I used to program in iOS language where every UIView class has its own UIViewController class to manage/populate the view itself. I'm trying now to write a simple android app that parse a JSONArray from url and then populate four views but I don't know how to implement a class for every view and pass them the strings parameters to populate them. Could you tell me what is the best way to implement the logic of the app? I have the new project with swipable-tabs then I have to use fragments. Are these fragments the same as the UIView in iOS? Help me please.
I did this, I would like to know if it is correct. I created a new Project with Blank activity and "Scrollable Tabs + Swipe" as Navigation type.
My main activity:
public class MyMainActvity extends FragmentActivity {
private static String url = "http://www.myurl.it";
static JSONObject jObj = null;
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
* will keep every loaded fragment in memory. If this becomes too memory
* intensive, it may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_activity);
new JSONParse().execute();
// Create the adapter that will return a fragment for each of the three
// primary sections of the app.
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main_activity, menu);
return true;
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a DummySectionFragment (defined as a static inner class
// below) with the page number as its lone argument.
switch (position) {
case 0:
{
HomeSection homeFrag= new HomeSection();
homeFrag.newInstance(jObj);
return homeFrag;
}
case 1:
{
ServiceSection servFrag= new ServiceSection();
servFrag.newInstance(jObj);
return servFrag;
}
case 2:
{
Fragment fragment = new DummySectionFragment();
Bundle args = new Bundle();
args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
fragment.setArguments(args);
return fragment;
}
case 3:
{
Fragment fragment = new DummySectionFragment();
Bundle args = new Bundle();
args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
fragment.setArguments(args);
return fragment;
}
}
return null;
}
@Override
public int getCount() {
// Show 4 total pages.
return 4;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.title_section1).toUpperCase(l);
case 1:
return getString(R.string.title_section2).toUpperCase(l);
case 2:
return getString(R.string.title_section3).toUpperCase(l);
case 3:
return getString(R.string.title_section4).toUpperCase(l);
}
return null;
}
}
/**
* A dummy fragment representing a section of the app, but that simply
* displays dummy text.
*/
public static class DummySectionFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
public static final String ARG_SECTION_NUMBER = "section_number";
public DummySectionFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(
R.layout.fragment_dummy, container, false);
TextView dummyTextView = (TextView) rootView
.findViewById(R.id.section_label);
dummyTextView.setText(Integer.toString(getArguments().getInt(
ARG_SECTION_NUMBER)));
return rootView;
}
}
private class JSONParse extends AsyncTask<String, String, JSONArray> {
private ProgressDialog pDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(MyMainActivity.this);
pDialog.setMessage("Getting Data ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected JSONArray doInBackground(String... args) {
JSONParser jParser= new JSONParser();
JSONArray json =jParser.getJSONFromUrl(url);
return json;
}
@Override
protected void onPostExecute(JSONArray json) {
pDialog.dismiss();
Log.d("JSONARRAY:", json.toString());
try {
JSONObject json_data = json.getJSONObject(0);
jObj= json_data;
mSectionsPagerAdapter = new SectionsPagerAdapter(
getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
}
catch(JSONException exception) {
Log.e("ERROR", exception.getMessage());
}
}
}
}
And this is one one my subclassed Fragments:
public class HomeSection extends Fragment {
JSONObject _jObj;
public HomeSection(){}
public void newInstance(JSONObject jObj) {
Bundle args = new Bundle();
_jObj= jObj;
try{
String content= _jObj.getString("descrizione");
args.putString("description", content);
}
catch(JSONException exception){
Log.e("ERROR JSON HOME", exception.getMessage());
}
// Put any other arguments
this.setArguments(args);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(
R.layout.fragment_dummy, container, false);
TextView dummyTextView = (TextView) rootView
.findViewById(R.id.section_label);
try {
dummyTextView.setText(_jObj.getString("descrizione"));
}
catch(JSONException exception){
Log.e("ERROR JSON HOME", exception.getMessage());
}
return rootView;
}
}
It works but I would like if it is a correct way to populate the views in my app. Then I didn't know if in the HomeSection class, the Bundle that I created in the "newIstance" method is effectively necessary because I set my text in the view within the method onCreateView. Could you help me please? Thanks
