Develop Reference

How can I have scrolling to last page working properly in a paginated scroll in android ListView

Attention! This question is not about dynamic loading of items into a very long ListView.
This is about adding PageUP and PageDown buttons to a ListView so that user can touch the button and scroll ListView page by page. Page means all fully and partially visible items on the screen.
I have partially implemented this in the following code, but my problem is that when I have lets say 10 items of approximately same height in the listview and 7 of them fit into the first page, then when I press PgDown button, user expects that item 8 to be on top of the screen (next page), but because there are only 10 items, ListView scrolls to the bottom of the list and because there is no extra scroll space I have item number 4 on top.
What is the best solution in this situation?
Should I add one item to the end of the list which will make the last page the height of the screen or there are any better options?
Here is my code:
public class cPaginatedListViewHelper {
Activity m_parentActivity;
private ListView mList;
//controls
private LinearLayout m_PagingLL;
//buttons
private ImageButton m_btnPrevPage;
private ImageButton m_btnNextPage;
private ImageButton m_btnExitPaginatedMode;
public cPaginatedListViewHelper(ListActivity mParent) {
this.m_parentActivity = mParent;
m_btnPrevPage=(ImageButton) mParent.findViewById(R.id.btnPrevPage);
m_btnNextPage=(ImageButton) mParent.findViewById(R.id.btnNextPage);
m_btnExitPaginatedMode =(ImageButton) mParent.findViewById(R.id.btnClosePage);
if(m_btnPrevPage!=null) {
m_btnPrevPage.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
showSiblingPage(-1);
}
});
m_btnPrevPage.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
mList.smoothScrollToPosition(0);
return true;
}
}
);
}
if(m_btnNextPage!=null) {
m_btnNextPage.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
showSiblingPage(1);
}
});
m_btnNextPage.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
mList.smoothScrollToPosition(mList.getCount());
return true;
}
}
);
}
m_btnExitPaginatedMode.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
setEnabled(false);
m_PagingLL.setVisibility(View.GONE);
}
});
mList=mParent.getListView();
m_PagingLL = (LinearLayout) mParent.findViewById(R.id.pageControls);
}
public void updateControlsVisibility()
{
ViewTreeObserver observer = mList.getViewTreeObserver();
observer.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
if (willMyListScroll()) {
boolean psm = isEnabled();
//enable or disable
m_PagingLL.setVisibility( psm ? View.VISIBLE : View.GONE);
((View)mList).setVerticalScrollbarPosition(psm ? View.SCROLLBAR_POSITION_LEFT: View.SCROLLBAR_POSITION_RIGHT);
}
else
{
m_PagingLL.setVisibility(View.GONE);
((View)mList).setVerticalScrollbarPosition(View.SCROLLBAR_POSITION_RIGHT);
}
}
});
}
private boolean willMyListScroll() {
try {
int pos = mList.getLastVisiblePosition();
if (mList.getChildAt(pos).getBottom() > mList.getHeight()) {
return true;
} else {
return false;
}
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
private void showSiblingPage(int shift)
{
if(mList!=null) {
int iScrollPageHeight = mList.getHeight();
mList.scrollListBy(iScrollPageHeight * shift);
}
}
public void setEnabled(boolean psm) {
MyApp.Pref.edit().putBoolean("PSModeEnabled", psm).commit();
}
public boolean isEnabled(){
return MyApp.Pref.getBoolean("PSModeEnabled", false);
}
public void pagedScrollEnableDisable() {
boolean pagingEnabled = isEnabled();
pagingEnabled=!pagingEnabled;
setEnabled(pagingEnabled);
m_PagingLL.setVisibility( pagingEnabled ? View.VISIBLE : View.GONE);
updateControlsVisibility();
}
}

I finished up with using ListView's footer with variable height as shown in the following code:
LayoutInflater inflater = m_parentActivity.getLayoutInflater();
m_footerView = inflater.inflate(R.layout.listview_paged_overscroll, mList, false );
ViewGroup.LayoutParams lp =m_footerView.getLayoutParams();
if(m_tvPageNum!=null) recalcPagination();
if(lp!=null) lp.height = m_extraScrollFooterHeight;
int iFooters = mList.getFooterViewsCount();
if(iFooters==0) mList.addFooterView(m_footerView);

Android Animation not work when i call visibility

The animation does not work after I set visibility to Invisible, I tried clear animation but not work. I have a button when I click the button it opens a linear layout with animation when I press back button I set the linear layout visibility to invisible again I click the button linear layout appear but no animation please help me.
l1 = (LinearLayout) findViewById(R.id.lnrlgn);
l2 = (LinearLayout) findViewById(R.id.lnrlgn1);
l2.setVisibility(View.INVISIBLE);
Animation uptodown = AnimationUtils.loadAnimation(this,R.anim.uptodown);
viewcrrd.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
l2.setAnimation(downtoup);
l2.clearanimation(); // is it right ?
l2.setVisibility(View.VISIBLE);
}
});
public void onBackPressed() {
// super.onBackPressed();
if (back_pressed + TIME_DELAY > System.currentTimeMillis()) {
// super.onBackPressed();
Exitdlg alert = new Exitdlg();
alert.showDialog(LoginActivity.this, "Are You Sure ");
l2.clearAnimation();
} else {
l2.clearAnimation();
l2.setVisibility(View.INVISIBLE);
}
back_pressed = System.currentTimeMillis();
}

Use startAnimation instead of setAnimation
viewcrrd.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
l2.setVisibility(View.VISIBLE);
l2.clearanimation();
l2.startAnimation(downtoup);
}
});

Disable click after clicking the textview

I have a TextView and I put a OnClickListener on this TextView. I use this action to load custom view onto a LinearLayout.
But when I click on this TextView twice, custom view is repeating on the LinearLayout. I clear all custom views on this LinearLayout before I load new custom views on to this LinearLaout.
This is my OnClickListener on TextView,
TextView rejectedTitleTextView = (TextView) findViewById(R.id.roster_menu_rejected_title);
rejectedTitleTextView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
rejectedTitleTextView.setBackgroundColor(getResources().getColor(R.color.acceptedPurpleColour));
newTitleTextView.setBackgroundColor(getResources().getColor(R.color.defaultBlack));
acceptedTitleTextView.setBackgroundColor(getResources().getColor(R.color.defaultBlack));
locationLinearLayout.removeAllViews();
rosterBottomLayout.setVisibility(View.GONE);
Log.d("CHECK_ACTION"," REJECTED_TEXT_VIEW ");
InternetConnectivity internetConnectivity = new InternetConnectivity();
final boolean isConnectedToInternet = internetConnectivity.isConnectedToInternet(context);
if(isConnectedToInternet==true) {
try {
Thread.sleep(1300);
} catch (Exception e) {
e.printStackTrace();
}
getDataFromServer("REJECTED");
}else{
Snackbar.make(mainView, "No Internet Connection", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
}
});
getDataFromServer("REJECTED");
is the method which I used to load custom view onto this LinearLayout.
How can I prevent this issue ?
Have any ideas ?

Inside onclickListener put
rejectedTitleTextView.setClickable(false);
and once finish your functionality make it as true because u need to click for next time .
rejectedTitleTextView.setClickable(true);

Inside setOnclickListener try below code:-
textView.setClickable(false);

Try this
rejectedTitleTextView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
mSpinner.setEnabled(false);
mSpinner.postDelayed(new Runnable() { #Override public
void run() {
mSpinner.setEnabled(true); }
}
// do your stuff here
});

You can maintain boolean value like this
boolean isClick=false;
rejectedTitleTextView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(!isClick)
{
//do your Stuff on onCLick
isClick=true;
}else
{
//leave it blank if you do not want to do anything second time
}
}
});

Change State of ToggleButton programmatically

I have placed a togglebutton with id toggleButton
and I am using the code below to check if it's on or off
public void toggleClick(View view){
boolean on = ((ToggleButton) view).isChecked();
if(on){
}else{
}
}
Everything works fine.. I am trying to change the state of the toggle button, I tried a lot of codes through internet but none changes the state of the toggle to off.
I tried this:
ToggleButton toggleButtons;
toggleButtons = (ToggleButton) findViewById(R.id.toggleButton); //In onCreate
toggleButtons.setChecked(false);
any ideas please?

Use setChecked(boolean checked) by example:
toggleButtons.setChecked(true)

I ended up using Toggle feature using ImageButton. The code below works fine.
*
private ImageButton ib;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
//......
ib = (ImageButton) rootView.findViewById(R.id.imagefavouriteButton);
if (checkFavorite()) {
ib.setImageDrawable(ContextCompat.getDrawable(getContext(), R.drawable.fav_on));
} else {
ib.setImageDrawable(ContextCompat.getDrawable(getContext(), R.drawable.fav_off));
}
ib.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (checkFavorite()) {
remFromFav();
} else {
addFavorites();
}
}
});
//.....
}
private boolean checkFavorite(){// code to check in db}
public void addFavorites() {
ib.setImageDrawable(ContextCompat.getDrawable(getContext(), R.drawable.fav_on));
Toast.makeText(getActivity(), "Added ...", Toast.LENGTH_SHORT).show();
}
public void remFromFav() {
ib.setImageDrawable(ContextCompat.getDrawable(getContext(), R.drawable.fav_off));
Toast.makeText(getActivity(), "Removed ...", Toast.LENGTH_SHORT).show();
}
Hope this helps you.

How to program 2 function C button in calculator?

I'm a beginner in Android Studio, and I want to make a C button in calc with 2 functions.
How do I do that on one tap the C button erases only one number, and on hold erase all numbers in TextView?
findViewById(R.id.btnClear).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
txtScreen.setText(""); // Clear the screen
// Reset all the states and flags
lastNumeric = false;
stateError = false;
lastDot = false;

You can set an onClickListener and onLongClickListener to achieve this.
cButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
String currentText = textView.getText().toString();
if(currentText.length >= 2){
currentText = currentText.substring(0, currentText.length - 2);
}else{
currentText = "";
}
textView.setText(currentText);
}
});
cButton.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
textView.setText("");
return true;
}
});

Have you looked in to the onClick() and onLongPress() methods?
cancelButton.setOnLongClickListener(new OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
myTextView.setText("");
return true;
}
});
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
removeOneCharacter();
}
});
private void removeOneCharacter()
{
String textViewValue = myTextView.getText().toString();
if (textViewValue != null && textViewValue.length >= 2)
{
myTextView.setText(textViewValue.substring(0, textViewValue.length() - 2);
}
}
The onClick() method removes on char from the TextView at a time. The onClick() method however removes the entire String from the TextView but only considering if there is already 2 or more characters to prevent an Exception from occurring due to the upper-bound of the substring.
An improvement here could be to add another if function that checks the character length within the Long press and performs a clear if there is only one character remaining.