Develop Reference

ScrollView not scrolling to end while adding a new view android

I have a scrollView in which while I am at end of the scrollView, on clicking a button at the end I need to show a view below that button. I am doing it by changing the visibility of that newly added view from GONE to VISIBLE. Its working but after clicking the button I am not able to see the newly added view i.e I need to scroll down the scrollView to show that view. Is there a way to scroll the ScrollView to that newly added view after clicking the button? and also to hide that view and scroll back to normal state after clicking that button again.
Thanks in advance!

it's an alternative which pretty much does the same thing.
Instead of Scrolling to the bottom of the screen, change the focus to a view which is located at the bottom of the screen.
That is, Replace:
scroll.scrollTo(0, scroll.getBottom());
with:
Footer.requestFocus();
Make sure you specify that the view, say 'Footer' is focusable.
android:focusable="true"
android:focusableInTouchMode="true"
or if above is not working try this
scrollView.post(new Runnable() {
#Override
public void run() {
scrollView.fullScroll(ScrollView.FOCUS_DOWN);
}
});

As the view that i was adding at the end was added with an expand animation so i used a countdown timer for it as follows:
new CountDownTimer(500, 1) {
public void onTick(long millisUntilFinished) {
myScrollView.scrollTo(0, R.id.bottomView);
}
public void onFinish() {
}
}.start();
Thats all.

setting text in Gallery onItemSelected causes scrolling to snap

In the galleryView onItemSelected I call setText that change the text for a textview thats part of the main layout:
#Override
public void onItemSelected(EcoGalleryAdapterView<?> parent, View view, int position, long id) {
// --- run asyncTask to update gallery view here
TextView myTextView = (TextView) findViewById(R.id.myTextView);
myTextView.setText("position is: ": position);
}
if I left everything as it is and just removed myTextView.setText the gallery works as expected but if I kept it then when scrolling the gallery snaps to the selected position really fast in an ugly way. What could be the issue?

"Ugly" is a pretty subjective term for describing a user interface transition.
However, it sounds as though what you want is a custom animation when an item is selected. onItemSelected() is called before the layout happens, so you can animate your Gallery or individual Views however you want in this method.
I would suggest reading the Animation and Graphics documentation from the Android developer documentation to more fully understand animations and to help decide what you actually want.
The code will vary depending on what you decide you want it to look like and what version of Android you are targeting. A simple View animation that will fade the selected view in might look something like this:
public void onItemSelected(EcoGalleryAdapterView<?> parent, View view,
int position, long id) {
view.setAnimation(new AlphaAnimation(0, 1));
}

// try this
TextView myTextView;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.image_full);
myTextView = (TextView) findViewById(R.id.myTextView);
}
#Override
public void onItemSelected(EcoGalleryAdapterView<?> parent, View view, int position, long id) {
// --- run asyncTask to update gallery view here
myTextView.setText("position is :"+ position);
myTextView.invalidate();
}

The setText commands sits on the UI Thread, maybe it's taking a higher priority or something from the current Gallery animation which disrupts it from acting as it should.
try setting your setText inside a handler:
new Handler().post(new Runnable() {
#Override
public void run() {
myTextView.setText("position is: ": position);
}
});

Clear the previous selected View Background and change the background of newly selected View in Onclick - Android

I want to change the background view when it's pressed (its working). My problem is, If i press the other view (not the same one) in the list, i want to set my background to Black of the newly selected view and change the background to White of the previous selected view. Here is my Implementation
for(final TotalPlayers player : this.playerData){
final ArrayList<View> addedPlayerViews1 = getPlayerView(player);
dropPlayersListView.addView(addedPlayerViews1.get(0));
addedPlayerViews1.get(0).setOnClickListener(new OnClickListener() {
boolean highlight = false;
#Override
public void onClick(View v) {
if (!highlight)
{
addedPlayerViews1.get(0).setBackgroundColor(Color.BLACK);
highlight=true;
}
else {
addedPlayerViews1.get(0).setBackgroundColor(Color.WHITE);
highlight=false;
}
}
});
}
}

addedPlayerViews1.get(1).setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
addedPlayerViews1.get(0).setBackgroundColor(Color.WHITE);
highlight=false;
}
});
I assumed that you can get the other view by get(1).
The problem of your code was you only handled the onClick event of your view where you want to change the background. but you also need to handle the onClick of other view too.

setSelected(true) not work on custom view

I have created custom View called Color. I use object of Color to fill GridView (same issue is in ListView also).
My task is to let user choose one color and highlight it.
Previously I do something like that but I used only in building widgets and everything worked. This time I use my own.
This cose is for item clicking:
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
int color = (int)id;
Log.d(TAG, "Selected color: " + id);
view.setSelected(true);
view.invalidate();
}
Color.onDraw:
#Override
public void onDraw(Canvas canvas) {
if (isSelected()) {
Log.d(TAG, "color draw selected");
} else {
Log.d(TAG, "not selected " + color);
}
}
Also I set setChoiceMode(AbsListView.CHOICE_MODE_SINGLE); to this GridView (AbsListView.CHOICE_MODE_MULTIPLE don't help also)
In log I see:
Selected color: 8355711
not selected 16711680
not selected 16743680
not selected 8355711
I am sure, Color items is not recreating more than on time.
I tried change GridView to ListView, user default widget (overrided only onDraw()). Nothing helps. Maybe I forgot something?
In my opinion GridView somehow drop selected status.
If you need more info just tell.
Addition:
I checked with debugger. View with color 8355711 is same object in both functions.
I used setOnItemSelectedListener(this); to track item selection. But nothing happen in this listener.

The method isSelected() is comming from the GridView which is a child of View.
Basically when calling isSelected() you're saying: "is the gridview selected" which is not what you want.
What you want is: "is there any selected view in the grid view ?"
Which could be achieved using getSelectedView()
As the documentation says, you will get a reference to the selected view or null if none is selected.
Also make sur your GridView is properly initialized to handle item selection.
EDIT : Ok i understand that isSelected() is called from the Color view. My first guess is then useless.
But I think you should try to make your item selected using the setSelection() of the GridView object.
Add something like:
myGridView.setSelection(position);

I fix this issue my self by making my own select. Its workaround.
In Color class added:
private boolean selected = false;
public boolean isSelected2() {
return selected;
}
public void setSelected2(boolean selected) {
this.selected = selected;
}
#Override
public void onDraw(Canvas canvas) {
....
if (isSelected2()) {
//draw selected state
} else {
....
}
On ColorChooser grid:
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
...
int i = getChildCount();
while (--i >= 0)
((Color)getChildAt(i)).setSelected2(false);
((Color)view).setSelected2(true);
....
}
Reason why I not to override natice setSelected(boolean state) is some other code in grid every time make all items in deselected state. I don't know why, because in other places same more native code work very fine.

Showing a List View when a button is clicked: Android

I am trying to implement a drop down list when a button is clicked.
So, I have a text view and a button in a navigation bar(nav.xml) and a corresponding list view. This navigation bar is included in another page( products.xml)
when the button is clicked i get the list view right below the button(which is what i want to acheive) but its my moving all the contents on the current page downwards, even the text view which is placed in nav bar moved downwards.
I am totally new to Android, any sample examples or a way how to achieve it
???

Sounds like you need a Spinner. It's the equivalent of a drop down list for Android. You can find an example here.

So, for our need we need to use ListPopupWindow.
The link to official description:
http://developer.android.com/reference/android/widget/ListPopupWindow.html
Let's dive in the code:
we have our own method:
public void downloadBtnSelected(View anchor) {
final ListPopupWindow lpw = new ListPopupWindow(this);
String[] data = { ".png", ".pdf", ".jpg", ".jpeg" };
PopupAdapter pa = new PopupAdapter(data, this);
lpw.setAdapter(pa);
//setting up an anchor view
lpw.setAnchorView(anchor);
//Setting measure specifications. I'v used this mesure specs to display my
//ListView as wide as my anchor view is
lpw.setHeight(android.widget.LinearLayout.LayoutParams.WRAP_CONTENT);
lpw.setWidth(anchor.getRight() - anchor.getLeft());
// Background is needed. You can use your own drawable or make a 9patch.
// I'v used a custom btn drawable. looks nice.
lpw.setBackgroundDrawable(this.getResources().getDrawable(
android.R.drawable.btn_default));
// Offset between anchor view and popupWindow
lpw.setVerticalOffset(3);
lpw.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
/// Our action.....
lpw.dismiss();
}
});
lpw.show();
}
and the button with an onClickListener to call this method:
Button btn = new Button(this);
btn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
downloadBtnSelected(v);
}
});
we pass the View v argument as our anchor, in order to let our PopupWindow to know where to display itself. It will be displayed in the bottom-left corner of our anchor view if there is enough room below. If not- it will displa