I'm new to android. Recently I learn how to create Tabwidget. This function is useful. But I find that I cannot add the widgets I want in R.layout.xxxx. So I try to do it by java code. But unfortunately it failed.
By using XML, I do the following. The program works without problem.
public class ShowBalanceActivity extends Activity implements AdapterView.OnItemSelectedListener
{
private Spinner monthview;
private ArrayAdapter monthadapter;
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.balance);
monthadapter = ArrayAdapter.createFromResource(
this, R.array.months, android.R.layout.simple_spinner_item);
monthadapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
monthview = (Spinner) findViewById(R.id.monthlist);
monthview.setOnItemSelectedListener(this);
monthview.setAdapter(monthadapter);
public void onItemSelected(AdapterView<?> parent, View view, int position, long id)
{
}
}
For the Java code part, I use the following,
public class BalanceLayout extends TabActivity implements TabHost.TabContentFactory
{
private Activity activity;
private LayoutInflater inflaterHelper = null;
private Spinner monthview = null;
private LinearLayout layout;
private static final String Tab1 = "By Date";
private static final String Tab2 = "By Categories";
private ArrayAdapter <String> monthadapter = null;
public BalanceLayout (Activity a)
{
activity = a;
inflaterHelper = a.getLayoutInflater();
}
public View addCustomView(String id)
{
layout = new LinearLayout(activity);
layout.setOrientation(LinearLayout.VERTICAL);
if(id.equals(Tab1))
{
Spinner monthview = new Spinner(activity);
ArrayAdapter <String> monthadapter = new ArrayAdapter <String> (this,
android.R.layout.simple_dropdown_item_1line, MONTHS);
monthadapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
monthview.setAdapter(monthadapter);
monthview.setOnItemSelectedListener(
new AdapterView.OnItemSelectedListener()
{
public void onItemSelected(AdapterView<?> parent, View view, int position, long id)
{
}
public void onNothingSelected(AdapterView<?> parentView)
{
}
});
layout.addView(monthview,
new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
}
else if(id.equals(Tab2))
{
}
return layout;
}
}
But it causes force close when I execute the program. It seems that I cannot use findViewById method to create the view like XML.
I read many documentations and search android docs and internet. I cannot find the solution. Hope that some of you know what happened to my code and solution to solve
Thanks !!
Tom
After I checked my code and debug. Finally it is easy to solve. But originally I don't know why. Then I isolate the problem by only inserting textview.
TextView tv = new TextView(activity);
tv.setText("This is a text view");
layout.addView(tv, new
LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
The problem for my code is using "this" not "activity". It is because I want to create layout dynamically not using content factory or intent method. So "this" was replaced by activity. Then the problem is solved. But I spent much time to troubleshoot. Android is amazing
monthadapter = ArrayAdapter.createFromResource(
activity, R.array.months, android.R.layout.simple_spinner_item);
monthadapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
Related
I've seen many other posts in this context, but none helped. Problem is when i click on the addField button, the listview inside dialog adds new view just once. But at other clicks it doesn't get updated though The adapter works correctly (I mean the getView is called and also the arrayList in the adapter is changed in size).
I've used notifyDataSetChanged() in the adapter class. No result! I used an instance of adpater class in activity and called myAdapter.notifyDataSetChanged(). No result!
here is my code:
public class MainActivity extends Activity {
ListView lvfid;
FieldAdapter fAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//some code
showFid();
}
private void showFiD(){
final ArrayList <HashMap<String,String>> al = new ArrayList<HashMap<String,String>>();
final Dialog dialog = new Dialog(MainActivity.this , R.style.DialogTheme);
dialog.setContentView(R.layout.field_dialog);
dialog.setCancelable(true);
dialog.show();
Button addField = (Button) dialog.findViewById(R.id.btnfidField);
lvfid = (ListView) dialog.findViewById(R.id.lvfid);
//Another plan i have tested, but no result:
//fAdapter = new FieldAdapter(dialog.getContext(),al);
//lvfid.setAdapter(fAdapter);
addField.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
HashMap<String,String> h = new HashMap<String,String>();
h.put("name", "");
h.put("value", "");
al.add(h);
lvfid.setAdapter(new FieldAdapter(dialog.getContext(), al));
//fAdapter.notifyDataSetChanged();
}
});
}
public class FieldAdapter extends BaseAdapter{
private ArrayList <HashMap <String,String>> arrayList;
private LayoutInflater inflater;
public FieldAdapter(Context context, ArrayList<HashMap <String,String>> arrayList) {
inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
this.arrayList = arrayList;
}
#Override
public int getCount() {
return arrayList.size();
}
#Override
public Object getItem(int position) {
return position;
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup arg2) {
View view = null;
if (convertView == null)
view = inflater.inflate(R.layout.field_inflater, null);
else
view = convertView;
Holder holder = new Holder();
holder.edName = (EditText) view.findViewById(R.id.edfidName);
holder.edValue = (EditText) view.findViewById(R.id.edfidValue);
//holder.edName.setText(arrayList.get(position).get("name"));
//holder.edValue.setText(arrayList.get(position).get("value"));
return view;
}
private class Holder {
private EditText edName;
private EditText edValue;
}
}
}
UPDATE:
I'm sorry i took everybody's time. The stupid problem was that my listview was inside a scrollview where it must not be! I hope this helps others who have the same issue!
Use the notifyDataSetChanged() every time the list is updated.
I had the same problem. I was facing with this problem when I wanted to update the listView after onDateChanged(). I resolved it with an extra ArrayList variable and an extra custom adapter in your case FieldAdapter variable.
Update your listView with a refresh adapter and array list variables after any operations. For example after button clicks.
1. Define a counter.
2. Check when the button is clicked, increase counter by one
3. Every time check the counter, if counter is greater than 1 it means the button is clicked more than once so update the list view with new variables (arrayList, FeildAdapter)
I recommend you to define the variables as a private class fields and name them such as refreshedArrayList and refreshedAdapter
Option
Try to use the ArrayAdapter. And don't create a new adapter every
time you click on the button.
only call the add(T o) function from the ArrayAdapter.
Other Option:
add a add function to your FieldAdapter in the add field adapter add the object to your arraylist and call notifiyDataSetChanged(the adapter has aslo one and the adapter notifies all his observers)
also don't create a new adapter every time you click the button.
public class MainActivity extends Activity {
ListView lvfid;
FieldAdapter fAdapter;
ArrayList <HashMap<String,String>> al ;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//some code
al = new ArrayList<HashMap<String,String>>();
lvfid.setAdapter(new FieldAdapter(MainActivity.this , al));
showFid();
}
private void showFiD(){
final Dialog dialog = new Dialog(MainActivity.this , R.style.DialogTheme);
dialog.setContentView(R.layout.field_dialog);
dialog.setCancelable(true);
dialog.show();
Button addField = (Button) dialog.findViewById(R.id.btnfidField);
lvfid = (ListView) dialog.findViewById(R.id.lvfid);
//Another plan i have tested, but no result:
//fAdapter = new FieldAdapter(dialog.getContext(),al);
//lvfid.setAdapter(fAdapter);
addField.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
HashMap<String,String> h = new HashMap<String,String>();
h.put("name", "");
h.put("value", "");
al.add(h);
fAdapter.notifyDataSetChanged();
}
});
}
I'm sorry i took everybody's time! The stupid problem was just my listview was inside a scrollview where it must not be! after getting the listview out of scrollview the problem got solved.
CustomListAdapter Class:
its like example for problem;
public class CustomList extends ArrayAdapter<String>{
private final Activity context;
private final List<FixtureData> list;
public CustomList(Activity context,List<FixtureData>list) {
super(context, R.layout.list_single);
this.context = context;
this.list = list;
}
#Override
public View getView(final int position, View view, ViewGroup parent) {
LayoutInflater inflater = context.getLayoutInflater();
View rowView= inflater.inflate(R.layout.list_single, null, true);
TextView txt_date = (TextView) rowView.findViewById(R.id.txt_date);
TextView txt_team1 = (TextView) rowView.findViewById(R.id.txt_team2);
TextView txt_team2 = (TextView) rowView.findViewById(R.id.txt_team1);
txt_date.setText(list.get(position).date.toString());
txt_team1.setText(list.get(position).team1.toString());
txt_team2.setText(list.get(position).team2.toString());
return rowView;
}
}
MainActivity Class:
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
public List<FixtureData> fixtureArray = new ArrayList<FixtureData>();
class FixtureData extends Object{
public String date=null;
public String team1=null;
public String team2=null;
}
FixtureData fixture = new FixtureData();
fixture.date="1990";
fixture.team1="Manchester";
fixture.team2="Barcelona";
fixtureArray.add(fixture);
final CustomList adapter2 = new CustomList(MainActivity.this, fixtureArray);
liste=(ListView)findViewById(R.id.list1));
liste.setAdapter(adapter2);
liste.setItemsCanFocus(true);
liste.setFocusable(false);
liste.setFocusableInTouchMode(false);
liste.setClickable(false);
}}
its just example for problem, dont check intention.
When i use single ArrayList my Codes Working like;
final List<String> date = new ArrayList<String>();
final List<Integer> team1= new ArrayList<String>();
final List<Integer> team2= new ArrayList<String>();
but when i tried custom ArrayList like this, its not working
public List<FixtureData> fixtureArray = new ArrayList<FixtureData>();
class FixtureData extends Object{
public String date=null;
public String team1=null;
public String team2=null;
}
FixtureData fixture = new FixtureData();
fixture.date="1990";
fixture.team1="Manchester";
fixture.team2="Barcelona";
fixtureArray.add(fixture);
with this codes giving me null ListView,
How can i solve my problem?
Override the getCount method in your CustomList
#Override
public int getCount()
{
return list.size();
}
OR
change
super(context, R.layout.list_single);
to
super(context, R.layout.list_single,list);
Your first line of Program shows
public class CustomList extends ArrayAdapter< String >{
It should be :
public class CustomList extends ArrayAdapter< FixtureData >{
Your ListAdapter class should know about what type of Object its going to handle
It looks like there's a lot going on in your code, but in addition to what Brijesh mentioned about changing ArrayAdapter to ArrayAdapter, one other thing that seems to be happening is that you never set your list to your adapter. You send in your list, and call super(context, R.layout.list_single), but you didn't include your list in that call and don't separately set it later. In addition, although this is not the only way to deal with this issue, since you are using a custom list item view with multiple text views, it might be easier to just send a 0 as a placeholder for the layout resource - that's okay bc you define it later in getView(). The super constructor for ArrayAdapter expects a layout with one text view. You probably want to check out the android developer reference page for ArrayAdapter http://developer.android.com/reference/android/widget/ArrayAdapter.html so you can see what your options are and what is expected, but one option would be to just call super(context,0,list). BTW - if you want to use this.list, make sure to define it before you use it in the call to super, instead of after as you currently have it.
I am not able get onItemCickListener to work. All I am doing is opening up a fragment using intents. Please do let me know if I am doing anything fishy here ?
public class MyListFragment extends ListFragment {
private ArrayList<String> myList = null;
private ArrayAdapter<String> myAdapter;
#Override
public void onActivityCreated(Bundle savedInstanceState){
Log.d("Example:", "In Fragement Calss");
super.onActivityCreated(savedInstanceState);
Resources myResources = getResources();
myList = new ArrayList<String>(Arrays.asList(myResources.getStringArray(R.array.myExamArray)));
myAdapter = new ArrayAdapter<String>(getActivity(),android.R.layout.simple_list_item_1,myList);
setListAdapter(myAdapter);
ListView lv = (ListView) getActivity().findViewById(R.id.listView);
lv.setOnItemClickListener(new OnItemClickListener(){
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Intent myIntent = new Intent(view.getContext(), DetailsFragment.class);
startActivity(myIntent);
}
});
}
}
Note that the ListView blocks clicks of an item that contains at least one focusable
descendant but it doesn’t make the content focus-reachable calling
setItemsCanFocus(true). One workaround is by disabling focusability of descendants, using
android:descendantFocusability="blocksDescendants"
in the layout defining your list item. (First learned of this myself from http://cyrilmottier.com/2011/11/23/listview-tips-tricks-4-add-several-clickable-areas/, but a few other SO posts also point this out.) Does your layout contain buttons? If so, you'd fall into this case.
I don't see where you are inflating a specific XML for this Fragment... but it is possible you are referencing the wrong ListView.
Regardless you should use the existing onListItemClick method:
public class MyListFragment extends ListFragment {
private ArrayList<String> myList = null;
private ArrayAdapter<String> myAdapter;
#Override
public void onActivityCreated(Bundle savedInstanceState){
// Remove the OnItemClickListener, but keep everything else
}
#Override
public void onListItemClick (ListView l, View v, int position, long id) {
Intent myIntent = new Intent(this, DetailsFragment.class);
startActivity(myIntent);
}
}
Alright, so I'm new to Android programming, so far my experience has been quite interesting and challenging. But I fear I have now encountered the first problem I'm not able to overcome on my own.
Simply put, all I want to do is have 2 Spinners:
1 for country selection
1 for province/state selection
What I want to accomplish is that when the user selects his/her country the province/state Spinner is updated with the correct adapter. Currently I'm only using 2 country for testing purposes.
When I launch the Activity, I get an exception and my app crashes.
Here's my code, any pointers would be appreciated !
public class ManageAccountActivity extends Activity {
final ArrayAdapter<CharSequence> adapterSexe = ArrayAdapter.createFromResource(ManageAccountActivity.this, R.array.sex_array_fr, android.R.layout.simple_spinner_item);
final ArrayAdapter<CharSequence> adapterProvince = ArrayAdapter.createFromResource(ManageAccountActivity.this, R.array.province_array_fr, android.R.layout.simple_spinner_item);
final ArrayAdapter<CharSequence> adapterStates = ArrayAdapter.createFromResource(ManageAccountActivity.this, R.array.state_array_fr, android.R.layout.simple_spinner_item);
final ArrayAdapter<CharSequence> adapterCountry = ArrayAdapter.createFromResource(ManageAccountActivity.this, R.array.country_array_fr, android.R.layout.simple_spinner_item);
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.account_management);
Spinner spinSexe = (Spinner) findViewById(R.id.spin_sex);
Spinner spinProvince = (Spinner) findViewById(R.id.spin_province);
Spinner spinCountry = (Spinner) findViewById(R.id.spin_country);
adapterSexe.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
adapterProvince.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
adapterStates.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
adapterCountry.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinSexe.setAdapter(adapterSexe);
spinProvince.setAdapter(adapterProvince);
spinCountry.setAdapter(adapterCountry);
spinCountry.setOnItemSelectedListener(new CountryOnItemSelectedListener());
}
public class CountryOnItemSelectedListener implements OnItemSelectedListener {
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
setContentView(R.layout.account_management);
Spinner spinProvince = (Spinner) view.findViewById(R.id.spin_province);
if (parent.getItemAtPosition(pos).toString().equals("Canada")) {
spinProvince.setAdapter(adapterProvince);
} else {
spinProvince.setAdapter(adapterStates);
}
}
public void onNothingSelected(AdapterView parent) {
// Do nothing.
}
}
}
Here's the LogCat message I'm getting.
01-10 20:41:01.024: E/AndroidRuntime(1275):
java.lang.RuntimeException: Unable to instantiate activity
ComponentInfo{gggolf.android.minutegolf/gggolf.android.minutegolf.ManageAccountActivity}:
java.lang.NullPointerException
You cannot instantiate your ArrayAdapter directly on class attribut, because createFromResource() use Context, and it's not exists at this time, do it in onCreate() methode instead.
In addition, you get spin province wrong in your listener, you can't call findViewById on view local variable, because it's not your layout, but an inflate of android.R.layout.simple_spinner_item
The good way:
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
Spinner spinProvince = (Spinner) findViewById(R.id.spin_province);
if (parent.getItemAtPosition(pos).toString().equals("Canada")) {
spinProvince.setAdapter(adapterProvince);
} else {
spinProvince.setAdapter(adapterStates);
}
}
Try having your Activity implement AdapterView.OnItemSelectedListener itself. Notice I've moved the Spinners and left out some of your code and replaced it with comments - make sure you include it where necessary...
public class ManageAccountActivity extends Activity
implements AdapterView.OnItemSelectedListener {
// Your ArrayAdapters as before
Spinner spinSexe = null;
Spinner spinProvince = null;
Spinner spinCountry = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.account_management);
spinSexe = (Spinner) findViewById(R.id.spin_sex);
spinProvince = (Spinner) findViewById(R.id.spin_province);
spinCountry = (Spinner) findViewById(R.id.spin_country);
// Call setDropDownViewResource on your ArrayAdapters
// Call setAdapter on your Spinners
spinCountry.setOnItemSelectedListener(this);
}
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
if (parent.getItemAtPosition(pos).toString().equals("Canada")) {
spinProvince.setAdapter(adapterProvince);
} else {
spinProvince.setAdapter(adapterStates);
}
}
public void onNothingSelected(AdapterView parent) {
}
}
Why do you have setContentView(R.layout.account_management); in your onItemSelected() method? That should not be necessary.
Furthermore, you should instantiate your adapters in the onCreate() method of your activity, and pass your actual activity instance as the context.
And the code for retrieving the Spinner object in the select listener should be changed from
Spinner spinProvince = (Spinner) view.findViewById(R.id.spin_province);
into
Spinner spinProvince = (Spinner) findViewById(R.id.spin_province);
Calling findViewById() on the local view object in your select listener will return NULL because the view does not contain the Spinner.
I am trying to change textview properties of a textview that looks like this:
In a seperate Activity that looks like this:
I tried to do this with bundles but I can't get it to work.
This is how my BookActivity looks like:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.book_activity);
//this is where the size property comes in
Integer size = getIntent().getExtras().getInt("SGRkey");
TextView test2 = (TextView) findViewById(R.id.booktext);
test2.setTextSize(size);
Spinner spinner = (Spinner) findViewById(R.id.kapitelspinner);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this, R.array.kapitel_array, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(new MyOnItemSelectedListener());
}
public class MyOnItemSelectedListener implements OnItemSelectedListener {
public void onItemSelected(AdapterView<?> parent,
View view, int pos, long id) {
Toast.makeText(parent.getContext(),
parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show();
final String[] theporn = getResources().getStringArray(R.array.allkapitel);
TextView text = (TextView) findViewById(R.id.booktext);
text.setText(theporn[pos]);
}
public void onNothingSelected(AdapterView parent) {
// Do nothing.
}
(i pick the chapter string in the spinner and that works just fine.)
And this is how my SettingsActivity looks like:
public class SettingsActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.settings_view);
Spinner SGRspinner = (Spinner) findViewById(R.id.schriftgroeße_spinner);
ArrayAdapter<CharSequence> SGRadapter = ArrayAdapter.createFromResource(
this, R.array.schriftgroesse_list, android.R.layout.simple_spinner_item);
SGRadapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
SGRspinner.setAdapter(SGRadapter);
}
public class SGROnItemSelectedListener implements OnItemSelectedListener {
public void onItemSelected(AdapterView<?> parent,
View view, int pos, long id) {
Intent answer = new Intent();
Toast.makeText(parent.getContext(),
parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show();
final String[] SGRstring = getResources().getStringArray(R.array.schriftgroesse_list);
int SGRint = Integer.parseInt(SGRstring[pos]);
Bundle size = new Bundle();
size.putInt("SGRkey", SGRint);
Intent nextActivity = new Intent(com.asm.reader.SettingsActivity.this, com.asm.reader.BookActivity.class);
nextActivity.putExtras(size);
com.asm.reader.SettingsActivity.this.startActivity(nextActivity);
}
public void onNothingSelected(AdapterView parent) {
// Do nothing.
}
}
I get an error when I try this. All activities are declared in the manifest. I really don't know how to go on. I'm pretty new to this, so sorry if this is something simple, but any help would be greatly appreciated!! :-)
Make your textview static. That is, declare it as a public static class variable. Then you can call it directly from the other activity like this: firstActivity.myTextView.setText("foo");