Develop Reference

Extend Button OnClick

I am trying to add specific behaviour to Button's onClick, so when they are clicked they have the custom behaviour on top of the specific action for each button.
I have recently started developing for Android and have little experience on the inner quirks of events and UI classes.
WHat I tried, the buttom performs the custom behaviour I write in the extended class, but then doesn't perform the onClick action I assigned to the button specifically.
This is the custom Button I'm trying to do.
public class CooldownButton extends Button implements View.OnClickListener
{
Timer cooldown;
public CooldownButton(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
}
public CooldownButton(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CooldownButton(Context context)
{
super(context);
}
#Override
public void onClick(View v)
{
cooldown= new Timer();
cooldown.schedule(cooldownRun(),0,500);
setEnabled(false);
//performClick();
}
private TimerTask cooldownRun()
{
return new TimerTask()
{
#Override
public void run()
{
cooldown.cancel();
cooldown.purge();
setEnabled(true);
}
};
}
}
Then I use it on xml layouts like this:
<CooldownButton android:id="#+id/btnNext"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onBtnNextClick" />
OnBtnNextClick is never called.
public void onBtnNextClick(View v)
{
if(v.getId() == R.id.btnNext)
{
//Do something
}
}

From what I am seeing you are disabling the button setEnabled(false); and then you want to perform some action on a next click onBtnNextClick(View v). You cannot click a button a second time if it has been disabled when it was first clicked.

I found a solution after following one of the comments indications.
It is not exactly the way I wanted to solve the issue but it gets close.
I scrapped the idea of making the click behaviour in a java class.
Instead I write a click listener in the MainActivity and then set the listener to all buttons I want to have this special click behaviour.
Button nextButton = (Button) layout.findViewById(R.id.btnNext);
nextButton.setOnClickListener(buttonClickListener);
The listener is as follows:
public View.OnClickListener buttonClickListener = new View.OnClickListener() {
#Override
public void onClick(View v) {
final Button btn = (Button) v;
btn.setEnabled(false);
new Thread(new Runnable() {
#Override
public void run() {
try {Thread.sleep(1000); }
catch (InterruptedException e) {e.printStackTrace();}
MainActivity.this.runOnUiThread(new Runnable()
{
#Override
public void run(){ btn.setEnabled(true); }
});
}
}).start();
switch (v.getId()) {
case R.id.btnNext:
doSomething();
break;
//case R.id.foobar:
//break;
}
}
};

how to find id of layout in a Bitmap Button java source that I made

I made a Bitmap button that has an animation effect on a layout
but it cannot find the id of the layout and it says it indicates Null point
Here is my source below
public class BitmapButton extends Button{
public BitmapButton(Context context) {
super(context);
init();
}
public BitmapButton(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
private void init(){
setBackgroundResource(R.drawable.background_selector);
setOnClickListener(new OnClickListener() {
boolean selected=true;
Animation anim;
LinearLayout layout_search = (LinearLayout)findViewById(R.id.layout_search);
#Override
public void onClick(View v) {
if(selected) {
setSelected(true);
anim = AnimationUtils.loadAnimation(getContext(), R.anim.translate_down);
***layout_search.startAnimation(anim);***
layout_search.setVisibility(View.VISIBLE);
selected =!selected;
}
else{
setSelected(false);
anim = AnimationUtils.loadAnimation(getContext(), R.anim.translate_up);
layout_search.startAnimation(anim);
layout_search.setVisibility(View.GONE);
selected =!selected;
}
}
});
}
}
=========================================================================
layout_search.startAnimation(anim);
from here it gets wrong saying
java.lang.NullPointerException: Attempt to invoke virtual method void android.widget.LinearLayout.startAnimation(android.view.animation.Animation) on a null object reference
I know findViewById method in Button Class is different from the one in the MainActivity but I just dont know then, how I can find the LinearLayout linear_search?? with this problem I can make the anim effection on this button.
plz let me know...

public class BitmapButton extends Button{
public BitmapButton(Context context) {
super(context);
init();
}
public BitmapButton(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
private void init(){
setBackgroundResource(R.drawable.background_selector);
setOnClickListener(new OnClickListener() {
boolean selected=true;
Animation anim;
// _____________ just commented out this line ______________
// LinearLayout layout_search = (LinearLayout)v.findViewById(R.id.layout_search);
#Override
public void onClick(View v) {
// i simply add this line here and add view v before findViewById
LinearLayout layout_search = (LinearLayout)v.findViewById(R.id.layout_search);
if(selected) {
setSelected(true);
anim = AnimationUtils.loadAnimation(getContext(), R.anim.translate_down);
***layout_search.startAnimation(anim);***
layout_search.setVisibility(View.VISIBLE);
selected =!selected;
}
else{
setSelected(false);
anim = AnimationUtils.loadAnimation(getContext(), R.anim.translate_up);
layout_search.startAnimation(anim);
layout_search.setVisibility(View.GONE);
selected =!selected;
}
}
});
}
}

LinearLayout layout_search = (LinearLayout)findViewById(R.id.layout_search);
From documentation:
Look for a child view with the given id. If this view has the given id, return this view.
You trying to search layout inside button. Try to use getParent().findViewById
if you want to start animation on parent of button.

Android-Prevent dismissal of dropdown in AutoCompleteTextView after item selection

Even though I'm setting the setOnItemClickListener on the AutoCompleteTextView and performing some custom operations in it, once that method is done, the list dismisses and prints out the object.toString in the editbox.
I want to prevent dismissal of the dropdown on item select and would also like it to not replace the edit box. How can I achieve this ?

I also want to implement the same i used below code to implement it.
Create a custom class and extend AutoCompleteTextView.
Override dismissDropDown() method and remove the super call from it.
Will work for you.
public class CustomAutoComplete extends AutoCompleteTextView {
public NoSelectionAutoComplete(Context context) {
super(context);
}
public NoSelectionAutoComplete(Context context, AttributeSet attrs) {
super(context, attrs);
}
public NoSelectionAutoComplete(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
protected void replaceText(CharSequence text) {
}
#Override
public void dismissDropDown() {
}
}

I added an onClickListener to the entire custom row layout that I was using for the dropdown adapter. This way whenever the row is clicked, my row onClickListener is invoked and the default one for the dropdown is not.

First Question - Prevent dropdown dismissal:
Solved below.
Second Question - Prevent text replacement: (For others interested)
You can extend AutoCompleteTextView and override
protected void replaceText(CharSequence text) {}
to do nothing.
As others mentioned, overriding performCompletion() won't help here.

well at least it seems like they are planning to add this in near future.
/**
* Sets whether the drop-down should remain visible as long as there is there is
* {#link #enoughToFilter()}. This is useful if an unknown number of results are expected
* to show up in the adapter sometime in the future.
*
* The drop-down will occupy the entire screen below {#link #getDropDownAnchor} regardless
* of the size or content of the list. {#link #getDropDownBackground()} will fill any space
* that is not used by the list.
*
* #param dropDownAlwaysVisible Whether to keep the drop-down visible.
*
* #hide Pending API council approval
*/
public void setDropDownAlwaysVisible(boolean dropDownAlwaysVisible) {
mPopup.setDropDownAlwaysVisible(dropDownAlwaysVisible);
}

edit,new answer:
this worked for me but it closes for a sec,and opens again.
class task extends TimerTask {
#Override
public void run() {
runOnUiThread(new Runnable() {
#Override
public void run() {
autoComplete.showDropDown();
}
});
}
};
autoComplete.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
new Timer().schedule(new task(),0, 10);
}
});

Overriding replaceText without calling super works fine (prevents entering suggested text into AutoCompleteTextView), but overriding dismissDropDown causes not-dismissing dropdown not only when item clicked, but also when onBackPressed, touched outside dialog etc...
I've ended with NOT using setOnItemClickListener method from AutoCompleteTextView at all. I'm creating custom onClick in my custom ArrayAdapter and set it for all Views returned by getView method
View.OnClickListener onClick=null;
public void setOnItemClickListener(View.OnClickListener onClick) {
this.onClick=onClick;
/*this.onClick=new View.OnClickListener(){
#Override
public void onClick(View v) {
if(v.getTag()==null)
return;
Integer position = (Integer) v.getTag();
Toast.makeText(v.getContext(), "position: "+postion, Toast.LENGTH_SHORT).show();
}
});*/
}
#NonNull
#Override
public View getView(int position, View convertView, #NonNull ViewGroup parent) {
... call super/inflate convertView and do your stuff here
setCustomOnClick(convertView, position);
return convertView;
}
private void setCustomOnClick(final View view, final int position){
view.setTag(position);
view.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
if(onClick==null)
return;
// inside called onClick method v.getTag() will return pressed position
onClick.onClick(v);
}
});
}
in fact setting onClick for whole view will cover "original" always-dismissing and always-replacing-text onClick (not called at all then). Remember about adding custom graphic representation, when pressed (ripple/selector are shown when "original" onClick called only)
I've needed also always-visible functionality, because my autocomplete must always show first position (functional), even when there is no suggestions (if present then shown below on positions 1+)
public class AlwaysVisibleAutoCompleteTextView extends AppCompatAutoCompleteTextView {
private boolean showAlways=true;
public AlwaysVisibleAutoCompleteTextView(Context context) {
super(context);
}
public AlwaysVisibleAutoCompleteTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public AlwaysVisibleAutoCompleteTextView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
public void setShowAlways(boolean showAlways) {
this.showAlways = showAlways;
}
#Override
public boolean enoughToFilter() {
return showAlways || super.enoughToFilter();
}
#Override
protected void onFocusChanged(boolean focused, int direction, Rect previouslyFocusedRect) {
super.onFocusChanged(focused, direction, previouslyFocusedRect);
showDropDownIfFocused();
}
private void showDropDownIfFocused() {
if (enoughToFilter() && isFocused() && getWindowVisibility() == View.VISIBLE)
showDropDown();
}
#Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
showDropDownIfFocused();
}
}
when AlwaysVisibleAutoCompleteTextView is focused, but dropdown dismissed and user press view again, then dropdown is not showing, because focus state not changing (onFocusChanged not called), so
autoComplete.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_UP)
autoComplete.showDropDown();
return false;
}
});
If you aren't planning using setOnTouchListener for your AutoCompleteTextView for any other purpose, then OnTouchListener may be set inside AlwaysVisibleAutoCompleteTextView class (in every constructor)

Click on Text and Checkbox separately in CheckBoxPreference

I am creating a PreferenceActivity by using the PreferenceScreen xml. I wants to open a new preference screen when click on the label(title) of a CheckBoxPreference and when the user click on check box of this CheckBoxPreference then normal preference functionality will work.
So how can I do it?
For Example: Change a user profile(by click on radio buttons) and changing its properties(by clicking on label of this radio button) in android

I think it's hard to do with a default preference. But you can try extending the original onBindView method, according to the documentation: This is a good place to grab references to custom Views in the layout and set properties on them. So, this is an example for CheckBoxPreference to be clickable on text.
public class MyCheckBoxPreference extends CheckBoxPreference {
static final String TAG = "MyCheckBoxPreference";
public MyCheckBoxPreference(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
public MyCheckBoxPreference(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyCheckBoxPreference(Context context) {
super(context);
}
#Override
protected void onBindView(View v) {
super.onBindView(v);
((ViewGroup) v).getChildAt(1).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.i(TAG, "onClick " + getKey());
}
});
}
}

Disabling rows in ListPreference

I am creating a settings menu for a free version of my app. I have a ListPreference displaying many different options. However, only some of these options are to be made available in the free version (I would like all options to be visible - but disabled, so the user knows what they are missing!).
I'm struggling to disable certain rows of my ListPreference. Does anybody know how this can be achieved?

Solved it.
I made a custom class extending ListPreference. I then used a custom ArrayAdapter and used methods areAllItemsEnabled() and isEnabled(int position).
public class CustomListPreference extends ListPreference {
public CustomListPreference (Context context, AttributeSet attrs) {
super(context, attrs);
}
protected void onPrepareDialogBuilder(Builder builder) {
ListAdapter listAdapter = new CustomArrayAdapter(getContext(), R.layout.listitem, getEntries(), resourceIds, index);
builder.setAdapter(listAdapter, this);
super.onPrepareDialogBuilder(builder);
}
}
and
public class CustomArrayAdapter extends ArrayAdapter<CharSequence> {
public CustomArrayAdapter(Context context, int textViewResourceId,
CharSequence[] objects, int[] ids, int i) {
super(context, textViewResourceId, objects);
}
public boolean areAllItemsEnabled() {
return false;
}
public boolean isEnabled(int position) {
if(position >= 2)
return false;
else
return true;
}
public View getView(int position, View convertView, ViewGroup parent) {
...
return row;
}

I searched through and through all over the web, and couldn't find a way to achieve this. The answer above did not help me. I found the entire "ArrayAdapter" method very unintuitive , unhelpful, and hard to implement.
Finally, I actually had to look inside the source code for "ListPreference", to see what they did there, and figure out how to override the default behavior cleanly and efficiently.
I'm sharing my solution below. I made the class "SelectiveListPreference" to inherit the behavior of "ListPreference", but add a positive button, and prevent closing when an option is pressed. There is also a new xml attribute to specify which options are available in the free version.
My trick is not to call ListPreference's version of onPrepareDialogBuilder, but instead implement my own, with a custom click handler. I did not have to write my own code for persisting the selected value, since I used ListPreference's code (that's why I extended "ListPreference" and not "Preference").
The handler looks for the boolean resource "free_version" and if it's true, it only allows the options specified in "entry_values_free" xml attribute. If "free_version" is false, all options are allowed. There's also an empty method for inheritors, if something should happen when an option is chosen.
Enjoy,
Tal
public class SelectiveListPreference extends ListPreference
{
private int mSelectedIndex;
private Collection<CharSequence> mEntryValuesFree;
private Boolean mFreeVersion;
public SelectiveListPreference(Context context)
{
super(context);
}
//CTOR: load members - mEntryValuesFree & mFreeVersion
public SelectiveListPreference(Context context, AttributeSet attrs)
{
super(context, attrs);
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.SelectiveListPreference);
try
{
CharSequence[] entryValuesFree = a
.getTextArray(R.styleable.SelectiveListPreference_entryValuesFree);
mEntryValuesFree = new ArrayList<CharSequence>(
Arrays.asList(entryValuesFree));
}
finally
{
a.recycle();
}
Resources resources = context.getResources();
mFreeVersion = resources.getBoolean(R.bool.free_version);
}
//override ListPreference's implementation - make our own dialog with custom click handler, keep the original selected index
#Override
protected void onPrepareDialogBuilder(android.app.AlertDialog.Builder builder)
{
CharSequence[] values = this.getEntries();
mSelectedIndex = this.findIndexOfValue(this.getValue());
builder.setSingleChoiceItems(values, mSelectedIndex, mClickListener)
.setPositiveButton(android.R.string.ok, mClickListener)
.setNegativeButton(android.R.string.cancel, mClickListener);
};
//empty method for inheritors
protected void onChoiceClick(String clickedValue)
{
}
//our click handler
OnClickListener mClickListener = new OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
if (which >= 0)//if which is zero or greater, one of the options was clicked
{
String clickedValue = (String) SelectiveListPreference.this
.getEntryValues()[which]; //get the value
onChoiceClick(clickedValue);
Boolean isEnabled;
if (mFreeVersion) //free version - disable some of the options
{
isEnabled = (mEntryValuesFree != null && mEntryValuesFree
.contains(clickedValue));
}
else //paid version - all options are open
{
isEnabled = true;
}
AlertDialog alertDialog = (AlertDialog) dialog;
Button positiveButton = alertDialog
.getButton(AlertDialog.BUTTON_POSITIVE);
positiveButton.setEnabled(isEnabled);
mSelectedIndex = which;//update current selected index
}
else //if which is a negative number, one of the buttons (positive or negative) was pressed.
{
if (which == DialogInterface.BUTTON_POSITIVE) //if the positive button was pressed, persist the value.
{
SelectiveListPreference.this.setValueIndex(mSelectedIndex);
SelectiveListPreference.this.onClick(dialog,
DialogInterface.BUTTON_POSITIVE);
}
dialog.dismiss(); //close the dialog
}
}
};
}
EDIT: we also need to override the implemented onDialogClosed from ListPreference (and do nothing), otherwise, things valued do not get persisted. Add:
protected void onDialogClosed(boolean positiveResult) {}

Maybe you can do it by overrding default getView:
Steps:
Extend ListPreference
Override onPrepareDialogBuilder and replace mBuilder in DialogPreference with ProxyBuilder
Handle getView in ProxyBuilder->AlertDialog->onShow->getListView->Adapter
Code samples are in custom row in a listPreference?

Having the same problem I found a solution (maybe "hack" is more appropriate). We can register an OnPreferenceClickListener for the ListPreference. Inside this listener we can get the dialog (since the preference was clicked we are pretty safe that it is not null). Having the dialog we can set a OnHierarchyChangeListener on the ListView of the dialog where we are notified when a new child view is added. With the child view at hand we can disable it.
Assuming that the ListView entries are created in the same order as the entry values of the ListPreference we can even get the entry value.
I hope somebody finds this helpful.
public class SettingsFragment extends PreferenceFragment {
private ListPreference devicePreference;
private boolean hasNfc;
#Override
public void onCreate(android.os.Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// load preferences
addPreferencesFromResource(R.xml.preferences);
hasNfc = getActivity().getPackageManager().hasSystemFeature(PackageManager.FEATURE_NFC);
devicePreference = (ListPreference) getPreferenceScreen().findPreference(getString(R.string.pref_device));
// hack to disable selection of internal NFC device when not available
devicePreference.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
public boolean onPreferenceClick(Preference preference) {
final ListPreference listPref = (ListPreference) preference;
ListView listView = ((AlertDialog)listPref.getDialog()).getListView();
listView.setOnHierarchyChangeListener(new OnHierarchyChangeListener() {
// assuming list entries are created in the order of the entry values
int counter = 0;
public void onChildViewRemoved(View parent, View child) {}
public void onChildViewAdded(View parent, View child) {
String key = listPref.getEntryValues()[counter].toString();
if (key.equals("nfc") && !hasNfc) {
child.setEnabled(false);
}
counter++;
}
});
return false;
}
});
}
}