Develop Reference

How can I work around strange S Pen bugs with the spinner?

When using a Spinner with all default settings, I found some weird bugs when using the S Pen:
If you open the spinner and hover the S Pen at the bottom of the list, so it scrolls to the bottom, and then lift the S Pen up (so that the "hover circle" disappears), the list jumps back to the top
If you open the spinner and hover the S Pen at the bottom of the list, so it scrolls to the bottom, and then select an option, sometimes (intermittently - maybe about 1 in 4 times) it ignores the selected option and just jumps back to the top
I am testing on a tablet device in landscape orientation, the device is running Android 9 but I have done some tests on other devices and seems to be the same.
For comparison I tried using an app I use regularly which makes heavy use of spinners - "Packing List" by dotnetideas. This app was last updated in 2019 and has target SDK 27. You can easily test the spinners in the app by going into the settings and adding multiple items of luggage, then trying to edit the luggage on any packing list item. I found the S Pen works fine with this app, and it doesn't have the bugs described above, so there must be some way to work around it. That's not an open source app so I can't get ideas from their source code. I tried changing my target SDK to 27, but didn't make any difference.
Here is my code for what seems to me to be a completely vanilla implementation of spinner with all default settings - and still has these same "S Pen bugs" which are not reproducible in Packing List.
AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.penpoc">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.SPenControlExperiment">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
MainActivity.java:
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.replace(R.id.container, MainFragment.newInstance())
.commitNow();
}
}
}
main_activity.xml:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" />
MainFragment.java:
public class MainFragment extends Fragment {
public static MainFragment newInstance() {
return new MainFragment();
}
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container,
#Nullable Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.main_fragment, container, false);
Spinner spDefault = root.findViewById(R.id.spDefault);
ArrayAdapter<String> defaultSpinnerAdapter = new ArrayAdapter<>(getContext(), android.R.layout.simple_spinner_item);
defaultSpinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spDefault.setAdapter(defaultSpinnerAdapter);
defaultSpinnerAdapter.addAll(getExampleList());
defaultSpinnerAdapter.notifyDataSetChanged();
return root;
}
private List<String> getExampleList() {
List<String> list = new ArrayList<>();
list.add("Alpha");
list.add("Bravo");
list.add("Charlie");
list.add("Delta");
list.add("Echo");
list.add("Foxtrot");
list.add("Golf");
list.add("Hotel");
list.add("India");
list.add("Juliet");
list.add("Kilo");
list.add("Lima");
list.add("Mike");
list.add("November");
list.add("Oscar");
list.add("Papa");
list.add("Quebec");
list.add("Romeo");
return list;
}
}
main_fragment.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainFragment">
<!-- Add some text views to push the spinner further down the page, this is not strictly necessary -->
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="one" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="two" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="three" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="four" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="five" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="six" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="seven" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="eight" />
<Spinner
android:layout_width="350dp"
android:layout_height="wrap_content"
android:id="#+id/spDefault" />
</LinearLayout>
Gradle deps:
implementation 'androidx.appcompat:appcompat:1.3.0'
implementation 'com.google.android.material:material:1.3.0'

I exactly faced the same problem with the S Pen. For an old app, API 25 Spinners were working great, but not any more with API 30. The only way I can resolve it was to replace Spinners by AutoCompleteTextViews. The drop down it generates seems to work correctly with the S Pen.
A few adaptations are needed to make it look like a Spinner:
1. Make AutoCompleteTextView not editable
From the documentation, you can make it by adding android:inputType="none". But, as said in MaterialAutoCompleteTextView code:
// Due to a framework bug, setting android:inputType="none" on xml has no effect. Therefore,
// we check it here in case the autoCompleteTextView should be non-editable.
So you have two options:
Set the input type programmatically autoComplete.setInputType(InputType.TYPE_NULL)
Use MaterialAutoCompleteTextView having a workaround for this
2. Handle clicks to show the drop down list
The default behavior with AutoCompleteTextView is to show suggestions by typing a few characters. So you have to force the drop down show when view gets focused.
autoComplete.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
void onFocusChange(View v, boolean hasFocus) {
if (hasFocus) {
autoComplete.showDropDown();
}
}
});
autoComplete.setOnDismissListener(new AutoCompleteTextView.OnDismissListener() {
#Override
void onDismiss() {
// Force focus change after selection
autoComplete.clearFocus()
}
});
3. Style the drop down list
Contrary to Spinner calling both getView() and getDropDownView() from Adapter, AutoCompleteTextView only calls getView(). So, to provide the correct view, you need to check the parent type in getView() call:
#Override
public #NonNull View getView(int position, #Nullable View convertView, #NonNull ViewGroup parent) {
// Workaround for AutoCompleteTextView using only this method
if (parent instanceof ListView) {
return getDropDownView(position, convertView, parent);
} else {
return super.getView(position, convertView, parent);
}
}
4. Style the AutoCompleteTextView
One last thing is to add the little caret at the end of the AutoCompleteTextView to make it look like a Spinner. You can use the android:drawableEnd attribute in your XML layout file to handle this.
5. Other tips
AutoCompleteTextView drop down list selection triggers AdapterView.OnItemClickListener instead of AdapterView.OnItemSelectedListener as Spinners do. Methods signatures are almost the same.
There is no proper way to trigger this listener for initial values. As a workaround, you can set the initial value, then attach listener and put your first validation logic in its constructor.

Automatically Generating java code for xml layout in Eclipse

I have got an idea to get rid of some coding when we do initializion of views.
When we create an xml layout in android. At that movement same name class is created with UpperCase Letters with a dialogue with permission. And as i created views with ids. It should create Views and initialize them automatically.
for e.g
close.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<Button
android:id="#+id/closeBtn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/close_img" />
<TextView
android:id="#+id/closeText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Testing Text" />
</LinearLayout>
And automatically generated java code should be.
public class Close extends Activity
{
TextView CloseText;
Button CloseBtn;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CloseText = (TextView)findViewById(R.id.closeText);
CloseBtn = (Button)findViewById(R.id.closeBtn);
}
}
I can read xml and do the other stuff as I explained. But how could i add this module to eclipse and How could i create a service which work in Background all the time in eclipse.
Suggest me how to add this module(Plugin) to eclipse and i am going to use JAXB to generate Java Objects from XML document. Is there any better option.

Here in this website i find that just paste the xml and you will get your java code ready for activity class.
i had attached the link

Android Programmatically setting button text

Does anybody know how to programmatically set the text of a button?
thing is i'm not calling this from the main layout(setContentView) i'm calling it in a view thats inflated after an asynctask
heres what i have tried but this is giving a null pointer exception on the 2nd line
Button mButton=(Button)findViewById(R.id.contact);
mButton.setText("number");
heres my layout where i am calling the button
<Button
android:id="#+id/contact"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/address"
android:layout_toLeftOf="#+id/badge"
android:background="#drawable/ic_btn_call"
android:textSize="10dp"
android:textStyle="bold"
android:textColor="#color/white"/>
here my view i'm inflating
ClubInfo = LayoutInflater.from(getBaseContext()).inflate(R.layout.clubinfocell,
null);
TextView TeamNameText = (TextView) ClubInfo.findViewById(R.id.TeamName);
TeamNameText.setText(teamName);
TextView AddressText = (TextView) ClubInfo.findViewById(R.id.address);
AddressText.setText(address1);
Button mButton=(Button)ClubInfo.findViewById(R.id.contact);
mButton.setText(telephone);

Then use your view's object to initialize it:
Button mButton = (Button)your_view_object.findViewById(R.id.contact);
mButton.setText("number");
When you try to identify a view other than your Activity's layout, you have to pass the reference of that view like this. If not Android will keep looking for this element from the layout which you provided in the setContentView().
For example, consider you have inflated a view like this:
View View = mInflater.inflate(R.layout.gridelement, null);
Then use this View's object for the Button present in that inflated layout:
Button mButton = (Button)View.findViewById(R.id.contact);

change your code as:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);//set layout here in which u have add contact in xml
Button mButton=(Button)findViewById(R.id.contact);
mButton.setText("number");
EDIT:
Your \res\layout\main.xml look like as:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<Button
android:id="#+id/contact"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/address"
android:layout_toLeftOf="#+id/badge"
android:background="#drawable/ic_btn_call"
android:textSize="10dp"
android:textStyle="bold"
android:textColor="#color/white"/>
</LinearLayout>

your mButton is null.so NPE.are you refrenced xml resources after setContentView
onCreate(){
...
setContentView(R.layout.yourlayout);
Button mButton=(Button)findViewById(R.id.contact);
mButton.setText("number");
}

check R.java files import statement
are you sure that you have import it of the project you use ..
and just format your layout (.xml ) file save it and again type the same statement

creating a countdowntimer

I've created a countdown timer that counts Days:Hrs:Mins:Sec. using regular text view and updating it using my handler works fine for me.
however I want to create a cool animation for the changing digits:
1st Q:
I have 2 options as I see it to draw the numbers:
1. using a home made font applied with a style
2. using a textview/btn with no text on them and applying a backrgound image using setBackgroundResource()
--what should I choose?
2nd Q:
I've created a wrapper for ViewFlipper(not extending it)
public class transitionair extends Activity {
SpecialFlipperWrapper m_thousand;
SpecialFlipperWrapper m_hundred;
SpecialFlipperWrapper m_tens;
SpecialFlipperWrapper m_ones;
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
ViewFlipper flipper_Tsnds=(ViewFlipper)findViewById(R.id.yearThousand);
m_thousand = new SpecialFlipperWrapper(flipper_Tsnds, this, 9);
ViewFlipper flipper_Hndrds=(ViewFlipper)findViewById(R.id.yearHundread);
m_hundred = new SpecialFlipperWrapper(flipper_Hndrds, this, 9);
ViewFlipper flipper_Tns=(ViewFlipper)findViewById(R.id.yearTens);
m_tens = new SpecialFlipperWrapper(flipper_Tns, this, 9);
ViewFlipper flipper_Ons=(ViewFlipper)findViewById(R.id.yearOnes);
m_ones = new SpecialFlipperWrapper(flipper_Ons, this, 9);
m_thousand.startFlipping();
m_hundred.startFlipping();
m_tens.startFlipping();
m_ones.startFlipping();
}
}
however trying to fetch one of the latter views that come after the yearThousand id are retrieving null
XML I'm Using is:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<ViewFlipper
android:id="#+id/yearThousand"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<ViewFlipper
android:id="#+id/yearHundread"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<ViewFlipper
android:id="#+id/yearTens"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<ViewFlipper
android:id="#+id/yearOnes"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
ps xml's for the animation itself are working so I left them out
Main questions is: can I make it better?
second question is: how?
third question is why is my layout returning null on the second call to it and how can I avoid it?
10XX

ViewStub reinflates last view inflated on first pass of onCreate

I have a bug with my activity.
I have three view stubs in my linear layout like so -
<ViewStub
android:id="#+id/index_1"
android:layout="#layout/index_edittext"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<ViewStub
android:id="#+id/index_2"
android:layout="#layout/index_edittext"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<ViewStub
android:id="#+id/index_3"
android:layout="#layout/index_edittext"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
my onCreate conditionally checks what to inflate:
for (int i = 0; i < 3; i++) {
int id = convertIndexToId(i); //will turn i into R.id.index_1
ViewStub stub = findViewById(id);
if (bShouldBeSpinner) {
stub.setLayoutResource(R.layout.index_spinner);
View root = stub.inflate();
Spinner spin = (Spinner)root.findViewById(R.id.my_spinner);
spinner.setAdapter(adapter);
spinner.setSelection(0);
}
else {
stub.setLayoutResource(R.layout.index_edittext);
View root = stub.inflate();
EditText et = (EditText)root.findViewById(R.id.my_edittext);
//et.phoneHome(); just kidding
et.setText(String.valueOf(System.currentTimeMillis()));
}
}
I force bShouldBeSpinner to false. The output of the edittext's is as follows:
1300373517172
1300373517192
1300373517221
However, when I rotate the screen and onCreate is called a second time the output is this:
1300373517221
1300373517221
1300373517221
Initially that made me think you should only inflate the view once, and the heirarchy is kept inbetween onCreate's... however when i only run it the first time the second time no views are shown for the stubs.
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<Spinner style="#style/SearchInput" android:id="#+id/my_spinner" />
</LinearLayout>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<EditText style="#style/SearchInput" android:id="#+id/my_edittext" />
</LinearLayout>
I feel the documentation is assuming something that I did not notice or am missing. Does anyone see what I am doing wrong?
EDIT
I added to the view stubs android:inflatedId="index_1_root"... etc
it is the strangest thing, when I add these lines after the for loop:
EditText v = indexRoot1.findViewById(R.id.index_edit_text);
Log.d(TAG, "EditTExt: " + v);
EditText v2 = indexRoot2.findViewById(R.id.index_edit_text);
Log.d(TAG, "EditTExt: " + v2);
the output says (I believe) they are references to different EditTexts.
EditTExt: android.widget.EditText#47210fe8
EditTExt: android.widget.EditText#47212ba8
So they are getting inflated again, but the text is set to what the last edittext was set to on the first pass.

There may be some issues when recreating views of different types with the same id.
ViewStub is replaced by inflated view.
I suggest using
setInflatedId(int inflatedId)
to distinguish inflated views.
Hope that help.

Instead of using ViewStubs, I added an id to the root of those stubs (android:id="index_roots") and used
view.addView( (isSpinner) ?
new Spinner(this) : new EditText(this) );
to fix this problem, I will however not accept this answer right away, I'll allow others to answer using the method I was going for.