Java 带有片段和自定义列表的NullPointerException

我正在开发一个android应用程序，我从一个例子中得到了这段代码作为列表。此页面是3页ViewPager的片段活动部分。代码：

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class OverviewFragment extends Fragment {

private ViewGroup mContainerView;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_overview, container, false);

    // Initialize
    mContainerView = (ViewGroup)getActivity().findViewById(R.id.container);

    // Add some items
    addItem();
    addItem();
    addItem();
    addItem();

    return rootView;
}

public boolean onCreateOptionsMenu(Menu menu) {
    super.onCreateOptionsMenu(menu, null);
    getActivity().getMenuInflater().inflate(R.menu.activity_overviewfragment, menu);
    return true;
}

private void addItem() {
    // Instantiate a new "row" view.
    final ViewGroup newView = (ViewGroup) LayoutInflater.from(getActivity()).inflate(
            R.layout.upcoming_list_item, mContainerView, false);

    // Set the text in the new row to a random country.
    ((TextView) newView.findViewById(android.R.id.text1)).setText(
            UPCOMING[(int) (Math.random() * UPCOMING.length)]);

    // Set a click listener for the "X" button in the row that will remove the row.

    /**
    newView.findViewById(R.id.delete_button).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            // Remove the row from its parent (the container view).
            // Because mContainerView has android:animateLayoutChanges set to true,
            // this removal is automatically animated.
            mContainerView.removeView(newView);

            // If there are no rows remaining, show the empty view.
            if (mContainerView.getChildCount() == 0) {
                findViewById(android.R.id.empty).setVisibility(View.VISIBLE);
            }
        }
    });
    */

    // Because mContainerView has android:animateLayoutChanges set to true,
    // adding this view is automatically animated.
    mContainerView.addView(newView, 0);
}

private static final String[] UPCOMING = new String[] {
    "Apartmen loan -- 200 $", "Car fix invoice -- 300 $", "Internet bill -- 70$", "dinner -- 20$"
};
}

错误：

06-23 13:57:44.440: E/AndroidRuntime(6200): FATAL EXCEPTION: main
06-23 13:57:44.440: E/AndroidRuntime(6200): Process: com.acceleratedcode.apps.myApp, PID: 6200
06-23 13:57:44.440: E/AndroidRuntime(6200): java.lang.NullPointerException
06-23 13:57:44.440: E/AndroidRuntime(6200):     at com.acceleratedcode.apps.myApp.OverviewFragment.addItem(OverviewFragment.java:47)
06-23 13:57:44.440: E/AndroidRuntime(6200):     at com.acceleratedcode.apps.myApp.OverviewFragment.onCreateView(OverviewFragment.java:27)
06-23 13:57:44.440: E/AndroidRuntime(6200):     at android.support.v4.app.Fragment.performCreateView(Fragment.java:1500)
06-23 13:57:44.440: E/AndroidRuntime(6200):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:938)
06-23 13:57:44.440: E/AndroidRuntime(6200):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1115)
06-23 13:57:44.440: E/AndroidRuntime(6200):     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
06-23 13:57:44.440: E/AndroidRuntime(6200):     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1478)

错误在addItem方法的某个地方（非常确定）

Xml:

---

您的问题最有可能出现在这一行：

 ((TextView) newView.findViewById(android.R.id.text1)).setText(
            UPCOMING[(int) (Math.random() * UPCOMING.length)]);

将其更改为：（假设布局中的

TextView

具有id“text1”）

您引用的id已被Android占用，并且（可能）在布局文件中找不到

除此之外：

---

尝试使用View而不是

ViewGroup

作为“新视图”。并使用

LinearLayout

而不是

ViewGroup

来创建“mContainerView”。

android.R.id.text1不能直接用于下面的代码中

（（TextView）newView.findviewbyd（android.R.id.text1））.setText(
即将到来的[（int）（Math.random（）*即将到来的.length）]

你应该创建一个文本视图，然后使用它。
你的概览片段的第47行到底在哪里？如果不手动计算，我怎么能找到呢？我对eclipse有点陌生：（（TextView）newView.findViewById（android.R.id.text1））.setText（好的，请看Philipp Jahoda的回答，这很可能是问题所在。现在我在第27行：addItem（）和第71行：mContainerView.addView（newView，0）；@Philipp Jahoda仍然在这一行抛出NullPoinerException：mContainerView=（LinearLayout）getView（）.findViewById（R.id.container）；Magic！将其第25行从getView（）更改为rootView.findViewById，成功了！很好！谢谢；）
 ((TextView) newView.findViewById(android.R.id.text1)).setText(
            UPCOMING[(int) (Math.random() * UPCOMING.length)]);

 ((TextView) newView.findViewById(R.id.text1)).setText(
            UPCOMING[(int) (Math.random() * UPCOMING.length)]);