How to make Android list item pass id on to next view?

Question

In my (first) Android App I have a list of items. Each item is displayed using item.xml in which I have a RelativeLayout. In this layout I defined android:onClick="showItemDetails" of which the method looks like this:

public void showItemDetails(View view) {
    Intent intent = new Intent(this, itemDetails.class);
    intent.putExtra("itemId", "5");
    this.startActivity(intent);
}

As you can see I pass on a hardcoded id, so whatever item you currently click on, it obviously only shows item nr 5. I now need to dynamically give this method the id. The itemlist is created in the ItemListAdapter class of which a part is this:

holder.description.setText(rowItem.eventDescription);
holder.amount.setText(rowItem.getDisplayAmount());

I also have the id under rowItem.id , but I'm kinda lost on what I should do with it.

Can anybody help me out a bit here? What do I need to do to have the list items correctly pass the id through to the itemDetails class? All tips are welcome!

Answer 1

First few assumptions:

• you're not using Fragments just plain Activity called OuterActivityClass
• rowItem var has typ RowItemClass
• your ItemListAdapter is extending ArrayAdapter<RowItemClass>
• you do it "right" ( ItemListAdapter do not have own List<RowItemClass> field, rowItem in getView(...) is assigned like rowItem = getItem(possition); not like rowItem = yourListFieldInAdapter.get(position); (I do not know why Ppls using such field since ArrayAdapter<?> already has it internally) ... if you do it "bad" replace all getItem(possition) occurrence in my answer with yourListFieldInAdapter.get(position)
• id field of RowItemClass is long or int (if not use "or:" version)

What you have to do:

1. get rid of android:onClick from item.xml
2. override hasStableIds() in ItemListAdapter : public boolean hasStableIds () { return true; } public boolean hasStableIds () { return true; }
3. override getItemId(...) in adapter: public long getItemId (int position) { return getItem(position).id; } public long getItemId (int position) { return getItem(position).id; }
4. in Activity onCreate(...) get ListView: ListView listView = findViewById(R.id.your_listview_id);
5. then assign the listener to your listView(in onCreate, too)

code:

listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
   void onItemClick(AdapterView<?> parent, View view, int position, long id){
      Intent intent = new Intent(OuterActivityClass.this, itemDetails.class);
      intent.putExtra("itemId", id + ""); //+ "" to make it string, of course you can use long but you have to remeber to use intent.getLongExtra(...) in details Activity
      startActivity(intent);
   }
});

or:

listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
   void onItemClick(AdapterView<?> parent, View view, int position, long id){
      final RowItemClass clickedItem  = (RowItemClass)parent.getItemAtPosition(position);
      Intent intent = new Intent(OuterActivityClass.this, itemDetails.class);
      intent.putExtra("itemId", clickedItem.id + "");
      startActivity(intent);
   }
});

with second method you can omit points 2. and 3. (if you are using "bad" way remeber to override getItem ( return yourListFieldInAdapter.get(pos) ) and getCount ( return yourListFieldInAdapter.size() )in your adapter implementation)

Offtopic hint: do not use lower case as first letter in class name itemDetails => ItemDetails ... for your sanity :) (OMG, OMG, itemDetails is variable or class name )

Answer 2

In your Main Activity

String item =  country.getName();
           Intent intent= new Intent(MainActivityActivity.this,AnotherActivity.class);
                    intent.putExtra(EXTRA_RESPONSE, item);
                    startActivity(intent);





In Next Activity
String country =  getIntent().getStringExtra(MainActivity.EXTRA_COUNTRY);
    TextView textView = (TextView) findViewById(R.id.tvPhone);
    textView.setText(country);

Answer 3

If I understand correctly your problem then you might try to set OnClickListener in your adapter(don't set onClick in xml). And in your adapter try something like:

public View getView(int position, View convertView, ViewGroup parent) {
     ...
     View rootLayout = convertView.findViewById(R.id.item_layout_root);  
     ...
     rootLayout.setOnClickListener(new OnClickListener() {
         public void onClick(View v) {
           showItemDetails(rowItem.id);  
         }
     });
return convertView;

And your showItemDetails will change to

showItemDetails(int id) {
    Intent intent = new Intent(this, itemDetails.class);
    intent.putExtra("itemId", id);
    this.startActivity(intent);
}