我还在做我的Android应用。现在我面临这个问题。
代码:
package smoca.ch.kreagen.Fragments;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import io.realm.Realm;
import io.realm.RealmQuery;
import smoca.ch.kreagen.R;
import smoca.ch.kreagen.models.Idea;
public class SingleIdeaFragment extends Fragment{
private TextView title;
private TextView owner;
private TextView description;
private Realm realm;
private Idea idea;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View layout = inflater.inflate(R.layout.single_idea_fragment_layout, container, false); // inflate layout for Fragment
idea = getSingleIdea(getActivity().getBaseContext());
title = (TextView) container.findViewById(R.id.singleIdeaTitle);
owner = (TextView) container.findViewById(R.id.singleIdeaOwner);
description = (TextView) container.findViewById(R.id.singleIdeaDescription);
title.setText(idea.getTitle());
owner.setText(idea.getOwnerId());
description.setText(idea.getText());
return layout;
}
public Idea getSingleIdea(Context ctx) {
realm = Realm.getInstance(ctx);
RealmQuery<Idea> ideaQuery = realm.where(Idea.class);
idea = ideaQuery.findFirst();
return idea;
}
}
Error.Error.I know, the problem is my TextViews (title, owner, description) are null:
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at smoca.ch.kreagen.Fragments.SingleIdeaFragment.onCreateView(SingleIdeaFragment.java:35)
我知道,问题是我的TextViews(标题,所有者,描述)是空的。但我不知道为什么。我从布局中把它们分配给了TextViews,引用了ID。
我到底做错了什么?
当你调用 inflater.inflate
你指定了第三个参数。attachToRoot作为 false
. 这就意味着,充气机返回的仅仅是视图的 R.layout.single_idea_fragment_layout
. 因此: findViewById
应召 layout
而非 container
title = (TextView) layout.findViewById(R.id.singleIdeaTitle);
owner = (TextView) layout.findViewById(R.id.singleIdeaOwner);
description = (TextView) layout.findViewById(R.id.singleIdeaDescription);