Question

当我单击alertdialog保存按钮时，我想将新项目添加到recyclerview并刷新它以同时显示新项目...。它从sqlite数据库中获取数据。并从同一数据库中检索

 EditText title, description;
    Button save;
    RecyclerView recycler;

    insertDatadb db = new insertDatadb(this);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        recycler = findViewById(R.id.data_recycle);
        adapter=new Adapter(this,db.getData());
        recycler.setItemAnimator(new DefaultItemAnimator());
        showData();
        recycler.setAdapter(adapter);
    }


    public boolean onCreateOptionsMenu (Menu menu){

        getMenuInflater().inflate(R.menu.mymenu,menu);
        return super.onCreateOptionsMenu(menu);


    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {

            case R.id.menu_add:
                displaydialog();

        }
        return super.onOptionsItemSelected(item);
    }




    public void displaydialog(){
        final View myview = getLayoutInflater().inflate(R.layout.custom_dialog, null);

        final AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this)
                .setTitle("Add New Task")
                .setMessage("What do You Want to do ?")
                .setPositiveButton("Save", new DialogInterface.OnClickListener() {
                    @Override

                    public void onClick(DialogInterface dialogInterface, int i) {

                        title = myview.findViewById(R.id.et_title);
                        description = myview.findViewById(R.id.et_description);
                        String mytitle = title.getText().toString();
                        String mydesc = description.getText().toString();




                        if (mytitle.isEmpty() && mydesc.isEmpty()) {
                            Toast.makeText(MainActivity.this, "No Data ", Toast.LENGTH_LONG).show();
                        } else {

                            boolean result = db.insertData(mytitle, mydesc);

                            if (result == true) {
                                Toast.makeText(MainActivity.this, "Add Successfully", Toast.LENGTH_LONG).show();
                                title.setText("");
                                description.setText("");



                            } else {
                                Toast.makeText(MainActivity.this, "Add Failed", Toast.LENGTH_LONG).show();
                            }
                        }
                    }



                })
                .setNegativeButton("Cancel",null);



        builder.setView(myview);
        AlertDialog dialog = builder.create();
        dialog.show();

    }
    public void showData ( ) {
        recycler.setLayoutManager(new LinearLayoutManager(this));
        recycler.setAdapter(adapter);

    }

}

这是。适配器和支架类..................................... .................... ...................... ...... 。 .............. ...... ........... ........ ......

`上下文上下文； ArrayList项目；私有ArrayList数据；

public Adapter(Context context, ArrayList<MyHolder> items) {

    this.context=context;
    this.items=items;

}

@NonNull
@Override
public MyHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
    LayoutInflater inflate = LayoutInflater.from(context);
    View v = inflate.inflate(R.layout.recyclerlayout,viewGroup,false);
    MyHolder holder=new MyHolder(v);

    return holder;
}



@Override
public void onBindViewHolder(@NonNull MyHolder myHolder, int i) {
    myHolder.txt.setText((CharSequence) items.get(i));

    myHolder.setItemClickListenet(new refresh_recycle() {
        @Override
        public void onItemClick(int pos) {

        }
    });


}


@Override
public int getItemCount() {
    return items.size();
}






public class MyHolder extends RecyclerView.ViewHolder implements  View.OnClickListener{


    TextView txt;
    refresh_recycle refresh ;


    public MyHolder(@NonNull View itemView) {
        super(itemView);
        txt=itemView.findViewById(R.id.txt_recycle);

    }

    public void setItemClickListenet(refresh_recycle refresh)
    {
        this.refresh=refresh;

    }

    @Override
    public void onClick(View view) {
        this.refresh.onItemClick(getLayoutPosition());
    }
}
public void setData(ArrayList<MyHolder> data){
    this.data = data;
    notifyDataSetChanged();
    // where this.data is the recyclerView's dataset you are 
    // setting in adapter=new Adapter(this,db.getData());
}

}`......

Answer 1

将新数据添加到数据库后，必须重置recyclerView中的数据并调用notifyDataSetChanged()。您将需要在recyclerView中使用setData方法，就像这样

public void setData(List<YourDataType> data){
   this.data = data;
   notifyDataSetChanged();
 // where this.data is the recyclerView's dataset you are 
 // setting in adapter=new Adapter(this,db.getData());
}

添加新数据时，必须在代码中添加以下行。

if (result == true) {
    Toast.makeText(MainActivity.this, "Add 
                    Successfully",Toast.LENGTH_LONG).show();
    title.setText("");
    description.setText("");
    adapter.setData(db.getData);
    //this will reset your recyclerView's data set and notify the change
    //and reload the list 
}

Answer 2

以最简单的方式，您必须将DataList和adapter定义为字段，并在显示对话框后，将新的object(s)添加到DataList中。然后致电adapter.notifyDataSetChanged()。它对我有用，但是有一些更好的方法。

单击对话框按钮时如何刷新recyclerview？

2 个答案: