I am using a custom ArrayAdapter to populate a ListView.
My adapter code:
public class LocationAdapter extends ArrayAdapter<Location> {
public LocationAdapter(#NonNull Context context, ArrayList<Location> locationArrayList) {
super(context, 0, locationArrayList);
}
static class ViewHolder {
public TextView nameText;
public TextView descriptionText;
public ImageView image;
}
#NonNull
#Override
public View getView(int position, #Nullable View listItemView, #NonNull ViewGroup parent) {
ViewHolder viewHolder;
// check if the existing view is being reused
if (listItemView == null) {
// if not, inflate the view using location_list_itemlist_item.xml
listItemView = LayoutInflater.from(getContext()).inflate(R.layout.location_list_item, parent, false);
// configure view holder
viewHolder = new ViewHolder();
viewHolder.nameText = listItemView.findViewById(R.id.name_text_view);
viewHolder.image = listItemView.findViewById(R.id.image_view);
viewHolder.descriptionText = listItemView.findViewById(R.id.description_text_view);
listItemView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) listItemView.getTag();
}
// getting Location object in this position in ArrayList
Location currentLocation = getItem(position);
// using ViewHolder to set text/images to views
viewHolder.nameText.setText(currentLocation.getName());
viewHolder.descriptionText.setText(currentLocation.getDescription());
viewHolder.image.setImageResource(currentLocation.getImageResourceId());
return listItemView;
}
}
My list item XML code, very simple:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/name_text_view"
android:layout_width="368dp"
android:layout_height="22dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:textSize="18sp"
android:textStyle="bold"
android:textColor="#android:color/white"
app:layout_constraintBottom_toBottomOf="#+id/image_view"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
tools:text="Oleviste church"
android:elevation="2dp" />
<ImageView
android:id="#+id/image_view"
android:layout_width="match_parent"
android:layout_height="160dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:contentDescription="#string/image_content_description"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/description_text_view"
android:layout_width="0dp"
android:layout_height="51dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/image_view"
tools:text="This modern museum is located inside a former seaplane hangar and boasts a submarine and an ice breaker among its exhibits." />
</android.support.constraint.ConstraintLayout>
</LinearLayout>
Also, my ListView XML code just in case:
<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/list_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="never"
android:scrollingCache="false"
android:animationCache="false"/>
I experience some stuttering when scrolling the view in the app. Note that the images that I use are local drawables.
So far I have tried the following:
Cropping the drawables in Photoshop to fit the desired aspect ratio - significant improvement in speed but still a bit slow.
Using ViewHolder - maybe marginal improvement in speed.
Adding attributes android:scrollingCache="false" and android:animationCache="false" to the ListView - maybe marginal improvement in speed.
Using ConstraintLayout instead of RelativeLayout - maybe marginal improvement in speed.
Any ideas what I should try next?
Just use RecyclerView from the support library instead of a ListView. That should improve performance.
Refer to this SO question for more insight.
Android Recyclerview vs ListView with Viewholder
I was able to solve the issue with ListView scrolling using Glide framework. It is a robust framework focused on making scrolling lists with any kind of images fast and smooth.
All I had to do was to modify build.gradle:
repositories {
mavenCentral()
}
dependencies {
implementation 'com.github.bumptech.glide:glide:4.7.1'
annotationProcessor 'com.github.bumptech.glide:compiler:4.7.1'
}
Then in my adapter code I removed the following line (as setImageresource is not used anymore to load drawables):
viewHolder.image.setImageResource(currentLocation.getImageResourceId());
And added the following line to load drawables using Glide:
Glide.with(getContext()).load(currentLocation.getImageResourceId()).into(viewHolder.image);
More detailed information on how to use Glide is provided in the documentation.
Related
I have a RecyclerView with a fixed Dimension-Ratio
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
...>
<androidx.recyclerview.widget.RecyclerView
android:layout_width="0dp"
android:layout_height="0dp"
android:orientation="horizontal"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
app:layout_constraintDimensionRatio="35:16"
... />
</androidx.constraintlayout.widget.ConstraintLayout>
I Need to show list of ImageView inside the RecyclerView, but with a fixed number of images shown on the screen, and the rest of the images need to scroll to be shown, similar to the image
I Create this layout with ImageView inside it:
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/image"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginStart="4dp"
android:layout_marginEnd="4dp"
android:adjustViewBounds="true"
android:scaleType="centerCrop"
android:src="#drawable/image2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
The problem here
I try a lot, but the image doesn't show without setting the layout_width and layout_hieght with a fixed number.
and What i want is to set ImageView hight-width dynamicly with RecyclerView Hight and Screen Width.
The solution is super easy:
pass DisplayMetrics In The Adapter Constructor for getting screen width.
DisplayMetrics displayMetrics;
public SearchSliderOneAdapter(DisplayMetrics displayMetrics) {
this.displayMetrics = displayMetrics;
}
and calculate the width of ImageView = ScreenWidth\numberOfImage inside onCreateViewHolder function of the adapter.
public SearchSliderOneViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View inflate = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_image_slider, parent, false);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
displayMetrics.widthPixels / numberOfImage,
GridLayout.LayoutParams.MATCH_PARENT, 1);
inflate.setLayoutParams(params);
return new SearchSliderOneViewHolder(inflate, listener);
}
I'm trying to make Recyclerview like Shareit app. It uses sticky header and something like Cardview. I searched and found somethings for implementing sticky header with itemdecoration and it's okay. But for Cardview part, I tried to make nested Recyclerview but performance was so bad, Because using two vertical Recyclerview is not good at all. Is there any better way to achieve this?
The problem with performance is for when i scroll down. It makes lag on creating second item in parent Recyclerview.
AppheaderAdapter:
#Override
public AppHeaderAdapter.HeaderHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
final View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_media_header, parent, false);
HeaderHolder headerHolder = new HeaderHolder(view);
return headerHolder;
}
class HeaderHolder extends RecyclerView.ViewHolder { //story
final ImageView arrow;
final TextView tarikh;
final TextView tedad;
final CheckBox tick;
final RecyclerView item_recyc;
HeaderHolder(View itemView) {
super(itemView);
arrow = itemView.findViewById(R.id.header_arrow);
tarikh = itemView.findViewById(R.id.header_tarikh);
tedad = itemView.findViewById(R.id.header_tedad);
tick = itemView.findViewById(R.id.header_tick);
item_recyc = itemView.findViewById(R.id.header_recyc);
}
}
#Override
public void onBindViewHolder(#NonNull AppHeaderAdapter.HeaderHolder headerHolder, int position) {
final AppHeader appHeader = appHeaders.get(position);
...
GridLayoutManager gridLayoutManager = new GridLayoutManager(context, span);
gridLayoutManager.setRecycleChildrenOnDetach(true);
headerHolder.item_recyc.setLayoutManager(gridLayoutManager);
headerHolder.item_recyc.setNestedScrollingEnabled(false);
AppItemAdapter adapter = new AppItemAdapter(context, appHeader.getAppList(), fr_parent, width);
headerHolder.item_recyc.swapAdapter(adapter, true);
...
}
item_media_header.xml:
<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/header_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:background="#drawable/so_round_so_white"
app:cardCornerRadius="10dp"
app:cardElevation="5dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/header_arrow"
android:layout_width="30dp"
android:layout_height="30dp"
android:padding="8dp"
android:src="#drawable/header_arrow"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/header_tarikh"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="#dimen/fragment_file"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toRightOf="#id/header_arrow"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/header_tedad"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="2dp"
android:textColor="#AAAAAA"
android:textSize="#dimen/fragment_file"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toRightOf="#id/header_tarikh"
app:layout_constraintTop_toTopOf="parent" />
<CheckBox
android:id="#+id/header_tick"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="10dp"
android:button="#null"
android:clickable="false"
android:drawableRight="#drawable/file_checkbox"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/header_recyc"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</androidx.cardview.widget.CardView>
EDIT 1:
I find that just first Cardview is loaded and second one is not loaded until I scroll to end of first one and then load second CardView item and it lags because of second RecyclerView.
I found that Shareit use previous created adapter and just change its internal datalist, So i do that, but still has lag on second item.
Edite 2:
I use one time created adapter on all RecyclerView but still has lag.
Edit 3:
It's a known bug that innerRecyclerView load all items at first and that cause my lag too. because inner Recyclerview is inside NestedScrollView (RV) and it loads all content.Using constant height doesn't work, But I'll update question if I find something better.
You can achieve this with ConstraintLayout and Flow.
EDIT: Sorry, I just realised I wrote everything in Kotlin. If you cannot understand something I can try to translate it to Java.
xml:
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/constraintLayout"
...>
<androidx.constraintlayout.helper.widget.Flow
android:id="#+id/flow"
app:flow_wrapMode="aligned"
app:flow_horizontalStyle="spread_inside"
app:flow_maxElementsWrap="4"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
Adding of items:
val constraintLayout = itemView.findViewById(R.id.constraintLayout)
val flow = itemView.findViewById(R.id.flow)
val items // items given to the viewHolder to display
val layoutInflater = LayoutInflater.from(context)
items.forEach { item ->
val view = // create item view, e.g. DataBinding, ...
view.id = ViewCompat.generateViewId()
constraintLayout.addView(root)
flow.addView(root)
}
}
// if there are less than 4 items you have to add invisible dummy items. Otherwise, the alignment will look different for these ViewHolders
if(items.size>=4) return
for (i in 0..(4-items.size)) {
val view = // create dummy view
view.id = ViewCompat.generateViewId()
constraintLayout.addView(root)
flow.addView(root)
}
So far, Using vertical RV inside vertical RV has bug. Because of inner RV make long height and outer RV has no idea of this, So it create just first Item, but all items in inner RV. using all solution on Stack O.F. had no effect!
FrameLayout for some reason doesn't work perfectly in listview. I got this incorrect displaying in emulator. In Android Studio items looks nicely. Please help me :)
In Android Studio
In emulator
item.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="100dp"
android:padding="10dp">
<TextView
android:id="#+id/txtName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Title"
android:layout_gravity="center"
android:textSize="27sp"
android:textStyle="bold"/>
<TextView
android:id="#+id/txtGenre"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Genre"
android:layout_gravity="bottom|right"
android:textSize="18sp"
android:textStyle="italic"/>
<TextView
android:id="#+id/txtId"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="ID"
android:textSize="18sp"
android:textStyle="italic"
android:layout_gravity="bottom|left"/>
</FrameLayout>
Adapter code
public class MyFilmListAdapter extends ArrayAdapter<Film> {
Context context;
ArrayList<Film> films;
public MyFilmListAdapter(#NonNull Context context, ArrayList<Film> films) {
super(context, R.layout.item_film, films);
this.context = context;
this.films = films;
}
#NonNull
#Override
public View getView(int position, #Nullable View convertView, #NonNull ViewGroup parent) {
Film f = films.get(position);
LayoutInflater inflater = LayoutInflater.from(context);
View v = inflater.inflate(R.layout.item_film, null, false);
TextView name = v.findViewById(R.id.txtName);
TextView genre = v.findViewById(R.id.txtGenre);
TextView id = v.findViewById(R.id.txtId);
name.setText(f.getName() + "");
genre.setText(f.getGenre() + "");
id.setText(f.getId() + "");
return v;
}
}
I tried to use LinerLayout and it has correct displaying, however I need FrameLayout.
According to the official documentation
FrameLayout is designed to block out an area on the screen to display a single item. Generally, FrameLayout should be used to hold a single child view, because it can be difficult to organise child views in a way that's scalable to different screen sizes without the children overlapping each other.
You can, however, add multiple children to a FrameLayout and control their position within the FrameLayout by assigning gravity to each child, using the android:layout_gravity attribute.
So you can use LinearLayout inside it.
and nowadays better is you should use Recyclerview with ConstraintLayout
I have a page in which I'm taking the START TIME and END TIME from DATABASE.
Let's say the START TIME is 7:00 and END TIME is 22:00
I want to use this START TIME and END TIME to show in my page as textview like 7:00 8:00 9:00 and sooo on till 22:00 as textview
Also I have an imageview that will also increase when the text increases.
How can I achieve this?
Also I want the result text in Horizontal Scroll View with Imageview at top and text view as bottom of each imageview
char first = StartTime.charAt(0);
int StartTimeint = Integer.parseInt(String.valueOf(first));
int l;
for( l = StartTimeint; l<=22; l++){
Log.d("SeatsPage", "Time is "+l);
}
timeofseats.setText(Integer.toString(l));
This is I have done so far but I'm getting 23 as a result, the textview is not increasing
This is my XML File
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:id="#+id/llMain"
android:layout_height="match_parent"
tools:context=".SeatsPagewithDB.SeatsPage">
<ImageView
android:id="#+id/imageView11"
android:layout_width="150px"
android:layout_height="150px"
android:layout_marginStart="28dp"
android:layout_marginEnd="326dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/seat" />
<TextView
android:id="#+id/timeofseats"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="40dp"
android:layout_marginTop="12dp"
android:layout_marginEnd="334dp"
android:background="#FF0000"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:text="7:00"
android:textColor="#fff"
android:textSize="20dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/imageView11" />
</android.support.constraint.ConstraintLayout>
This is the result I am getting as layout
This what I want programmatically
The XML code that you write in your layout.xml file to create the UI is for static UI only. What you are asking is to create views dynamically during runtime. Although you can definitely create views using java code on a click of a button or something. But it is better to code less for the UI whenever possible and keep it separated from the program code. Instead use the tools given to us by the framework we are using.
In Android those tools include stuff like ListView, GridView and the newer and better RecyclerView. These views help you add other views dynamically to your UI in runtime. You define one of them or more (depending on your UI needs) once in your layout.xml and configure them using java code like any other view.
This is how you can use RecyclerView to achieve your goal. I can't explain everything how RecyclerView works and what each line of code does as it will make a very long post but I have tried to highlight main things briefly.
1. Add RecyclerView in your layout file.
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
2. Create another layout file and define the template UI of the item that the RecyclerView is going to display. RecyclerView will populate each item that it holds with this layout.
item_view.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="vertical">
<ImageView
android:id="#+id/imageView_alarm"
android:layout_width="90dp"
android:layout_height="90dp"
android:src="#drawable/alarm" />
<TextView
android:id="#+id/textView_Time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:background="#FF0000"
android:paddingLeft="8dp"
android:paddingRight="8dp"
android:text="Time"
android:textColor="#android:color/background_light"
android:textSize="24sp" />
</LinearLayout>
3. Create a ViewHolder class that extends from RecyclerView.ViewHolder. View holder is a RecyclerView related concept. In short it works as a wrapper around the view of a single item and aids in binding new data to the view of the item. Create a bind() function inside view holder to make your life easier.
EDIT: I have updated the class by implementing the View.OnClickListener interface, modified the constructor to pass in the context from onCreateViewHolder() and adding a setItemPosition() just for the sake to pass the item position number from onBindViewHolder() all over to here so we can use this position number in our onClick() method of the interface
MyViewHolder.java [UPDATED]
public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private TextView textView;
private int itemPosition;
private Context mContext;
public MyViewHolder(#NonNull View itemView, Context context) {
super(itemView);
itemView.setOnClickListener(this);
mContext = context;
textView = itemView.findViewById(R.id.textView_Time);
}
void bind(String timeText)
{
textView.setText(timeText);
}
void setItemPosition(int position)
{
itemPosition = position;
}
#Override
public void onClick(View v) {
Toast.makeText(mContext, "You clicked item number: " + itemPosition , Toast.LENGTH_SHORT).show();
}
}
4. Create an Adapter class that extends from RecyclerView.Adapter. Adapter works as a bridge between the UI data and RecyclerView itself. An Adapter tells the RecyclerView what layout file to inflate and how many to inflate. RecyclerView job is to deal with how to inflate it on the UI.
EDIT : Just changed myViewHolder in onCreateViewHolder() to match the modified constructor of MyViewHolder. Added the call to setItemPosition() in the onBindViewHolder().
MyAdapter.java [UPDATED]
public class MyAdapter extends RecyclerView.Adapter {
List<String> timeIntervalList = new ArrayList<>();
#NonNull
#Override
public RecyclerView.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_view, parent, false);
MyViewHolder myViewHolder = new MyViewHolder(view , parent.getContext());
return myViewHolder;
}
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder holder, int position) {
MyViewHolder viewHolder = (MyViewHolder) holder;
viewHolder.setItemPosition(position);
viewHolder.bind(timeIntervalList.get(position));
}
#Override
public int getItemCount() {
return timeIntervalList.size();
}
public void addItem (String timeText)
{
timeIntervalList.add(timeText);
notifyItemInserted(getItemCount());
}
}
In this adapter you will see two functions. OnCreateViewHolder() inflates the view using the template layout file for a single item and OnBindViewHolder() binds new data to the default values of the of the view just created. The data used for binding is stored in a list inside this Adapter called the timeIntervalList. This list will hold your time interval strings so they can be updated on the view.
5. Finally, use this RecyclerView where you want to use it. Like in your MainActivity.java. RecyclerView needs to be told in what fashion to display the items (e.g list , grid etc ) using a LayoutManager. LinearLayoutManager will display items either vertically or horizontally. You can see I am using your logic to increment time from string and adding new views to RecyclerView using the addItem() function of the MyAdapter class.
MainActivity.java
public class MainActivity extends AppCompatActivity {
private RecyclerView myRecyclerView;
private MyAdapter myAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myRecyclerView = findViewById(R.id.recyclerView);
myAdapter = new MyAdapter();
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this , LinearLayoutManager.HORIZONTAL, false);
myRecyclerView.setLayoutManager(linearLayoutManager);
myRecyclerView.setAdapter(myAdapter);
// This is how you will populate the recycler view
String START_TIME = "7:00";
String END_TIME = "22:00";
char first = START_TIME.charAt(0);
int StartTimeint = Integer.parseInt(String.valueOf(first));
int l;
for( l = StartTimeint; l<=22; l++){
// This is where new item are added to recyclerView.
myAdapter.addItem(l + ":00");
}
}
}
This is the final result.
Change your activity layout XML code as follows,
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:id="#+id/llMain"
android:layout_height="match_parent"
tools:context=".SeatsPagewithDB.SeatsPage">
<HorizontalScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content"
...
...>
<LinearLayout
android:id="#+id/container"
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</HorizontalScrollView>
</android.support.constraint.ConstraintLayout>
Move the textview and imageview to another XML file let's call it item_view.xml (you can name it whatever you wish). we are doing so because the root view of this file will be reused.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/imageView11"
android:layout_width="150px"
android:layout_height="150px"
app:srcCompat="#drawable/seat"/>
<TextView
android:id="#+id/timeofseats"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#FF0000"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:text="7:00"
android:textColor="#fff"
android:textSize="20dp"/>
</LinearLayout>
Now make following changes in your Java file
LinearLayout container = findViewById(R.id.container); // or rootView.findViewById() for custom View and Fragment
char first = StartTime.charAt(0);
int StartTimeint = Integer.parseInt(String.valueOf(first));
for(int l = StartTimeint; l<=22; l++){
Log.d("SeatsPage", "Time is "+l);
View view = LayoutInflater.from(container.getContext()).inflate(R.layout.item_view, null);
TextView timeofseats = view.findViewById(R.id.timeofseats);
timeofseats.setText(Integer.toString(l));
container.addView(view);
}
I'm developing an Android app for an online blog that retrieves data from its API (the company made it so I could use it in it, so it can be modified).
The app shows a ListView with n blog entries on load. The thing is I've spent the last three days searching for a way to add a Previous/Next button at the bottom of said ListView, just to finally give up and try another way.
I've seen apps update and append contents pulled from a server to a list (not sure which type) while the user scrolls up and down on it.
Is this possible? If so, how can it be done?
Any revealing piece of information, example (as simple as it may be) or help would be much appreciated!
EXTRA INFO
I'm loading the ListView in a LinearLineout, which is called in the onCreate method.
content_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="com.company.myApp.MainActivity"
tools:showIn="#layout/app_bar_main"
tools:layout_editor_absoluteY="81dp"
tools:layout_editor_absoluteX="0dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ListView
android:id="#+id/lv"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:background="#color/myGrey"
android:scrollbars="none"
android:visibility="visible" />
</LinearLayout>
</LinearLayout>
I also use a custom adapter to fill the ListView with the data retrieved. This data is retrieved by a custom class and stored in a List and that list is then passed as a parameter to the method I use to set such adapter.
public class AdaptadorPosts extends ArrayAdapter {
public AdaptadorPosts(Context context, List objects) {
super(context, 0, objects);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View v = convertView;
if (null == convertView) {
v = inflater.inflate(R.layout.lista_posts, parent, false);
}
TextView titulo = (TextView)v.findViewById(R.id.titulo);
TextView resumen = (TextView)v.findViewById(R.id.resumen);
TextView fecha = (TextView)v.findViewById(R.id.fecha);
TextView autor = (TextView)v.findViewById(R.id.autor);
Post item = (Post) getItem(position);
titulo.setText(Html.fromHtml(item.getTitulo()));
if(item.getResumen().isEmpty() || item.getResumen().equals(null)) {
resumen.setText("¡No hay resumen!");
} else {
resumen.setText(Html.fromHtml(item.getResumen()));
}
fecha.setText(Html.fromHtml(item.getFecha()));
autor.setText(Html.fromHtml(item.getAutor().getNombre()));
return v;
}
}
If I understand correctly you want to:
Add a Prev/Next button on the bottom of your screen
You have endless content which you want to show dynamically
The first can be easily achieved by using RelativeLayout and for the second you should use RecyclerView.
For your layout you can use something like this:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/light_gray">
<android.support.v7.widget.RecyclerView
android:id="#+id/lv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:scrollbars="none"
android:visibility="visible"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:src="#drawable/btn_prev"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:src="#drawable/btn_next"/>
</RelativeLayout>
If you want your buttons to be directly below the list, you can attach them by using android:layout_below="#id/lv" and removing android:layout_alignParentBottom="true"
The Android RecyclerView displays a given number of items (e.x. 10) and preloads some of the next and previous items. It's ideal for endless lists. If you want to add items to it dynamically, you need to do that in the adapter by adding the item to the list and calling the notifyItemInserted(int position) method.