Develop Reference

Menu option to clear all <EditText>

I am designing an app in Android Studio, but I am having trouble creating a clear option in the menu of my app.
Can someone show me how to add a menu option that will clear all the <EditText> items in my app I am creating?

You can try with below code and change the id of "your_group" with your main layout id.
ViewGroup group = (ViewGroup)findViewById(R.id.your_group);
for (int i = 0, count = group.getChildCount(); i < count; ++i) {
View view = group.getChildAt(i);
if (view instanceof EditText) {
((EditText)view).setText("");//here it will be clear all the EditText field
}
}
Please let me know if have any doubts.

ListView items aren't updating with notifyDataSetChanged()

Apparently the notifyDataSetChanged() only updates the visible items in the listview, I have a system that changes the background color of an item when its clicked (to dkgray), and I set everything else to transparent(the default), however other items that aren't visible remain selected(dkgray) (I only want the currently selected item to be dkgray). Is there a way to force notifyDataSetChanged() to update all items.
Here's example:
//makes all item backgrounds transparent
public void resetListViewBackground(){
for (int i = 0; i < listView.getChildCount(); i++){ //parent.getChildCount()
listView.getChildAt(i).setBackgroundColor(Color.TRANSPARENT);
}
}
//reloads the listview
private void reloadListView() {
listItems.clear();
adapter.notifyDataSetChanged();
listView.invalidateViews();
ArrayList<HashMap<String, String>> notesArrayList = dbTools.getAllNotes();
for (int i = 0; i < notesArrayList.size(); i++){
String temp = "";
if (notesArrayList.get(i).get("note").length() > 51){
temp = notesArrayList.get(i).get("note").substring(0,50).toString() + "...";
} else {
temp = notesArrayList.get(i).get("note").toString();
}
listItems.add(temp);
adapter.notifyDataSetChanged();
}
}
Everywhere I call resetListViewBackground(), I call reloadListView() after.
And this is what I use to highlight the selected item.
view.setBackgroundColor(Color.DKGRAY);
Also, the most common occurrence of this problem is that every 6th item is highlighted. The listview only shows about 4 items at a time.

The getChildCount() method won't work for all list items as view recycling is done.
Astral is right as he writes in the comments.
1) Create a custom adapter.(See http://windrealm.org/tutorials/android/listview-with-checkboxes-without-listactivity.php)
2)Inside the onListItemClick listener's onItemClick() method, call your adapter's notifyDataSetChanged() method(whenever the user clicks a list item).
I modified the project that I mentioned and posted it on my Dropbox.(Just import it in Eclipse and run).
Check it out at https://www.dropbox.com/s/gchccjzpkxk8n2z/Planets_modified.zip

Strike out and unstrikeout in ListItem of a list view

I have a little functionality to strike out and unstrike out a list view when a list item is clicked. My code goes Here:
public void markComplete(View v)
{
Button b1 = (Button)findViewById(R.id.Completeit);
Button b2 = (Button)findViewById(R.id.InCompleted);
try{
TextView tv = (TextView)findViewById(R.id.textViewx);
tv.setPaintFlags(tv.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
}catch(Exception e){e.printStackTrace();}
b1.setVisibility(-1);
b2.setVisibility(1);
}
public void markInComplete(View v)
{
Button b1 = (Button)findViewById(R.id.Completeit);
Button b2 = (Button)findViewById(R.id.InCompleted);
try{
TextView tv = (TextView)findViewById(R.id.textViewx);
tv.setPaintFlags( tv.getPaintFlags() & (~ Paint.STRIKE_THRU_TEXT_FLAG));
}catch(Exception e){e.printStackTrace();}
b1.setVisibility(1);
b2.setVisibility(-1);
}
I have two buttons for checking and unchecking the list item.It works for the first list item alone. If i try to click 2nd list item, the striking & unstriking is done only on 1st item. Any help is appreciated and Thanks in advance

Your findViewById call is going to return the first element in your view that it finds. If you have multiple, then this is going to be a problem. It will always find the first table cell. The solution here is to save your buttons, and treat each cell as a separate view.

Android instanceof detecting all widgets?

I'm trying to set a font across all TextView's by iterating through the LinearLayout's views and using instanceof.
The form currently consists of 4 TextView's and one Button.
The below code is detecting all Views, even the Button as a TextView?
/* Set fonts */
LinearLayout ll = (LinearLayout) findViewById(R.id.ll_screenincourse_wrapper);
for (int i = 0; i < ll.getChildCount(); i++) {
View v = ll.getChildAt(i);
if (v instanceof TextView) {
((TextView) v).setTypeface(Fonts.get3dDumbFont(this));
}
}
If I log each view's class name it returns the TextView and the Button so I know the correct controls are being picked up.
The problem is the Button and TextView's fonts are being set, and I only want the TextView's.
I have found a work around and that is to do the following but am intrigued as to why the above code does not work as expected.
/* Set fonts */
LinearLayout ll = (LinearLayout) findViewById(R.id.ll_screenincourse_wrapper);
for (int i = 0; i < ll.getChildCount(); i++) {
View v = ll.getChildAt(i);
if (v.getClass().getName().contains("TextView")) {
((TextView) v).setTypeface(Fonts.get3dDumbFont(this));
}
}
Is it because both Button and TextView are of type View? If so, what would be the correct way about doing this?
Any help appreciated, thanks. Ricky.

Actually, Button is a subclass of TextView! That's why you see it as a TextView (it is also a TextView).
http://developer.android.com/reference/android/widget/Button.html
public class Button extends TextView
You could make a second if instanceof to exclude Buttons or use
if (v.getClass() == TextView.class)
But this won't match any other subclasses of TextView (if you use them).

It is simple
Button Class extends TextView Class
Check the documentaion

Android ListView center selection

I have a ListView that shows the closest word matches to a search.
For example if I search "hi" I get the following results in the ListView
...
hi
hi five
hi-five
high
highlight
....
I am using
ListView.setSelection(wordList.indexOf(searchWord));
ListView.setSelected(true);
The above code puts the selected word "hi" at the top and doesnt highlight the selection.
I want the "hi" to be centrally positioned , selected and highlighted automatically.
See below
...
hello
hello there
hi
hi-five
hi five
...
What code can I use to achieve the above?
Many thanks.

ListView view = (ListView)findViewById(R.id.YourListView);
int height = view.getHeight();
int itemHeight = view.getChildAt(0).getHeight();
view.setSelectionFromTop(position, height/2 - itemHeight/2);
The position (int) is the listitem you want to center in the listview!!

try setSelectionFromTop() you'll have to do the math yourself. setSelection() bring the selected item to the top of the view, which is what you are seeing.

try this.
first, get visible item count of listview
int count=0;
for (int i = 0; i <= listview.getLastVisiblePosition(); i++)
{
if (listview.getChildAt(i)!= null)
{
count++;
}
}
second, scroll the item to the center of listview.
int target = position-count/2;
if (target<0) target = 0;
listview.setSelection(target);

Try this:
ListView lv = getListView();
lv.setTextFilterEnabled(true);
lv.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// When clicked, show a toast with the TextView text
Toast.makeText(getApplicationContext(), ((TextView) view).getText(),
Toast.LENGTH_SHORT).show();
}
});
for more information :
http://developer.android.com/resources/tutorials/views/hello-listview.html