Develop Reference

Getting a button to work in the list view

I am new to android and my code has got a bit messy. I have successfully created a list view extended from item_layout.xml. When I click on the list view It works exactly how I want it. However in each item of the list view I have a button that when clicked I want the item of the list to delete.
When researching I have come across that you need to create a customer adapter to do this however I have come so far in the project that I wouldn't even know where to start.
This code it used successfully to when the list items are clicked it works. This is just put in the Main Activity class
mylist.setOnItemClickListener(
new AdapterView.OnItemClickListener(){
#Override
public void onItemClick(AdapterView<?> parent, View view, final int position, long id) {
}
}
);
I populate the list using this function just outside the main activity class. It is needed to be written like this as It gets the items from a database and has to be called depending on different circumstances
private void populatelistView() {
Cursor res = userDb.getAllRows();
String[] fromFeildnames = new String[]{ DatabaseUser.KEY_1, DatabaseUser.KEY_2};
int[] toViewIds = new int[]{R.id.textViewNum, R.id.textViewItem};
SimpleCursorAdapter myCursorAdaptor;
myCursorAdaptor = new SimpleCursorAdapter(getBaseContext(), R.layout.item_layout, res, fromFeildnames, toViewIds, 0);
//ListView mylist = (ListView) findViewById(R.id.listViewID);
mylist.setAdapter(myCursorAdaptor);
}
I would like to be able to get the button on each items to work by not changing much of what I have already written. I have tried just using the following code. But because it is in a different xml layout it display an error of null reference towards the item button
delete.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View v) {
View parentRow = (View) v.getParent();
ListView listView = (ListView) parentRow.getParent();
final int position = listView.getPositionForView(parentRow);
Toast.makeText(getApplicationContext(), "Button " + position, Toast.LENGTH_SHORT).show();
}
}
);
Please could someone help me make the button work without changing much code or give me a step by step tutorial on how to add an adapter but make my populateListView function do the same thing.
Ps. I have looked at so many tutorials about list adapters but can't find ones that are for my specific need

How to display drop-down list-view below particular view in android?

I have one filter button.I need to open expandable/dropdown filter same as given below image.I tried popup menu and Listpopup window but,I did not get any success.
Thanks in advance

you can make use of fragment which will be below the filter button,layout will include the ui you expect i.e upper arrow and expandable view or any view you are using..
After clicking on filter just visible the fragment and with fragment transition,for the effect you can use animation too...
This i already done,you can refer carwale app used car section..click on filter button one same dilog will come..
for any thing let me know further..

I did code by the help of above comments. but the code looks as below.
final View popUpView = getLayoutInflater().inflate(R.layout.exp, null);
listPopupWindow = new PopupWindow(popUpView, LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT, true);
expandableListView= (ExpandableListView) popUpView.findViewById(R.id.expandableListView);
btnticker.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
expandableListDetail = ExpandableListDataPump.getData();
expandableListTitle = new ArrayList<String>(expandableListDetail.keySet());
expandableListAdapter = new CustomExpandableListAdapter(MainActivity.this, expandableListTitle, expandableListDetail);
expandableListView.setAdapter(expandableListAdapter);
listPopupWindow.showAsDropDown(v);
}
});

Can't unselect ListView item when deleting it

Trudging my way through my introduction to Java and Android on a simple app and have run into an issue with ListView item selection. For one of my activities, I have a layout with two buttons, one of which is a "Delete" button, and a ListView of "passages" which are essentially timestamps for when a device has passed a sensor.
I have implemented the ability to click on an item to select it, which then enables the "Delete" button. A click of the "Delete" button removes the "passage" but I still end up with a selected item, which I don't want.
To implement selection, I added the following property to the ListView:
android:id="#+id/passagesListView"
android:choiceMode="singleChoice"
android:listSelector="#666666"
Selection is supported in OnCreate via a an OnItemClickListener:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_passages);
passagesViewAdapter = new PassagesViewAdapter(this, R.layout.passages_row_layout, passages);
final ListView passagesListView = (ListView) findViewById(R.id.passagesListView);
assert passagesListView != null;
final Button deleteButton = (Button) findViewById(R.id.deleteButton);
deleteButton.setEnabled(false);
buildPassageList();
passagesListView.setAdapter(passagesViewAdapter);
passagesListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapter, View view, int position,long arg3) {
Toast.makeText(ViewPassagesActivity.this, "position is " + position,
Toast.LENGTH_LONG).show();
view.setSelected(true);
passagesViewAdapter.notifyDataSetChanged();
selectedItemPos = position;
deleteButton.setEnabled(true);
}
});
}
This part works. However, there is some issue with deletion. As you can see in the comments, I have tried several methods that I found on StackOverflow that seemed to apply but, although I am able to delete the correct item from the list, I am still ending up with a selected item after the call to delete().
public void delete (View view)
{
final Button deleteButton = (Button) findViewById(R.id.deleteButton);
ListView passagesListView = (ListView) findViewById(R.id.passagesListView);
if(selectedItemPos != -1)
{
Toast.makeText(ViewPassagesActivity.this, "remove " + selectedItemPos,
Toast.LENGTH_LONG).show();
// This did not work, which is strange since it worked similarly for selection when clicked
// View itemView = passagesListView.getChildAt(selectedItemPos);
View itemView = passagesViewAdapter.getView(selectedItemPos, null, passagesListView);
itemView.setSelected(false);
// This was also recommended in various posts on StackOverflow.
// Not clear whether clearChoices applies only to checkBoxes?
// passagesListView.clearChoices();
// passagesListView.requestLayout();
passages.remove(selectedItemPos);
deleteButton.setEnabled(false);
selectedItemPos = -1;
passagesViewAdapter.notifyDataSetChanged();
}}
}
I also ran into some issues trying to track which item is selected via setSelected() and getSelectedItemPosition() and punted by just tracking the index myself. So, as I am new to this, I'm sure there is something I am not understanding about Views or maybe something else such as a misunderstanding of how selection works?
How can I clear the selection?
Thanks!

I don't know what your PassagesViewAdapter class looks like. Maybe you can try
passagesViewAdapter.remove(passages.get(selectedItemPos));
passages.remove(selectedItemPos);
deleteButton.setEnabled(false);
selectedItemPos = -1;
passagesViewAdapter.notifyDataSetChanged();

Destroy a button that was added programatically multiple times on its click

The title may sound confusing I know, I 'm adding a view everytime I click on a button, composed by a textview and a button. I'm setting every added view an ID with simply view.setID(++i) and every added button (inside the views) an ID simply with button.setID(++n), n starting at 1000, since I won't have more than 1000 added views.
Here's what I got:
public class MainActivity extends AppCompatActivity {
GridLayout gridLayout;
static int i;
static int n = 1000;
private Button theButton;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
gridLayout = (GridLayout)findViewById(R.id.gamehistory);
Button b = (Button)findViewById(R.id.Button01);
b.setOnClickListener(new View.OnClickListener(){
public void onClick(View v) {
theButton = new Button(MainActivity.this);
TextView theText = new TextView(MainActivity.this);
theText.setGravity(Gravity.CENTER_HORIZONTAL);
LinearLayout theLayout = new LinearLayout(MainActivity.this);
theLayout.setOrientation(LinearLayout.VERTICAL);
theLayout.setBackgroundColor(Color.parseColor("#8BAAC3"));
theLayout.setId(++i);
theButton.setId(++n);
theButton.setText(theButton.getId() + "");
theText.setText(theLayout.getId() + "");
theLayout.addView(theButton);
theLayout.addView(theText);
gridLayout.addView(theLayout);
GridLayout.LayoutParams lp = (GridLayout.LayoutParams) theLayout.getLayoutParams();
lp.setMargins(10, 10, 10, 10);
}
});
What I need is when I click on a button that was created, the correspondent view is destroyed, and the next views take one step back feeling the gap in the parent which is a GridLayout

Add this where you are adding views to GridLayout -
theLayout.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
gridLayout.removeView(theLayout);
}
});
theButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
gridLayout.removeView(theLayout);
}
});
For this , you need to make theLayout final
final LinearLayout theLayout = new LinearLayout(LauncherActivity.this);

The simplest method would be.
View v = gridLayout.findViewById(<some id>);
gridLayout.removeView(v);
However it seems like you may want to consider using a RecyclerView. You can add/remove items from the Adapter and the views will be updated for you.
EDIT
When using A RecyclerView you have to specify two essential components.
RecyclerAdapter - This converts data into views (rows, cards, cells, ect.)
LayoutManger - Most common are LinearLayoutManger and GridLayoutManager which define how the views from the adapter are presented out in relation to one another, and handle scrolling.
There are a few more option additions you can can use if needed.
ItemDecoration - define backgrounds, or overlays for cells. (E.G. draw a gray background for every other view in a list)
ItemTouchHelper - does most of the heavy lifting for swipe (e.g. swipe to delete) and drag (e.g. drag to re-arrange) operations.
I would highly suggest getting familiar with the RecyclerView it should be your goto component when you need to display a list of items on the screen.

Show delete button inside row of a ListView when clicking a button Android

I need to implement a kind of Slide to Delete inside my ListView but what I want is not to slide the row but when the user clicks a button inside the row the delete button should show up. Is it possible? I've already implemented the Button and I know when the user press it but I pretty much have no idea on how to implement the delete button slide in effect from the right of the row.
Can someone give me an Idea on how to start?

If you don't want Swipe-to-delete, then the implementation is pretty simple.
Basically you are gonna show/hide that button on button click.
Since Android ListView reuses the Views, if you show/hide the button of a View of ListItem in onItemClick(), then when the list is scrolled the state will be lost and will result in incorrect behavior.
So we need to maintain this selection state in the Adapter's modal class. Just add a field like selected in the modal class. For instance, if you are showing list of Contact objects, then your modal class will be all like,
class Contact {
private String name;
private String number;
private boolean selected;
..........
}

from what I've understand; you need to implement lets say an edit button, then when user clicks on it, it will disappear and another button called delete will popup instead of it on the same position.
here is a possible approach to achieve that:
in your list_view_adapter.xml:
1-create a frame layout contain both of the buttons on top of each other.
2-default state of delete button is GONE -> android:visibility="gone"
3-when edit is pressed delete button will be visible and you will programmatically set Edit visibility to GONE
4-set your delete button:
#Override
public View getView(final int pos, View convertView, ViewGroup parent) {
View v = convertView;
// Some other things...
Button delete = (Button) v.findViewById(R.id.delete);
delete.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// After you delete the object from Parse database here,
notifyDataSetChanged();
}
}