I am looking to integrate MergeAdapter into my project and I am having an issue trying to retrieve which section the user has clicked. I want to set it up so when user clicks any item in any section, the section number is returned so I know which section the user is in. The app I am working on requires this.
Code below sets up 3 sections with some data in each section.
public class SectionTesting extends Activity
{
ListView listView;
private MergeAdapter mergeAdapter = null;
private static final String[] items =
{ "One", "Two", "Three" };
Context context;
#Override
protected void onCreate(Bundle savedInstanceState)
{
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.mergelayout);
context = this;
listView = (ListView) findViewById(R.id.mergeListView);
mergeAdapter = new MergeAdapter();
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, new ArrayList<String>(
Arrays.asList(items)));
TextView sectionHeader = new TextView(this);
sectionHeader.setText("Section One");
mergeAdapter.addView(sectionHeader);
mergeAdapter.addAdapter(adapter);
TextView sectionHeaderTwo = new TextView(this);
sectionHeaderTwo.setText("Section Two");
mergeAdapter.addView(sectionHeaderTwo);
mergeAdapter.addAdapter(adapter);
TextView sectionHeaderThree = new TextView(this);
sectionHeaderThree.setText("Section Three");
mergeAdapter.addView(sectionHeaderThree);
mergeAdapter.addAdapter(adapter);
listView.setAdapter(mergeAdapter);
listView.setOnItemClickListener(new OnItemClickListener()
{
#Override
public void onItemClick(AdapterView<?> arg0, View v, int position,
long arg3)
{
Toast.makeText(
context,
"You clicked Section "
+ mergeAdapter.getSectionForPosition(position),
Toast.LENGTH_SHORT).show();
}
});
}
}
I was hoping getSectionForPosition method would return the value I require, but it just returns 0 everytime. I tried calling the method getSections().length as well to check it was returning the correct number of sections, but again it comes back as 0 everytime.
Any help would be much appreciated!!
Edit
I managed to come up with this messy solution. In the MergeAdapter class, under the addView method, I added this line of code
view.setId(1000);
Then I added this method here
public int getSectionNumber(int position)
{
int section = 0;
for (ListAdapter piece : getPieces())
{
int size = piece.getCount();
if (position < size)
{
return section-=1;
}
position -= size;
if(size == 1)
{
if(piece.getItem(0) instanceof TextView)
{
TextView tv = (TextView) piece.getItem(0);
if(tv.getId() == 1000)
{
section++;
}
}
}
}
return (-1);
}
The code seems to work fine, its just a bit sloppy I think. If anyone can come up with a cleaner solution that would be much appreciated, if not, then I will just add this as the answer when I can and accept it
You have at least two problems:
In order to use getSectionForPosition(), your Adapter has to implement the SectionIndexer interface. ArrayAdapter<> does not. All MergeAdapter does is try to use any SectionIndexer implementations passed to it, and you have passed zero such implementations.
You are trying to reuse the same Adapter instance several times inside of the MergeAdapter, and I have no idea if that will work and certainly do not recommend it.
To address these, create individual adapters per section, and have those adapters implement SectionIndexer.
Related
In listView I marked a line selected by a particular color, scrolling down the list and going back up - a marked line becomes colored even though there is still a mark (I did a test for it). Have you encountered such a phenomenon and if so how can you handle it.
'''
public class CustomDesignList extends AppCompatActivity {
ArrayList<Fruit> list;
ListView listView;
FruitAdapter adapter;
String[] fruitNames= {"apple", "apricot", "banana", "cherry", "coconut", "grapes",
"kiwi","mango", "melon","orange", "peach","pear",
"pineapple","strawberry", "watermelon"};
int[] imageResourceArray= {R.drawable.apple,R.drawable.apricot,R.drawable.banana,
R.drawable.cherry,R.drawable.coconut,R.drawable.grapes,
R.drawable.kiwi,R.drawable.mango,R.drawable.melon,R.drawable.orange,
R.drawable.peach,R.drawable.pear,R.drawable.pineapple,
R.drawable.strawberry,R.drawable.watermelon};
int[] arrCounter=new int[15];// מערך מונים לסימון ברשימה
int sum=0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_custom_design_list);
for(int i = 0; i< arrCounter.length;i++)
arrCounter[i] = 0;
listView=findViewById(R.id.lvCustom);
list=new ArrayList<>();
for(int i=0; i<fruitNames.length;i++)
list.add(new Fruit(fruitNames[i],
(int)((Math.random() * (100 - 10 + 1)) + 10),
imageResourceArray[i]));
//Connect all data to all elements in the list
//Layout where we defined what one element in the list would look like
adapter=new FruitAdapter(this,R.layout.my_custom_list,this.list);
//Connect the full list of data to xml
this.listView.setAdapter(adapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
arrCounter[position]++;
if( arrCounter[position] %2==1)
{
view.setBackgroundColor(Color.parseColor("#EBBEF3"));
sum+=list.get(position).getFruitWeight();//
}
else
{
view.setBackgroundColor(Color.TRANSPARENT);
sum-=list.get(position).getFruitWeight();//
}
}
});
}'''
You have a bunch of problems here.
1)You shouldn't be using ListView these days. RecyclerView replaced it most of a decade ago.
2)In a ListView click handler, you can't change anything in the UI. If you do and you don't really know what you're doing, you're going to screw it up. Like you did here. Instead of changing the UI, you should change the data in the adapter, and then tell the view to reload new data from the adapter. Anything else and you're going to have problems when the views recycle themselves on scroll.
I'd really look at changing to recycler view, but at a minimum you need to change how your click handler works completely so that it doesn't make any UI changes directly and only changes the data.
I want to Convert the Languages. So i am using two Spinners one is "From Language" and Another one is for "To Language". If One Language is Selected in "From Language" Spinner, it shouldn't display (or it should be disabled) in 2nd spinner. how can i achieve it?
Ex. if i Select English in 1st Spinner, 2nd Spinner Shouldn't display English in its dropdown.
This is may not be the best way try this.
ArrayList<String> languages = new ArrayList<>();
languages.add("English");
languages.add("Hindi");
languages.add("Telugu");
languages.add("Tamil");
languages.add("Kannada");
languages.add("Malayalam");
// make a array list of languages
String option1 = null;
Spinner spinnerOption1 = (Spinner) findViewById(R.id.spinner1);
final ArrayAdapter<String> adapterOpton1 = new ArrayAdapter<String>(getContext(), android.R.layout.simple_spinner_item, languages);
spinnerOption1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerOption1.setAdapter(adapterOpton1);
spinnerOption1.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
option1 = adapterOpton1.getItem(position);
}
});
int selectedIndex;
for (String item : languages) {
if (item.equals(option1)) {
selectedIndex == languages.indexOf(item);
}
}
ArrayList<String> languages2 = languages;
languages2.remove(selectedIndex);
Spinner spinnerOption2 = (Spinner) findViewById(R.id.spinner2);
final ArrayAdapter<String> adapterOption2 = new ArrayAdapter<String>(getContext(), android.R.layout.simple_spinner_item, languages2);
spinnerOption2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerOption2.setAdapter(adapterOption2);
Explanation:
lets create a arraylist with languages
bind it to the adapter on the spinner, on selection to the spinner one keep a track of that selection, then find the index of the selection in the arraylist.
create second arraylist with the same languages and find and remove the user selected item, create an adapter and bind the data.
Hope it helps.
Use Hashmaps it will be easier. Create an Adapter that uses Key Values for populating adapter.
This is a snippet I found from another link on how to do that, in case you are not familiar
public class HashMapAdapter extends BaseAdapter {
private HashMap<String, String> mData = new HashMap<String, String>();
private String[] mKeys;
public HashMapAdapter(HashMap<String, String> data){
mData = data;
mKeys = mData.keySet().toArray(new String[data.size()]);
}
#Override
public int getCount() {
return mData.size();
}
#Override
public Object getItem(int position) {
return mData.get(mKeys[position]);
}
#Override
public long getItemId(int arg0) {
return arg0;
}
#Override
public View getView(int pos, View convertView, ViewGroup parent) {
String key = mKeys[pos];
String Value = getItem(pos).toString();
//do your view stuff here
return convertView;
}
}
Credit What adapter shall I use to use HashMap in a ListView
Now for your management of the adapters.
LanguageOneMap.put (all your keys 0-whatever) value (english-whatever)
LanguageTwoMap.put (same as above)
LanguageAllMap.put (same as above)
Adapter 1 selects Language Callback(languageSelectedFromOneKey){
LanguageTwoMap.clearAll
LanguageTwoMap.put (all again)
LanguageTwoMap.remove(languageSelectedFromOneKey)
LanguageTwoAdapter.notifyDataSetChanged()
}
The above is just pseudo code meant to give the idea, not exact copy and paste. Hope that is enough to get you going. There are many ways to skin this cat, you could even use the same list for both adapters. Then when one is selected from one or the other, set a property of "selectedOtherLanguage" in the opposite adapter, then in the GetView method if data.get(pos) == selectedFromOtherListItem return, don't draw.
Many ways to do this, just a matter of how you want to do it. Goodluck.
Background
Hi, I am new to Android and trying to get familiar with ListView. So I decide to write a simple program for user to enter quotes and display them in order. I implement a StringAdapter and call the notifyDataSetChanged every time when the user confirms.
Question
The weird thing is that the ListView would sometimes update the oldest quotes and sometimes the newer one. and I don't know the problem.
Please ignore the view data button. In this state, I have entered four quotes:
Quotes: hi - Signature:William Shakespeare
Quotes: hello - Signature:William Shakespeare
Quotes: Virtue is bold and goodness never fearful. - Signature:William Shakespeare
Quotes: Love all, trust a few, do wrong to none. - Signature:William Shakespeare
(in reverse order, meaning in time sequence, it goes 4,3,2,1)
Code
main activity
public class storage extends AppCompatActivity {
// the adapter
private StringAdapter sa;
// the edit text view
public EditText etString,etSignature;
// the list view
public ListView lv;
// the array list to capture the quotes and signature
private ArrayList<String[]> dataString = new ArrayList<String[]>();
// add the string and notify
public void addString(String[] s){
this.dataString.add(0,s);
((BaseAdapter)this.lv.getAdapter()).notifyDataSetChanged();
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_storage);
// Link the view elements
this.etString = (EditText) findViewById(R.id.etInput);
this.etSignature = (EditText) findViewById(R.id.etSignature);
this.lv = (ListView) findViewById(R.id.stringList);
Button btn_confirm = (Button) findViewById(R.id.btnConfirm),
btn_viewData = (Button) findViewById(R.id.btnViewData);
// load the adapter
this.sa = new StringAdapter(this,this.dataString);
lv.setAdapter(sa);
btn_confirm.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
storage s = (storage) v.getContext();
// get the String
String sString = s.etString.getText().toString(),
sSignature = s.etSignature.getText().toString();
System.out.println("Quotes: " + sString + "\nSignature:" + sSignature);
// verify it is not empty
if (!sString.isEmpty()&&!sSignature.isEmpty()) {
// add new string and notify
s.addString(new String[]{s.etString.getText().toString(),
s.etSignature.getText().toString()});
((StringAdapter) s.lv.getAdapter()).print_stringData();
// prompt the result
Toast.makeText(s.getBaseContext(),
"Enter Quotes from"+etSignature.getText().toString(),Toast.LENGTH_SHORT).show();
} else {
// prompt the result
Toast.makeText(s.getBaseContext(),
"Please Enter Quotes and Signatures!",Toast.LENGTH_SHORT).show();
}
}
});
}
}
StringAdapter
public class StringAdapter extends BaseAdapter {
private Context mContext;
private ArrayList<String[]> dataStrings = new ArrayList<String[]>();
public StringAdapter(Context c,ArrayList<String[]> dataStrings){this.mContext=c;this.dataStrings=dataStrings;}
public int getCount(){return this.dataStrings.size();}
public Object getItem(int position){ return this.dataStrings.get(position);}
public long getItemId(int postion){ return (long) postion;}
public void print_stringData(){
System.out.println("String Adapter Output:");
for(String [] s: this.dataStrings){
System.out.println("Quotes: "+s[0]+"\nSignature:"+s[1]);
}
}
public View getView(int position, View convertView, ViewGroup parent){
LinearLayout ll;
if(convertView == null){
// set the linear layout
ll = new LinearLayout(this.mContext);
ll.setOrientation(LinearLayout.VERTICAL);
ll.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
// get the data and set the text inside
String[] data = this.dataStrings.get(position);
TextView //tvNo = new TextView(this.mContext),
tvString = new TextView(this.mContext),
tvSignature = new TextView(this.mContext);
ll.addView(tvString);
ll.addView(tvSignature);
tvString.setText(data[0]);
tvString.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT));
tvSignature.setText(data[1]);
tvSignature.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT));
tvSignature.setGravity(Gravity.RIGHT);
}
else{
ll = (LinearLayout) convertView;
}
return ll;
}
}
Comments
Some might notice that I add the String[] always to the first element. Actually I have tried to add to the last. The weird behavior still exists.
Environment
Android SDK Version: API 23 lollipop
Emulator Version: Nexus S API 23
Yes, of course, you get that error. Why? Because ListView always re-use convertView in your getView function of Adapter.
Look at your if,else:
else{
ll = (LinearLayout) convertView;
}
return ll;
At this block, you tell the adapter reuse the convertView, but you dont re-set the data. As a result, it will show the data of the previous row.
How to resolve it? just set the data in else block as you do in if one.
P/s: you should learn how to use ViewHolder in ListView to avoid laggy in when scrolling.
I am developing an app in which I need a ListView whose rows have a TextView, 2 CheckBox and a Spinner.
However, I am experiencing issues with onItemSelected() of the Spinner, as it gets called each time it is displayed for each row. In this method I am updating database records with the selected option, but as Android calls it automatically, every time the items get reset because Android calls it with position 0 and this is the value updated in the database.
I have read a lot of links about the issue with onItemSelected() and some hacks, but all of them are to use without a ListView. Any points here?
I have tried to track in a List which positions are actually displayed to make it work but it does not. I think it is because of the recycling in Android that causes the troubleshooting method get called for Spinners already shown!
So the point is: How can I differenciate a real call to onItemSelected() because of a user selection from the Android call when displaying the Spinner?
Here is the code of my adapter that extends SimpleCursorAdapter.
Thank you so much in advance.
public ParticipationAdapter(Context context, int layout, Cursor c, String[] from, int[] to) {
super(context, layout, c, from, to);
mActivity = (Activity)context;
ParticipationComment.ParticipationCommentManager commentManager = new ParticipationComment.ParticipationCommentManager(mActivity);
mParticipationCommentsCursor = commentManager.get();
mActivity.startManagingCursor(mParticipationCommentsCursor);
commentManager.detach();
mPositionsOfCursorIds = getPositionsOfCursorIds(mParticipationCommentsCursor);
mSpinnerPositionsDisplayed = new ArrayList<Integer>();
}
#Override
public View getView(final int participationPosition, View convertView, ViewGroup parent) {
final Cursor participationsCursor = getCursor();
mActivity.startManagingCursor(participationsCursor);
participationsCursor.moveToPosition(participationPosition);
View participationRow;
if (convertView == null) {
participationRow = LayoutInflater.from(mActivity).inflate(R.layout.participation_row_student, null);
} else {
mSpinnerPositionsDisplayed.remove((Integer)convertView.getTag());
participationRow = convertView;
}
participationRow.setTag(participationPosition);
Spinner commentSpinner = (Spinner)participationRow.findViewById(R.id.participation_comment_id_spinner);
SimpleCursorAdapter commentSpinnerAdapter = new SimpleCursorAdapter(
mActivity,
android.R.layout.simple_spinner_item,
mParticipationCommentsCursor,
new String[] {DatabaseManager.NAME},
new int[] {android.R.id.text1}
);
commentSpinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
commentSpinner.setAdapter(commentSpinnerAdapter);
long participationCommentId = participationsCursor.getLong(participationsCursor.getColumnIndex(DatabaseManager.PARTICIPATION_COMMENT_ID));
if (participationCommentId != 0) {
commentSpinner.setSelection(mPositionsOfCursorIds.get(participationCommentId));
}
commentSpinner.setOnItemSelectedListener(new OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
participationsCursor.moveToPosition(participationPosition);
if (!mSpinnerPositionsDisplayed.contains(participationPosition)) {
// Android calls this method the first time a Spinner is displayed,
// to differentiate from a real user click we check if the current Spinner's position
// in the ListView is being shown
mSpinnerPositionsDisplayed.add(participationPosition);
} else {
ParticipationComment participationComment = new ParticipationComment((Cursor)parent.getItemAtPosition(position));
Participation.ParticipationManager participationManager = new Participation.ParticipationManager(mActivity);
Participation participation = new Participation(participationsCursor);
participation.setConnectionProfileParticipationCommentId(participationComment.getConnectionProfileId());
participation.setParticipationCommentId(participationComment.getIdOpenErp());
participation.setChanged(true);
participationManager.update(participation);
participationManager.detach();
}
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
// Not used
}
});
TextView studentName = (TextView)participationRow.findViewById(R.id.participation_student_name);
studentName.setText(participationsCursor.getString(participationsCursor.getColumnIndex(DatabaseManager.NAME)));
CheckBox expectedPresent = (CheckBox)participationRow.findViewById(R.id.participation_expected_present_value);
expectedPresent.setChecked(participationsCursor.getInt(participationsCursor.getColumnIndex(DatabaseManager.EXPECTED_PRESENT)) == 1);
CheckBox present = (CheckBox)participationRow.findViewById(R.id.participation_present_value);
present.setChecked(participationsCursor.getInt(participationsCursor.getColumnIndex(DatabaseManager.PRESENT)) == 1);
return participationRow;
}
A better way is to use a AlertDialog Variant.. like this.. and create a button which initially has the first selection as its Text and its changed based on the AlertDialog choice..
What about using a small flag to discard first call of ItemSelected ?
I need to display a list of text items to the screen and make them clickable. So it would be something like a list of links on a web application.
How can I do that in an Android Activity screen?
It would be some random number of items that I have to pull from a db and display all as links.
Any idea how that can be done?
You should read the doc about ListActivity, ListView and follow the Hello ListView tutorial.
Yes you can do it. Create a DataExchange class to fetch it from Db..
Store the Strings in an Array.
Create a ArrayAdapter to display the array of Strings you got from the database.
for Example
public class AndroidListViewActivity extends ListActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// storing string resources into Array
String[] numbers = {"one","two","three","four"}
// here you store the array of string you got from the database
// Binding Array to ListAdapter
this.setListAdapter(new ArrayAdapter<String>(this, R.layout.list_item, R.id.label, numbers));
// refer the ArrayAdapter Document in developer.android.com
ListView lv = getListView();
// listening to single list item on click
lv.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// selected item
String num = ((TextView) view).getText().toString();
// Launching new Activity on selecting single List Item
Intent i = new Intent(getApplicationContext(), SingleListItem.class);
// sending data to new activity
i.putExtra("number", num);
startActivity(i);
}
});
}
}
The secondActivity to display the Particular item you have clicked should be
public class SingleListItem extends Activity{
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.single_list_item_view);
TextView txtProduct = (TextView) findViewById(R.id.product_label);
Intent i = getIntent();
// getting attached intent data
String product = i.getStringExtra("number");
// displaying selected product name
txtProduct.setText(product);
}
}
you have to create various layout files accordingly..
Hope this helps you :)
You should use a ListView. It's very simple, just create a ListActivity, put your items inside an Adapter and then set it as the Adapter of your ListActivity.
You can read more about ListViews here
There is also a new paradigm called ListFragment.
I have used ListViews before but prefer the fragments approach now - it's just very straight forward and quite flexible esp on tablets since the interation with another area on the screen when selecting an item is quite flexible and only requires very little code.
Just one example:
public class Select_FoodCategories_Fragment extends android.app.ListFragment {
private static final boolean DEBUG = true;
#Override
public void onCreate(Bundle savedInstanceState) {
if (DEBUG)
Log.i(this.getClass().getSimpleName(), " ->"
+ Thread.currentThread().getStackTrace()[2].getMethodName());
super.onCreate(savedInstanceState);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if (DEBUG)
Log.i(this.getClass().getSimpleName(), " ->"
+ Thread.currentThread().getStackTrace()[2].getMethodName());
HoldingActivity a = (HoldingActivity) getActivity();
//accessing a variable of the activity is easy
a.visibleListViewInFragment = getListView();
List<XYZ> listTodisplay = a.getListToDisplay();
MyAdapter adapter = new MyAdapter(
getActivity(), 0, listTodisplay);
setListAdapter(adapter);
}
#Override
public void onListItemClick(ListView l, View v, int position, long id) {
if (DEBUG)
Log.i(this.getClass().getSimpleName(), " ->"
+ Thread.currentThread().getStackTrace()[2].getMethodName());
XYZ item = (XYZ) getListAdapter()
.getItem(position);
}
}
More info here: http://developer.android.com/reference/android/app/ListFragment.html
By the way, I find it really worth it to get familiar with the new fragments concept - it just makes live much easier - esp on tablets!
ps I left the debug statements in on purpose - since it helps alto to understand the whole concept much faster in my experience