Wie sende ich Daten vom Listenadapter an Aktivitäten in Android?

Question

Ich habe einen benutzerdefinierten Listenadapter. Ich möchte Werte von diesem Listenadapter an eine Aktivität übergeben, für die ich den Adapter festgelegt habe. Das ist mein Adaptercode.

public class RoleList extends ArrayAdapter<String> 
{ 
    private ArrayList<String> name; 
    private ArrayList<String> username; 
    private ArrayList<String> password; 
    private ArrayList<String> role; 
    private Activity context; 

    private MyActionCallback callback; 
public RoleList(Activity context, ArrayList<String> name, ArrayList<String> username, ArrayList<String> password, ArrayList<String> role, MyActionCallback callback) 
{ 
    super(context, R.layout.role_list,name); 
    this.context = context; 
    this.name = name; 
    this.username =username; 
    this.password = password; 
    this.role = role; 
    this.callback = callback; 
} 

    @Override 
    public View getView(final int position, View convertView, ViewGroup parent) 
    { 
     LayoutInflater inflater = context.getLayoutInflater(); 
     final View listViewItem = inflater.inflate(R.layout.role_list, null, true); 
     final TextView textViewName = (TextView) listViewItem.findViewById(R.id.tv_empname); 
     final TextView textViewusername = (TextView) listViewItem.findViewById(R.id.tv_empusername); 
     final TextView textViewPass = (TextView) listViewItem.findViewById(R.id.tv_emppassword); 
     final TextView textViewRole = (TextView) listViewItem.findViewById(R.id.tv_emprole); 
     Button edit = (Button) listViewItem.findViewById(R.id.btn_editRole); 
     Button delete = (Button) listViewItem.findViewById(R.id.btn_delRole); 


     delete.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) 
      { 
       name.remove(position); 
       username.remove(position); 
       password.remove(position); 
       role.remove(position); 
       callback.onActionPerformed(position); 
       notifyDataSetChanged(); 
      } 
     }); 
     edit.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) 
      { 
       Log.d("Emp Info", name.get(position) + " " + username.get(position) + " " + password.get(position) + " " + role.get(position)); 

       final Dialog dialog = new Dialog(getContext()); 
       dialog.setContentView(R.layout.userreg); 
       dialog.setTitle("Edit Employee " + name.get(position) + " details"); 
       final String[] arraySpinner = new String[]{"Manager","Stockist","Cashier","Accountant"}; 
       dialog.setCancelable(false); 
       dialog.setCanceledOnTouchOutside(false); 
       final EditText emp_name = (EditText) dialog.findViewById(R.id.editTextName); 
       final EditText emp_uname = (EditText) dialog.findViewById(R.id.editTextUserName); 
       final EditText emp_pw = (EditText) dialog.findViewById(R.id.editTextPassword); 
       final Spinner emp_role = (Spinner) dialog.findViewById(R.id.spinner_role); 
       final TextView textRole = (TextView) dialog.findViewById(R.id.tv_selected_role); 
       ArrayAdapter<String> adapter = new ArrayAdapter<String>(getContext(),android.R.layout.simple_spinner_item, arraySpinner); 
       emp_role.setAdapter(adapter); 
       emp_role.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
        @Override 
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { 
         Toast.makeText(getContext(), "Role Selected is " + arraySpinner[position], Toast.LENGTH_SHORT).show(); 

         String employee_role = arraySpinner[position]; 
         textRole.setText(employee_role); 

        } 

        @Override 
        public void onNothingSelected(AdapterView<?> parent) { 

        } 
       }); 


       emp_name.setText(name.get(position)); 
       emp_uname.setText(username.get(position)); 
       emp_pw.setText(password.get(position)); 
       emp_role.setSelection(position); 

       Button buttoncancel = (Button) dialog.findViewById(R.id.buttonCancel); 
       buttoncancel.setOnClickListener(new View.OnClickListener() { 
        @Override 
        public void onClick(View v) { 
         dialog.dismiss(); 
        } 
       }); 

       Button buttonChange = (Button) dialog.findViewById(R.id.buttonRegister); 
       buttonChange.setText("Change"); 
       buttonChange.setOnClickListener(new View.OnClickListener() { 
        @Override 
        public void onClick(View v) 
        { 
         textViewName.setText(emp_name.getText().toString()); 
         textViewusername.setText(emp_uname.getText().toString()); 
         textViewPass.setText(emp_pw.getText().toString()); 
         textViewRole.setText(textRole.getText()); 
         dialog.dismiss(); 

        } 
       }); 



       dialog.show(); 
      } 
     }); 


     textViewName.setText(name.get(position)); 
     textViewusername.setText(username.get(position)); 
     textViewPass.setText(password.get(position)); 
     textViewRole.setText(role.get(position)); 

     return listViewItem; 
    } 
public interface MyActionCallback{ 
void onActionPerformed(int position); 
} 
    } 

Protokoll für Nullzeiger Ausnahme.

04-23 14: 59: 24.919 bis 24.919 16,462/org.bordetuts.com.goldmine E/Android Runtime: fatal EXCEPTION: main 04-23 14: 59: 16,462 24.919-24.919/org.bordetuts .com.goldmine E/AndroidRuntime: Prozess: org.bordetuts.com.goldmine, PID: 24919 04-23 14: 59: 16.462 24919-24919/org.bordetuts.com.goldmine E/AndroidRuntime: java.lang .NullPointerException 04-23 14: 59: 16.462 24919-24919/org.bordetuts.com.goldmine E/AndroidRuntime: um org.bordetuts.com.goldmine.adapter.RoleList $ 1.onClick (RoleList.java:67) 04-23 14: 59: 16.462 24919-24919/org.bordetuts.com.goldmine E/AndroidRuntime: um android.view.View.performClick (View.java:4444) 04-23 14: 59: 16.462 24919-24919/org.bordetuts.com.goldmine E/AndroidRuntime: um android.view .View $ PerformClick.run (View.java:18440) 04-23 14: 59: 16.462 24919-24919/org.bordetuts.com.goldmine E/AndroidRuntime: um android.os.Handler.handleCallback (Handler.java : 733) 04-23 14: 59: 16.462 24919-24919/org.bordetuts.com.goldmine E/AndroidRuntime: um android.os.Handler.dispatchMessage (Handler.java:95) 04-23 14:59: 16.462 24919-24919/org.bordetuts.com.goldmine E/AndroidRuntime: um android.os.Looper.loop (Looper.java:136) 04-23 14: 59: 16.462 24919-24919/org.bordetuts. com.goldmine E/AndroidRuntime: um android.app.ActivityThread.main (ActivityThread.java:5028) 04-23 14: 59: 16.462 24919-24919/org.bordetuts.com.goldmine E/AndroidRuntime: bei java.lang.reflect.Method.invokeNative (Native Methode) 04-23 14: 59: 16.462 24919-24919/org.bordetuts.com.goldmine E/AndroidRuntime: bei java.lang.reflect.Method.invoke (Methode.java: 515) 04-23 14 : 59: 16.462 24919-24919/org.bordetuts.com.goldmine E/AndroidRuntime: um com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run (ZygoteInit.java:788) 04-23 14:59: 16.462 24919-24919/org.bordetuts.com.goldmine E/AndroidRuntime: um com.android.internal.os.ZygoteInit.main (ZygoteInit.java:604) 04-23 14: 59: 16.462 24919-24919/org.bor detuts.com.goldmine E/Android Runtime: bei dalvik.system.NativeStart.main (Mutter Methode)

Ich möchte die Tätigkeit informieren, dass etwas in der geändert adapter.For zB. Löschen wurde für eine bestimmte Position gedrückt. Alle Vorschläge, Hilfe oder Hinweise helfen. Danke.

Answer 1

Ihre Aktivität:

public class MainActivity extends AppCompatActivity implements YourCustomAdapter.MyActionCallback { 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    // or something like that 
    ListView listView = findViewById(R.id.my_list_view); 
    listView.setAdapter(new YourCustomAdapter(this)); 
} 



@Override 
public void onActionPerformed(int position) { 
    //do here something with your data 

} 

Ihr Adapter:

public class YourCustomAdapter extends BaseAdapter { 

public YourCustomAdapter(
     MyActionCallback actionCallback) { 
    mActionCallback = actionCallback; 
} 

private MyActionCallback mActionCallback; 

@Override 
public int getCount() { 
    return 0; 
} 

@Override 
public Object getItem(int position) { 
    return null; 
} 

@Override 
public long getItemId(int position) { 
    return 0; 
} 

@Override 
public View getView(final int position, View convertView, ViewGroup parent) { 
    // your case specific code 
    // don't forget to implement view re-using properly, 
    // don't inflate view each time 
    delete.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) 
     { 
      name.remove(position); 
      username.remove(position); 
      password.remove(position); 
      role.remove(position); 
      //pass position of deleted object or any other thing you want 
      mActionCallback.onActionPerformed(position); 
      notifyDataSetChanged(); 
     } 
    }); 
    return null; 
} 

public interface MyActionCallback{ 
    void onActionPerformed(int position); 
} 

Auch können Sie den Event-Bus, Otto zum Beispiel, aber ich denke, für Ihren Fall nur eine benutzerdefinierte Callback wird genug. Es kommt darauf an.