我正在使用Firebase Firestore进行更新。我目前可以在RecyclerView中单击一个位置，然后从那里获取相关信息到我的编辑文本框中。但是，我当前的问题是我正在努力选择正确的ID进行更新。我试图弄清楚如何在更新时将代码用于原始选择位置。
当前，当我单击该职位时，会有一个吐司显示器显示正确的ID和位置，然后将您带到我的更新活动，当我单击“保存”时，它将显示不正确的ID。我正在尝试使该ID匹配，以便随后可以使我的更新正常工作。
我目前正在努力使代码正常工作，但是没有运气。我要做的一件事是更改代码，以便当我单击更新时它告诉我正在选择哪个ID。这样做时会导致选择错误的ID /随机ID。这使我认为我的问题在于选择ID。
ReadActivity
这是我在RecyclerView中选择位置时的代码。当前，此功能可以正常运行，并选择正确的ID。
public void onItemClick(DocumentSnapshot documentSnapshot, int position) {
Book book = documentSnapshot.toObject(Book.class);
String id = documentSnapshot.getId();
String path = documentSnapshot.getReference().getPath();
Toast.makeText(AdminReadActivity.this,
"Position: " + position + " ID: " + id, Toast.LENGTH_SHORT).show();
String chapterName = adapter.getItem(position).getChapterName();
String chapterInfo = adapter.getItem(position).getChapterInfo();
Integer chapterNumber = adapter.getItem(position).getChapterNumber();
Intent intent = new Intent(AdminReadActivity.this, AdminUpdateActivity.class);
intent.putExtra("mChapterName", chapterName);
intent.putExtra("mChapterInfo", chapterInfo);
intent.putExtra("mChapterNumber", chapterNumber);
intent.putExtra("mMyId", id);
startActivity(intent);
已编辑：UpdateActivity
这是我的updateBook方法。到目前为止，这只是显示了不正确的ID。
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.save_icon:
updateBook();
Intent intent = new Intent(AdminUpdateActivity.this, AdminReadActivity.class);
startActivity(intent);
return true;
default:
return super.onOptionsItemSelected(item);
}
private void updateBook() {
Intent intent = getIntent();
String id = intent.getStringExtra("id");
FirebaseFirestore db = FirebaseFirestore.getInstance();
DocumentReference bookRef = db.collection("Book").document(id);
bookRef.addSnapshotListener(new EventListener<DocumentSnapshot>() {
@Override
public void onEvent(@Nullable DocumentSnapshot documentSnapshot, @Nullable FirebaseFirestoreException e) {
String id = documentSnapshot.getId();
FirebaseFirestore db = FirebaseFirestore.getInstance();
DocumentReference bookRef = db.collection("Book").document(id);
Toast.makeText(AdminUpdateActivity.this, " ID: " + id, Toast.LENGTH_SHORT).show();
}
});
}
BookAdapter
itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION && listener != null)//ensure the user does not click deleted items
{
listener.onItemClick(getSnapshots().getSnapshot(position), position);
}
}
});
public interface OnItemClickListener {
void onItemClick(DocumentSnapshot documentSnapshot, int position);
}
有人可以建议我单击UpdateActivity中的“保存”以显示与第一次从RecyclerView中选择ID时相同的ID的方法。
更改后，我现在从OnOptionSelected和UpdateBook（）类中收到此错误。
编辑：添加了错误日志
java.lang.NullPointerException: Provided document path must not be null.
at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:906)
at com.google.firebase.firestore.CollectionReference.document(com.google.firebase:firebase-firestore@@18.2.0:110)
at com.example.home.optometryapplication.AdminUpdateActivity.updateBook(AdminUpdateActivity.java:155)
at com.example.home.optometryapplication.AdminUpdateActivity.onOptionsItemSelected(AdminUpdateActivity.java:101)
at android.app.Activity.onMenuItemSelected(Activity.java:3204)
at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:407)
at android.support.v7.app.AppCompatActivity.onMenuItemSelected(AppCompatActivity.java:195)
at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:108)
at android.support.v7.app.AppCompatDelegateImplV9.onMenuItemSelected(AppCompatDelegateImplV9.java:674)
at android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:822)
at android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:171)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:973)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:963)
at android.support.v7.widget.ActionMenuView.invokeItem(ActionMenuView.java:624)
at android.support.v7.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:150)
at android.view.View.performClick(View.java:5610)
at android.view.View$PerformClick.run(View.java:22265)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
答案 0 :(得分：1)
您需要通过OnItemClick方法将ID传递给UpdateActivity
public void onItemClick(DocumentSnapshot documentSnapshot, int position) {
Book book = documentSnapshot.toObject(Book.class);
String id = documentSnapshot.getId();
String path = documentSnapshot.getReference().getPath();
Toast.makeText(AdminReadActivity.this,
"Position: " + position + " ID: " + id, Toast.LENGTH_SHORT).show();
String chapterName = adapter.getItem(position).getChapterName();
String chapterInfo = adapter.getItem(position).getChapterInfo();
Integer chapterNumber = adapter.getItem(position).getChapterNumber();
Intent intent = new Intent(AdminReadActivity.this, AdminUpdateActivity.class);
intent.putExtra("mChapterName", chapterName);
intent.putExtra("mChapterInfo", chapterInfo);
intent.putExtra("mChapterNumber", chapterNumber);
intent.putExtra("mId", id); // Add this line
startActivity(intent);
然后在UpdateActivity中获取ID（以与获取mChapterName，mChapterInfo ...相同的方式）并在UpdateBook1（）方法中使用此ID
private void updateBook1() {
FirebaseFirestore db = FirebaseFirestore.getInstance();
DocumentReference bookRef = db.collection("Book").document(id); // ID got from the Intent Extras
}