Develop Reference

Back button restores modified text Views

I will simplify my code to address the problem specifically:
I have an activity A with some TextViews, which text is set to certain key values stored in SharedPreferences, in the activity's OnCreate method. Each textview has a button besides it. When a button is clicked it opens a new activity B which displays an adapter with different text strings. When the user clicks one, the new string is stored in preferences and the user is directed back to Activity A through an intent, and so OnCreate method is called and the textview is updated with the selected text. This works perfectly.
However, my problem is:
When a user does this and updates the textview, if they press Back button once, it will take them to Activity B, but if pressed twice that will take them to Activity A before updating the TextView and thus displaying the old textview, despite having stored in SharedPreferences the updated value. How can this be fixed?
A more simplified version of my problem is, I have a TextView in my layout, and a button which if pressed, deletes it and refreshes the Activity. User presses the delete button, text view disappears, but then presses back button and TextView is restored. That's what I dont want.
I have researched all the back button methodologies and savedInstanceState documentation but I still havent found something that works. I also tried adding an UpNavigation button in my action bar but it does the same effect than the back button.
ACTIVITY A (All these bits of code are called in OnCreate)
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
String sound1name = prefs.getString("sound1", "1");
TextView sound1TV = findViewById(R.id.sound1);
sound1TV.setText(sound1Name);
ImageView sound1btn = findViewById(R.id.sound1_btn);
sound1btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent1 = new Intent(getApplicationContext(), SoundSelector.class);
startActivity(intent1);
}
});
ACTIVITY B (calls adapter)
AudioFileAdapter aFilesAdapter = new AudioFileAdapter(SoundSelector.this, audioFileList, soundID);
ListView listView = findViewById(R.id.sounds_list);
listView.setAdapter(aFilesAdapter);
ADAPTER IN ACTIVITY B (OnClickListener when text is selected)
SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(contextL);
SharedPreferences.Editor editor = settings.edit();
editor.putString("sound1", sound1string);
editor.apply();
Intent intent1 = new Intent(getContext(), SoundEditor.class);
con.startActivity(intent1);
Im not sure if it is the Activity Lifecycle I have to modify, or intents, or something else but if someone could point me in the right direction I would really appreciate it, if you need any more information or code I'll post as soon as possible.

For storing and retrieving shared preferences try the following:
Storing
SharedPreferences preferences = getSharedPreferences("com.appname", Context.MODE_WORLD_WRITEABLE);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("sound1", "YOUR STRING HERE");
editor.apply();
Retrieving
SharedPreferences prfs = getSharedPreferences("com.appname", Context.MODE_PRIVATE);
String soundString = prfs.getString("sound1", "");
Your intent looks fine, are you sure you're passing Activity A's name?
For your second scenario, you could store if the text view was deleted in the shared preference, so when the back button is pressed, it won't display it again in the previous activity.
Something like this
if (isDeleted.equals("Yes")) {
textView.setVisibility(View.INVISIBLE);
}

The way Activity B is navigating back to Activity A by restarting the activity in the front and not by onBackPressed() navigation. Besides if the navigation is an important component to update the string value then the recommended method would be to use startActivityForResult() and update the preference and the TextView upon onActivityResult() of Activity A
class ActivityA extends AppCompatActivity {
private static final int activityRequest = 0x22;
public static final String keyPref = "keyToSharedPrefData";
private TextView mTextView;
private boolean isHidden = false;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.a_activity);
mTextView = findViewById(R.id.someTextView);
final String textForTextView = SharedPrefUtils.getString(keyPref);
mTextView.setText(textForTextView);
final Button button = findViewById(R.id.someButton);
if (button != null) {
button.setOnClickListener((view) -> {
final Intent intent = new Intent(ActivityA.this, AcitivtyB.class);
startActivityForResult(intent, activityRequest);
});
}
final deleteButton = findViewById(R.id.delete_button);
if (deleteButton != null) {
deleteButton.setOnClickListener((view) -> {
mTextView.setText("");
isHidden = true;
});
}
}
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data){
if (requestCode == activityRequest && resultCode == ActivityB.resultSuccess && data != null) {
if (data.containsKey(ActivityB.resultKey)) {
SharedPrefUtils.saveString(keyPref,
data.getString(ActivityB.resultKey, SharedPrefUtils.getString(keyPref));
if (mTextView != null) {
mTextView.setText(SharedPrefUtils.getString(keyPref));
}
}
}
if (isHidden) {
mTextView.setVisibility(View.GONE);
}
}
}
in ActivityB you can
class ActivityB extends AppCompatActivity {
public static final int resultSuccess = 0x11
public static final int resultFailure = 0x33
public static final String resultKey = "keyForResult"
private void onListItemClick(final String soundString) {
// optional you can also do this
SharedPrefUtils.saveString(ActivityA.keyPref, soundString);
// better to do this
final Intent returnIntent = getIntent() != null ? getIntent() : new Intent();
returnIntent.putExtra(resultKey, soundString);
if (getCallingActivity() != null) {
setResult(returnIntent, resultSuccess);
}
onBackPressed();
}
}

How can I store ArrayList<Class> in SharedPreferences to store game progress?

I'm new to android development and I am creating an android application that works like "4 Pics 1 Word" for my project. I'm having difficulties in storing ArrayList in SharedPreferences or in the internal storage of the android phone. The reason why is because I am randomizing the next activity using random generator and ArrayList. Any suggestions or ideas that my help my case? Thank you in advance! I've been stuck here for hours now.
This is my MainActivity
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
Button btnStart;
Context context;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btnStart = (Button) findViewById(R.id.btnStart);
btnStart.setOnClickListener(this);
}
#Override
public void onClick(View v) {
// We are creating a list, which will store the activities that haven't been opened yet
ArrayList<Class> activityList = new ArrayList<>();
activityList.add(first.class);
activityList.add(second.class);
activityList.add(third.class);
activityList.add(fourth.class);
activityList.add(fifth.class);
Random generator = new Random();
int number = generator.nextInt(5) + 1;
Class activity = null;
// Here, we are checking to see what the output of the random was
switch(number) {
case 1:
activity = first.class;
// We are adding the number of the activity to the list
activityList.remove(first.class);
break;
case 2:
activity = second.class;
activityList.remove(second.class);
break;
case 3:
activity = third.class;
activityList.remove(third.class);
break;
case 4:
activity = fourth.class;
activityList.remove(fourth.class);
break;
default:
activity = fifth.class;
activityList.remove(fifth.class);
break;
}
// We use intents to start activities
Intent intent = new Intent(getBaseContext(), activity);
// `intent.putExtra(...)` is used to pass on extra information to the next activity
intent.putExtra("ACTIVITY_LIST", activityList);
startActivity(intent);
}
}
And here's my first activity:
public class first extends AppCompatActivity implements View.OnClickListener{
EditText etAnswer;
Button btnGo;
Context context;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_first);
etAnswer = (EditText) findViewById(R.id.etAnswer);
btnGo = (Button) findViewById(R.id.btnGo);
btnGo.setOnClickListener(this);
}
#Override
public void onClick(View v) {
switch(v.getId()){
case R.id.btnGo:
String answer = etAnswer.getText().toString();
if(answer.equals("Jose Rizal") || answer.equals("jose rizal") || answer.equals("Rizal") || answer.equals("rizal") ){
AlertDialog.Builder dlgAlert = new AlertDialog.Builder(this);
dlgAlert.setMessage("The famous Rizal monument in Luneta was not the work of a Filipino but a Swiss sculptor named Richard Kissling?" +
"Source: http://www.joserizal.ph/ta01.html");
dlgAlert.setTitle("Did you know that ...");
dlgAlert.setPositiveButton("Next",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
ArrayList<Class> activityList = new ArrayList<>();
Bundle extras = getIntent().getExtras();
activityList = (ArrayList<Class>) extras.get("ACTIVITY_LIST");
if(activityList.size() == 0) {
Context context = getApplicationContext();
CharSequence last = "Congratulations! You just finished the game! Please wait for the next update!";
int durationFinal = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(context, last, durationFinal);
toast.show();
} else {
// Now, the random number is generated between 1 and however many
// activities we have remaining
Random generator = new Random();
int number = generator.nextInt(activityList.size()) + 1;
Class activity = null;
// Here, we are checking to see what the output of the random was
switch(number) {
case 1:
// We will open the first remaining activity of the list
activity = activityList.get(0);
// We will now remove that activity from the list
activityList.remove(0);
break;
case 2:
// We will open the second remaining activity of the list
activity = activityList.get(1);
activityList.remove(1);
break;
case 3:
// We will open the third remaining activity of the list
activity = activityList.get(2);
activityList.remove(2);
break;
case 4:
// We will open the fourth remaining activity of the list
activity = activityList.get(3);
activityList.remove(3);
break;
default:
// We will open the fifth remaining activity of the list
activity = activityList.get(4);
activityList.remove(4);
break;
}
// Note: in the above, we might not have 3 remaining activities, for example,
// but it doesn't matter because that case wouldn't be called anyway,
// as we have already decided that the number would be between 1 and the number of
// activities left.
// Starting the activity, and passing on the remaining number of activities
// to the next one that is opened
Intent intent = new Intent(getBaseContext(), activity);
intent.putExtra("ACTIVITY_LIST", activityList);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);
}
}
});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
}else{
Context context = getApplicationContext();
CharSequence text = "Wrong! Try Again.";
int duration = Toast.LENGTH_SHORT;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
break;
}
}
}

Okay, this is a horrible hack and I don't endorse it in any way, but since you are so close to finishing your app, I propose a workaround:
Instead of storing an ArrayList<Class> in your SharedPreferences (which is impossible), store a HashSet<String> containing the fully qualified names of your classes via putStringSet().
In order to get the String representations of the fully qualified names of your classes you need to call getName(), e.g. first.class.getName().
Then, you can get your Set<String> from SharedPreferences using getStringSet() and create a Class instance for each String in that set via Class.forName().

Android: send data from adapter class to Activity

I want to add pictures to my favorite activity when a user tap on a picture. So far I'm able to get the data and display it but for some reason whenever I tap on an image it displays the favorited image, however, when I recheck the favorite activity by clicking on it, it shows empty.
Here's the little flow chart.
imageOnTap is implemented on RecyclerAdapter class. I have my Favorite activity and MainActivity.Any help would be appreciated. Thanks
Here's my MyRecyclerAdapter class
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.nameTxt.setText(albums.get(position).getName());
holder.img.setImageResource(albums.get(position).getImage());
//listener
holder.setItemClickListener(new ItemClickListener() {
#Override
public void onItemClick(View v, int pos) {
Toast.makeText(c,albums.get(pos).getName() + " ,added to favorite ",Toast.LENGTH_SHORT).show();
SharedPreferences settings = c.getSharedPreferences(PREFS_NAME,0);
SharedPreferences.Editor editor = settings.edit();
editor.putInt("favorite",albums.get(pos).getImage());
editor.commit();
Toast.makeText(c,albums.get(pos).getName() + " ,added to favorite ",Toast.LENGTH_SHORT).show();
Intent intent = new Intent(c, favorite.class);
// intent.putExtra(Intent.EXTRA_TEXT, albums.get(pos).getImage());
c.startActivity(intent);
}
});
}
Here's my favorite activity
public class favorite extends AppCompatActivity {
int favImage;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_favorite);
ImageView displayImage = (ImageView) findViewById(R.id.movieImage);
SharedPreferences settings = getSharedPreferences(PREFS_NAME,0);
displayImage.setImageResource(settings.getInt("Favorite", 0));
// Intent intent = getIntent();
// if (intent.hasExtra(Intent.EXTRA_TEXT)) {
// favImage = intent.getIntExtra(Intent.EXTRA_TEXT,image);
// displayImage.setImageResource(favImage);
//
// }
}
}
Here's my MainActivity
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_favorite) {
Intent intent = new Intent(this,favorite.class);
startActivity(intent);
}

If you are checking favourite activity from nav menu then it will not display anything afterall you are not passing any intent extras in it. Is it being display when you click the image? Are you getting intent params null here?

Use those preferences:
SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(ctx.getApplicationContext());
In your case it might be different activities observe different areas of settings.
THAT IS:
use:
SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(ctx.getApplicationContext());
SharedPreferences.Editor editor = settings.edit();
editor.putInt("favorite",albums.get(pos).getImage());
editor.commit();
instead of:
SharedPreferences settings = c.getSharedPreferences(PREFS_NAME,0);
SharedPreferences.Editor editor = settings.edit();
editor.putInt("favorite",albums.get(pos).getImage());
editor.commit();
AND
this:
SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(ctx.getApplicationContext());
displayImage.setImageResource(settings.getInt("Favorite", 0));
instead of:
SharedPreferences settings = getSharedPreferences(PREFS_NAME,0);
displayImage.setImageResource(settings.getInt("Favorite", 0));

Have an OnBackPressed() alert box to appear only for 2 out of the 3 fragments

I am looking for a way to have an "Are you sure you have finished?" alert box to come up when the user presses the back navigation button whilst on the edit note and add note fragment but not whilst they're on the view note fragment. Below I have attached code from the activity which each fragment is linked to. If you need more of my code from different areas, please let me know.
public class NoteDetailActivity extends AppCompatActivity {
public static final String NEW_NOTE_EXTRA = "New Note";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_note_detail);
createAndFragment();
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
getSupportActionBar().setHomeButtonEnabled(false);
}
private void createAndFragment(){
Intent intent = getIntent();
MainActivity.FragmentToLaunch fragmentToLaunch = (MainActivity.FragmentToLaunch) intent.getSerializableExtra(MainActivity.NOTE_FRAGMENT_TO_LOAD_EXTRA);
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
switch(fragmentToLaunch){
case EDIT:
NoteEditFragment noteEditFragment = new NoteEditFragment();
setTitle(R.string.edit_fragment_title);
fragmentTransaction.add(R.id.note_container, noteEditFragment, "NOTE_EDIT_FRAGMENT");
break;
case VIEW:
NoteViewFragment noteViewFragment = new NoteViewFragment();
setTitle(R.string.view_fragment_title);
fragmentTransaction.add(R.id.note_container, noteViewFragment, "NOTE_VIEW_FRAGMENT");
break;
case CREATE:
NoteEditFragment noteCreateFragment = new NoteEditFragment();
setTitle(R.string.create_fragment_title);
Bundle bundle = new Bundle();
bundle.putBoolean(NEW_NOTE_EXTRA, true);
noteCreateFragment.setArguments(bundle);
fragmentTransaction.add(R.id.note_container, noteCreateFragment, "NOTE_CREATE_FRAGMENT");
break;
}
fragmentTransaction.commit();
}
#Override
public void onBackPressed() {
new AlertDialog.Builder(this)
.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
NoteDetailActivity.this.finish();
}
})
.setNegativeButton("No", null)
.show();
}
}

Do this by getting the fragment tag
get tag like this
Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.main_container);
String tag = fragment.getTag(); // This will return the tag of fragment
Then use if-else to do the task
if (tag.equalsIgnoreCase("Home")) {
// Open aLERT box
}else if (tag.equalsIgnoreCase("Home2")) {
// Open aLERT box
}else if (tag.equalsIgnoreCase("Home2")) {
// Open aLERT box
}else{
// dO STUFF HERE
}
Don't forget to add the tag of fragment

First of all, try refraining from taking static tags as the names of fragment. Instead,you can set fragment's name as ABCFragment.class.getSimpleName().
Now for the checks on dialogs, create a method
/**
* This method is used to get the top fragmnet on the stack
*
* #return {#link Fragment}
*/
protected final Fragment getTopFragmentStack() {
FragmentManager fm = getSupportFragmentManager();
Fragment fragment = null;
for (int entry = 0; entry < fm.getBackStackEntryCount(); entry++) {
fragment = fm.findFragmentByTag(fm.getBackStackEntryAt(entry)
.getName());
}
return fragment;
}
After this to check which fragment is visible at the moment, you can use the following code
Fragment topRunningFragment = getTopFragmentStack();
if (topRunningFragment instanceof ABCFragment) {
showDialog();
} else if (topRunningFragment instanceof ABCDFragment) {
showDialog();
} else if (topRunningFragment instanceof ABCDEFragment) {
// Do nothing
}

Linking ListView objects to layouts android

Ive searched for this all over the internet and there seems to be no simple explanation or tutorial on how to do this.
Basically, I want a layout that has a ListView where the user can click on an object and it will take them to the next layout.
In other words, using the listview as links to other layouts.
Everything Ive found on the internet has the end result of using a Toast... However I dont want a toast, i want to link to the next page.

Your question is slightly confusing so I'm going to make an assumption.
Is [LinearLayout1 LinearLayout2 Breadcrumb] suppose to be navigation or tabs that when selected insert their corresponding content into the Main Content?
If so I would suggest using fragments for each piece of content. Then when you click the navigation/tab, perform an animation of the fragment which slides the content in and out.
See the google docs for how to use fragments: http://developer.android.com/guide/components/fragments.html
See another stackoverflow answer for how to do the slide animation: Android Fragments and animation
or
http://android-developers.blogspot.com/2011/08/horizontal-view-swiping-with-viewpager.html

Here is some code that outlines how to invoke an activity following a click on a list row. Hopefully you can adapt the Toast example you mention to make this work for you.
The basic idea is that you launch a new Activity with a new Intent. You can pass any data you need from the listView row as an extra in the Intent.
final static String[] months = new String[] {"Jan","Feb","Mar"};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
R.layout.row_layout, R.id.text1, months);
setListAdapter(adapter);
}
#Override
protected void onListItemClick(ListView l, View v, int position, long id) {
int intItem = (int)id;
Intent intent= new Intent(this, SecondaryActivity.class);
intent.putExtra("MONTH", intItem);
startActivity(intent);
}

Why using ListView for it?
Each row must lead to different layout?
Its main benefits is in displaying dynamically changing data, but in your case data is constant, right?
Use vertical LinearLayout, fill it programmatically with "list elements", and add
leListComponent.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
startActivity(new Intent(YourActivity.this, TargetActivity.class));
}
});
to each.
If i didn't get it, and you feel good of using some adapter, it can be like this:
public class LeWrapper {
private String caption;
private Class<? extends Activity> target;
...POJO here...
}
v.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
//get leWrapper object from adapter
startActivity(new Intent(MenuActivity.this, leWrapper.getTarget()));
}
});
but its kinda overkill

Thanks for all the help guys. Sorry ive took my time replying. My solution is below :)
public class FP_WL1_ListView extends Activity {
private ListView lv1;
private String lv_arr[]={"Exercise Bike", "Treadmill", "Cross Trainer", "Squats", "Lunges"};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.fitnessprograms_wlday_one);
lv1=(ListView)findViewById(R.id.list);
lv1.setAdapter(new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1 , lv_arr));
lv1.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
final TextView mTextView = (TextView)view;
switch (position) {
case 0:
Intent newActivity0 = new Intent(FP_WL1_ListView.this,FitnessPrograms_Wlone_sp.class);
startActivity(newActivity0);
break;
case 1:
Intent newActivity1 = new Intent(FP_WL1_ListView.this,FitnessPrograms_Wlone_Treadmill.class);
startActivity(newActivity1);
break;
case 2:
Intent newActivity2 = new Intent(FP_WL1_ListView.this,FitnessPrograms_Wlone_Crosstrainer.class);
startActivity(newActivity2);
break;
case 3:
Intent newActivity3 = new Intent(FP_WL1_ListView.this,FitnessPrograms_Wlone_Squats.class);
startActivity(newActivity3);
break;
case 4:
Intent newActivity4 = new Intent(FP_WL1_ListView.this,FitnessPrograms_Wlone_Lunges.class);
startActivity(newActivity4);
break;
}
}
});
} }