I have a ListView.
I populate this list from 2 editTexts
When I move activity and go back to it the entries are gone again.
I kind of understand why this is but dont know how to correct it.
ListView lv2 = (ListView) findViewById(R.id.listView2);
final SimpleAdapter simpleAdpt = new SimpleAdapter(this, planetsList, android.R.layout.simple_list_item_1, new String[]{"planet"}, new int[]{android.R.id.text1});
planetsList.add(createPlanet("planet", "testme"));
lv2.setAdapter(simpleAdpt);
button21.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
iinitList();
simpleAdpt.notifyDataSetChanged();
editText5.setText("");
editText6.setText("");
}
});
}
private void iinitList() {
String st,str;
Double db;
if (editText5.getText().toString()!= "" && editText6.getText().toString()!="") {
st = editText5.getText().toString();
str = editText6.getText().toString();
db = Double.parseDouble(str);
planetsList.add(createPlanet("planet", ""+st+
": \n" +db+""));
}
}
HashMap<String, String> createPlanet(String key, String name) {
HashMap<String, String> planet = new HashMap<String, String>();
planet.put(key, name);
return planet;
}
As you can see I have added a value to the list manually called test also, when I move activity this stays in the list, I would love if the editText entries were to stay in there also when I move activities.
Activities can be destroyed when you navigate to a new one or rotate. This will clear anything that is only referenced by the activity, like your EditTexts. However, Android provides a nice utility for saving things you want to remain in a method called, which you can override in your activity:
#Override
protected void onSaveInstanceState(Bundle state) {
// Put your values in the state bundle here
}
#Override
protected void onCreate(Bundle savedState) {
// Load your UI elements as usual
if (savedState != null) {
// Load your state from the bundle
}
}
That same bundle will be given back to you in onCreate, where you create your UI to begin with so you can reload the state from it.
This is a really good description of how activities work:
http://developer.android.com/reference/android/app/Activity.html
Related
I am currently building an Android app where I display quotes from famous people. I have a home screen and 2 other screens, where I am displaying all quotes and the other where I display favourite quotes.
So, when I hit the like button in the screen of AllQuotesActivity the quote and author will be saved in a LinkedHashSet, which will be saved in SharedPreferences, so my FavouriteQuotes Activity can obtain the data. I can obtain the data, but the data is mixed, even though other links say that LinkedHashSet maintains the insertion order. Maybe I did something wrong. Here are the important code snippets:
AllQuotesActivity.java:
SharedPreferences sharedPref;
Set<String> set = new LinkedHashSet();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.all_quotes);
Resources res = getResources();
Context context = getApplicationContext();
this.sharedPref = context.getSharedPreferences(
"MyPref", Context.MODE_PRIVATE);
final String[] quotesAndAuthors = res.getStringArray(R.array.quotes);
button3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
set.add(quotesAndAuthors[counter]);
set.add(quotesAndAuthors[counter + 1]);
}
});
}
#Override
public void onPause() {
super.onPause();
Log.d("RichQuotes", "Its paused mkay");
Editor editor = sharedPref.edit();
editor.putStringSet("quotesAndAuthors", this.set);
editor.commit();
}
}
FavouriteQuotesActivity.java:
SharedPreferences sharedPref;
Set<String> set = new LinkedHashSet();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.favourite_quotes);
Resources res = getResources();
Context context = getApplicationContext();
this.sharedPref = context.getSharedPreferences(
"MyPref", Context.MODE_PRIVATE);
set = sharedPref.getStringSet("quotesAndAuthors", null);
for (Iterator<String> it = set.iterator(); it.hasNext(); ) {
String s = it.next();
Log.v("test", s);
}
I removed unnecessary code.
In the FavouriteQuotesActivity.java I am logging the set to check its values. The log-outputs and the outputs on the screen are the same, both unsorted the same way.
Set set = new LinkedHashSet();
In this line, you instantiate a new empty LinkedHashSet object. This object was then assigned to the variable named set.
set = sharedPref.getStringSet("quotesAndAuthors", null);
In this line, you reassigned the set variable to point to some other object, some Set object returned by your call to getStringSet. We do not know the concrete class of this second object that implements the Set interface. You can ask by calling getClass.
Your first set, the empty LinkedHashSet, went unused. With no other references pointing to it, that set became a candidate for eventual garbage-collection.
I'm writing a simple program to request a JOSN request of a list of earthquakes to display for users. I use Asynctask to put the request in the background thread and use an ArrayList Adaptor to display the relevant information. I declare an empty ArrayList and then extract the JOSN request and put them in a temporary list and then assign the temporary list to the empty ArrayList.
I use a debugger tool to see that in the updateEarthquakeList method. I set the break point in the updateEarthquakeList method. this.earthquak and earthquakes both have 10 elements. Pics are as follow:
But when I set the break point after task.execute(USGS_REQUEST_URL) in the onCreate method, I got this:
As the pics shown after execute the AsyncTask the ArrayList is empty. But inside the AsyncTask The array was actually updated. (To do a little experiment I create an int haha as 0 and change it to 1 in the Asynctask, but it changed back to 0 afterwards)
How is this happen and how do I supposted to make it right?
public class EarthquakeActivity extends AppCompatActivity {
public static final String LOG_TAG = EarthquakeActivity.class.getName();
ArrayList<Earthquake> earthquak = new ArrayList<Earthquake>();
int haha = 0;
private static final String USGS_REQUEST_URL = "http://earthquake.usgs.gov/fdsnws/event/1/query?format=geojson&eventtype=earthquake&orderby=time&minmag=6&limit=10";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.earthquake_activity);
EarthquakeAsyncTask task = new EarthquakeAsyncTask();
task.execute(USGS_REQUEST_URL);
// Create a fake list of earthquake locations.
// Find a reference to the {#link ListView} in the layout
ListView earthquakeListView = (ListView) findViewById(R.id.list);
// Create a new {#link ArrayAdapter} of earthquakes
EarthquakeAdapter adapter = new EarthquakeAdapter(this, earthquak);
// Set the adapter on the {#link ListView}
// so the list can be populated in the user interface
earthquakeListView.setAdapter(adapter);
//OPEN a web page of a specific when textview is clicked.
earthquakeListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent intent = new Intent(Intent.ACTION_VIEW, earthquak.get(position).getUrl());
if (intent.resolveActivity(getPackageManager()) != null) {
startActivity(intent);
}
}
});
}
private void updateEarthquakeList(ArrayList<Earthquake> earthquake) {
this.earthquak = earthquake;
haha = 1;
}
private class EarthquakeAsyncTask extends AsyncTask<String, Void, ArrayList<Earthquake>> {
#Override
protected ArrayList<Earthquake> doInBackground(String... urls) {
if (urls.length < 1 || urls[0] == null) {
return null;
}
ArrayList<Earthquake> earthquakes = QueryUtils.fetchEarthquakeData(urls[0]);
return earthquakes;
}
#Override
protected void onPostExecute(ArrayList<Earthquake> earthquakes) {
updateEarthquakeList(earthquakes);
}
}
I am creating an android dictionary app with sounds... I have listview, when an item is selected, a new activity open, inside the new activity contains 4 textviews and an image button, the textviews function perfectly but the image button was not. The audio files are placed in raw folder. How can I put the specific sounds of an item that was clicked?
Here's the code:
MainActivityJava
public class MainActivity extends AppCompatActivity {
ListView lv;
SearchView sv;
String[] tagalog= new String[] {"alaala (png.)","araw (png.)","baliw (png.)","basura (png.)",
"kaibigan (png.)","kakatuwa (pu.)", "kasunduan (png.)","dambuhala (png.)",
"dulo (png.)","gawin (pd.)","guni-guni (png.)","hagdan (png.)","hintay (pd.)",
"idlip (png.)","maganda (pu.)","masarap (pu.)", "matalino (pu.)"};
int[] sounds= new int[]{R.raw.alaala,
R.raw.araw,
R.raw.baliw,
R.raw.basura,
R.raw.kaibigan,
R.raw.kakatuwa,
R.raw.kasunduan,
};
ArrayAdapter<String> adapter;
#TargetApi(Build.VERSION_CODES.HONEYCOMB)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv = (ListView) findViewById(R.id.listView1);
sv = (SearchView) findViewById(R.id.searchView1);
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,tagalog);
lv.setAdapter(adapter);
lv.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String tagword =tagalog[position];
String[] definition = getResources().getStringArray(R.array.definition);
final String definitionlabel = definition[position];
String[] cuyuno = getResources().getStringArray(R.array.cuyuno);
final String cuyunodefinition = cuyuno[position];
String[] english = getResources().getStringArray(R.array.english);
final String englishdefinition = english[position];
Intent intent = new Intent(getApplicationContext(), DefinitionActivity.class);
intent.putExtra("tagword", tagword);
intent.putExtra("definitionlabel", definitionlabel);
intent.putExtra("cuyunodefinition",cuyunodefinition);
intent.putExtra("englishdefinition", englishdefinition);
startActivity(intent);
}
});
sv.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
#Override
public boolean onQueryTextSubmit(String text) {
return false;
}
#Override
public boolean onQueryTextChange(String text) {
adapter.getFilter().filter(text);
return false;
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
return super.onCreateOptionsMenu(menu);
}
}
DefinitionActivity.java
public class DefinitionActivity extends AppCompatActivity {
MediaPlayer mp;
String tagalogword;
String worddefinition;
String cuyunoword;
String englishword;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_definition);
TextView wordtv = (TextView) findViewById(R.id.wordtv);
TextView definitiontv = (TextView) findViewById(R.id.definitiontv);
TextView cuyunotv = (TextView) findViewById(R.id.cuyunotv);
TextView englishtv = (TextView) findViewById(R.id.englishtv);
ImageButton playbtn = (ImageButton) findViewById(R.id.playbtn);
final Bundle extras = getIntent().getExtras();
if (extras != null) {
tagalogword = extras.getString("tagword");
wordtv.setText(tagalogword);
worddefinition = extras.getString("definitionlabel");
definitiontv.setText(worddefinition);
cuyunoword = extras.getString("cuyunodefinition");
cuyunotv.setText(cuyunoword);
englishword = extras.getString("englishdefinition");
englishtv.setText(englishword);
}
playbtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
}
});
}
you can pass the raw id in the intent extra and play it on meadiaPlayer
What you want to accomplish is pretty simple.
you can ofcourse pass the id.
But I created this method for your case you can paste it in your activity or class and make a call to it. In my case, I put this method in a class that holds all the common functions, methods, strings, etc. The choice is yours :
public static void playDisSound(Context c, int soundID){
//Play short tune
MediaPlayer mediaPlayer = MediaPlayer.create(c, soundID);
mediaPlayer.setOnCompletionListener( new OnCompletionListener(){
#Override
public void onCompletion( MediaPlayer mp){
mp.release();
}
});
mediaPlayer.start();
}
And this is how to use it in your case :
Example I want to play an audio track from :
int[] sounds= new int[]{R.raw.alaala,
R.raw.araw,
R.raw.baliw,
R.raw.basura,
R.raw.kaibigan,
R.raw.kakatuwa,
R.raw.kasunduan,
};
So I just do :
//TODO ~ pls. remember to define context inside "onCreate" as
//call this before "onCreate"
Context context;
//And do this inside "onCreate" :
context = getApplicationContext();
OR
context = MainActivity.this;
//Then here comes the solution, just make a call to the playDisSound method with the id , in this case the "sounds[postion_referencer_i]"
playDisSound(context, sounds[postion_referencer_i]);
//And now on the question of what your "position_referencer_i" would be .... it also depends on how you intend to pass the id.
Are your going to make a match between the position picked and the position of the sound. It depends on you. But I would have created a set of integers to signify which try I want to play and do a matching simple calculation between the position picked for the item clicked to arrive at the position_referencer_id.
//But simply : note that in your array if I want to play for example "R.raw.baliw" I would just call :
playDisSound(context, R.raw.baliw);
I hope this works perfectly for you. So if I elaborated too much. Do let me know if you may need to stream the sound so I would just paste/send you a very cool method I have been using here in an app am working.
//FINALLY PLS. Remember this : this method would play the sound alright but it wont hesitate to play the sound all over again if you repeat the process. So do remember to check if the sound did play and finished before allowing the user to repeat, if not it could lead to repeated or kind of two speakers playing from the same song but at different time. (And the user may start to think that there is problem with the app. Pls. be very logical and sensitive in using this method)
In solving that, you can disable the button or the UI element that initiates the sound playing until the sound has finished playing, by way of monitoring duration of the track (which I am sure you should know and inculcate into your logic or by simply listening if sound is already playing)
All the best. Era. :)
My program is that when a user enteres some information and clicks the "Submit" button, this data will be stored in a separate activity's list View.I have a Shared Preferences incorporated so that the data will be stored. The problem is that only one piece of information gets stored at a time. If I enter a new piece of data, the previous one is overwritten.
public class PreviousPractices extends Activity {
int minutes,hours;
String description;
String date;
ListView practiceList;
ArrayAdapter<String> adapter;
ArrayList<String> listItems = new ArrayList<String>();
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.previous_practices_layout);
practiceList=(ListView)findViewById(R.id.practiceList);
adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1,listItems);
practiceList.setAdapter(adapter);
getIntents();
LoadPreferences();
}
public void getIntents(){
if (getIntent().getExtras() == null) {
}
else {
Bundle extras = getIntent().getExtras();
hours = extras.getInt("Hours");
minutes = extras.getInt("Minutes");
description = extras.getString("Description");
date = extras.getString("dateOfPractice");
adapter.notifyDataSetChanged();
SavePreferences("LISTS", date);
}
}
Right now I'm only working with the date to simplify things. I'm not sure what the issue is, and I'd appreciate some help.
I have a ListView in a ListFragment that is populated via a database query. It loads all the data just fine when it first populates the list in onCreate(). But when I requery the database, assign the return value to assignmentsCursor, and call notifyDataSetChanged(), it doesn't update adapter.mCursor. If I go into the Debugging mode in Eclipse I can see that assignmentsCursor.mCount has changed, but when I look at adapter.mCursor.mCount, it's the same as before. (Yes, I'm checking after notifyDataSetChanged() has been called.)
The relevant parts of my code:
SimpleCursorAdapter adapter;
Cursor assignmentsCursor;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState != null) {
course = savedInstanceState.getShort(Values.ASSIGNMENT_KEY_COURSE);
}
setRetainInstance(true);
// Create and array to specify the fields we want
String[] from = new String[] { Values.KEY_TITLE, Values.ASSIGNMENT_KEY_COURSE };
// and an array of the fields we want to bind in the view
int[] to = new int[] { R.id.assignment_list_title, R.id.assignment_list_course };
// Need to give assignmentsCursor a value -- null will make it not work
updateAdapter();
adapter = new SimpleCursorAdapter(context, R.layout.assignment_list_item, assignmentsCursor, from, to);
setListAdapter(adapter);
}
public void onResume() {
super.onResume();
updateAdapter();
refresh();
}
/**
* Updates the content in the adapter.
*/
public void updateAdapter() {
SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(context);
boolean showingCompleted = sharedPrefs.getBoolean(Values.ASSIGNMENT_KEY_SHOWING_COMPLETED, false);
if (course < 0) // Showing assignments from all courses
if (showingCompleted)
assignmentsCursor = DbUtils.fetchAllAssignments(context, Values.ASSIGNMENT_LIST_FETCH, null, true);
else
assignmentsCursor = DbUtils.fetchIncompleteAssignments(context, Values.ASSIGNMENT_LIST_FETCH, null, true);
else // Showing assignments from specified course
if (showingCompleted)
assignmentsCursor = DbUtils.fetchAllAssignments(context, Values.ASSIGNMENT_LIST_FETCH, course, true);
else
assignmentsCursor = DbUtils.fetchIncompleteAssignments(context, Values.ASSIGNMENT_LIST_FETCH, course, true);
}
private void refresh() {
updateAdapter();
adapter.notifyDataSetChanged();
}
Help me!! ;)
P.S. If you need any more details/code, just let me know. I am positive that the database is querying correctly though.
Thanks to Deucalion, I have determined that I incorrectly assumed that the adapter was referencing the assignmentsCursor variable as opposed to creating a copy of the Cursor for itself. What I needed to do was just call adapter.changeCursor(assignmentsCursor) so that it updated its local copy. Thanks again Deucalion!