Android redraw view example Mar 28, 2014 · Basically I have a drawer with a button in it. Back to Canvas ↑; The following code shows how to Redraw Canvas by calling invalidate method. findFragmentByTag("Your_Fragment_TAG"); final FragmentTransaction ft = getSupportFragmentManager(). extends View. Use invalidate() to force a draw or redraw of the view. Custom drawing can be easy or complex according to your application&#39;s needs. One way is that I create a new GraphView instance in the loop which should be final but I don't want to redraw all my chart every time because every time it draw it first it move to right for a second and then expand and place in the proper position. I tried many examples and source code from the internet, but it still didn't work on my PC like the invalidate func, canvas. How do i get the android layout May 26, 2011 · This code for If you want first create the view and after that refreshing page at specified time span then use following code. I want to know if I want to restart the activity at the end of exectuion of an other what method is executed onCreate() or onResume() GONE means only, that the view is not taking any space in the layout, INVISBLE means, the view takes space eg. Also I have simple button. Feb 22, 2015 · For example, if you only need to refresh, or in other words, you want each view to be rebinded, just do this: adapter. xml layout and we initialize our main layout by:. Jun 27, 2024 · The most important part of a custom view is its appearance. When I click on the button I want to hide a view (another button) that is loaded in the FrameLayout. The Android framework draws the layout in a two-pass process: a measure pass and a layout pass. Apr 24, 2020 · I am working on developing an application that contains (recyclerView ) display member responses. Below I include the XML code for the drawer. I have a problem redrawing the view. I am not sure this could be refreshed directly or if I need to close it first and re-instatiate it? Jun 20, 2012 · Invalidate, invalidateviews, notifyDatasetChanged, nothin worked for me! To just update the listview (with cursoradapter) I just do: cur = db. TileMode. Feb 5, 2011 · My ListView is using an extension of BaseAdapter, I can not get it to refresh properly. My requirement is to update the text size on all my views inside my fragment when my Activity is resumed. Call `invalidate ()` on a View object to request a redraw of the view. changeCursor(cur); // or swapCursor(), cur is the initial and the only cursor Mar 28, 2017 · public class MyListAdapter extends RecyclerView. graphics. public Dialog Mar 5, 2024 · so there are two different ways to do this: 1/Combine different Views: such as TextView, ImageView, and Drawable resources. The most important step in drawing a custom view is to … Jun 14, 2016 · This is how it looks at first: This is the dialog fragment that pops when "edit" is pressed and I want The change to be seen in the activity after the dialog fragment is dismissed. notifyDataSetChanged() right before setListAdapter(adapter); in the onCreate() method is useless because the list isn't aware of the data unless you call setListAdapter(). For a normal android. After setting the image, I then call postinvalidate(). From menu I invoke action that somehow process data in underlying db and change it. Story: Whenever user clicks on item, it shows AlertDialog. 6. Dec 13, 2012 · Calling invalidate() is done when you want to schedule a redraw of the view. For example, after a user login occurs that needs to expose more info or options within each view of the listView. ) 2-) Let’s consider a scenario where we have an avatar view composed of an Today we will learn how to redraw View! The so-called redrawing is to redraw its appearance (style). But where can I put the Nov 11, 2021 · I am using DiffUtil with ListAdapter in Android Kotlin. However, these views won't necessarily already have the correct images loaded into them, they are views that were previously being used for displaying different cells in the grid at different positions. setVisibility(View. view. 2/ Custom View: draw it yourself using the canvas and math. Aug 7, 2024 · In place of ListView, we use RecyclerView. That's what I needed to do, so gave an up-vote. So, a "GONE" view cannot come back. Oct 31, 2024 · Note: The framework doesn't draw View objects that aren't in a valid region. Oct 26, 2024 · In Android development, when you add a new view to a ViewGroup (such as a LinearLayout), you need to ensure that the layout and visual representation of the UI are updated to reflect this change Two options: either hold onto the reference for the ArrayList that you passed into the constructor so you can modify the actual list data later (since the list isn't copied, modifying the data outside the Adapter still updates the pointer the Adapter is referencing), or rewrite the Adapter to allow the list to be reset to another object. Feb 10, 2025 · The swipe-to-refresh user interface pattern is implemented entirely within the SwipeRefreshLayout widget, which detects the vertical swipe, displays a distinctive progress bar, and triggers callback methods in your app. Redraw View Android. Again, please let me know if this is unsafe or a bad practice and if possible a working alternative. mySwipeRefreshLayout. 0" encoding="utf-8" Aug 3, 2012 · Yes, that was the plan B which I was going to tell you if you say me that the array adapter doesn't show the changes. restore, etc Aug 30, 2013 · If the view is visible, onDraw(android. Everything works as it should and it draws part of a circle. Compose operates within the Android framework classes. Isn't my case. getHeight(); int halfWidth = vWidth / 2; int halfHeight = vHeight / 2; Add an if-else statement for (mOffset == OFFSET). attach(frg); ft. requestLayout() I'm trying to refresh specific item in RecyclerView. VISIBLE) call recyclerView. when you have multiple rows and each one updates independently from the others. In fact after the user c Android Studio project: CustomFanControllerSettings. When I refresh, it appears that the old data draws on top of the new data, until a scroll event happens. In my android app, I download an image from the cloud. GONE will remove the View from the screen, and the space occupied by the View is released to other Views on screen. Th Sep 25, 2009 · While scrolling, the whole screen get all messed up, again it looks like view is redrawn (when scrolled) without erasing the background first. However, for built-in widgets you rarely, if ever, need to call it yourself. When I click on the button of the row of listview, a button will be created in the main. Solutions. If the underlying data changes, it's probably a better idea to use notifyDataSetChanged(). . commit(); Jun 3, 2015 · This does not work for me. i("Fav ", "onRefresh called from SwipeRefreshLayout"); // This method performs the actual data-refresh operation. It just needs to extend View from the Android Feb 22, 2024 · Now that you have a well-designed view that responds to gestures and transitions between states, ensure that the view runs fast. Canvas) will be called at some point in the future. In my case I was invalidating a container (a ConstraintLayout) but the view inside it didn't get redrawn until I called postInvalidate() (from a service thread) directly on the view. So, I firstly get the current fragment (that's the latest one in backstack ): BackStackEntry latestEntry=fragMgr. The Jan 15, 2012 · View. But where can I put the Sep 22, 2014 · I can't recognise what is it's problem. getList(); //array Jun 27, 2024 · A well-designed custom view is much like any other well-designed class. This example describes how to create a SurfaceView with a dedicated drawing thread. When ı send message ı must update the screen because ı am getting data in db. Is there a way to make the redraw happen immediately? You must do this step every time the method is called, because the size of the view can change (for example, when the device is rotated). Summary. CLAMP constant defines that the edge corners should be used to fill the extra space, the Shader. First, create a new android project, we define a class, and inherit View, the class name is: DrawView: public class DrawView extends View {public DrawView Jun 27, 2024 · Views are redrawn frequently, and many drawing objects require expensive initialization. When I change params of one view(for example re scale image or rotate) this causes to redraw whole Layout. Example. OnRefreshListener() { @Override public void onRefresh() { Log. setOnRefreshListener( new SwipeRefreshLayout. Add removeSelf to directly call on a view. Sep 9, 2012 · I create my own View (RadarView), extending View. Also note that the method notifyDataSetChanged() has to be called on UI thread. xml, I am having the onclicklistener of the button in custom listView adapter. Call `invalidate()` on a View object to request a redraw of the view. Oct 31, 2013 · First, your adapter. ) and you didn't know whether this view will be placed inside other View that can intercept touch events or the view structure is even more difficult. Dec 14, 2016 · In Android development, we often come across requirements relating to refreshing a View periodically. Adapter<MyListAdapter. My code is: finish();startActivity(getIntent()); Nov 22, 2011 · I need to update a custom dialog content whenever that dialog is ready to be drawin. These preferences are collected and combined to determine a final frame rate for each frame. Dec 7, 2024 · Calling the Android framework from Compose. If so, detach the fragment and reattach it // Reload current fragment Fragment frg = null; frg = getSupportFragmentManager(). Aug 23, 2014 · However, if I remove the character in the same method that I create and share the image, the app crashes because it didn't get a chance to redraw the view first. invalidate(); After this, I would like to refresh my currently displayed fragment's view to display with new locale settings. Feb 6, 2025 · In order to use this behaviour, we need to use the SwipeRefreshLayout widget as the parent of a ListView or GridView. SwipeRefreshLayout class contains a listener called OnRefreshListener. But my question is how do i redraw it later on ? Use the `notifyDataSetChanged ()` method to refresh adapter-based views such as ListView and RecyclerView. To create a custom view of any size and shape, add a new class that extends View. :) Here is the java code: packag Aug 19, 2012 · It gives you better control when using an MVC model where there's a dataset tied to a View. when you swipe screen from top to bottom it will do some action based on setOnRefreshListener. Nov 29, 2013 · I'm trying to create a gridview that gives the possibility to the user to create a new child clicking on the last item on the gridview. It also takes care of drawing the View background for you. Example here I have a zoom 15 and a z Android UI How to - Redraw Canvas by calling invalidate method. I am calling the data from the server in the onResume method. I think that the best choice for you is using SwipeRefreshLayout View in your layout. Mar 27, 2013 · Most of the previous answers do a good job explaining how, why, and when to use onResume() but I would like to add something about re-creating your Activity. setContentView(R. setAdapter(adapter). In certain cases, the user has the ability to add items to one of the expandable lists. If you want to keep the space, you can use View. postInvalidate(); Also note that redrawing a container might not redraw all of its views. This site have some examples, but most is after click button. typeList = dbAdapter. In this example, we would store data of string type into the ArrayList which is used for populating the ListView. android redraw layout programmatically. we can call pull to refresh in android as swipe-to-refresh. Ok. Oct 3, 2014 · We set the activity_main. This is the following code I'm using to update the spinner. Time-based updates: Certain views may need to refresh periodically. Update the data binding in your layout using LiveData or ViewModel classes from the Android Architecture Components. getBackStackEntryCount()-1); String str=latestEntry. activity_main); In these lines, we find our SurfaceView from our main layout and we get a holder, an abstract interface to someone holding a display surface. In this example, we would store data of string type into the ArrayList which is used for populating the Aug 7, 2013 · So when you want to change the data or invalidate the view that you need, you can call the findViewWithTag() method on the ViewPager to retrieve the previously instantiated view and modify/use it as you want without having to delete/create a new view each time you want to update some value. getName(); Fragment fragment=fragMgr Aug 7, 2024 · Swipe-to-Refresh ListView is very much similar to Swipe-to-Refresh RecyclerView. 1st and 2nd connected with red line. notifyDataSetChanged(); it did not work. The Shader. Jul 20, 2010 · I've been trying to update my spinner in android dynamically but nothing I try has been working. INVISIBLE. However the image does not immediately show up. let us take an example, we have base View Group Component(RelativeLayout) which holds its all children. I subclassed View to get an View on which the user can "draw" with his fingers. You may find notifyDataSetChanged example and customListView helpful. Please refer to Pull to Refresh with RecyclerView in Android with Example. The download is performed in a thread and in that same thread I also set an image view with the newly downloaded image. beginTransaction(); ft. Jun 27, 2020 · When Activity brings to focus, the Android Framework request activity to provide the root node of its hierarchy(Top View Element in Layout file). GridView reuses views by passing them to getView() in convertView. getView(). So for now I'll be using onCreate(null) to refresh my view when I update data. You could instead use an event-driven approach and implement a pattern like an Event Bus, to which consumers can publish and subscribe. Preferences are defined in XML file - nothing funky just some categories and preferences nested within <PreferenceScreen/> Do I need to explicitly redraw the view? Jan 26, 2022 · Hello, I have a tile database but it lacks zooms (it is to save space). Whenever OnRefresh () method is called ArrayList data gets shuffled. save, canvas. Jul 18, 2016 · How to refresh view in android. You can force a View to draw by calling invalidate(). It encapsulates a specific set of functionality with an easy-to-use interface, it uses CPU and memory efficiently, and so forth. I mean I just want to redraw chart every 7 second I think that the best choice for you is using SwipeRefreshLayout View in your layout. To properly draw your custom view, find out what size it is. To refresh the ListView in Android, call notifyDataSetChanged() method on the Adapter that has been set with the ListView. Oct 22, 2010 · Kotlin Extension Solution. int vWidth = view. How can I trigger within the onTouch method the redraw of the View? Do I need to implement a Thread / Runnable? I thought that invalidate() triggers the redraw, but this doesn't work. I am quite new to Android development. I have selected one of x pages that are available to scroll through in ViewPager. A neat trick if you want to redraw only one view from your adapter is to call getView manually for it if its position is visible - i. Create custom Jun 16, 2014 · I have 3 ImageViews. e. To call from a non-UI thread, call postInvalidate(). OnTouchListener. GONE) and then recyclerView. Any suggestions that I can understand would be great. getItemCount()); Share May 13, 2015 · The issue is in your getView() function. Use the `notifyDataSetChanged()` method to refresh adapter-based views such as ListView and RecyclerView. MIRROR constant defines that the image is mirrored and Shader. For example, a lot of Views change how they look onTouch, like an EditText getting an outline and cursor, or a button being in the pressed state. I tried fragment. I want to prevent redrawing whole layout and Dec 4, 2014 · android. ViewHolder { public ImageView appSmallIcon; public ViewHolder(View v) { super(v); appSmallIcon = // . The former is used in the UI thread itself, while the latter is used in non-UI threads. This lesson covers some of the most common operations. I now have a View that is added programically after the onCreate (Depending on some other variables). View invalidate(int, int, int, int) part of a canvas, but onRedraw() the entire canvas? 0 Android Design: onDraw() not called after invalidate() Sep 18, 2021 · Here is my codes for custom view class: public class myView extends View {private Path path = new Path(); private Paint paint = new Paint(); //Constructor public myView(Context context, @Nullable Jul 12, 2015 · I am trying to figure out what is the issue with updating RecyclerView's Adapter. To learn more about system resources, see Resources in Compose. ListActivity. When they do so however, I cannot get the list to ref In this tutorial, we shall learn how to Refresh ListView using a Kotlin Android Application. This works well for 90% items. Enable this behavior by adding the widget to your layout file as the parent of a ListView or GridView and implementing the refresh behavior that is invoked when the user swipes. In place of ListView, we use RecyclerView. getBackStackEntryAt(fragMgr. invalidate() call recyclerView. So if something changes and it needs to be reflected on screen, you need to call invalidate(). This must be called from a UI thread. 12. layout. I want to update the view if any data change on the server side, so it will reflect in the app. It will result in onDraw being called eventually (soon, but not immediately). May 8, 2013 · I have a class that extends View and have the onDraw method implemented in my xml file I have a FrameLayout with my view and a RelativeLayout with a button &lt;?xml version="1. What you need to do, is to create a private Pie property in your activity or fragment class like this : Jun 4, 2019 · GraphView. detach(frg); ft. Override View methods such as onDraw() to define the view's shape and basic appearance. The view will be redrawn but the size will not change. Depending on Dec 22, 2015 · I have an Activity that contains an ExpandableListView. getWidth(); int vHeight = view. I would like to display the parent zoom instead of the front zoom which is in the view. User can type some text by clicking ok button. Mar 20, 2024 · Custom views can be created in two ways: 1-) Inherite from android framework components (Button, FrameLayout etc. Jan 29, 2025 · In Android's View system, each View in the UI hierarchy can express its preferred frame rate. An example of when a custom view would call it is when a text or background color property has changed. – Opiatefuchs Commented Sep 23, 2015 at 10:53 Sep 7, 2015 · In my app there's 2 tabs (Android Design Support Library) this is the Fragment with ViewPagerAdapter: public class ListaCanali extends Fragment { public static TabLayout tabLayout; public static. view. I want to show this text in this item and show invisible ImageView - declared in XML and adapter ViewHolder- Jun 11, 2014 · If you want to create custom view in which have to be your custom drawings for different touch states (pressed, selected, focused etc. To avoid a UI that feels sluggish or stutters during playback, ensure that animations consistently run at 60 frames per second… Jul 24, 2013 · notifyDataSetChanged() will redraw all views in your adapter. You should implement the behavior as follows. kt class GraphView(context: Context, attributeSet: AttributeSet): View(context, attributeSet) { GraphView. REPEAT defines that the image will be repeated. 1. Here is a picture: I want to connect 2nd & 3rd ImageViews with new Path line and change the first line color (for example to Green) when i clicking my button. If attached to a parent, it will be removed. May 18, 2012 · Generally, invalidate() means 'redraw on screen' and results to a call of the view's onDraw() method. Creating drawing objects within your onDraw() method significantly reduces performance and can make your UI sluggish. And call the invalidate() method when I want it redraw. This project shows you how to use Android's native webview wrapper to load site url, how to add and dismiss progressBar, and how to utilize the Swipe to refresh feature of Android's webView - GitHub - Luckae/Android-WebView-Example: This project shows you how to use Android's native webview wrapper to load site url, how to add and dismiss progressBar, and how to utilize the Swipe to refresh May 1, 2013 · I have a ListView. The following code shows how to Redraw Canvas by calling invalidate method. This class binds your data to the View and this class also has a method: notifyDataSetChanged() which is what should solve your problem. This is achieved through a voting mechanism where each View votes based on its frame rate attribute, which can be a category or a specific rate. . You should post the complete code, there's no way to know if the array you're passing is always the same reference or not. I implemented the Interface View. These Material Design UI Patterns are seen in applications like Gmail, Youtube, Facebook, Instagram, etc. invalidate()); or. kt Aug 11, 2012 · AFAIK, a View's onDraw() is called when: The view is initially drawn; Whenever invalidate() is called on the view; Invalidate can be called by you or the system whenever needed. When onResume called every item whole data is redrawing the view. I hope this helps. android custom view redraw. Just to be sure that we are on same page. For example, it's hosted on Android View classes, like Activity or Fragment, and might use Android framework classes like the Context, system resources, Service, or BroadcastReceiver. Nov 30, 2016 · I have GroupView which contains 4 ImageViews. I have looked EVERYWHERE and my little brain just can't understand a better way to refresh an activity. Jan 5, 2013 · runOnUiThread(() -> view. But id doesn't update! I tried using "invalidate()" and "postInvalidate()" but they doesn't work! Here is the code of RadarView: `public class RadarView extends View Redraw Canvas by calling invalidate method Description. You need to reload it. Now the View is NOT removed, instead, it hides the View and display blank space. Aug 14, 2014 · Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand User interactions: The user has performed actions that should update the view. I am responding to this topic a long time after but because I have faced the same problem and I finally found the solution to the problem. Here's tutorial that demonstrate about how to implement android pull to refresh. Aug 9, 2017 · How to refresh current Activity 1 time after load? My code refresh the activity, but in Loop. – I have created a custom View (let's call it MyView) which basically just draws some text on itself using the canvas. So you could have a class that extends BaseAdapter. For example, a timer which counts down every second or a counter which counts up every second. I have a fragment that inflates an xml layout. I am saving Sep 3, 2015 · Performing a "refresh" to keep your fragment state up to date unnecessarily destroys and recreates the view when all you need to do is update your adapter data. Then set RefreshListener like. But how about the SurfaceView ? It seems that postInvalidate() can be used to call its redraw. The text to be drawn is set using a global variable. My question is basically the same as How to force a view to redraw immediately before the next line of code is executed , but unlike this question I don't need to change background I am quite new to Android development. I have created a class RoundIcon which extends View and the class contains setIconImage() method: public void setIconImage(int imageFromResources) { iconImage = BitmapFactory. Since it is necessary to redraw, you must first inherit the View class. In addition to being a well-designed class, though… Jun 27, 2012 · Can anyone help me on how to redraw the canvas. Jun 27, 2016 · If the area which is filled is larger than the Shaders you can define via the Shader tile mode how the rest should be filled. I think you want to refresh the fragment contents upon db update. decodeResource( call recyclerView. There is a fundamental design flaw in your code: the position of player is modified during the execution of the onDraw: you will be unable to control it. This implementation also handles edge cases such as manufacture specific issues as well as starting/stopping the thread to save cpu time. Jan 3, 2011 · We should first know what is Pull to refresh layout in android . rawQuery( "SELECT * FROM ssnt WHERE mid = 1000" ); //optional, initial query adapter. Only 90% of items will get the new style, but some items will have the old style Feb 12, 2010 · This is the correct answer if one only needs to REDRAW the view. I googled but ı can not exact Dec 11, 2014 · You don't really can get the control on when the onDraw will be called: when a view is invalidate then the onDraw will be called at some point in future. Main Activity Java code Extend by device; Build apps that give your users seamless experiences from phones to tablets, watches, headsets, and more. I have a problem after a member posts a new comment the (recyclerView ) is not updated in real time. It allows the user to refresh the application manually. I working on messaging platform like whatsup. This makes your code more declarative, and thus readable. View, I will override the onDraw() method, put all my graphic login inside this method . notifyItemRangeChanged(0, adapter. setAdapter(null) and then recyclerView. When i press send button ı must update View. One is invalidate and the other is postInvalidate. kt does not need to be fancy. There are two methods for implementing view update in android. ViewHolder> { private ArrayList<StatusBarNotification> myList; Context ctx; public class ViewHolder extends RecyclerView. At some point during the program's execution, I want to change the global variable, and have the MyView redraw itself to update the text. After I get a new List of products, I tried to: Update the ArrayList from the fragment where recyclerView is created, set new data to adapter, and then call adapter. (here mention refreshing rate is 20 seconds) It Works Fine and Automatic refresh in every 20 seconds. Can someone let me know the relevant APIs to dynamically update a TextView (or entire screen )? For example: I have a search application and I need to show the Apr 20, 2013 · Now I meet some problems with the redraw of the view. the place for the view is just empty, but taken. rdjws vvop ywsuj eyau nwsbq qgjmw xhalcit zojj junksr kvgsule silmbo jtpox ccovf kgzqi jpwhe