ID”和网站的url；这还将返回一个json数组。然后我将解析json并显示它；希望这不会给我带来问题 我遇到的困难是试图发送“ID”并启动“NewsDetails” 到目前为止，我一直在这样做： 所有主要活动类Java 为什么我不能将此JSON对象传递给另一个活动,java,android,json,Java,Android,Json,我正在使用截取从Json获取新闻条目。在MainActivity中，我成功地获取并解析了json，因此我对此没有问题。 现在，每个新闻项目都包含一个标题和新闻摘录。我想要的是，每次点击新闻摘录时，它都会启动另一个名为“新闻详细信息”的活动， 在启动过程中，单击的新闻摘录的“ID”（一个json对象）将被发送到NewsDetails 在新闻详情中，我将连接“ID”和网站的url；这还将返回一个json数组。然后我将解析json并显示它；希望这不会给我带来问题 我遇到的困难是试图发送“ID”并启动“
public class MainActivity extends AppCompatActivity{
private final String TAG = "MainActivity";
//Creating a list of newss
private List<NewsItems> mNewsItemsList;
//Creating Views
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private ProgressDialog mProgressDialog;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(TAG, "Device rotated and onCreate called");
//Initializing Views
recyclerView = (RecyclerView) findViewById(R.id.news_recycler);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
//Initializing the newslist
mNewsItemsList = new ArrayList<>();
adapter = new NewsAdapter(mNewsItemsList, this);
recyclerView.setAdapter(adapter);
//Caling method to get data
getData();
}
//This method will get data from the web api
private void getData(){
Log.d(TAG, "getData called");
//Showing progress dialog
mProgressDialog = new ProgressDialog(MainActivity.this);
mProgressDialog.setCancelable(false);
mProgressDialog.setMessage(this.getResources().getString(R.string.load_news));
mProgressDialog.show();
//Creating a json request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(ConfigNews.GET_URL,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, "onResponse called");
//Dismissing the progress dialog
if (mProgressDialog != null) {
mProgressDialog.hide();
}
/*progressDialog.dismiss();*/
//calling method to parse json array
parseData(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
//Creating request queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(jsonArrayRequest);
}
//This method will parse json data
private void parseData(JSONArray array){
Log.d(TAG, "Parsing array");
for(int i = 0; i<array.length(); i++) {
NewsItems newsItem = new NewsItems();
JSONObject jsonObject = null;
try {
jsonObject = array.getJSONObject(i);
newsItem.setNews_title(jsonObject.getString(ConfigNews.TAG_NEWS_TITLE));
newsItem.setNews_excerpt(jsonObject.getString(ConfigNews.TAG_NEWS_EXCERPT));
newsItem.setNewsId(jsonObject.getInt(ConfigNews.TAG_NEWS_ID));
} catch (JSONException w) {
w.printStackTrace();
}
mNewsItemsList.add(newsItem);
}
adapter.notifyItemRangeChanged(0, adapter.getItemCount());
}
@Override
public void onDestroy() {
super.onDestroy();
Log.d(TAG, "onDestroy called");
if (mProgressDialog != null){
mProgressDialog.dismiss();
Log.d(TAG, "mProgress dialog dismissed");
}
}
}
public class NewsItems {
private String news_title;
private String news_excerpt;
private String news_id;
public String getNews_title() {
return news_title;
}
public void setNews_title(String news_title) {
this.news_title = news_title;
}
public String getNews_excerpt() {
return news_excerpt;
}
public void setNews_excerpt(String news_excerpt) {
this.news_excerpt = news_excerpt;
}
public String getNews_id() {
return news_id;
}
public void setNews_id(String news_id) {
this.news_id = news_id;
}
}
public class NewsAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
private ImageLoader imageLoader;
private Context mContext;
//List of newss
private List<NewsItems> mNewsItems;
private final int VIEW_ITEM = 0;
private final int VIEW_PROG = 1;
private int lastPosition = -1;
public NewsAdapter(List<NewsItems> newsItems, Context context) {
super();
//Getting all newss
this.mNewsItems = newsItems;
this.mContext = context;
}
@Override
public int getItemViewType(int position) {
if (isPositionItem(position))
return VIEW_ITEM;
return VIEW_PROG;
}
private boolean isPositionItem(int position) {
return position != getItemCount()-1;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder (ViewGroup parent, int viewType) {
if (viewType == VIEW_ITEM) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.news_summ, parent, false);
return new TextViewHolder(v);
} else if (viewType == VIEW_PROG){
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.recyclerfooter, parent, false);
return new ProgressViewHolder(v);
}
return null;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof TextViewHolder) {
NewsItems newsList = mNewsItems.get(position);
((TextViewHolder) holder).newsTitle.setText(newsList.getNews_title());
((TextViewHolder) holder).newsExcerpt.setText(newsList.getNews_excerpt());
((TextViewHolder) holder).newsId.setText(String.valueOf(newsList.getNewsId()));
} else {
((ProgressViewHolder) holder).progressBar.setIndeterminate(true);
((ProgressViewHolder) holder).loadButton.setText(R.string.reload);
}
}
@Override
public int getItemCount(){
//Return the number of items in the data set
return mNewsItems.size();
}
public static class TextViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView newsTitle,newsExcerpt, newsId;
public ImageButton imageButton;
public NewsItems dNewsItems;
public TextViewHolder (final View newsView) {
super(newsView);
newsTitle = (TextView) newsView.findViewById(R.id.news_title);
newsExcerpt = (TextView) newsView.findViewById(R.id.news_excerpt);
newsId = (TextView) newsView.findViewById(R.id.news_id);
newsExcerpt.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == newsExcerpt.getId()) {
if (v.getId() == newsExcerpt.getId()) {
Intent i = NewsDetails.newIntent(getActivity(), dNewsItems.getNews_id());
startActivity(i);
}
}
}
}
public static class ProgressViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
Button loadButton;
ProgressBar progressBar;
public ProgressViewHolder(View footerView){
super(footerView);
loadButton = (Button) footerView.findViewById(R.id.reload_button);
progressBar = (ProgressBar) footerView.findViewById(R.id.progress_load);
loadButton.setOnClickListener(this);
if(NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
progressBar.setVisibility(View.VISIBLE);
} else if (!NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
loadButton.setVisibility(View.VISIBLE);
}
}
@Override
public void onClick(View v) {
if (v.getId() == loadButton.getId()) {
//
}
}
}
}
public class NewsAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
private ImageLoader imageLoader;
private Context mContext;
//List of newss
private List<NewsItems> mNewsItems;
private final int VIEW_ITEM = 0;
private final int VIEW_PROG = 1;
private int lastPosition = -1;
public NewsAdapter(List<NewsItems> newsItems, Context context) {
super();
//Getting all newss
this.mNewsItems = newsItems;
this.mContext = context;
}
@Override
public int getItemViewType(int position) {
if (isPositionItem(position))
return VIEW_ITEM;
return VIEW_PROG;
}
private boolean isPositionItem(int position) {
return position != getItemCount()-1;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder (ViewGroup parent, int viewType) {
if (viewType == VIEW_ITEM) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.news_summ, parent, false);
return new TextViewHolder(v, mContext);
} else if (viewType == VIEW_PROG){
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.recyclerfooter, parent, false);
return new ProgressViewHolder(v);
}
return null;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof TextViewHolder) {
NewsItems newsList = mNewsItems.get(position);
((TextViewHolder) holder).newsTitle.setText(newsList.getNews_title());
((TextViewHolder) holder).newsExcerpt.setText(newsList.getNews_excerpt());
((TextViewHolder) holder).newsId.setText(String.valueOf(newsList.getNewsId()));
} else {
((ProgressViewHolder) holder).progressBar.setIndeterminate(true);
((ProgressViewHolder) holder).loadButton.setText(R.string.reload);
}
}
@Override
public int getItemCount(){
//Return the number of items in the data set
return mNewsItems.size();
}
public static class TextViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView newsTitle,newsExcerpt, newsId;
public ImageButton imageButton;
public NewsItems dNewsItems;
private Context context;
public TextViewHolder (final View newsView, final Context context) {
super(newsView);
newsTitle = (TextView) newsView.findViewById(R.id.news_title);
newsExcerpt = (TextView) newsView.findViewById(R.id.news_excerpt);
newsId = (TextView) newsView.findViewById(R.id.news_id);
newsExcerpt.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == newsExcerpt.getId()) {
int newsid = 4536;
Intent myItent = new Intent(context, NewsDetails.class);
myItent.putExtra("key", newsid);
context.startActivity(myItent);
}
}
}
}
public static class ProgressViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
Button loadButton;
ProgressBar progressBar;
public ProgressViewHolder(View footerView){
super(footerView);
loadButton = (Button) footerView.findViewById(R.id.reload_button);
progressBar = (ProgressBar) footerView.findViewById(R.id.progress_load);
loadButton.setOnClickListener(this);
if(NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
progressBar.setVisibility(View.VISIBLE);
} else if (!NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
loadButton.setVisibility(View.VISIBLE);
}
}
@Override
public void onClick(View v) {
if (v.getId() == loadButton.getId()) {
//
}
}
}
}
04-12 20:15:25.424 8772-8772/com.newsus.app E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.newsus.app, PID: 8772
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference
at android.content.ComponentName.<init>(ComponentName.java:77)
at android.content.Intent.<init>(Intent.java:4336)
at com.newsus.app.NewsAdapter$TextViewHolder.onClick(NewsAdapter.java:181)
at android.view.View.performClick(View.java:5076)
at android.view.View$PerformClick.run(View.java:20279)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5910)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1405)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1200)
getActivity（）startActivity（i）它是“无法解析方法'startActivity（android.content.Intent）'”
所以现在，我的问题是我做错了什么，我应该如何纠正它
实施Rohit Arya回答后的新闻适配器
public class NewsAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
private ImageLoader imageLoader;
private Context mContext;
//List of newss
private List<NewsItems> mNewsItems;
private final int VIEW_ITEM = 0;
private final int VIEW_PROG = 1;
private int lastPosition = -1;
public NewsAdapter(List<NewsItems> newsItems, Context context) {
super();
//Getting all newss
this.mNewsItems = newsItems;
this.mContext = context;
}
@Override
public int getItemViewType(int position) {
if (isPositionItem(position))
return VIEW_ITEM;
return VIEW_PROG;
}
private boolean isPositionItem(int position) {
return position != getItemCount()-1;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder (ViewGroup parent, int viewType) {
if (viewType == VIEW_ITEM) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.news_summ, parent, false);
return new TextViewHolder(v);
} else if (viewType == VIEW_PROG){
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.recyclerfooter, parent, false);
return new ProgressViewHolder(v);
}
return null;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof TextViewHolder) {
NewsItems newsList = mNewsItems.get(position);
((TextViewHolder) holder).newsTitle.setText(newsList.getNews_title());
((TextViewHolder) holder).newsExcerpt.setText(newsList.getNews_excerpt());
((TextViewHolder) holder).newsId.setText(String.valueOf(newsList.getNewsId()));
} else {
((ProgressViewHolder) holder).progressBar.setIndeterminate(true);
((ProgressViewHolder) holder).loadButton.setText(R.string.reload);
}
}
@Override
public int getItemCount(){
//Return the number of items in the data set
return mNewsItems.size();
}
public static class TextViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView newsTitle,newsExcerpt, newsId;
public ImageButton imageButton;
public NewsItems dNewsItems;
public TextViewHolder (final View newsView) {
super(newsView);
newsTitle = (TextView) newsView.findViewById(R.id.news_title);
newsExcerpt = (TextView) newsView.findViewById(R.id.news_excerpt);
newsId = (TextView) newsView.findViewById(R.id.news_id);
newsExcerpt.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == newsExcerpt.getId()) {
if (v.getId() == newsExcerpt.getId()) {
Intent i = NewsDetails.newIntent(getActivity(), dNewsItems.getNews_id());
startActivity(i);
}
}
}
}
public static class ProgressViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
Button loadButton;
ProgressBar progressBar;
public ProgressViewHolder(View footerView){
super(footerView);
loadButton = (Button) footerView.findViewById(R.id.reload_button);
progressBar = (ProgressBar) footerView.findViewById(R.id.progress_load);
loadButton.setOnClickListener(this);
if(NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
progressBar.setVisibility(View.VISIBLE);
} else if (!NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
loadButton.setVisibility(View.VISIBLE);
}
}
@Override
public void onClick(View v) {
if (v.getId() == loadButton.getId()) {
//
}
}
}
}
public class NewsAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
private ImageLoader imageLoader;
private Context mContext;
//List of newss
private List<NewsItems> mNewsItems;
private final int VIEW_ITEM = 0;
private final int VIEW_PROG = 1;
private int lastPosition = -1;
public NewsAdapter(List<NewsItems> newsItems, Context context) {
super();
//Getting all newss
this.mNewsItems = newsItems;
this.mContext = context;
}
@Override
public int getItemViewType(int position) {
if (isPositionItem(position))
return VIEW_ITEM;
return VIEW_PROG;
}
private boolean isPositionItem(int position) {
return position != getItemCount()-1;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder (ViewGroup parent, int viewType) {
if (viewType == VIEW_ITEM) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.news_summ, parent, false);
return new TextViewHolder(v, mContext);
} else if (viewType == VIEW_PROG){
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.recyclerfooter, parent, false);
return new ProgressViewHolder(v);
}
return null;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof TextViewHolder) {
NewsItems newsList = mNewsItems.get(position);
((TextViewHolder) holder).newsTitle.setText(newsList.getNews_title());
((TextViewHolder) holder).newsExcerpt.setText(newsList.getNews_excerpt());
((TextViewHolder) holder).newsId.setText(String.valueOf(newsList.getNewsId()));
} else {
((ProgressViewHolder) holder).progressBar.setIndeterminate(true);
((ProgressViewHolder) holder).loadButton.setText(R.string.reload);
}
}
@Override
public int getItemCount(){
//Return the number of items in the data set
return mNewsItems.size();
}
public static class TextViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView newsTitle,newsExcerpt, newsId;
public ImageButton imageButton;
public NewsItems dNewsItems;
private Context context;
public TextViewHolder (final View newsView, final Context context) {
super(newsView);
newsTitle = (TextView) newsView.findViewById(R.id.news_title);
newsExcerpt = (TextView) newsView.findViewById(R.id.news_excerpt);
newsId = (TextView) newsView.findViewById(R.id.news_id);
newsExcerpt.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == newsExcerpt.getId()) {
int newsid = 4536;
Intent myItent = new Intent(context, NewsDetails.class);
myItent.putExtra("key", newsid);
context.startActivity(myItent);
}
}
}
}
public static class ProgressViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
Button loadButton;
ProgressBar progressBar;
public ProgressViewHolder(View footerView){
super(footerView);
loadButton = (Button) footerView.findViewById(R.id.reload_button);
progressBar = (ProgressBar) footerView.findViewById(R.id.progress_load);
loadButton.setOnClickListener(this);
if(NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
progressBar.setVisibility(View.VISIBLE);
} else if (!NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
loadButton.setVisibility(View.VISIBLE);
}
}
@Override
public void onClick(View v) {
if (v.getId() == loadButton.getId()) {
//
}
}
}
}
04-12 20:15:25.424 8772-8772/com.newsus.app E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.newsus.app, PID: 8772
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference
at android.content.ComponentName.<init>(ComponentName.java:77)
at android.content.Intent.<init>(Intent.java:4336)
at com.newsus.app.NewsAdapter$TextViewHolder.onClick(NewsAdapter.java:181)
at android.view.View.performClick(View.java:5076)
at android.view.View$PerformClick.run(View.java:20279)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5910)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1405)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1200)
公共类NewsAdapter扩展了RecyclerView.Adapter{
私有图像加载器；
私有上下文；
//新闻列表
私人物品清单；
私有最终int视图_项=0；
私有最终int视图_PROG=1；
private int lastPosition=-1；
公共新闻适配器（列出新闻项、上下文）{
超级（）；
//得到所有消息
this.mNewsItems=新闻项；
this.mContext=上下文；
}
@凌驾
public int getItemViewType（int位置）{
if（位置项目（位置））
返回视图_项；
返回视图程序；
}
私有布尔值isPositionItem（int位置）{
返回位置！=getItemCount（）-1；
}
@凌驾
public RecyclerView.ViewHolder onCreateViewHolder（视图组父级，int-viewType）{
if（视图类型==视图项）{
视图v=LayoutInflater.from（parent.getContext（））
.充气（R.layout.news_sum，parent，false）；
返回新的TextViewHolder（v，mContext）；
}else if（viewType==VIEW\U PROG）{
视图v=LayoutInflater.from（parent.getContext（））
.充气（R.layout.recyclerfooter、parent、false）；
返回新的ProgressViewHolder（v）；
}
返回null；
}
@凌驾
BindViewHolder上的公共无效（RecyclerView.ViewHolder，int位置）{
if（文本视图保持架的保持架实例）{
NewsItems newsList=mNewsItems.get（位置）；
（（TextViewHolder）holder.newsttitle.setText（newsList.getNews_title（））；
（（TextViewHolder）holder.newsExtrapt.setText（newsList.getNews_extract（））；
（TextViewHolder）holder.newsId.setText（String.valueOf（newsList.getNewsId（））；
}否则{
（（ProgressViewHolder）holder）.progressBar.SetUndeterminate（true）；
（（ProgressViewHolder）holder.loadButton.setText（R.string.reload）；
}
}
@凌驾
public int getItemCount（）{
//返回数据集中的项目数
返回mNewsItems.size（）；
}
公共静态类TextViewHolder扩展了RecyclerView.ViewHolder实现了View.OnClickListener{
公共文本查看新闻标题、新闻摘录、新闻ID；
公共图像按钮图像按钮；
公共新闻项目；
私人语境；
公共文本视图持有者（最终视图新闻视图，最终上下文）{
超级（新闻视图）；
newsTitle=（TextView）newsView.findViewById（R.id.news\u title）；
NewsExcept=（TextView）newsView.findViewById（R.id.news_摘录）；
newsId=（TextView）newView.findViewById（R.id.news\u id）；
newsextract.setOnClickListener（this）；
}
@凌驾
公共void onClick（视图v）{
if（v.getId（）==newsextract.getId（））{
int newsid=4536；
Intent myItent=newintent（上下文，NewsDetails.class）；
myItent.putExtra（“key”，newsid）；
背景。起始触觉（myItent）；
}
}
}
}
公共静态类ProgressViewHolder扩展了RecyclerView.ViewHolder实现了View.OnClickListener{
按钮加载按钮；
ProgressBar ProgressBar；
公共ProgressViewHolder（视图页脚视图）{
超级（页脚视图）；
loadButton=（按钮）footerView.findViewById（R.id.reload_按钮）；
progressBar=（progressBar）footerView.findViewById（R.id.progress\u load）；
loadButton.setOnClickListener（此）；
if（NetworkCheck.isAvailableAndConnected（footerView.getContext（）））{
progressBar.setVisibility（View.VISIBLE）；
}如果（！NetworkCheck.isAvailableAndConnected（footerView.getContext（）），则为else{
loadButton.setVisibility（View.VISIBLE）；
}
}
@凌驾
公共void onClick（视图v）{
如果（v.getId（）==loadButton.getId（））{
//
}
}
}
}
public class NewsAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
private ImageLoader imageLoader;
private Context mContext;
//List of newss
private List<NewsItems> mNewsItems;
private final int VIEW_ITEM = 0;
private final int VIEW_PROG = 1;
private int lastPosition = -1;
public NewsAdapter(List<NewsItems> newsItems, Context context) {
super();
//Getting all newss
this.mNewsItems = newsItems;
this.mContext = context;
}
@Override
public int getItemViewType(int position) {
if (isPositionItem(position))
return VIEW_ITEM;
return VIEW_PROG;
}
private boolean isPositionItem(int position) {
return position != getItemCount()-1;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder (ViewGroup parent, int viewType) {
if (viewType == VIEW_ITEM) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.news_summ, parent, false);
return new TextViewHolder(v);
} else if (viewType == VIEW_PROG){
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.recyclerfooter, parent, false);
return new ProgressViewHolder(v);
}
return null;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof TextViewHolder) {
NewsItems newsList = mNewsItems.get(position);
((TextViewHolder) holder).newsTitle.setText(newsList.getNews_title());
((TextViewHolder) holder).newsExcerpt.setText(newsList.getNews_excerpt());
((TextViewHolder) holder).newsId.setText(String.valueOf(newsList.getNewsId()));
} else {
((ProgressViewHolder) holder).progressBar.setIndeterminate(true);
((ProgressViewHolder) holder).loadButton.setText(R.string.reload);
}
}
@Override
public int getItemCount(){
//Return the number of items in the data set
return mNewsItems.size();
}
public static class TextViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView newsTitle,newsExcerpt, newsId;
public ImageButton imageButton;
public NewsItems dNewsItems;
public TextViewHolder (final View newsView) {
super(newsView);
newsTitle = (TextView) newsView.findViewById(R.id.news_title);
newsExcerpt = (TextView) newsView.findViewById(R.id.news_excerpt);
newsId = (TextView) newsView.findViewById(R.id.news_id);
newsExcerpt.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == newsExcerpt.getId()) {
if (v.getId() == newsExcerpt.getId()) {
Intent i = NewsDetails.newIntent(getActivity(), dNewsItems.getNews_id());
startActivity(i);
}
}
}
}
public static class ProgressViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
Button loadButton;
ProgressBar progressBar;
public ProgressViewHolder(View footerView){
super(footerView);
loadButton = (Button) footerView.findViewById(R.id.reload_button);
progressBar = (ProgressBar) footerView.findViewById(R.id.progress_load);
loadButton.setOnClickListener(this);
if(NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
progressBar.setVisibility(View.VISIBLE);
} else if (!NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
loadButton.setVisibility(View.VISIBLE);
}
}
@Override
public void onClick(View v) {
if (v.getId() == loadButton.getId()) {
//
}
}
}
}
public class NewsAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
private ImageLoader imageLoader;
private Context mContext;
//List of newss
private List<NewsItems> mNewsItems;
private final int VIEW_ITEM = 0;
private final int VIEW_PROG = 1;
private int lastPosition = -1;
public NewsAdapter(List<NewsItems> newsItems, Context context) {
super();
//Getting all newss
this.mNewsItems = newsItems;
this.mContext = context;
}
@Override
public int getItemViewType(int position) {
if (isPositionItem(position))
return VIEW_ITEM;
return VIEW_PROG;
}
private boolean isPositionItem(int position) {
return position != getItemCount()-1;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder (ViewGroup parent, int viewType) {
if (viewType == VIEW_ITEM) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.news_summ, parent, false);
return new TextViewHolder(v, mContext);
} else if (viewType == VIEW_PROG){
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.recyclerfooter, parent, false);
return new ProgressViewHolder(v);
}
return null;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof TextViewHolder) {
NewsItems newsList = mNewsItems.get(position);
((TextViewHolder) holder).newsTitle.setText(newsList.getNews_title());
((TextViewHolder) holder).newsExcerpt.setText(newsList.getNews_excerpt());
((TextViewHolder) holder).newsId.setText(String.valueOf(newsList.getNewsId()));
} else {
((ProgressViewHolder) holder).progressBar.setIndeterminate(true);
((ProgressViewHolder) holder).loadButton.setText(R.string.reload);
}
}
@Override
public int getItemCount(){
//Return the number of items in the data set
return mNewsItems.size();
}
public static class TextViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView newsTitle,newsExcerpt, newsId;
public ImageButton imageButton;
public NewsItems dNewsItems;
private Context context;
public TextViewHolder (final View newsView, final Context context) {
super(newsView);
newsTitle = (TextView) newsView.findViewById(R.id.news_title);
newsExcerpt = (TextView) newsView.findViewById(R.id.news_excerpt);
newsId = (TextView) newsView.findViewById(R.id.news_id);
newsExcerpt.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == newsExcerpt.getId()) {
int newsid = 4536;
Intent myItent = new Intent(context, NewsDetails.class);
myItent.putExtra("key", newsid);
context.startActivity(myItent);
}
}
}
}
public static class ProgressViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
Button loadButton;
ProgressBar progressBar;
public ProgressViewHolder(View footerView){
super(footerView);
loadButton = (Button) footerView.findViewById(R.id.reload_button);
progressBar = (ProgressBar) footerView.findViewById(R.id.progress_load);
loadButton.setOnClickListener(this);
if(NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
progressBar.setVisibility(View.VISIBLE);
} else if (!NetworkCheck.isAvailableAndConnected(footerView.getContext())) {
loadButton.setVisibility(View.VISIBLE);
}
}
@Override
public void onClick(View v) {
if (v.getId() == loadButton.getId()) {
//
}
}
}
}
04-12 20:15:25.424 8772-8772/com.newsus.app E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.newsus.app, PID: 8772
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference
at android.content.ComponentName.<init>(ComponentName.java:77)
at android.content.Intent.<init>(Intent.java:4336)
at com.newsus.app.NewsAdapter$TextViewHolder.onClick(NewsAdapter.java:181)
at android.view.View.performClick(View.java:5076)
at android.view.View$PerformClick.run(View.java:20279)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5910)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1405)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1200)
04-12 20:15:25.424 8772-8772/com.newsus.app E/AndroidRuntime:FATAL EXCEPTION:main
进程：com.newsus.app，PID:8772
java.lang.NullPointerException：尝试在空对象上调用虚拟方法“java.lang.String android.content.Context.getPackageName（）”