在我的
UI中，我使用了两个按钮将不同的数据加载到RecyclerView。第一次单击每个按钮时正确显示数据。但是，如果我第二次单击该按钮，数据将两次添加到适配器中。我的意思是适配器未清除。它继续在单击按钮时添加数据。我想我必须在单击按钮时对适配器做点什么。任何人都可以让我知道如何清除适配器或我出错的地方..
这是代码。
public class GstVendorLocRetrieve extends AppCompatActivity {
private String vault;
private TextView txt;
public static final String DATA_URL = "http://oursite.com/getgstvendorlocation.php?vault_no=";
public static final String DATA_URL1 = "http://oursite.com/getgstcustomerlocation.php?vault_no=";
//Tags for my JSONRes
public static final String TAG_VendorID = "VendorID";
public static final String TAG_CustomerID = "Customer_ID";
public static final String TAG_ADDRESS = "Address";
private Button vendor;
private Button customer;
//Creating a List of superheroes
private List<GstVendLoc> listSuperHeroes;
private List<GstCustLoc> listSuperHeroes1;
//Creating Views
private RecyclerView recyclerView;
private RecyclerView.LayoutManager layoutManager;
private RecyclerView.Adapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.locationretrieve);
SharedPreferences sharedPreferences = getSharedPreferences(GstLogin.SHARED_PREF_NAME, MODE_PRIVATE);
vault = sharedPreferences.getString(GstLogin.EMAIL_SHARED_PREF,"Not Available");
vendor = (Button) findViewById(R.id.login);
customer = (Button) findViewById(R.id.login1);
recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
recyclerView.setHasFixedSize(true);
layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
//Initializing our superheroes list
listSuperHeroes = new ArrayList<>();
listSuperHeroes1 = new ArrayList<>();
vendor.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
recyclerView.setAdapter(null);
getData();
}
});
customer.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
recyclerView.setAdapter(null);
getData1();
}
});
}
//This method will get data from the web api
private void getData(){
//Showing a progress dialog
final ProgressDialog loading = ProgressDialog.show(this,"Loading Data", "Please wait...",false,false);
//Creating a json array request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(DATA_URL+vault,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
//Dismissing progress dialog
loading.dismiss();
//calling method to parse json array
parseData(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
//Creating request queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(jsonArrayRequest);
}
//This method will parse json data
private void parseData(JSONArray array){
for(int i = 0; i<array.length(); i++) {
GstVendLoc gst1 = new GstVendLoc();
JSONObject json = null;
try {
json = array.getJSONObject(i);
gst1.setVendorID(json.getString(TAG_VendorID));
gst1.setAddress(json.getString(TAG_ADDRESS));
} catch (JSONException e) {
e.printStackTrace();
}
listSuperHeroes.add(gst1);
}
//Finally initializing our adapter
adapter = new CardAdapter17(listSuperHeroes, this);
//Adding adapter to recyclerview
recyclerView.setAdapter(adapter);
}
private void getData1(){
//Showing a progress dialog
final ProgressDialog loading = ProgressDialog.show(this,"Loading Data", "Please wait...",false,false);
//Creating a json array request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(DATA_URL1+vault,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
//Dismissing progress dialog
loading.dismiss();
//calling method to parse json array
parseData1(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
//Creating request queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(jsonArrayRequest);
}
//This method will parse json data
private void parseData1(JSONArray array){
for(int i = 0; i<array.length(); i++) {
GstCustLoc gst1 = new GstCustLoc();
JSONObject json = null;
try {
json = array.getJSONObject(i);
gst1.setCustomer_ID(json.getString(TAG_CustomerID));
gst1.setAddress(json.getString(TAG_ADDRESS));
} catch (JSONException e) {
e.printStackTrace();
}
listSuperHeroes1.add(gst1);
}
//Finally initializing our adapter
adapter = new CardAdapter18(listSuperHeroes1, this);
//Adding adapter to recyclerview
recyclerView.setAdapter(adapter);
}
}
使用此代码清除回收视图项目
public void clear() {
int size = listSuperHeroes.size();
listSuperHeroes.clear();
notifyItemRangeRemoved(0, size);
}
您需要
在第二次获取数据之前清除Array List。
在for loop之前parseData1方法中执行此操作。
listSuperHeroes.clear();
listSuperHeroes1.clear();
你要做的是更新回收器查看按钮点击，把下面的方法放在你的适配器中
public void updateData(ArrayList<ViewModel> viewModels) {
items.clear();
items.addAll(viewModels);
notifyDataSetChanged();
}
比使用新数据调用此方法
ArrayList<ViewModel> viewModelsWithNewData = new ArrayList<ViewModel>();
adapter.updateData(viewModelsWithNewData );
从
在线获取数据后无需设置适配器
//Finally initializing our adapter
adapter = new CardAdapter18(listSuperHeroes1, this);
//Adding adapter to recyclerview
recyclerView.setAdapter(adapter);
您可以在创建时初始化设置适配器，并在'listSuperHeroes1'中添加数据，在解析数据后，您可以执行adapter.notifyDataSetChanged(); 这将更改列表数据。
以及获取先前数据的解决方案，您必须从listsuperHeroes1中删除所有数据，如果您遇到任何问题，这将对您有所帮助，请发表评论。
我只是在改进@Rony的答案。如果在尝试调用 .size() 之前应始终检查 ArrayList 是否为空，否则，最终可能会出现空指针异常
if (listSuperHeroes != null && !listSuperHeroes.isEmpty()) {
int size = listSuperHeroes.size();
listSuperHeroes.clear();
notifyItemRangeRemoved(0, size);
}