[我有一个Android应用,在其中显示带有某些复选框的表单。我想根据选中的复选框来查询firestore。我无法获取已选中复选框的数组/数组列表。为了进行测试,我添加了一个textview。如果我的测试正常,我想使用新填充的数组/数组列表的成员设置textview的文本。
[当我选中任何复选框并单击按钮时,我的应用程序崩溃。假设我选中了box4。条件(item4.isChecked)应该为true,因此必须将item4添加到我的数组列表中,该数组列表的大小现在不等于零
if(item4.isChecked()){
testingArrayList.add("item4");
}
为什么我会得到数组长度为零的错误?
这是我的代码:
package com.example.XX;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.firestore.CollectionReference;
import com.google.firebase.firestore.DocumentSnapshot;
import com.google.firebase.firestore.FieldPath;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.Query;
import com.google.firebase.firestore.QuerySnapshot;
import java.util.ArrayList;
import java.util.List;
public class todayQuestionFragment extends Fragment {
FirebaseFirestore db = FirebaseFirestore.getInstance();
CheckBox item1;
CheckBox item2;
CheckBox item3;
CheckBox item4;
CheckBox item5;
CheckBox item6;
CheckBox item7;
CheckBox item8;
CheckBox item9;
CheckBox item10;
Button button;
ProgressBar progressBar;
TextView textView;//just for testing
public todayQuestionFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_today_question, container, false);
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
item1=view.findViewById(R.id.checkBox_item1);
item2=view.findViewById(R.id.checkBox_item2);
item3=view.findViewById(R.id.checkBox_item3);
item4=view.findViewById(R.id.checkBox_item4);
item5=view.findViewById(R.id.checkBox_item5);
item6=view.findViewById(R.id.checkBox_item6);
item7=view.findViewById(R.id.checkBox_item7);
item8=view.findViewById(R.id.checkBox_item8);
item9=view.findViewById(R.id.checkBox_item9);
item10=view.findViewById(R.id.checkBox_item10);
textView=view.findViewById(R.id.testingCheckBox);
Button button=view.findViewById(R.id.toMainQueryButton);
final NavController navController= Navigation.findNavController(view);
final ArrayList<String> testingArrayList = new ArrayList<String>();
if(item1.isChecked()){
testingArrayList.add("item1");
}
if(item2.isChecked()){
testingArrayList.add("item2");
}if(item3.isChecked()){
testingArrayList.add("item3");
}if(item4.isChecked()){
testingArrayList.add("item4");
}
if(item5.isChecked()){
testingArrayList.add("item5");
}
if(item6.isChecked()){
testingArrayList.add("item6");
}
if(item7.isChecked()){
testingArrayList.add("item7");
}if(item8.isChecked()){
testingArrayList.add("item8");
}if(item9.isChecked()){
testingArrayList.add("item9");
}
if(item10.isChecked()){
testingArrayList.add("item10");
}
final String[] testArray = new String[testingArrayList.size()];
for(int j =0;j<testingArrayList.size();j++){
testArray[j] = testingArrayList.get(j);
}
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
textView.setText(testArray[0]);
}
});
}
}
Logcat:
2020-06-12 14:48:10.772 4622-4622/com.example.XX E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.XX, PID: 4622
java.lang.ArrayIndexOutOfBoundsException: length=0; index=0
at com.example.XX.todayQuestionFragment$1.onClick(todayQuestionFragment.java:140)
at android.view.View.performClick(View.java:7201)
at android.view.View.performClickInternal(View.java:7170)
at android.view.View.access$3500(View.java:806)
at android.view.View$PerformClick.run(View.java:27582)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7710)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
发现我的错误。我的所有带有if条件和arraylist / array的逻辑都需要在我的按钮的onClickListener内添加]