I am new to android. I had declare layout hierarchy in main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout class="com.android.MyLayout"
android:id="#+id/mylayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
xmlns:android="http://schemas.android.com/apk/res/android"
>
<LinearLayout
android:id="#+id/widget36"
android:layout_width="fill_parent"
android:layout_height="42dp"
android:background="#color/darkgray"
android:orientation="horizontal"
>
</LinearLayout>
<LinearLayout
android:id="#+id/widget38"
android:layout_width="fill_parent"
android:layout_height="390dp"
android:background="#color/black"
android:orientation="horizontal"
>
</LinearLayout>
</LinearLayout>
I also use this layout in my java class
class MyLayout extends LinearLayout
{
public MyLayout(Main context)
{
super(context);
}
public MyLayout(Context context,AttributeSet attribute)
{
super(context,attribute);
}
protected void onLayout (boolean changed, int l, int t, int r, int b)
{
super.onLayout(changed,l,t,r,b);
}
}
Now the problem is that I want to perform draw operation using Canvas on one of the child Layout eg. Layout of id "widget38". How can I proceed ?
Put the views inside the bigger ones. You have to define them in a nested way, not sequentially, closing the parent layout after having defined the child layouts.
Related
I am using a horizontal RecyclerView and showing images using the CircleImageView widget (See image below).
I am really struggling on how to make the list of items loop around, so that if you are in the last item, you will move to the first item in the list?
I have tried quite a few similar examples but I can’t make them work as they are in Java, or are quite complex. following is my code
MainActivity.kt
class MainActivity : AppCompatActivity() {
lateinit var adapter: ConcatAdapter
lateinit var userVerticalAdapter: UsersAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
setupDataInRecyclerView()
}
private fun setupDataInRecyclerView() {
recyclerView.layoutManager = LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false)
userVerticalAdapter = UsersAdapter(DataSource.getUser())
val listOfAdapters = listOf(userVerticalAdapter)
adapter = ConcatAdapter(listOfAdapters)
recyclerView.adapter = adapter
}
}
Adapter.kt
class UsersAdapter(
private val users: ArrayList<User>
) : RecyclerView.Adapter<UsersAdapter.DataViewHolder>() {
class DataViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
fun bind(user: User) {
itemView.textViewUserName.text = user.name
Glide.with(itemView.imageViewAvatar.context)
.load(user.avatar)
.into(itemView.imageViewAvatar)
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
DataViewHolder(LayoutInflater.from(parent.context)
.inflate(R.layout.item_layout, parent,false))
override fun getItemCount(): Int = users.size
override fun onBindViewHolder(holder: DataViewHolder, position: Int) =
holder.bind(users[position])
}
}
DataSource.kt
object DataSource {
fun getUser() = ArrayList<User>().apply {
add(User(1, "Chillis", R.drawable.chilli))
add(User(2, "Tomato", R.drawable.tomatoe))
add(User(3, "Sweetcorn", R.drawable.sweeetcorn))
add(User(4, "Potatoe", R.drawable.potatoe))
add(User(5, "Aubergine", R.drawable.aubmain))
add(User(12, "Onion", R.drawable.onion))
}
}
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:orientation="horizontal"
android:padding="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:listitem="#layout/item_layout_banner"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
item_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_margin="1dp">
<androidx.cardview.widget.CardView
android:layout_width="120dp"
android:layout_height="120dp"
app:cardCornerRadius="4dp"
app:cardMaxElevation="2dp"
app:cardElevation="1dp"
android:layout_centerInParent="true">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<de.hdodenhof.circleimageview.CircleImageView
android:layout_width="90dp"
android:layout_height="90dp"
android:scaleType="centerCrop"
android:layout_centerHorizontal="true"
app:civ_border_width= "3dp"
app:civ_border_color= "#color/colorPrimary"
android:id="#+id/imageViewAvatar"
android:src="#drawable/ic_launcher_background"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="20dp"
android:text="Veg"
android:layout_below="#+id/imageViewAvatar"
android:id="#+id/textViewUserName"
android:gravity="center"
android:layout_marginTop="5dp"
android:layout_centerHorizontal="true"
android:textColor="#000"
android:layout_marginBottom="5dp"
android:autoSizeTextType="uniform"
android:autoSizeMinTextSize="8sp"
android:autoSizeMaxTextSize="15sp"/>
</RelativeLayout>
</androidx.cardview.widget.CardView>
</RelativeLayout>
To achieve this first you have to override the getItemCount function of UsersAdapter to return a very large value such as Int.MAX_VALUE
// This enables your adapter to scroll past the actual list size
override fun getItemCount(): Int = Int.MAX_VALUE
Now change your onBindViewHolder to calculate actual position
// Lets say your list had 100 items
override fun onBindViewHolder(holder: DataViewHolder, position: Int) {
// position can be larger than 100 (ex 101), because our getItemCount doesn't return actual list size
// so if we receive position as 101, which item should we display?
// that should be item 1. (for 102 -> 2, 201 -> 1) and so on
// this suggests use of modules
val pos = position % users.size
holder.bind(users[pos]) // bind the actual item
}
Now in your MainActivity after recyclerView.adapter = adapter line, add following line
// When RV is loaded scroll it to middle, so that user doesn't hit limit on both ends(easily)
rv.scrollToPosition(Int.MAX_VALUE/2)
I have the following simple recyclerview layout:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".SurvivorPicksheetActivity">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
This recycler view links to the detailed layout of the list items as such:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<FrameLayout 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/rootView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.cardview.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<ImageView
android:id="#+id/background"
android:layout_width="match_parent"
android:layout_height="180dp"
android:layout_centerHorizontal="true"
app:srcCompat="#drawable/gamefield_background" />
<ImageView
android:id="#+id/away"
android:layout_width="160dp"
android:layout_height="150dp"
android:layout_gravity="top|left"/>
<ImageView
android:id="#+id/home"
android:layout_width="160dp"
android:layout_height="150dp"
android:layout_gravity="top|right"
android:scaleX="-1"/>
</androidx.cardview.widget.CardView>
</FrameLayout>
</LinearLayout>
Inside my Adapter java class I have an setOnClickListener for the two ImageView items.
If a user clicks on them the item is selected while the old item is unselected.
The problem I am encountering if that lets say the list of items has 25 items. If I click on the lets say 3rd item, everything works as expected.
Then I scroll to the end of the list, and scroll back up to the top, the selection is not longer valid even thought I clicked/selected prior to scrolling to the end of the list.
I can reclick and item at the top, scroll down and scroll back up and my selection is gone!?
Does anyone know why this is happening and more importantly how i can resolve it!?
UPDATE:
The following is my Adapter class:
public class GameAdapter extends
RecyclerView.Adapter<GameAdapter.GameViewHolder> {
// variable that holds the selected team
private String selectedTeam = "";
#Override
public void onBindViewHolder(GameViewHolder holder, int position) {
final Games game = gameList.get(position);
holder.awayTeamImageView.setOnClickListener(new Button.OnClickListener() {
#Override
public void onClick(View v) {
if (selectedTeam.equals(String.valueOf(game.getHomeId()))) {
// RESET PLAYER SELECTION
selectedTeam = "";
selectedGame = "";
} else {
// SET PLAYER SELECTION
selectedTeam = String.valueOf(game.getHomeId());
selectedGame = String.valueOf(game.getKey());
}
}
}
}
class GameViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public GameViewHolder(#NonNull View itemView) {
super(itemView);
itemView.setOnClickListener(this);
awayImageView = itemView.findViewById(R.id.away);
homeImageView = itemView.findViewById(R.id.home);
homeImageView.setOnClickListener(this);
awayImageView.setOnClickListener(this);
}
}
Based on my code above, I 'think' I am setting and unsetting the selected team so that when I scroll to the end and back to the top the selected team should remain vs being recycled and not displaying anymore?!
That's because the old Views are being recycled, back to the initial state. And this is a natutral behavior of RecyclerView.
In order to make each item View "memorize" its check/select state, you need to create a field in your model class to record the state, like isChecked or isSelected.
You can use own domain ViewHolder and ViewModel for recycleview.
Android developer documents gives basic understanding of how to create dynamic RecycleView in below link.
https://developer.android.com/guide/topics/ui/layout/recyclerview
This is expected as the views are recycled and lose their values accordingly whenever you scroll up/down the list; further for configuration changes (like screen rotation) the selected views will be lost.
To fix this, you should go for ViewModel to have persistent data even for configuration changes.
But, as a rescuer, assuming the adapter provided list of games gameList is in a persistent storage like mentioned above; then you can:
Create a selection boolean in the Games model class with getter/setter which has a false initially.
When a row is selected from the RecyclerView, then set the boolean to true like gameList.get(selectedPosition).setIsSelected(true)
Then notifyItemChanged() of that position.
I am new to Android Learning. I am trying to make a customAdapter that will display an image and a text in every row. In my Main_Activity, I have following code:`
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String [] foods= {"Biryani","Matar Qeema","Chicken"};
ListAdapter faizisAdapter= new CustomAdapter(this,foods);
ListView faizisListView= (ListView)findViewById(R.id.faizisListView);
faizisListView.setAdapter(faizisAdapter);
faizisListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String food= String.valueOf(parent.getItemAtPosition(position));
Toast.makeText(MainActivity.this,food,Toast.LENGTH_LONG).show();
}
});
}
}
Here is my CustomAdapter:
class CustomAdapter extends ArrayAdapter<String>{
CustomAdapter(Context context, String []foods)
{
super(context,R.layout.custom_row, foods);
}
public View getView(int position, #Nullable View convertView, #NonNull
ViewGroup parent) {
LayoutInflater faisizInflater = LayoutInflater.from(getContext());
View faizisView = faisizInflater.inflate(R.layout.custom_row, parent,
false);
String food = getItem(position);
TextView _foodsDisplay = (TextView)
faizisView.findViewById(R.id._foodDisplay);
ImageView _imageDisplay = (ImageView)
faizisView.findViewById(R.id._imageDisplay);
_imageDisplay.setImageResource(R.drawable.zaheer8423);
_foodsDisplay.setText(food);
return faizisView;
}
}
My Main_Activity_XML_FILE is:
<?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:layout_height="match_parent"
tools:context=".MainActivity">
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/faizisListView"
>
</ListView>
XML_FILE_FOR_customAdapter:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/_imageDisplay"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/zaheer8423"
/>
<TextView
android:id="#+id/_foodDisplay"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</android.support.constraint.ConstraintLayout>
I haved saved image file in app/src/main/res/drawable/zaheer8423.jpg. I have connected my android device with android studio externally. When I run the app It opens and suddenly closes.
I have seen ways that use bitmap but I could not use them effectively, because I have very little knowledge about them.
Please help me here.
Looks like your Image size is big,You might need to scale down image something like this.
// Decode with inSampleSize
BitmapFactory.Options option = new BitmapFactory.Options();
option.inSampleSize = scale;
//You need to calculate appropriate sample size
Bitmap bitmap =
BitmapFactory.decodeResource(getContext().getResources(),R.drawable.zaheer8423,option);
imageDisplay.setImageBitmap(bitmap);
As its adapter you need to manage caching the bitmap and creating bitmap should be done in worker thread (Non Main thread i.e. UI Thread ) to avoid ANRs.
I'm sorry if this has been already answered but it's been a while and I'm still searching. Since the FAB has a behaviour class you can assign to it which will work with scrolling inside a coordinator layout, I was wondering if it was possible to include behaviour to make the FAB automatically get placed above an adview when it is visible similar to how it reacts to a snack bar. Thank you in advance.
Work Around!
I figured out a work around as I was just playing around some time back, even forgot about the question. Instead of putting my adview inside a container with the rest of my views I simply had to wrap the coordinator view in a Relative layout and set the coordinator layout above the adview ID. I'm sure this might not be the best way to do it.
So what I ended up having is this: NB My adview is set to visibility gone by default and I only set the visibility when the adrequest is complete
<RelativeLayout
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">
<android.support.design.widget.CoordinatorLayout
android:layout_above="#+id/ad_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<include layout="#layout/content_main" />
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="#dimen/fab_margin"
android:visibility="gone"
app:layout_behavior="utils.FabBehavior_Main"
app:rippleColor="#color/fab_ripple"
app:srcCompat="#drawable/ic_fab" />
</android.support.design.widget.CoordinatorLayout>
<com.google.android.gms.ads.AdView
android:id="#+id/ad_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:visibility="gone"
app:adSize="SMART_BANNER"
app:adUnitId="#string/banner_ad_unit_id"
/>
</RelativeLayout>
The utils.FabBehavior_Main is the relative package class that contains the behaviour properties for the view, utils being the package. So in your own application you could have the name space com.myapp.utils.ScrollAwareFab which would have be like this:
public class ScrollAwareFab extends FloatingActionButton.Behavior {
public ScrollAwareFab(Context context, AttributeSet attrs) {
super();
}
#Override
public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout,
FloatingActionButton child, View directTargetChild, View target, int nestedScrollAxes) {
return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL ||
super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target,
nestedScrollAxes);
}
#Override
public void onNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child,
View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed,
dyUnconsumed);
if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) {
child.hide(new FloatingActionButton.OnVisibilityChangedListener() {
/**
* Called when a FloatingActionButton has been hidden
*
* #param fab the FloatingActionButton that was hidden.
*/
#Override
public void onHidden(FloatingActionButton fab) {
super.onShown(fab);
fab.setVisibility(View.INVISIBLE);
}
});
} else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
child.show();
}
}
}
I have linear layout with viewpager on top and another vew (button in this example) bottom. Views in the pager have different heights. I would like the pager to have wrap_content height on all pages and button view to fill the rest of the screen.
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.view.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:text="New Button"
android:id="#+id/button3"
android:layout_weight="1"/>
</LinearLayout>
This doesn't work. If I give layout_weight=1 to both pager and button, they share screen 50:50 no matter of content height. I tried to call requestLayout() in ViewPager.OnPageChangeListener.onPageSelected() but it doesn't help. Also tried this
Have you tried setting the layout_weight=1 for the pager and the layout_weight=2 for the button?
This works for me, but I don't consider it perfect.
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
View titlestrip = getChildAt(0);
int h = titlestrip.getMeasuredHeight();
View fv = ((FragmentPagerAdapter)getAdapter()).getItem(getCurrentItem()).getView();
if (fv != null) {
fv.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
h += fv.getMeasuredHeight();
}
super.onMeasure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(h, MeasureSpec.EXACTLY));
}
It relies on the fact that my FragmentPagerAdapter.getItem() doesn't instantiate new fragments but return it from container.