您忘了alertDialog.show();
用来显示您的
alertDialog
检查你的代码，你已经把 alertDialog.show();
里面 builder.setNegativeButton
，这就是为什么你
alertDialog不显示
像下面的代码一样更改代码
add_button.setonClickListener(new View.onClickListener() { @Override public void onClick(View v) { final alertDialog.Builder builder = new alertDialog.Builder(MainActivity.this); builder.setTitle("Create item list"); final EditText enter_item_list=new EditText(MainActivity.this); enter_item_list.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_FLAG_CAP_WORDS); enter_item_list.setHint("Type a name"); enter_item_list.setHintTextColor(Color.RED); builder.setView(enter_item_list); builder.setPositiveButton("Add", new DialogInterface.onClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { String item_name = enter_item_list.getText().toString().trim(); add_item_to_list(item_name); } }); builder.setNegativeButton("Cancel", new DialogInterface.onClickListener() { @Override public void onClick(DialogInterface dialogInterface, int which) { dialogInterface.dismiss(); } }); alertDialog alertDialog=builder.create(); alertDialog.show(); itemList_ref = Firestore_ref.collection("itemList").document(UserEmail).collection("user_item_list"); } });
