java - 如何将 boolean 值从主 Activity 发送到基本适配器

Question

这是我的 MainActivity.java :

public class MainActivity extends AppCompatActivity {

    FirebaseDatabase firebaseDatabase = FirebaseDatabase.getInstance ();
    DatabaseReference databaseReference = firebaseDatabase.getReference ();
    private JazzyListView listView;
    int check=0;
    MyAdapter adapter;
    ProgressDialog progressDialog;
    List<String> ListString = new ArrayList<String> ();
    @Override
    protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate (savedInstanceState);
        setContentView (R.layout.activity_main22);
        final PullToRefreshView pullToRefreshView=(PullToRefreshView) findViewById (R.id.pull);
        pullToRefreshView.setOnRefreshListener (new PullToRefreshView.OnRefreshListener () {
            @Override
            public void onRefresh() {
                ListString.clear ();
                databaseReference.addValueEventListener (new ValueEventListener () {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {
                            DataSnapshot snapshot = dataSnapshot.child ("User");
                            for(DataSnapshot s: snapshot.getChildren ())
                            {
                                if(s.getValue ().toString ().isEmpty ())
                                    Toast.makeText (MainActivity.this, "Empty", Toast.LENGTH_SHORT).show ();
                                else
                                    ListString.add(s.getKey ().toString ());
                            }
                            adapter.notifyDataSetChanged ();
                            pullToRefreshView.setRefreshing (false);
                    }

                    @Override
                    public void onCancelled(DatabaseError databaseError) {
                        Toast.makeText (MainActivity.this, databaseError.getMessage (), Toast.LENGTH_SHORT).show ();
                    }
                });
            }
        });
        Connectivity connectivity = new Connectivity (MainActivity.this);
        if(connectivity.isConnected ()){
            progressDialog = new ProgressDialog (MainActivity.this);
            progressDialog.setCancelable (false);
            progressDialog.setMessage ("Loading");
            progressDialog.setTitle ("Retrieving Data");
            progressDialog.show ();
            ListString.add ("Adding");
            adapter = new MyAdapter (MainActivity.this, ListString);
            databaseReference.addValueEventListener (new ValueEventListener () {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    check++;
                    if(check<=1) {
                        ListString.remove ("Adding");
                        DataSnapshot snapshot = dataSnapshot.child ("User");
                        for(DataSnapshot s: snapshot.getChildren ())
                        {
                            if(s.getValue ().toString ().isEmpty ())
                                Toast.makeText (MainActivity.this, "Empty", Toast.LENGTH_SHORT).show ();
                            else
                                ListString.add(s.getKey ().toString ());
                        }
                        progressDialog.dismiss ();
                        adapter.notifyDataSetChanged ();
                    }else{

                    }
                }

                @Override
                public void onCancelled(DatabaseError databaseError) {
                    Toast.makeText (MainActivity.this, databaseError.getMessage (), Toast.LENGTH_SHORT).show ();
                }
            });
        }else{
                AlertDialog.Builder builder = new AlertDialog.Builder (MainActivity.this);
                builder.setTitle("No Network")
                        .setMessage ("No Network Available").setPositiveButton ("Ok", new DialogInterface.OnClickListener () {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        dialogInterface.dismiss ();
                    }
                }) ;
                AlertDialog alertDialog = builder.create ();
                alertDialog.show ();
        }

        listView = (JazzyListView) findViewById (R.id.listview);
        listView.setTransitionEffect (new FadeEffect ());
        listView.setAdapter (adapter);
        //adapter.notifyDataSetChanged ();
        listView.setOnItemClickListener (new AdapterView.OnItemClickListener () {
            @Override
            public void onItemClick(final AdapterView<?> adapterView, final View view, int i, long l) {
                final String itemname = adapterView.getItemAtPosition (i).toString ();
                try{
                    AlertDialog.Builder builder = new AlertDialog.Builder (MainActivity.this);
                    builder.setTitle("Present?")
                            .setMessage ("Present or Absent:").setPositiveButton ("Present", new DialogInterface.OnClickListener () {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
                            try{
                                //view.setBackgroundColor (getColor (android.R.color.holo_green_light));
                                Calendar calendar = Calendar.getInstance ();
                                SimpleDateFormat simpleDateFormat = new SimpleDateFormat ("dd MMM yyyy");
                                DatabaseReference user = databaseReference.child ("Attendence");
                                DatabaseReference date = user.child (simpleDateFormat.format (calendar.getTime ()));
                                DatabaseReference name = date.child (itemname);
                                name.setValue ("Present");
                            }catch (Exception e){
                                Toast.makeText (MainActivity.this, e.getMessage (), Toast.LENGTH_SHORT).show ();
                            }
                        }
                    }).setNegativeButton ("Absent", new DialogInterface.OnClickListener () {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
                            Calendar calendar = Calendar.getInstance ();
                            SimpleDateFormat simpleDateFormat = new SimpleDateFormat ("dd MMM yyyy");
                            DatabaseReference user = databaseReference.child ("Attendence");
                            DatabaseReference date = user.child (simpleDateFormat.format (calendar.getTime ()));
                            DatabaseReference name = date.child (itemname);
                            name.setValue ("Absent");
                        }
                    });
                    AlertDialog alertDialog = builder.create ();
                    alertDialog.show ();
                }catch (Exception e){
                    Toast.makeText (MainActivity.this, e.getMessage (), Toast.LENGTH_SHORT).show ();
                }
            }
        });

    }
}

这是我的 MyAdapter.java 文件:

public class MyAdapter extends BaseAdapter{

    List thisList;
    Context thiscontext;
    LayoutInflater inflater;
    public MyAdapter(Context context,List list) {
        thiscontext = context;
        thisList = list;
        inflater= (LayoutInflater) context.getSystemService (Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        return  thisList.size ();
    }

    @Override
    public Object getItem(int i) {
        return thisList.get (i);
    }

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

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        view = inflater.inflate (R.layout.list_main, null);
        TextView textView = (TextView) view.findViewById (R.id.textView);
        String upper = thisList.get (i).toString ().substring (0,1).toUpperCase () + thisList.get (i).toString ().substring (1);
        TextView boxText = (TextView) view.findViewById (R.id.boxText);
        TextView boxView = (TextView) view.findViewById (R.id.boxView);
        String first = thisList.get (i).toString ().toUpperCase ().substring (0,1);
        textView.setText (upper);
        boxText.setText (first);
        return view;
    }
}

我想这样做，当用户单击列表项时，列表应通过 MainActivity.java 将当前值发送到 MyAdapter.java 类中的 boxView TextView，然后 boxView 应在每个项目中设置当前或不存在 ListView 。

Answer 1

首先，您首先在 MyAdapter 类中创建一个新的 boolean 变量。然后，您创建新方法 setPresent() 并使用它来设置您需要的 boolean 值。

您的代码已更改:

Activity 中

builder.setTitle("Present?")
                            .setMessage ("Present or Absent:").setPositiveButton ("Present", new DialogInterface.OnClickListener () {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
                            try{
                                //view.setBackgroundColor (getColor (android.R.color.holo_green_light));
                                Calendar calendar = Calendar.getInstance ();
                                SimpleDateFormat simpleDateFormat = new SimpleDateFormat ("dd MMM yyyy");
                                DatabaseReference user = databaseReference.child ("Attendence");
                                DatabaseReference date = user.child (simpleDateFormat.format (calendar.getTime ()));
                                DatabaseReference name = date.child (itemname);
                                name.setValue ("Present");
                                adapterView.updateView(true, i); // to get the present value form your alert;

                            }catch (Exception e){
                                Toast.makeText (MainActivity.this, e.getMessage (), Toast.LENGTH_SHORT).show ();
                            }
                        }
                    }).setNegativeButton ("Absent", new DialogInterface.OnClickListener () {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
                            Calendar calendar = Calendar.getInstance ();
                            SimpleDateFormat simpleDateFormat = new SimpleDateFormat ("dd MMM yyyy");
                            DatabaseReference user = databaseReference.child ("Attendence");
                            DatabaseReference date = user.child (simpleDateFormat.format (calendar.getTime ()));
                            DatabaseReference name = date.child (itemname);
                            name.setValue ("Absent");
                            adapterView.updateView(false, i); // to get the absent value form your alert;

                        }
                    });

在你的适配器中；

 public class MyAdapter extends BaseAdapter{
        List thisList;
        Context thiscontext;
        LayoutInflater inflater;
        public MyAdapter(Context context,List list) {
            thiscontext = context;
            thisList = list;
            inflater= (LayoutInflater) context.getSystemService (Context.LAYOUT_INFLATER_SERVICE);
        }

        @Override
        public int getCount() {
            return  thisList.size ();
        }

        @Override
        public Object getItem(int i) {
            return thisList.get (i);
        }

        @Override
        public long getItemId(int i) {
            return i;
        }
        // new method

        private void updateView(Boolean value, int index){
        View v = thisList.getChildAt(index - 
        thisList.getFirstVisiblePosition());

        if(v == null)
        return;

        TextView boxView = (TextView) v.findViewById (R.id.boxView);
        if (value && value != null) {
        boxView.setText("Present");
        } else if (!value && value !=null) {
        boxView.setText("Absent");
        }

}

        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
            view = inflater.inflate (R.layout.list_main, null);
            TextView textView = (TextView) view.findViewById (R.id.textView);
            String upper = thisList.get (i).toString ().substring (0,1).toUpperCase () + thisList.get (i).toString ().substring (1);
            TextView boxText = (TextView) view.findViewById (R.id.boxText);
            TextView boxView = (TextView) view.findViewById (R.id.boxView);
            String first = thisList.get (i).toString ().toUpperCase ().substring (0,1);
            textView.setText (upper);
            boxText.setText (first);
            return view;
        }
    }

设置值后，您应该通知适配器该行发生了更改。就是这样 !您传递了 boolean 值。