从OpensubcontentActivity中的oncreate调用我的异步任务类，它正在执行正常但在onBindViewHolder中从vivcontentAdapter调用相同的异步任务类时，它在progressdialog中给出了空指针错误。
OpensubcontentActivity
public class OpenSubContentActivity extends AppCompatActivity {
private RecyclerView recyclerView;
private vivcontentAdapter vivcontentAdapteradapter;
static String stack_info[] = new String[10];
static int top = -1;
static String ObjectId;
static List<Information> data_content = new ArrayList<>();
public static Map info_map = null;
Boolean file_flag;
File file;
Context context;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_open_sub_content);
setEveryThing();
Intent mIntent = getIntent();
context = this;
ObjectId = mIntent.getStringExtra("CabinetID");
new getData().execute();
}
public void setEveryThing() {
floatingActionMenu = (FloatingActionMenu) findViewById(R.id.floating_menu);
newfolder = (FloatingActionButton) findViewById(R.id.idtem__folder);
newdoc = (FloatingActionButton) findViewById(R.id.idtem_doc);
upload = (FloatingActionButton) findViewById(R.id.idtem_upload);
capture = (FloatingActionButton) findViewById(R.id.idtem_photo);
toolbar = (Toolbar) findViewById(R.id.toolBar);
toolbar.setTitleTextColor(0xFFFFFFFF);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle(("Example"));
recyclerView = (RecyclerView) findViewById(R.id.list_file);
vivcontentAdapteradapter = new vivcontentAdapter(this, data_content);
recyclerView.setAdapter(vivcontentAdapteradapter);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
}
class getData extends AsyncTask<Void, Void, String> {
ProgressDialog pDialog;
@Override
protected void onPreExecute() {
pDialog = new ProgressDialog(OpenSubContentActivity.this);
pDialog.setMessage("Fetching Content...");
pDialog.show();
pDialog.setCanceledOnTouchOutside(false);
}
@Override
protected String doInBackground(Void... voids) {
info_map = new HashMap();
String title = "";
String results = "";
int count = 0;
if (ObjectId.startsWith("0c")) {
Log.d("first", "coming");
CmisObject object = MainActivity.session.getObject(MainActivity.session.createObjectId(ObjectId));
Folder folder = (Folder) object;
//Document document = (Document)object;
OperationContext operationContext = MainActivity.session.createOperationContext();
ItemIterable<CmisObject> childrenn = folder.getChildren(operationContext);
ItemIterable<CmisObject> page = childrenn.getPage();
Iterator<CmisObject> pageItems = page.iterator();
while (pageItems.hasNext()) {
CmisObject item = null;
item = pageItems.next();
//System.out.println(item.getId());
if (item != null && item.getName() != null) {
if (item.getId().startsWith("0b")) {
Information info = new Information();
info.title = item.getName();
info.iconId = icons[0];
info.folderId_open_Id = item.getId();
title = title + "\n" + item.getName();
info_map.put(count, info.folderId_open_Id);
data_content.add(info);
count++;
}
return results;
}
@Override
protected void onPostExecute(String s) {
pDialog.dismiss();
vivcontentAdapteradapter.notifyDataSetChanged();
}
}
}
}
}
}
vivcontentAdapter
在这个活动中，我正在调用opensubcontentactivity的异步任务类。但是从这里进行调用时，它在asynctask类中给出错误getData（）
使用 -
OpenSubContentActivity openSubContentActivity=new OpenSubContentActivity();
openSubContentActivity.new getData().execute();
vivcontentAdapter
public class vivcontentAdapter extends RecyclerView.Adapter<vivcontentAdapter.MyViewHolder> {
private final LayoutInflater inflater;
List<Information> data_content = Collections.emptyList();
Context context;
public vivcontentAdapter(Context context, List<Information> data) {
this.context = context;
inflater = LayoutInflater.from(context);
this.data_content = data;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.customrow, parent, false);
MyViewHolder holder = new MyViewHolder(view);
return holder;
}
@Override
public void onBindViewHolder(final vivcontentAdapter.MyViewHolder holder, final int position) {
Information current = data_content.get(position);
holder.title.setText(current.title);
holder.icon.setImageResource(current.iconId);
holder.keyicon.setImageResource(current.checkin_icon);
holder.title.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String store_objectID = (String) OpenSubContentActivity.info_map.get(position);
if (store_objectID.startsWith("0b")) {
OpenSubContentActivity.top++;
OpenSubContentActivity.stack_info[OpenSubContentActivity.top] = store_objectID; OpenSubContentActivity.ObjectId = store_objectID;
OpenSubContentActivity openSubContentActivity=new OpenSubContentActivity();
openSubContentActivity.new getData().execute();
} else {
OpenSubContentActivity.ObjectId = store_objectID;
OpenSubContentActivity openSubContentActivity=new OpenSubContentActivity();
openSubContentActivity.new getData().execute();
}
Toast.makeText(context, "Open", Toast.LENGTH_SHORT).show();
}
});
holder.txtOptionDigit.setOnClickListener(new View.OnClickListener() {
@SuppressLint("RestrictedApi")
@Override
public void onClick(View v) {
//Display option menu
});
}
@Override
public int getItemCount() {
return data_content.size();
}
class MyViewHolder extends RecyclerView.ViewHolder {
TextView title, txtOptionDigit;
ImageView icon, keyicon;
public MyViewHolder(View itemView) {
super(itemView);
title = (TextView) itemView.findViewById(R.id.textvw);
icon = (ImageView) itemView.findViewById(R.id.imageView);
keyicon = (ImageView) itemView.findViewById(R.id.key_icon);
txtOptionDigit = (TextView) itemView.findViewById(R.id.txtOptionDigit);
}
}
}
}
错误 -
03-30 00:21:40.690 10385-10385/reva.irving E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
03-30 00:21:40.690 10385-10385/reva.irving E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
03-30 00:22:04.228 10385-10385/reva.irving E/AndroidRuntime: FATAL EXCEPTION: main
Process: reva.irving, PID: 10385
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ProgressDialog.setMessage(java.lang.CharSequence)' on a null object reference
at reva.irving.OpenSubContentActivity$getData.onPreExecute(OpenSubContentActivity.java:103)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:620)
at android.os.AsyncTask.execute(AsyncTask.java:567)
at reva.irving.OpenSubContentActivity.call(OpenSubContentActivity.java:84)
at reva.irving.vivcontentAdapter$1.onClick(vivcontentAdapter.java:59)
at android.view.View.performClick(View.java:5647)
at android.view.View$PerformClick.run(View.java:22462)
at android.os.Handler.handleCallback(Handler.java:754)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:163)
at android.app.ActivityThread.main(ActivityThread.java:6205)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
答案 0 :(得分：0)
要在Recycler视图中执行点击，您需要更改适配器。添加一个接口作为点击监听器并在您的活动中实现它，如下所示：
public class vivcontentAdapter extends RecyclerView.Adapter<vivcontentAdapter.MyViewHolder> {
private final LayoutInflater inflater;
List<Information> data_content = Collections.emptyList();
Context context;
private OnClickItem clickListener;
public vivcontentAdapter(Context context, List<Information> data) {
this.context = context;
inflater = LayoutInflater.from(context);
this.data_content = data;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.customrow, parent, false);
MyViewHolder holder = new MyViewHolder(view);
return holder;
}
@Override
public void onBindViewHolder(final vivcontentAdapter.MyViewHolder holder, final int position) {
Information current = data_content.get(position);
holder.title.setText(current.title);
holder.icon.setImageResource(current.iconId);
holder.keyicon.setImageResource(current.checkin_icon);
holder.txtOptionDigit.setOnClickListener(new View.OnClickListener() {
@SuppressLint("RestrictedApi")
@Override
public void onClick(View v) {
//Display option menu
});
}
@Override
public int getItemCount() {
return data_content.size();
}
public void setClickListener(OnClickItem listener){
this.listener = listener;
}
class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView title, txtOptionDigit;
ImageView icon, keyicon;
public MyViewHolder(View itemView) {
super(itemView);
title = (TextView) itemView.findViewById(R.id.textvw);
icon = (ImageView) itemView.findViewById(R.id.imageView);
keyicon = (ImageView) itemView.findViewById(R.id.key_icon);
txtOptionDigit = (TextView) itemView.findViewById(R.id.txtOptionDigit);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View v) {
int pos = getAdapterPosition();
listener.onClickListItem(pos);
}
}
public interface OnClickItem{
void onClickListItem(int position);
}
}
现在，在您的活动中，您可以捕获cliicks并运行异步任务：
public class OpenSubContentActivity extends AppCompatActivity implements vivcontentAdapter.OnClickItem{
private RecyclerView recyclerView;
private vivcontentAdapter vivcontentAdapteradapter;
static String stack_info[] = new String[10];
static int top = -1;
static String ObjectId;
static List<Information> data_content = new ArrayList<>();
public static Map info_map = null;
Boolean file_flag;
File file;
Context context;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_open_sub_content);
setEveryThing();
Intent mIntent = getIntent();
context=this;
ObjectId = mIntent.getStringExtra("CabinetID");
new getData().execute();
}
public void setEveryThing() {
floatingActionMenu = (FloatingActionMenu) findViewById(R.id.floating_menu);
newfolder = (FloatingActionButton) findViewById(R.id.idtem__folder);
newdoc = (FloatingActionButton) findViewById(R.id.idtem_doc);
upload = (FloatingActionButton) findViewById(R.id.idtem_upload);
capture = (FloatingActionButton) findViewById(R.id.idtem_photo);
toolbar = (Toolbar) findViewById(R.id.toolBar);
toolbar.setTitleTextColor(0xFFFFFFFF);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle(("Example"));
recyclerView = (RecyclerView) findViewById(R.id.list_file);
vivcontentAdapteradapter = new vivcontentAdapter(this, data_content);
vivcontentAdapteradapter.setClickListener(this);
recyclerView.setAdapter(vivcontentAdapteradapter);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
}
@Override
public void onClickListItem(int position){
new getData().execute();
}
class getData extends AsyncTask<Void, Void, String> {
ProgressDialog pDialog;
@Override
protected void onPreExecute() {
pDialog = new ProgressDialog(OpenSubContentActivity.this);
pDialog.setMessage("Fetching Content...");
pDialog.show();
pDialog.setCanceledOnTouchOutside(false);
}
@Override
protected String doInBackground(Void... voids) {
info_map = new HashMap();
String title = "";
String results = "";
int count = 0;
if (ObjectId.startsWith("0c")) {
Log.d("first", "coming");
CmisObject object = MainActivity.session.getObject(MainActivity.session.createObjectId(ObjectId));
Folder folder = (Folder) object;
//Document document = (Document)object;
OperationContext operationContext = MainActivity.session.createOperationContext();
ItemIterable<CmisObject> childrenn = folder.getChildren(operationContext);
ItemIterable<CmisObject> page = childrenn.getPage();
Iterator<CmisObject> pageItems = page.iterator();
while (pageItems.hasNext()) {
CmisObject item = null;
item = pageItems.next();
//System.out.println(item.getId());
if (item != null && item.getName() != null) {
if (item.getId().startsWith("0b")) {
Information info = new Information();
info.title = item.getName();
info.iconId = icons[0];
info.folderId_open_Id = item.getId();
title = title + "\n" + item.getName();
info_map.put(count, info.folderId_open_Id);
data_content.add(info);
count++;
}
return results;
}
@Override
protected void onPostExecute(String s) {
pDialog.dismiss();
vivcontentAdapteradapter.notifyDataSetChanged();
}
}
}