[英]ArrayList IndexOfBound exceptions when to get data from firestore database, why?
我有一個 Recycler 視圖,其中填充了 2 個數組列表,第一個是卡片視圖標題,第二個是它的內容,問題發生在第二個數組列表中,例如,它從 Firestore 接收數據。
下面是我如何填充從本地雲和字符串接收到的數據數組列表的代碼。
valorCard.add(0, "R$: 16.402,98"); // must be added on first position
DocumentReference dbRef = db.collection("Usuarios").document(firebaseAuth.getCurrentUser().getUid().toString());
dbRef.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>(){
@Override
public void onSuccess(DocumentSnapshot documentSnapshot) {
valorCard.add(1, documentSnapshot.get("quantBois").toString()); // must be added on second position
}
});
valorCard.add(2,"25.000,00$"); // must be added on thrid position
valorCard.add(3,"25/05/2020"); // must be added on fourth position
當代碼運行時,返回:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.agrolucros2019, PID: 29318
java.lang.IndexOutOfBoundsException: Index: 2, Size: 1
at java.util.ArrayList.add(ArrayList.java:483)
at com.example.agrolucros2019.fragmentos.home.HomeFragment.onCreateView(HomeFragment.java:65)
at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2600)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:881)
at androidx.fragment.app.FragmentManagerImpl.addAddedFragments(FragmentManagerImpl.java:2100)
at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1874)
at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1830)
at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManagerImpl.java:1727)
at androidx.fragment.app.FragmentManagerImpl.dispatchStateChange(FragmentManagerImpl.java:2663)
at androidx.fragment.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManagerImpl.java:2613)
at androidx.fragment.app.Fragment.performActivityCreated(Fragment.java:2624)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:904)
at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1238)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1303)
at androidx.fragment.app.FragmentManagerImpl.dispatchStateChange(FragmentManagerImpl.java:2659)
at androidx.fragment.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManagerImpl.java:2613)
at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:246)
at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:542)
at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:201)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1395)
at android.app.Activity.performStart(Activity.java:7361)
at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3150)
at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:180)
at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:165)
at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:142)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1960)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7094)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:975)
我相信這是由於雲中的數據請求需要一些時間來接收數據,並且由於我需要將數據准確插入第二(1)位置,這會導致延遲導致 0 跳轉對於 2(因為 1 尚未填寫)出錯。
快速解決方法是在將數據添加到索引 2 和 3 之前檢查 ArrayList 的大小。如果尚未收到來自數據庫的數據,您可以:
或者
第二種選擇的例子:
dbRef.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>(){
@Override
public void onSuccess(DocumentSnapshot documentSnapshot) {
valorCard.add(1, documentSnapshot.get("quantBois").toString()); // must be added on second position
}
});
if (valorCard.size() == 1){ // Check here
valorCard.add(null);
}
valorCard.add(2,"25.000,00$"); // must be added on thrid position
valorCard.add(3,"25/05/2020"); // must be added on fourth position
您會收到此exception
因為您的ArrayList
( valorCard
) 大小為 1 並且您要在位置 2 添加項目
您可以通過在創建數組時設置數組列表大小來糾正此問題:
ArrayList<String> valorCard = ArrayList<>(4);
但是未設置的值將為null
以防止null
您可以在創建valorCard
時使用此代碼:
ArrayList<String> valorCard = ArrayList<>();
valorCard.addAll( { "", "", "", "" } );// four strings for size of 4
我的問題的這個原因是 ArrayList 中的一個方法“add”,這個方法覆蓋了位置的最舊值並“放置”到下一個地址,解決方案是使用 Set 方法,所以,然后是“valorCard.add”我'm 覆蓋到 valorCard.set。
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