Android ListView 如何获取每一行的值

Question

I have a custom ListView working. What I would like to know is how can I check the value or get the text of the rows in the ListView in the GetView method . I essentially got a list of car names in the ListView such as Honda, Ford etc . When a user clicks the name of a car or car make then an image with that Car appears next to the text. When the click event happens the car name/make is added to the String ArrayList selected_fields.add(selectedFromList) . What I would like to do now is find a way where I can get the value of the rows inside the ListView so that I can see if they contain any value that is found in the selected_fields array. As you know that things are recycled inside the ListView . This is my code below

     @Override
    public View getView(final int positions, View convertView, ViewGroup parent) {
         final ViewHolder holder;
 // what I would like to do here is get the Value of the ListView Rows here
// I can then check if that value matches up with things inside the
// selected_fields array so that I can do something like
 // If convertView.Rows[value].contains(selected_genre) then show image . 


     if(convertView==null){
         inflater = (LayoutInflater) c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
         convertView = inflater.from(c).inflate(R.layout.car_names, null);

         holder.Car_Names=(TextView) convertView.findViewById(R.id.car_names);

     }



        binding.ListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {


                String selectedFromList = ((String)binding.ListView.getItemAtPosition(position));
                  selected_fields.add(selectedFromList);

                holder.selected_genres = (ImageView)  view.findViewById(R.id.car_names);
                holder.car_names.setVisibility(View.VISIBLE);

            }

        });

        names= genres.toArray(new String[0]);
        holder.text1.setText(names[pos]);



  notifyDataSetChanged();

        return convertView;
    }


}

For example this snippet of code inside the Onclick method gets the value of the ListView row that is clicked . I now want to get the value of all ListView Rows outside the OnClick method and check if the ListView Rows contains a value inside the selected_fields array .

((String)binding.ListView.getItemAtPosition(position));
                      selected_fields.add(selectedFromList);

Answer 1

The easiest way to get the value associated with a row in a ListView is to call getItem() on its adapter. If you use ArrayAdapter , this method returns the correct type due to the magic of generics so no carry is necessary.

Answer 2

Step 1: create an interface in your activity or fragment with a method that having single parameters of the vo that use used to pass to the adapter.

step 2:

create the interface object and pass it to the adapter

step 3:

create a click in adapter using the single items container.

step 4:

inside the click get the single item vo using position

step 5:

make the interface method call using interface object . method name with the single item vo

step 6:

inside the activity/fragment interface method use will get the data

step 7:

inside that method do what ever you wants to do.

FOR EXAMPLE

public interface ProcessClick {
     void getItem(Model model);
}






  public class MainActivity extends AppCompatActivity implements ProcessClick {
           private ArrayList<Model> model;
            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);
     adapter = new Adapter(this, model);
            }

            @Override
            public void getItem(Model model) {

            }
        }

In Adapter

private ProcessClick onclick;
 holder.container.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Model model = models.get(position);
                onclick;.getItem(model);

            }
        });

Answer 3

in Your Adapter you can create Interface like this

 Listener mListener;
    interface Listener {
        void onClick(int position, Model mModel,mListArray);
    }

     @Override
    public View getView(final int positions, View convertView, ViewGroup parent) {

    ...
     holder.yourWidget.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Model mModel = mListArray.get(position);
                mListener.onClick(position, mModel, mListArray);

            }
        });

        ...
    }

and in your activity you can impliment your interface like this

public class yourActivity extends Activity implements yourAdapter.Listener
{
......

 @Override
public void onClick(int position, Model mModel, ArrayList<Model> mListArray) {
    do whatever you want to do with this perticular position
}
.....
}