我不确定我现在缺少什么。当我在视图上尝试draggin时，列表将出现，它有点显示RecyclerView存在，但它没有数据。我没有收到任何错误，但视图中没有填充远程数据。我有一个MainActivity来托管Fragment，其内容是在json的响应中动态生成的。
这是我的片段：RCurrency.java
public class RCurrency extends Fragment {
RecyclerView mRecyclerView;
List<CurrencyItem> mCurrencyItems;
String currencies = "Currency";
Context mContext;
public static final String URL_STRING = "https://linktoapi.com/";
public RCurrency(){
//required empty constructor
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView( LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
//fragment inflater
View view = inflater.inflate(R.layout.fragment_currency_home,container, false);
//recycler view
mRecyclerView = (RecyclerView) view.findViewById(R.id.currency_recycler_view);
mCurrencyItems = new ArrayList<CurrencyItem>();
StringRequest stringRequest = new StringRequest(Request.Method.GET, URL_STRING,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
try {
JSONArray jsonArray = new JSONArray(response);
JSONObject jsonObject;
for (int i = 0; i <= jsonArray.length()-1; i++) {
jsonObject = jsonArray.getJSONObject(i);
CurrencyItem currencyItem = new CurrencyItem();
currencyItem.setCurrencyLogo(jsonObject.getString("id"));
currencyItem.setSymbol(jsonObject.getString("symbol"));
currencyItem.setCurrencyName(jsonObject.getString("name"));
mCurrencyItems.add(currencyItem);
}
CurrencyItemAdapter adapter = new CurrencyItemAdapter(getContext(), mCurrencyItems);
//Problem at this point
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getContext());
mRecyclerView.setLayoutManager(layoutManager);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setAdapter(adapter);
adapter.notifyDataSetChanged();
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e("Check response", error);
}
}){
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> params = new HashMap<>();
params.put("name",currencies);
return params;
}
//add request to the volley queue
};
RequestQueue requestQueue = Volley.newRequestQueue(getContext());
requestQueue.add(stringRequest);
return view;
}
}
我在此处主持片段的主要活动：MainActivity.java
public class MainActivity extends AppCompatActivity {
private Button logInBtn;
private CurrencyListFragment RCurrency;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// fragment manager to manage fragments and transactions
FragmentManager fragmentManager = getSupportFragmentManager();
Fragment fragment = fragmentManager.findFragmentById(R.id.fragment_container);
if (fragment == null){
fragment = new RCurrency();
fragmentManager.beginTransaction()
.add(R.id.fragment_container, fragment)
.commit();
}
logInBtn = (Button) findViewById(R.id.log_in_main_page);
logInBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, info.lansachia.cryptoinvest.LoginActivity.class);
finish();
startActivity(intent);
}
});
}
}
我的适配器：CurrencyItemAdapter.java
public class CurrencyItemAdapter extends RecyclerView.Adapter<CurrencyItemAdapter.MyViewHolder> {
private List<CurrencyItem> mCurrencyItems;
private Context mContext;
public CurrencyItemAdapter(Context context, List<CurrencyItem> currencyItems){
this.mContext = context;
this.mCurrencyItems = currencyItems;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item_currency, parent, false);
return new MyViewHolder(view);
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
CurrencyItem currencyItem = mCurrencyItems.get(position);
//setting text to currency symbol
holder.mSymbol.setText(currencyItem.getSymbol());
holder.mSymbol.setTextSize(17);
//currency name
holder.mName.setText(currencyItem.getCurrencyName());
holder.mName.setTextSize(17);
}
@Override
public int getItemCount() {
return mCurrencyItems.size();
}
public class MyViewHolder extends RecyclerView.ViewHolder{
TextView mSymbol;
TextView mPrice;
TextView mName;
TextView mRecommendation;
ImageView mCurrencyLogo;
public MyViewHolder(View itemView) {
super(itemView);
mSymbol = (TextView)itemView.findViewById(R.id.currency_symbol);
mPrice = (TextView)itemView.findViewById(R.id.currency_price);
mName = (TextView)itemView.findViewById(R.id.currency_name);
mRecommendation = (TextView)itemView.findViewById(R.id.currency_recommendation);
// mCurrencyLogo= (ImageView)itemView.findViewById(R.id.currency_icon);
}
}
}
list_item_currency.xml布局是..
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/linearLayout2"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="@+id/currency_icon"
android:layout_width="75dp"
android:layout_height="74dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:contentDescription="@string/currecy_logo"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
<TextView
android:id="@+id/currency_symbol"
android:layout_width="177dp"
android:layout_height="75dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toEndOf="@+id/currency_icon"
app:layout_constraintTop_toTopOf="parent"/>
<TextView
android:id="@+id/currency_name"
android:layout_width="176dp"
android:layout_height="29dp"
android:layout_marginBottom="8dp"
android:layout_marginStart="91dp"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/currency_symbol"
app:layout_constraintVertical_bias="0.0"/>
<TextView
android:id="@+id/currency_recommendation"
android:layout_width="101dp"
android:layout_height="25dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/currency_name"
app:layout_constraintTop_toBottomOf="@+id/currency_price"/>
<TextView
android:id="@+id/currency_price"
android:layout_width="101dp"
android:layout_height="74dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/currency_symbol"
app:layout_constraintTop_toTopOf="parent"/>
</android.support.constraint.ConstraintLayout>
fragment_currency.xml是包含RecyclerView的布局，但最终RecyclerView托管在main_activity.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:id="@+id/fragment_home_page"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/currency_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"/>
</LinearLayout>
此处的堆栈跟踪：
3-03 10:07:16.102 5337-5337/? I/zygote: Not late-enabling -Xcheck:jni (already on)
03-03 10:07:16.176 5337-5337/? W/zygote: Unexpected CPU variant for X86 using defaults: x86
03-03 10:07:16.387 5337-5337/info.myapp.currency W/ActivityThread: Application info.myapp.currency is waiting for the debugger on port 8100...
03-03 10:07:16.400 5337-5337/info.myapp.currency I/System.out: Sending WAIT chunk
03-03 10:07:17.018 5337-5346/info.myapp.currency I/zygote: Debugger is active
03-03 10:07:17.032 5337-5337/info.myapp.currency I/System.out: Debugger has connected
03-03 10:07:17.032 5337-5337/info.myapp.currency I/System.out: waiting for debugger to settle...
03-03 10:07:17.233 5337-5337/info.myapp.currency I/System.out: waiting for debugger to settle...
03-03 10:07:17.435 5337-5337/info.myapp.currency I/System.out: waiting for debugger to settle...
03-03 10:07:17.636 5337-5337/info.myapp.currency I/chatty: uid=10085(u0_a85) info.myapp.currency identical 1 line
03-03 10:07:17.838 5337-5337/info.myapp.currency I/System.out: waiting for debugger to settle...
03-03 10:07:18.039 5337-5337/info.myapp.currency I/System.out: waiting for debugger to settle...
03-03 10:07:18.241 5337-5337/info.myapp.currency I/System.out: waiting for debugger to settle...
03-03 10:07:18.443 5337-5337/info.myapp.currency I/System.out: waiting for debugger to settle...
03-03 10:07:18.645 5337-5337/info.myapp.currency I/System.out: debugger has settled (1460)
03-03 10:07:19.002 5337-5337/info.myapp.currency W/zygote: Skipping duplicate class check due to unrecognized classloader
03-03 10:07:19.008 5337-5337/info.myapp.currency W/DynamiteModule: Local module descriptor class for com.google.firebase.auth not found.
03-03 10:07:19.013 5337-5337/info.myapp.currency W/DynamiteModule: Local module descriptor class for com.google.firebase.auth not found.
03-03 10:07:19.058 5337-5337/info.myapp.currency I/BiChannelGoogleApi: [FirebaseAuth: ] No Fallback module; NOT setting up for lazy initialization
03-03 10:07:19.095 5337-5337/info.myapp.currency D/FirebaseApp: com.google.firebase.crash.FirebaseCrash is not linked. Skipping initialization.
03-03 10:07:19.125 5337-5359/info.myapp.currency W/DynamiteModule: Local module descriptor class for com.google.firebase.auth not found.
03-03 10:07:19.156 5337-5359/info.myapp.currency I/FirebaseAuth: [FirebaseAuth:] Loading module via FirebaseOptions.
03-03 10:07:19.156 5337-5359/info.myapp.currency I/FirebaseAuth: [FirebaseAuth:] Preparing to create service connection to gms implementation
03-03 10:07:19.249 5337-5337/info.myapp.currency I/FirebaseInitProvider: FirebaseApp initialization successful
03-03 10:07:19.252 5337-5337/info.myapp.currency I/InstantRun: starting instant run server: is main process
03-03 10:07:19.293 5337-5362/info.myapp.currency I/FA: App measurement is starting up, version: 11910
03-03 10:07:19.293 5337-5362/info.myapp.currency I/FA: To enable debug logging run: adb shell setprop log.tag.FA VERBOSE
03-03 10:07:19.293 5337-5362/info.myapp.currency I/FA: To enable faster debug mode event logging run:
adb shell setprop debug.firebase.analytics.app info.myapp.currency
03-03 10:07:19.293 5337-5362/info.myapp.currency D/FA: Debug-level message logging enabled
03-03 10:07:19.611 5337-5337/info.myapp.currency D/Currency List: Fragment added
03-03 10:07:19.630 5337-5337/info.myapp.currency D/RCurrency: onCreate Called
03-03 10:07:19.715 5337-5366/info.myapp.currency D/NetworkSecurityConfig: No Network Security Config specified, using platform default
03-03 10:07:19.777 5337-5337/info.myapp.currency D/RCurrency: onCreateView Called
03-03 10:07:19.805 5337-5373/info.myapp.currency D/OpenGLRenderer: HWUI GL Pipeline
03-03 10:07:19.806 5337-5362/info.myapp.currency D/FA: Logging event (FE): screen_view(_vs), Bundle[{firebase_event_origin(_o)=auto, firebase_screen_class(_sc)=MainActivity, firebase_screen_id(_si)=-8822734687014467414}]
03-03 10:07:19.884 5337-5373/info.myapp.currency I/OpenGLRenderer: Initialized EGL, version 1.4
03-03 10:07:19.884 5337-5373/info.myapp.currency D/OpenGLRenderer: Swap behavior 1
03-03 10:07:19.884 5337-5373/info.myapp.currency W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
03-03 10:07:19.884 5337-5373/info.myapp.currency D/OpenGLRenderer: Swap behavior 0
03-03 10:07:19.913 5337-5373/info.myapp.currency D/EGL_emulation: eglCreateContext: 0x8edb3ec0: maj 2 min 0 rcv 2
03-03 10:07:19.973 5337-5373/info.myapp.currency D/EGL_emulation: eglMakeCurrent: 0x8edb3ec0: ver 2 0 (tinfo 0x9e4d6200)
03-03 10:07:20.128 5337-5373/info.myapp.currency D/EGL_emulation: eglMakeCurrent: 0x8edb3ec0: ver 2 0 (tinfo 0x9e4d6200)
03-03 10:07:20.254 5337-5362/info.myapp.currency D/FA: Connected to remote service
03-03 10:07:20.385 5337-5337/info.myapp.currency D/RCurrency: parseData Called
03-03 10:07:20.385 5337-5337/info.myapp.currency D/RCurrency: requestData Called
03-03 10:07:20.437 5337-5344/info.myapp.currency I/zygote: Do partial code cache collection, code=30KB, data=21KB
03-03 10:07:20.440 5337-5344/info.myapp.currency I/zygote: After code cache collection, code=30KB, data=21KB
03-03 10:07:20.440 5337-5344/info.myapp.currency I/zygote: Increasing code cache capacity to 128KB
03-03 10:07:46.609 5337-5346/? W/zygote: Debugger told VM to exit with status -1
[ 03-03 10:07:46.610 5337: 5346 D/ ]
HostConnection::get() New Host Connection established 0xa09e4b00, tid 5346