Add list to ArrayList<String> and show on ListView

Question

I want to make a ListView from the time that I get from a TimePicker' I succeed to add the time into a variable. but when I'm trying to add them into the ListView I don't get anything.

    addArray = new ArrayList<String>();
    ArrayAdapter<String> adapter = new ArrayAdapter(chart_houres_cosher.this,android.R.layout.simple_list_item_1,addArray);
    ListView listView = (ListView) findViewById(R.id.leassons);
    listView.setAdapter(adapter);

Clicked button

    textView.setText( firstHouer + " : " + firstdMinute + " - " + seccoundHouer + " : " + seccoundMinute );
    addArray.add(firstHouer + " : " + firstdMinute + " - " + seccoundHouer + " : " + seccoundMinute);

I can see the outcome on the TextView but not on the ListView.

Pavneet_Singh · Accepted Answer · 2018-08-12 19:19:03Z

3

Once you change the data of adapter you have to invoke notifyDataSetChanged() to see the effects in the list view.

textView.setText( firstHouer + " : " + firstdMinute + " - " + seccoundHouer + " : " + seccoundMinute );
addArray.add(firstHouer + " : " + firstdMinute + " - " + seccoundHouer + " : " + seccoundMinute);
addArray.notifyDataSetChanged();
//^^^^^^^^^^^^^^^^^^^
// once adapter is linked and later data source is modified , notify it
// only then adapter go though the data source 
//and update the listView/RecyclerView accordingly

edited Aug 12, 2018 at 19:19

answered Aug 12, 2018 at 3:52

Pavneet_Singh

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1 Comment

Lalit Fauzdar Over a year ago

@Mayli Plus why use same string concatenation again in the addArray.add() when you can use addArray.add(textView.getText()) or as string concatenation is not even recommended to be used with setText(), set it to a temp string and pass it to both setText() and add().

Stanislav Batura · Accepted Answer · 2018-08-12 06:35:32Z

1

And where is your data? From your code you are trying to add an empty Array.

addArray = new ArrayList<String>();

You just declare addArray, it dosen't have any data in it. And you are adding empty array into ListView.

answered Aug 12, 2018 at 6:35

Stanislav Batura

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