[英]How to refresh listView after database operation
对ListView
进行操作后,如何更新它的数据? 在自定义适配器的onClick
中? 在MainActivity中OnResume
吗? 我看到了很多关于此的文章,但是每次他们只给出一行代码,但没有放在哪里。
我的自定义适配器:
class CustomAdapter extends ArrayAdapter {
private Context context;
private LayoutInflater inflater;
private ArrayList<Contact> arrayList; //Lui transmettre le tableau adapter
private ContactDatabase db;
public CustomAdapter(Context context, ArrayList<Contact> arrayList){
super(context, R.layout.contact_list, arrayList);
db = new ContactDatabase(context);
this.context = context;
inflater = LayoutInflater.from(context);
this.arrayList = arrayList;
}
private class ViewHolder{
TextView txtName, txtPhone;
ImageView tete, dial;
}
@NonNull
@Override
public View getView(final int position, @Nullable View convertView, @NonNull ViewGroup parent) {
ViewHolder viewHolder;
if(convertView == null){
//Reglage general
viewHolder = new ViewHolder();
convertView = inflater.inflate(R.layout.contact_list, parent, false); //Layout du design
//Recuperation des ID
viewHolder.txtName = convertView.findViewById(R.id.clName);
viewHolder.txtPhone = convertView.findViewById(R.id.clNumber);
viewHolder.tete = convertView.findViewById(R.id.cl_icone);
viewHolder.dial = convertView.findViewById(R.id.cl_dial);
//Definition du tag
convertView.setTag(viewHolder);
}else{
viewHolder = (ViewHolder) convertView.getTag();
}
//Definition des changements
final Contact contact = arrayList.get(position);
//viewHolder.txtName.setText(db.dbToString(position + 1));
viewHolder.txtName.setText(Integer.toString(contact.getId()));
viewHolder.txtPhone.setText(contact.getPhone());
viewHolder.tete.setImageResource(contact.getImage());
//Change color
// int backgroundColor = ContextCompat.getColor(context, contact.getColor());
// viewHolder.txtPhone.setTextColor(backgroundColor);
//OnClick sur l'icone telephone
viewHolder.dial.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(android.content.Intent.ACTION_VIEW,
Uri.parse("tel:" + contact.getPhone()));
//context.startActivity(intent);
db.delete(contact.getId());
}
});
// //OnClick sur l'icone image
viewHolder.tete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Intent intent = new Intent(context, AddContactActivity.class); //On creer l'intent de donnee
// intent.putExtra("BUNDLE", args); //On place les donnes enregistrer dans l'intent quon fera passe
// intent.putExtra("index", position); //On place les donnes enregistrer dans l'intent quon fera passe
// ((Activity) context).startActivityForResult(intent, 100);
}
});
return convertView;
}
}
My Main Activity:
public class MainActivity extends AppCompatActivity{
private ListView listView;
private FloatingActionButton btnAdd;
private ArrayList<Contact> contacts;
ContactDatabase db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Definition des ID
btnAdd = findViewById(R.id.btn_add);
listView = findViewById(R.id.list_view); //Recheche du listView
listView.setEmptyView(findViewById(R.id.empty_list)); //Si listView est vide alors on affiche ce message
//Listener pour le button ADD
btnAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, AddContactActivity.class);
startActivity(intent);
}
});
}
@Override
protected void onResume() {
super.onResume();
//Creation de ladapter
db = new ContactDatabase(this);
contacts = db.getData();
CustomAdapter adapter = new CustomAdapter(this, contacts);
listView.setAdapter(adapter);
}
}
您能给我代码放在正确的位置吗,以便在每次操作后我的listView自动刷新
每次操作后,我的
listView
自动刷新
只需调用adapter.notifyDataSetChanged();
当您需要刷新listView
adapter.notifyDataSetChanged();
notifyDataSetChanged()
通知附加的观察者基础数据已更改,任何反映该数据集的视图都应刷新自身。
样例代码
CustomAdapter adapter = new CustomAdapter(this, contacts);
adapter.notifyDataSetChanged();
在您的代码中
@Override
protected void onResume() {
super.onResume();
//Creation de ladapter
contacts.clear();
db = new ContactDatabase(this);
contacts.addAll(db.getData());
adapter.notifyDataSetChanged();
}
更改代码
private ListView listView;
private FloatingActionButton btnAdd;
private ArrayList<Contact> contacts;
ContactDatabase db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Definition des ID
btnAdd = findViewById(R.id.btn_add);
listView = findViewById(R.id.list_view); //Recheche du listView
listView.setEmptyView(findViewById(R.id.empty_list)); //Si listView est vide alors on affiche ce message
//Listener pour le button ADD
btnAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, AddContactActivity.class);
startActivity(intent);
}
});
}
@Override
protected void onResume() {
super.onResume();
//Creation de ladapter
db = new ContactDatabase(this);
contacts = db.getData();
CustomAdapter adapter = new CustomAdapter(this, contacts);
listView.setAdapter(adapter);
}
至
private ListView listView;
private FloatingActionButton btnAdd;
private ArrayList<Contact> contacts=new ArrayList<>();
ContactDatabase db;
CustomAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Definition des ID
btnAdd = findViewById(R.id.btn_add);
listView = findViewById(R.id.list_view); //Recheche du listView
listView.setEmptyView(findViewById(R.id.empty_list)); //Si listView est vide alors on affiche ce message
adapter = new CustomAdapter(this, contacts);
listView.setAdapter(adapter);
//Listener pour le button ADD
btnAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, AddContactActivity.class);
startActivity(intent);
}
});
@Override
protected void onResume() {
super.onResume();
//Creation de ladapter
contacts.clear();
db = new ContactDatabase(this);
contacts.addAll(db.getData());
adapter.notifyDataSetChanged();
}
采用
CustomAdapter adapter = new CustomAdapter ():
adapter.notifyDataSetChanged();
您在listview
中添加或删除的位置
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.