Develop Reference

Creating Rows in ListView with ArrayAdapter in Kotlin

I have an app that's getting information from an API request and then displaying a list of devices. After several hours of combing through documentation, I cannot figure out how to format the View that is created from the ArrayAdapter. Essentially, if the device has an error, I want to display a red circle to the right of the button and display a green button if there is no error.
deviceList is the name of a ListView that I am trying to display my list of buttons inside of. deviceNames is an array of strings that contains the names of the devices.
The TextViews that are created are also clickable, which is what the onItemClickListener is handling. This section works, but I wanted to leave it in because I do need the buttons to start an activity that displays device-specific information.
Ideally I would like to essentially create a template that I can just change the values of the text and the color of the indicator for
Below is my code:
// List of device names
val listView: ListView = findViewById(R.id.deviceList)
val arrayAdapter1: ArrayAdapter<*>
arrayAdapter1 = ArrayAdapter(
this#Homepage,
R.layout.device_button,
deviceNames
)
listView.setAdapter(arrayAdapter1)
listView.onItemClickListener =
AdapterView.OnItemClickListener { parent, view, position, id ->
val pos = position
println(pos)
val device = jsonArray.getJSONObject(pos)
val ID = device.get("id") as String
println(ID)
goToDeviceDetail(ID)
}
Below is the XML file for device_button. I tried to add formatting here and essentially create a template for a button that would allow me to change the text and the color of the indicator, but it got mad that it wasn't just a TextView.
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:gravity="center_vertical"
android:textColor="#25383C"
/>
Below is the button that I would like for it to look like. I'm likely going to just make the background a solid color rather than the image that is in the below picture:

I would say the biggest problem is your using a simple API for a more complex problem. It is entirely possible do it with a ListView and ArrayAdapter. But I would highly recommend looking into RecyclerView/RecyclerView.Adapter
The way it works out is...
RecyclerView.Adapter binds your list of data ie Devices to the individual RecyclerView.ViewHolder
The ViewHolder would inflate your xml layout that contains the button. You then have access to all View contained in that layout easily.
You then can put listeners on the button.
The Adapter then can be setup to receive new data, when received it can rebind the data that has changed.
Say the user clicks one of the device buttons it does a task. When it gets back it will say hey Adapter I have a new List for you.(The list now contains the "fixed" device).
ViewModel(contains observable data)->Fragment/Activity(Observers the data)->Adapter(Receives the data)->ViewHolder(Displays the data)->Activity("Fixes the data")->ViewModel->...loops
Here is a very good example.
https://medium.com/#atifmukhtar/recycler-view-with-mvvm-livedata-a1fd062d2280
If you really want to keep using the ListView and ArrayAdapter you are receiving the clicked view here.
OnItemClickListener {
/*Parent of the view*/ parent,
/*The view clicked*/ view,
/*position of data*/position,
/*id of the view clicked*/ id
->{
view.findById(R.id.text_view);
//onClick
}
}
With that you know what has been clicked so you know what has to be changed later when you get back from your other Activity.

Add name(textView) to gridView list items?

How can I add name to each gridview list of items ?
for example :-
I have some items and I want to show there names at bottom of each list item.
Anybody have any idea how can I do this ?

You can do it the following way:
// String[] items = {"list", "of", "items"}; -> I am using a string list. You will have to use your object list.
// setContentView(R.layout.viewWithGrid); -> whatever layout has the gridview in it
GridView g=(GridView) findViewById(R.id.grid);
g.setAdapter(new ArrayAdapter<String>(this, R.layout.cell, items));
Now you need to define your "cell.xml" layout which will have a LinearLayout that contains a TextView and an ImageView inside another linear layout (it looks like you are using images) as children.
<?xml version="1.0" encoding="utf-8"?>
<Parent Linear Layout> <!-- fill in attributes -->
<ImageView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="14dip"
/>
</ Parent Linear Layout>
Note that you will have to set the text and image dynamically through code (through some listener like onItemClick() or so).

You can do whatever you want, if you make it into a View and pass that into your Adapter. So figure out how to put your image/text overlay into an XML View, and do something like this:
ArrayAdapter<String> adapter=new ArrayAdapter(context,R.layout.image_with_text);
It seems likely that you will actually need to write a class that extends ArrayAdapter (Or CursorAdapter) to do what you want. In that case, extend the layout, and populate your view in getView(). Something like this would work.
View getView(int position, View convertView, ViewGroup parent) {
if (convertView==null) {
convertView = LayoutInflater.from(context).inflate(R.layout.image_with_text);
}
((ImageView)convertView.findViewById(R.id.image)).setImage(getImage(position));
((TextView)convertView.findViewById(R.id.text)).setText(getText(position));
return convertView;
}

Dynamically adding subitems to ListView in Android

I am trying to dynamically add information to a ListView. The information I am adding consists of a "Device Name" (the main item) and "MAC Address" (the sub item). An example from online is below. Note: I want to replace Item 1 with a device 1's name, sub item 1 with device 1's MAC address, and so on. This MUST be done dynamically because the list is being populated as devices are scanned for.
.
Before this is marked as a repeat, I have looked at the following questions and they have not helped me: Adding ListView Sub Item Text in Android, How to add subitems in a ListView, Adding Items and Subitems to a ListView
The conclusion I have come to through reading these questions is that I need to implement a custom ArrayAdapter and override the getView() method. I have created a custom layout with two text views in it:
cyan_list.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/main_item"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#color/cyan"/>
<TextView
android:id="#+id/sub_item"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#color/dark_cyan"/>
</LinearLayout>
I then try to create a custom ArrayAdapter in my Activity class, but I am lost as to what to put in my public View getView(final int position, View convertView, ViewGroup parent) method. Additionally, is creating a custom ArrayAdapter necessary if all I am trying to do is add a textview sub item?

The answer to your question is: NO, you don't need to create a custom ArrayAdapter if you just want to add items. I recommend, however, creating it if your layout is customized, as you'll gain so much control over the items you're displaying. You didn't add your code where you create your ArrayAdapter, but in your case I'd use this constructor. The important part is the third parameter: In your activity, you should store an ArrayList with the initial items you're adding to your ArrayAdapter, then, if you want to add a new item, you simply add it to the ArrayAdapter and call notifyDataSetChanged() on your adapter. Simply doing that, your item will be added to the layout and displayed. If you need to override the GetView method for your own ArrayAdapter, I recommend this link, it helped me understanding the whole thing.

are you searching some listview example in google like those tutorials :
http://www.vogella.com/tutorials/AndroidListView/article.html
http://www.mkyong.com/android/android-listview-example/
I think they explain step by step how to create a list adapter

You need to add getter method into your Adapter
YourAdapter ...{
List<Device> items = new ArrayList<Device>;
public List<Device> getItems(){
return items;
}
}
then change item that you need
...{
//for 1s item
Device item = getItems().get(0);
item.setTitle(macAdress)
}
and call notifyDataSetChanged for your adapter
...
yourListView.getAdapter().notifyDataSetChanged();
}
Thats it. Now you are able to change your list data.
And for your question, i think yes. Is better to create your own adapter in order to have simple possibility to exentd it later. And in your case (if you dont want to change your adapter after each title change) you deffinetly need custom one. Cheers

ListView onItemLongClickListener is not working properly

I am working on a ListView and I have used setBackgroundColor inside onItemLongClickListener on the selected item. My problem is that when I am doing this and scrolling, it is setting color of some invisible child of ListView too. How can it be solved.

Try putting the following attributes in your xml:
`
<ListView
android:dividerHeight="1dp"
android:scrollingCache="false" >
`

this is caused since a listview uses old views in order to avoid re-creation of views when you scroll.
in fact , this is common to all of the adapterView classes .
in order to handle this , store the status of the position of the view (using an arrayList or whatever collection you wish) and on the getView , if the position is set in the list to be of this background , use this background , otherwise use the default background.
for more information about listview , either read the API , or (and i highly recommend it) watch the video "the world of listView" .

In your adapter class:
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView == null) {
convertView = inflater.inflate(...);
}
convertView.setBackgroundColor(defaultcolor);
...
}
This however will overwrite the background you set in the onlongclicklistener when that view would be redrawn. So you might want to keep a list of the positions of the clicked items so you can set these in the getView method.

get first item only in a Android ListView?

How do you get the first list item in a listView? I want to get at a TextView in the first list item.
I am currently doing this:
View listItem=(View)myList.getChildAt(0);
TextView txtDep=(TextView)listItem.findViewById(R.id.txtDepart);
txtDep.setText("Hello!");
But this is not only changing the text in the first item but in every 8th, 16th and so on items. I would like to change the text in the first(top) item only.
Thank you.

Views are recycled so your TextView will be used for many different items in the list. If you want to change what a specific item displays then you need to change the data that is behind your ListItem and is being served up by the ListAdapter (in the getView() method). So whenever the ListView shows the item in the list, the adapter will show the correct data in the TextView.
And when you change data in your list or whatever, you will need to call notifyDataSetChanged() on your adapter.

If you want to get the specific item in the list and want to change its color you can get this through getView method in your Adapter class.
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView == null)
{
LayoutInflater inflater = (LayoutInflater)context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.crewlist_row, null);
}
TextView firstname = (TextView)convertView.findViewById(R.id.firstname);
firstname.setText(userArray.get(position).getFirstName());
return convertView;
}

Shouldn't you use getItem(0) ?
http://developer.android.com/reference/android/widget/Adapter.html#getItem%28int%29

What you want to do is change the data in the ListAdapter and then call the notifyDataSetChanged() method to get the list to re-render. See the discussion here, includes some sample code:
ListView adapter data change without ListView being notified

Same symptom but different cause for me. I changed my fragment layout to a controlled height instead of match_parent and that solves my issue.
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
to
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="50dp"
android:orientation="horizontal" >