我正在尝试解决与RecyclerView相关的问题。当我第一次尝试显示对象列表时,我什么也看不见。由于已知为异步的截击请求,数据将被传递。所以,我尝试过像onDataSetChanged()这样的各种解决方案,但没有任何反应。我想说的是解决方案有效,第二次看列表时我可以毫无问题地看到它。
这是我的代码:
public class MainActivity extends AppCompatActivity {
RecyclerView recyclerView;
private static MyAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
getSupportActionBar().setHomeButtonEnabled(false);
recyclerView = (RecyclerView) findViewById(R.id.myRecyclerView);
adapter = new MyAdapter(this,initData());
adapter.setParentClickableViewAnimationDefaultDuration();
adapter.setParentAndIconExpandOnClick(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setAdapter(adapter);
}
private List<ParentObject> initData() {
TitleCreator titleCreator = TitleCreator.get(this);
List<TitleParent> titles = titleCreator.getAll();
List<ParentObject> parentObject = new ArrayList<>();
for(TitleParent title:titles)
{
List<Object> childList = getList(title);
title.setChildObjectList(childList);
parentObject.add(title);
}
return parentObject;
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
((MyAdapter)recyclerView.getAdapter()).onSaveInstanceState(outState);
}
@Override
public void onBackPressed() {
super.onBackPressed();
overridePendingTransition(R.anim.left_enter, R.anim.right_out);
}
private List<Object> getList(final TitleParent title){
final List<Object> childList = new ArrayList<>();
// Tag used to cancel the request
String tag_string_req = "request";
StringRequest strReq = new StringRequest(Request.Method.POST,
AppConfig.URL_DASHBOARD, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.d("POL", "Response: " + response.toString());
try {
JSONObject jObj = new JSONObject(response);
for (int i = 0; i < jObj.getJSONArray("polizze").length(); i++) {
JSONObject user = jObj.getJSONArray("polizze").getJSONObject(i);
String certificate = user.getString("numero_contratto");
if(title.getTitle().contains(certificate)){
String scadenza = user.getString("scadenza");
String totale = user.getString("totale");
childList.add(new TitleChild(scadenza,totale));
}
}
Log.d("TRY", "Response: " + response.toString());
adapter.notifyDataSetChanged();
} catch (JSONException e) {
// JSON error
e.printStackTrace();
// Toast.makeText(getApplicationContext(), "Json error: " + e.getMessage(), Toast.LENGTH_LONG).show();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e("DASH", "Login Error: " + error.getMessage());
//Toast.makeText(getApplicationContext(),
// error.getMessage(), Toast.LENGTH_LONG).show();
}
});
// Adding request to request queue
AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
return childList;
}
感谢您的帮助!
答案 0 :(得分:1)
有几点
你必须尝试下面的东西。
public class MainActivity extends AppCompatActivity {
RecyclerView recyclerView;
private static MyAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
getSupportActionBar().setHomeButtonEnabled(false);
recyclerView = (RecyclerView) findViewById(R.id.myRecyclerView);
// show some loading bar
initData();
}
private void initData() {
TitleCreator titleCreator = TitleCreator.get(this);
List<TitleParent> titles = titleCreator.getAll();
List<ParentObject> parentObject = new ArrayList<>();
for(TitleParent title:titles)
{
List<Object> childList = getList(title);
title.setChildObjectList(childList);
parentObject.add(title);
}
}
private void setData(List<ParentObject> parentObject) {
// load the data here
adapter = new MyAdapter(this,parentObject);
adapter.setParentClickableViewAnimationDefaultDuration();
adapter.setParentAndIconExpandOnClick(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setAdapter(adapter);
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
((MyAdapter)recyclerView.getAdapter()).onSaveInstanceState(outState);
}
@Override
public void onBackPressed() {
super.onBackPressed();
overridePendingTransition(R.anim.left_enter, R.anim.right_out);
}
private List<Object> getList(final TitleParent title){
final List<Object> childList = new ArrayList<>();
// Tag used to cancel the request
String tag_string_req = "request";
StringRequest strReq = new StringRequest(Request.Method.POST,
AppConfig.URL_DASHBOARD, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.d("POL", "Response: " + response.toString());
try {
JSONObject jObj = new JSONObject(response);
for (int i = 0; i < jObj.getJSONArray("polizze").length(); i++) {
JSONObject user = jObj.getJSONArray("polizze").getJSONObject(i);
String certificate = user.getString("numero_contratto");
if(title.getTitle().contains(certificate)){
String scadenza = user.getString("scadenza");
String totale = user.getString("totale");
childList.add(new TitleChild(scadenza,totale));
}
setData(childList);
}
Log.d("TRY", "Response: " + response.toString());
} catch (JSONException e) {
// JSON error
e.printStackTrace();
// Toast.makeText(getApplicationContext(), "Json error: " + e.getMessage(), Toast.LENGTH_LONG).show();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e("DASH", "Login Error: " + error.getMessage());
//Toast.makeText(getApplicationContext(),
// error.getMessage(), Toast.LENGTH_LONG).show();
}
});
// Adding request to request queue
AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
return childList;
}