I guess you have all tried "Google Places" in Maps.
This is a list of POI close to you.
I really would like to do the same feature in my application with a list of GPS coordinates, but that seem really complicated.
Making the listview with the distance and the little arrow is very easy, but I cannot understand how to update this list and the arrow everytime the user move his phone.
For now I have a static listview.
I would like to know if someone succeed to create such a listview.
Thank a lot for any information.
There are a few options for what you're trying to achieve. Personally, I'd recommend implementing your own Adapter (most likely in this case by extending SimpleCursorAdapter) and encapsulating the updates to distance text and compass heading rotation within that.
To help with resource management, you probably want to create a SensorListener and LocationListener within the Activity that will host the ListView. Whenever you receive an update call your self-rolled updateCompassAndLocation method from within your Adapter class.
From within that method you have two options. Either iterate over each of the items that make up the data collection being represented and modify the compass graphic and distance text, or simply record the current location and heading as variables within the class, and call notifyDataSetChanged to force the adapter to update the views itself within the getView method. In either case (especially the latter), you'll need to set the distance text and heading compass values within getView.
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LinearLayout myView;
MyPOI item = getItem(position);
Location poiLocation = item.getLocation;
int compassHeading = // Calculate heading relative to current heading
float distance = // Calculate distance to POI
if (convertView == null) {
myView = new LinearLayout(getContext());
String inflater = Context.LAYOUT_INFLATER_SERVICE;
LayoutInflater vi = (LayoutInflater)getContext().getSystemService(inflater);
vi.inflate(resource, myView, true);
} else {
trainView = (LinearLayout) convertView;
}
TextView distanceView = (TextView)trainView.findViewById(R.id.distance);
ImageView compassView = (ImageView)trainView.findViewById(R.id.compass);
distanceView.setText(String.valueOf(distance);
compassView.setImageLevel(compassHeading);
}
Related
I want to add a feature on my project where if the user clicks one of the items on the listView then a checkbox would appear allowing the user to delete 1 or many items at once. Similar to Samsung Notes when you want to delete notes and or folders, etc. However, this concept is completely foreign to me and currently, I don't know where to begin to start this or what topic/resource/sample code I should look for. Also, I have a custom Array Adapter class that I used to order to work with my ListView but it came to my knowledge that you only need 1 array adapter class to make this work which made me confused since I don't know where to begin to manipulate it even further. Any help would be amazing!
Here is my Array Adapter that I have at the moment
//want to create our own custom ArrayAdapter. Going to extends the base class ArrayAdapter and hold our
//Word object
public class WordAdapter extends ArrayAdapter<WordFolder> {
//constructor - it takes the context and the list of words
WordAdapter(Context context, ArrayList<WordFolder> word){
super(context, 0, word);
}
#Override
public View getView(int position, View convertView, ViewGroup parent){
View listItemView = convertView;
if(listItemView == null){
listItemView = LayoutInflater.from(getContext()).inflate(R.layout.folder_view, parent, false);
}
//Getting the current word
WordFolder currentWord = getItem(position);
//making the 3 text view to match our word_folder.xml
TextView date_created = (TextView) listItemView.findViewById(R.id.date_created);
TextView title = (TextView) listItemView.findViewById(R.id.title);
TextView desc = (TextView) listItemView.findViewById(R.id.desc);
//using the setText to get the text and set it in the textView
date_created.setText(currentWord.getDateCreated());
title.setText(currentWord.getTitle());
desc.setText(currentWord.getTitleDesc());
return listItemView;
}
}```
In R.layout.folder_view add one and make it invisible or gone. OnLongClick make them Visible.
Is it possible to have methods and actual coding inside each item for a GridView?
The app that I am attempting to create is a currency converter, and I am currently displaying 3 images in the gridView: Euros, Pesos, and Rupees.
Once the user clicks on one, I want the open to open up a new XML which displays a textView. The user enters the value of US dollars in the textView and clicks the compute button. The app then displays the converted amount in the bottom of the screen.
The problem is that I am unable to figure out how to open up a new XML every time a picture is clicked on in the gridView. Assuming that I am able to do this, I am also unsure of where to place the code that goes behind the conversions. Would I make a new .java or just place is all in MainActivity.java?
Thanks.
What you might be best doing is when the user clicks on a currency it takes them to another activity where you would then load another xml for whatever you want to show.
In order to detect which item had been clicked you can implement an onItemClickListener for example
gridView.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
//this assumes you give the gridview a list of currency which it then displays. Here we get the currency selected to then pass to our new activity
String selectedCurrency = myArrayOfCurrencies.get(position);
//then start new activity and give it the currency. This means we won't have to create an activity for each currency. You just need to create 1 and then based on what currency you give it will change the functionality
Intent intent = new Intent(this, Converter.class);
Intent.putExtra("currency", selectedCurrency);
startActivity(intent);
}
First you should be able to detect the clicks on each item of the GridView by calling the setOnItemClickListener() method.
If you set the clicklistener and you still can't detect the clicks, then most probably you need to add those attribtutes to your imageView in the xml
android:focusable="false"
android:focusableInTouchMode="false"
Second, once you are able to detect the clicks you can start new activity or add fragment that contains that edit text that will promote the user to enter the value.
Third, I would suggest to put the code responsible for the currency conversion in a class separately and create static methods that takes a value and convert it to the other curreny such as:
public class CurrencyConverter {
public static double convertToRupees (String currencyType, double currencyValue){
....
return currencyInRupees;
}
}
and by the way I would suggest you to use RecyclerView with grid layout manager instead of GridView.
I would create more classes.
You asked how to open a different XML file for each gridView item.
Create a custom adapter that extends BaseAdapter.
Override getView and for each view attach the right Xml file, according to the position.
For example:
YourActivity.java:
GridView gridView;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
gridView = (GridView) findViewById(R.id.gridView);
gridView.setAdapter(new MyAdapter(getApplicationContext());
}
MyAdapter.java:
...
#Override
public int getCount() {
return XmlArr.length;
}
#Override
public Object getItem(int position) {
return XmlArr[position];
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
Xml myXml = (Xml) getItem(position);
Holder holder;
if (convertView == null) {
// Set your view's layout. Consider using LayoutInflater.
// Use a static holder to prevent re-initialization:
holder = new Holder();
// holder.textView = ...
// holder.Xml = ...
// Or whatever you decided to have in each gridView item.
convertView.setTag(holder);
} else {
holder = (Holder) convertView.getTag();
}
holder.Xml = myXml;
...
return convertView;
}
static class Holder() {
TextView tv;
Xml xml;
...
}
I assumed you would used an Xml array (xmlArr).
Now you have option to play with each gridView item as you wish. You can set each view/button/textView an onItemClickListener, or you can also set the whole gridView an onItemClickListener (from YourActivity.java).
Hope this helps.
I have a ListView that gets its layout for each item from "rowlayout".
I want to do something to one of the buttons in the rowlayout in my main activity, how do i get a reference to it findviewbyid doesn't work.
I guess i'm essentially not understanding a general concept of how to get a reference to a view in a custom layout- unless getting a view from a ListView is different. Can anyone help? thanks.
ListView is a ViewGroup so you can just iterate over its children:
int n = getChildCount();
for (int i = 0; i < n; i++) {
doSomethingToView(getChildAt(i));
}
However, you must be careful. ListView is pretty special and only has a subset of children that you might expect. It only holds (roughly) references to children that are currently visible and reuses them as they disappear.
What you might consider is changing underlying adapter instead and than notifying the ListView that its adapter changed, so it needs to redraw children. Or alternatively, you can make the child of ListView directly listen for events that are supposed to change it and then adjust itself.
If you are inflating a custom layout in the getView method of your adapter, you can get a view like this
LayoutInflater inflater = (LayoutInflater) context .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = inflater.inflate(R.layout.your_custom_layout, parent, false);
TextView tv = (TextView) rowView.findViewById(R.id.your_tv_id);
You can use partial refresh principle if you implement ListView in the way of ViewHolder, just like this:
private void refreshPartially(int position){
int firstVisiblePosition = listview.getFirstVisiblePosition();
int lastVisiblePosition = listview.getLastVisiblePosition();
if(position>=firstVisiblePosition && position<=lastVisiblePosition){
View view = listview.getChildAt(position - firstVisiblePosition);
if(view.getTag() instanceof ViewHolder){
ViewHolder vh = (ViewHolder)view.getTag();
//holder.play.setBackgroundResource(resId);//Do something here.
...
}
}
}
Possibly you can use the answer from this android - listview get item view by position to get the child view at a position then call findViewById() on that child view.
I have custom listview and array adapter with ViewHolder. When click listview item, it expands new layout below. Problem is: unfortunately it is opened for every +9th item in listview.. For example: if item 0 is clicked; 0,9,18th elements opens their expand layouts. Any idea without looking code ?
I have no idea, but this sounds familair with an issue I had. I had a listview with TextView objects and multiple were selected and got typed in the same value.
I had a very, very dirty fix for that, in my custom adapter I'd always make a new View, no matter what:
#Override
public View getView (final int position, View convertView, final ViewGroup parent) {
//if (convertView == null) {
// Inflate the view from the converter
final LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
convertView = layoutInflater.inflate(converter.getLayout(), parent, false);
//}
// Populate the view from the converter
converter.populateInflatedView(convertView, getItem(position));
return convertView;
}
Source can be found here if you want to know what the converter is about.
On a side note, I have created a sort of interface type of thing for a TreeView, however this is in Activity form which uses a ScrollView. So this is not really a ListView type of deal, but might help you. The Tree part can be found on the Tree-link, with an implementation in the subject package.
I have a listview implemented whenever my application is opened up, my idea is to change each row color based on a condition, which are the following, this is not actual code, just pseudocode to show my idea:
if condition = completed (row color is green)
if condition = in Progress (row color is blue)
if condition = pending (row color is red)
How would I implement this in my main activity class? please help!
Usually, when you create custom ListView items you have to create own implementation of ListAdapter for example extending BaseAdapter class. Inside adapter you will have items data where you bind it with created views.
View should be created with customized XML layout which contains element that changes color e.g. row background.
Your adapter getView() method which bind items data to view could look like this.
public View getView(int position, View convertView, ViewGroup parent) {
TextView textView;
if (convertView == null) { // if it's not recycled, initialize some attributes
textView= new TextView(mContext);
textView.setLayoutParams(new GridView.LayoutParams(85, 85));
textView.setPadding(8, 8, 8, 8);
} else {
textView= (TextView) convertView;
}
textView.setBackgroundColor(blue);
return textView;
}
That's the basic idea. If you provide code that you have tried already I would be able to support you further.
In order to process and test each entry you would need a custom adapter of some kind.
Here is a great tutorial on custom array adapters that I used. You could test and modify the text color within the loop in the adapter.
Custom Array Adapter Tutorial