I am new to Android. I would like to create an Activity very similar to "Add event" part of Android Calendar app. To me it looks like a ListView with different components in each row. I could be wrong. If I am right, I still don't know how to add different components to each row of a ListView, e.g., EditText in one row, TextView in another row, etc. If this app is not ListView at all, if anybody can tell me how I can create something similar, I'd appreciate that a lot.
hello check this link it be helpful 1
listView with different component
First you have to learn how to implement a custom Adapter (see this tutorial: http://www.vogella.com/tutorials/AndroidListView/article.html#adapterown)
Then in your getView overriden method (you'll learn about it in the tutorial) you have to do something like this:
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = null;
if (position == LAYOUT1_POSITION) //In this row you will place the layout named layout1
rowView = inflater.inflate(R.layout.rowLayout1, parent, false);
if (position == LAYOUT2_POSITION)
rowView = inflater.inflate(R.layout.rowLayout2, parent, false);
//Do similar for all your different layouts
return rowView;
}
Related
This is my listView
I want to add a February header on top of 2016-02-02 and January in 2016-01-31. Is it possible?
Yes, you can do this by returning a different view in your getView() method in your adapter class. In your master list, that you pass to your adapter, you can add a divider item, a String or however you are holding all this data, I assume a custom class, that you know is meant to show a Month title. You can do a quick check in your getView() method and return a different view that displays the month..
In your getView() method, you can do this...
#Override
public View getView(final int position, View convertView, ViewGroup parent){
LayoutInflater mInflator = LayoutInflater.from(getContext());
View customView = mInflator.inflate(R.layout.times_layout, parent, false);
Time temp = getItem(position);
//Check to see if the time is supposed to be a header
//This is where you check to see if it meant to be a section header
if(temp.getDate.equals("HEADER")){
//Header, return section view instead of normal view
View sectionHeader = mInflator.inflate(R.layout.layout_list_divider, parent, false);
TextView txt_Section = (TextView) sectionHeader.findViewById(R.id.txt_Header);
sectionHeader.setClickable(false);
return sectionHeader;
}
//Normal View... do what you would do normally
return customView;
}
I hope this helps! Let me know.. it worked for me
In android It's called ExpandableListView
You can try this tutorial:
http://www.androidhive.info/2013/07/android-expandable-list-view-tutorial/
It also has a sample to download.
In my listview I have a custom Adapter, which I build using a TreeMap, I defined the getView method which is as follows. I am trying to strike out the text in a certian textview of the listview on click, only those textviews will be striken off which contain a certain pattern of characters (y#y). However on clicking one row in the listview I am getting strike out effect on some other row.
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
convertView = inflater.inflate(R.layout.chklistlayout, parent, false);
}
TextView textView = ((TextView) convertView.findViewById(R.id.textView1));
TextView imageview = ((TextView) convertView.findViewById(R.id.textView2));
textView.setText(values[position]);
imageview.setText(mValues[position]);
String s = mValues[position];
if (s.contains("y#y")) {
System.out.println("In if of getview");
System.out.println(s);
imageview.setPaintFlags(imageview.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
} else {
}
return convertView;
}
}
I tried using a holder pattern too, using a static holder class, but the problem seems to persist. Any pointers?
this answer is half mine and half from Muhammad Babar that we both commented on the question making together a quite nice answer:
use else block to handle this, imageview.setPaintFlags() not to strike
that happens
Because of the convertView. When you scroll the list the same view
that was used before is give back to getView method. So the same
imageView that you painted with StrikeThrough before is still painted
with it. So you have to revert that action.
more over, because of this recycling, usually dealing with Adapters you must ALWAYS undo/revert/repaint/change text/change image to all the elements to make sure it will be on screen the way you want.
ps.: now you should apply a Holder pattern to get better performance.
I have a fully functional listview (in a ListFragment) with a custom ArrayAdapter.
The layout of the adapter consists of an imageview, a button, a gridview and a couple of textviews.
The problem is the listview is very jittery while scrolling. I have implemented the ViewHolder pattern and it improved the performance just a little.
The GridView consists of contact images which i am retrieving in a AsyncTask and also using application cache to display the bitmaps.
What else can i do to make this listview scroll smooth?
I have used view recycling as shown below in my getView method of the adapter
public View getView(int position, View convertView, ViewGroup parent) {
View myView;
holder = new ViewHolder();
if (convertView == null) {
inflater = (LayoutInflater) getContext().getSystemService(
Context.LAYOUT_INFLATER_SERVICE);
myView = inflater.inflate(R.layout.events_list_activity, parent, false);
}
else {
myView = convertView;
}
}
This question might have explanation for jittery behaviour of your list view.
If you are looking to improve scrolling speed, try this,
getListView().setFastScrollEnabled(true);
1.Flatten your ViewItem hierarchy & use merge tag
2.Implement ViewHolder pattern, or use inject feature of androidannotation
3.Do the heavyload in another thread.
It will give you the scroll from top of your layout and also it'll give you smooth scrolling experience.
mainScrollView=(ScrollView)findViewById(R.id.scrollview);
mainScrollView.smoothScrollTo(0, 0);
mainScrollView.fullScroll(mainScrollView.FOCUS_UP);
I'm new to android programming and doing the first steps with Adapters (for a ListView).
Overriding the Adapter.getView I often see things like this:
public View getView(int position, View convertView, ViewGroup parent) {
View itemView = null;
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) parent.getContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
itemView = inflater.inflate(R.layout.table_row, null);
} else {
itemView = convertView;
}
// play with itemView
return itemView;
}
My question is what speaks against this:
public View getView(int position, View convertView, ViewGroup parent) {
View itemView = super(position, convertView, parent);
// play with itemView
return itemView;
}
This seems to work for me but I'm sure there's a big point I'm missing :D
Thanks for reading and sorry for my bad english ...
You can use
View itemView = super(position, convertView, parent);
if only you are deriving from "ready to use" adapters (not BaseAdapter), like SimpleAdapter, or ArrayAdapter, as they already have their implementation for the getView().
Have a look at them: http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.0.4_r2.1/android/widget/ArrayAdapter.java#361 for the ArrayAdapter, and
http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.0.4_r2.1/android/widget/SimpleAdapter.java#113 for SimpleAdapter.
If you derive from BaseAdapter, you will have to manualy implement the whole method, as you've described in the first example, because it does not have it out of the box: http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.0.4_r2.1/android/widget/BaseAdapter.java#BaseAdapter
The getView(..)-method of the Adapter can be multiple ways. The only question is, which one is the most efficient?
An interesting article to read and make you understand the ListView more detailed: http://lucasr.org/2012/04/05/performance-tips-for-androids-listview/
If you mean that this piece of code:
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) parent.getContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
itemView = inflater.inflate(R.layout.table_row, null);
} else {
itemView = convertView;
}
seems unnecessary for you: this piece of code allows Android to create a relatively small number of cells (equals to the number of cells that are visible on your screen +-), and then "recycle" these cells - use them over and over again while the user scrolls the list, instead of creating a cell for each object in your array.
This will help you with:
Saving memory - because you don't create view for each element in your array
Saving CPU usage - creating a view object out of xml file ("inflating") is relatively expensive task and doing so for each item in your array might choke your UI thread
I have a ListView in a custom ArrayAdapter that displays an icon ImageView and a TextView in each row. When I make the list long enough to let you scroll through it, the order starts out right, but when I start to scroll down, some of the earlier entries start re-appearing. If I scroll back up, the old order changes. Doing this repeatedly eventually causes the entire list order to be seemingly random. So scrolling the list is either causing the child order to change, or the drawing is not refreshing correctly.
What could cause something like this to happen? I need the order the items are displayed to the user to be the same order they are added to the ArrayList, or at LEAST to remain in one static order. If I need to provide more detailed information, please let me know. Any help is appreciated. Thanks.
I was having similar issues, but when clicking an item in the custom list, the items on the screen would reverse in sequence. If I clicked again, they'd reverse back to where they were originally.
After reading this, I checked my code where I overload the getView method. I was getting the view from the convertedView, and if it was null, that's when I'd build my stuff. However, after placing a breakpoint, I found that it was calling this method on every click and on subsequent clicks, the convertedView was not null therefore the items weren't being set.
Here is an example of what it was:
public View getView(int position, View convertView, ViewGroup parent)
{
View view = convertView;
if (view == null)
{
LayoutInflater vi = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = vi.inflate(R.layout.listitemrow, null);
RssItem rssItem = (RssItem) super.getItem(position);
if (rssItem != null)
{
TextView title = (TextView) view.findViewById(R.id.rowtitle);
if (title != null)
{
title.setText(rssItem.getTitle());
}
}
}
return view;
}
The subtle change is moving the close brace for the null check on the view to just after inflating:
public View getView(int position, View convertView, ViewGroup parent)
{
View view = convertView;
if (view == null)
{
LayoutInflater vi = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = vi.inflate(R.layout.listitemrow, null);
}
RssItem rssItem = (RssItem) super.getItem(position);
if (rssItem != null)
{
TextView title = (TextView) view.findViewById(R.id.rowtitle);
if (title != null)
{
title.setText(rssItem.getTitle());
}
}
return view;
}
I hope this helps others who experience this same problem.
To further clarify the answer of farcats below in more general way, here is my explanation:
The vi.inflate operation (needed here for parsing of the layout of a row from XML and creating the appropriate View object) is wrapped by an if (view == null) statement for efficiency, so the inflation of the same object will not happen again and again every time it pops into view.
HOWEVER, the other parts of the getView method are used to set other parameters and therefore should NOT be included within the if (view == null) statement.
Similarily, in other common implementation of this method, some textView, ImageView or ImageButton elements need to be populated by values from the list[position], using findViewById and after that .setText or .setImageBitmap operations.
These operations must come after both creating a view from scratch by inflation and getting an existing view if not null.
Another good example where this solution is applied for BaseAdapter appears in BaseAdapter causing ListView to go out of order when scrolled
The ListView reuses view objects when you scroll. Are you overriding the getView method? You need to make sure you set each property for every view, don't assume that it will remember what you had before. If you post that method, someone can probably point you at the part that is incorrect.
I have a ListView, AdapterView and a View (search_options) that contains EditText and 3 Spinners. ListView items are multiple copies of (search_options) layout, where user can add more options in ListView then click search to send sql query built according to users options.
I found that convertView mixing indecies so I added a global list (myViews) in activity and passed it to ArrayAdapter. Then in ArrayAdapter (getView) I add every newly added view to it (myViews).
Also on getView instead of checking if convertView is null, I check if the global list (myViews) has a view on the selected (position).. It totally solved problems after losing 3 days reading the internet!!
1- on Activity add this:
Map<Integer, View> myViews = new HashMap<>();
and then pass it to ArrayAdapter using adapter constructor.
mSOAdapter = new SearchOptionsAdapter(getActivity(), resultStrs, myViews);
2- on getView:
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View view;
ViewHolder viewHolder;
if (!myViews.containsKey(position)) {
viewHolder = new ViewHolder();
LayoutInflater inflater = LayoutInflater.from(getContext());
view = inflater.inflate(R.layout.search_options, parent, false);
/// ...... YOUR CODE
myViews.put(position, view);
FontUtils.setCustomFontsIn(view, getContext().getAssets());
}else {
view = myViews.get(position);
}
return view;
}
Finally no more mixing items...