How to start Activity in adapter?

Question

I have a ListActivity with my customized adapter. and inside each of the view, it may have some buttons, in which i need to implement OnClickListener. I need to implement the OnClickListener in the adapter. However, I dont know how to call the function like startActivity() or setResult(). since the adapter doesnt extend to Activity.

so what is the best way to solve this problem ? thanks

Answer 1

Just pass in the current Context to the Adapter constructor and store it as a field. Then inside the onClick you can use that context to call startActivity().

pseudo-code

public class MyAdapter extends Adapter {
     private Context context;

     public MyAdapter(Context context) {
          this.context = context;     
     }

     public View getView(...){
         View v;
         v.setOnClickListener(new OnClickListener() {
             void onClick() {
                 context.startActivity(...);
             }
         });
     }
}

Answer 2

When implementing the onClickListener, you can use v.getContext.startActivity.

btn.setOnClickListener(new OnClickListener() {                  
    @Override
    public void onClick(View v) {
        v.getContext().startActivity(PUT_YOUR_INTENT_HERE);
    }
});

Answer 3

public class MyAdapter extends Adapter {
     private Context context;

     public MyAdapter(Context context) {
          this.context = context;     
     }

     public View getView(...){
         View v;
         v.setOnClickListener(new OnClickListener() {
             void onClick() {
                  Intent intent= new Intent(context, goto.class);
                   intent.putextra("your_extra","your_class_value");
                 context.startActivity(intent);
             }
         });
     }
}

Answer 4

For newer versions of sdk you have to set flag activity task.

public void onClick(View v)
 {
     Intent myactivity = new Intent(context.getApplicationContext(), OtherActivity.class);
     myactivity.addFlags(FLAG_ACTIVITY_NEW_TASK);
     context.getApplicationContext().startActivity(myactivity);
 }

Answer 5

callback from adapter to activity can be done using registering listener in form of interface: Make an interface:

      public MyInterface{
         public void  yourmethod(//incase needs parameters );
         }

In Adapter Let's Say MyAdapter:

    public MyAdapter extends BaseAdapter{
       private MyInterface listener;

    MyAdapter(Context context){
        try {
            this. listener = (( MyInterface ) context);
              } catch (ClassCastException e) {
               throw new ClassCastException("Activity must implement MyInterface");
          }

//do this where u need to fire listener l

          try {
                listener . yourmethod ();
            } catch (ClassCastException exception) {
               // do something
            }

      In Activity Implement your method:


         MyActivity extends AppCompatActivity implements MyInterface{

                yourmethod(){
                //do whatever you want
                     }
                     }

Answer 6

If you want to redirect on url instead of activity from your adapter class then pass context of with startactivity.

btnInstall.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent=new Intent(Intent.ACTION_VIEW, Uri.parse(link));
                intent.setData(Uri.parse(link));
                context.startActivity(intent);
            }
        });

Answer 7

Simple way to start activity in Adopter's button onClickListener:

Intent myIntent = new Intent(view.getContext(),Event_Member_list.class);                    myIntent.putExtra("intVariableName", eventsList.get(position).getEvent_id());
                view.getContext().startActivity(myIntent);