html2canvas（document.body）.then（function（canvas）{}不调用

Question

我想在public class UserRecyclerAdapterSavedUsers extends RecyclerView.Adapter<UserRecyclerAdapterSavedUsers.UserViewHolder> { private List<User> listUsers; Context mContext; ItemClickListenerLongPressed itemClickListenerLongPressed; View itemView; public UserRecyclerAdapterSavedUsers(List<User> listUsers) { this.listUsers = listUsers; } @Override public UserViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { itemView = LayoutInflater.from(parent.getContext()) .inflate(R.layout.item_user_recycler_second, parent, false); return new UserViewHolder(itemView); } @Override public void onBindViewHolder(UserViewHolder holder, int position) { holder.textViewID.setText(listUsers.get(position).getUserid()); holder.textViewName.setText(listUsers.get(position).getName()); holder.textViewPassword.setText(listUsers.get(position).getPassword()); holder.textViewRole.setText(listUsers.get(position).getRole()); } public void setItemClickListenerLongPressed(ItemClickListenerLongPressed itemClickListenerLongPressed){ this.itemClickListenerLongPressed=itemClickListenerLongPressed; } @Override public int getItemCount() { return listUsers.size(); } private void displayingAlertDialog() { //displaying alert dialog box AlertDialog.Builder builder = new AlertDialog.Builder(itemView.getContext()); builder.setMessage("your toast message here..."); builder.setCancelable(true); builder.setPositiveButton( "Ok", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { dialog.cancel(); } }); AlertDialog alert11 = builder.create(); alert11.show(); } /** * ViewHolder class */ public class UserViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener { //public AppCompatTextView ID; public AppCompatTextView textViewID; public AppCompatTextView textViewName; public AppCompatTextView textViewPassword; public AppCompatTextView textViewRole; LinearLayout layout; public UserViewHolder(View view) { super(view); textViewID = (AppCompatTextView) view.findViewById(R.id.textViewID); textViewName = (AppCompatTextView) view.findViewById(R.id.textViewName); textViewPassword = (AppCompatTextView) view.findViewById(R.id.textViewPassword); textViewRole = (AppCompatTextView) view.findViewById(R.id.textViewRole); layout = view.findViewById(R.id.list_view); layout.setOnClickListener(this); } @Override public void onClick(View v) { displayingAlertDialog(); } } javaScript的{​​{1}}函数中调用 html2canvas（document.body）.then（function（canvas）{}）; 。

工作代码：

button

错误代码

html2canvas（document.body）.then（function（canvas）{}）; 未得到调用，其余代码将正确执行。

click

这里没有什么问题。请帮助我。

Answer 1

您可以直接分配功能，而不是分配function action() {}

this.action => () {
    if (elementScope == "body") {
         alert("generating pdf.........2");
         //alert("canvas........."+canvas)

        alert("document.body......."+document.body)
        //mypdf();
        html2canvas(document.body).then(function(canvas){
            alert("html2canvas called...!!!");
            var imageFullQuality = canvas.toDataURL();
            var docDefinition = {
                content: [{
                    image : imageFullQuality,
                    width : widthCanvas,
                }]
            };
            alert("generating pdf.........4");
            new  pdfMake.createPdf(docDefinition).download(fileName + ".pdf");
        });
    }
}