android-recyclerview

问题 This question already has answers here : What is a NullPointerException, and how do I fix it? (12 answers) Closed 10 months ago . I am trying to remove a specific item when I click on it. I have run logs so I know that it's picking an item I just don't understand what the error means. If it is important I am using room database and using a recycler view. java.lang.NullPointerException: Attempt to invoke virtual method 'void uk.edu.le.co2103.myrecipebook.RecipeListAdapter.notifyItemRemoved(int

问题 I have a recyclerview that contains fields with editTexts . When scrolling, the data in the edit texts gets all mixed up or erased due to some functions I use and the views being recycled. This could be completely solved if I could save my data before the view gets recycled. How can I detect that happening from WITHIN the adapter? 回答1: Just add below code in your adapter's onBindViewHolder method: viewHolder.setIsRecyclable(false); so you never lose your data on the scroll. 回答2: The

问题 I have a Firestore database like this: I want to access each of the different symptom data's i.e. "Anxiety_data" and its children which consists of timestamps, and then a dictionary, and place them into a RecyclerView using FirebaseUI FirebaseRecyclerViewAdapter I have this model class: public class EntryDataModel { private String timestamp, symptom, severity, comment; public EntryDataModel() {} public EntryDataModel(String timestamp, String symptom, String severity, String comment) { this

问题 I'm creating an app with firebase as a backend, First I got output but after few changes I did for intent then it shows like this, Can anyone help me to solve this error. I used if to check whether I'm getting data or not and It goes through that if condition still it shows null. Activity 1: public class centerActivity extends AppCompatActivity { RecyclerView recyclerView; ArrayList<data> mArrayList; FrontlistAdapter mAdapter; FirebaseRecyclerOptions<data> options; FirebaseDatabase database =

问题 i Have recycle view as follow: <layout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto"> <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/colorWhite" android:orientation="vertical"> <TextView android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center_vertical|center_horizontal" android:textAlignment="center" /> <!-- items inside

问题 I've almost got this working by following the suggestions in this question Android percent screen width in RecyclerView item However that sets a height for all views, same height regardless of the content. In my case I just want to limit how tall an item inside the RecyclerView can be related to its height. In my RV I have items that have different heights, with some of those items capable of being even taller than the RV. My goal is to tell that the item can be at max 60% of the RecyclerView

问题 I've almost got this working by following the suggestions in this question Android percent screen width in RecyclerView item However that sets a height for all views, same height regardless of the content. In my case I just want to limit how tall an item inside the RecyclerView can be related to its height. In my RV I have items that have different heights, with some of those items capable of being even taller than the RV. My goal is to tell that the item can be at max 60% of the RecyclerView

问题 I've almost got this working by following the suggestions in this question Android percent screen width in RecyclerView item However that sets a height for all views, same height regardless of the content. In my case I just want to limit how tall an item inside the RecyclerView can be related to its height. In my RV I have items that have different heights, with some of those items capable of being even taller than the RV. My goal is to tell that the item can be at max 60% of the RecyclerView

问题 I am very new to android development and am building an app that can read characteristics from a BLE device. I am able to connect to a device and read its characteristics. However, I have a problem is displaying the characteristics using an adapter. Initially, I tried using the RecycleView adapter but my program kept going back to the main activity as soon as I tried to notify my recycleview adapter and everything left on the Logcat would be this: 2020-11-24 13:35:37.220 12966-12966/? I

问题 I am very new to android development and am building an app that can read characteristics from a BLE device. I am able to connect to a device and read its characteristics. However, I have a problem is displaying the characteristics using an adapter. Initially, I tried using the RecycleView adapter but my program kept going back to the main activity as soon as I tried to notify my recycleview adapter and everything left on the Logcat would be this: 2020-11-24 13:35:37.220 12966-12966/? I