Question

这是我的主要活动。我的微调器即使已经初始化也是null。无论何时访问任何布局元素，我的应用程序都会崩溃

对于我的生活，我无法弄清楚为什么。我花了很长时间在这上面，研究了许多在线帖子的解决方案，并尝试了一些修复。到目前为止，没有任何工作。有什么想法吗？

另外，忽略日期创建/排序代码。它非常混乱，我已经有了一个更简洁的方法，但是在我修复这个部分之前不会实现它。

注意：我的布局中的id都是正确的，我很确定这不是问题。

公共类RADIO_Live扩展了FragmentActivity {

SectionsPagerAdapter mSectionsPagerAdapter;

ViewPager mViewPager;
View fragviewLive;
View fragviewPod;

private int mYear, mMonth, mDay, cYear, cMonth, cDay;
private TextView mCurrentDate;
private TextView mSelectedDate;
private TextView TextCurrentTime;
private TextView TextTotalTime;

boolean firstRUN = true;

SeekBar Podseekbar;
int myProgress = 0;
int podMax = 0;
int CurrentPosition = 0;

boolean playerPODon = false;        // variable to keep track if live stream player and podcast player is on or off and if podacast player is paused
boolean playerPODon1st = true;

String mMonthName, cMonthName, cMonthFullName;
String podFileTest, podPlayName, SelectedHour, SelectedDate = null;
String showdate, HourShowText = null;

String[] podDates = new String[14];
String[] podDatesName = new String[14];
int testDay = 0;
int dayOfWeek;

private final Handler UIhandler = new Handler();

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    // Create the adapter that will return a fragment for each of the three primary sections
    // of the app.
    mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

    //context.startService(serviceIntent);
    startService(new Intent(this, RADIO_Service.class));

    // Set up the ViewPager with the sections adapter.
    mViewPager = (ViewPager) findViewById(R.id.pager);
    mViewPager.setAdapter(mSectionsPagerAdapter);
    fragviewPod = getLayoutInflater().inflate(R.layout.podcasts, null);

    // Capture the textview elements
    mCurrentDate = (TextView) fragviewPod.findViewById(R.id.currentdateDisplay);
    mSelectedDate = (TextView) fragviewPod.findViewById(R.id.selecteddateDisplay);

    TextTotalTime = (TextView) fragviewPod.findViewById(R.id.TotalTimeText);
    TextCurrentTime = (TextView) fragviewPod.findViewById(R.id.CurrentTimeText);

    // Retrieve the current date
    Calendar c = Calendar.getInstance();
    mYear = c.get(Calendar.YEAR);
    mMonth = c.get(Calendar.MONTH);
    mDay = c.get(Calendar.DAY_OF_MONTH);

    IntentFilter filt = new IntentFilter("fromService");
    RADIO_Live.this.registerReceiver(br, filt);

    IntentFilter Podfilt = new IntentFilter("fromServicePod");
    RADIO_Live.this.registerReceiver(PODbr, Podfilt);

    actBroadcast("null", "whatsplaying");

    ArrayList<CharSequence> dateadapterarray = new ArrayList<CharSequence>();

    int ArrayMarker = 0;
    for (int podtest = 1; podtest < 15; podtest++)  {
        MakeDateList(podtest);
        if (dayOfWeek != (1|7)) {
            podFileTest = cMonthName + " " + cDay + ", " + cYear;
            podDatesName[ArrayMarker] = podFileTest;
            String cYearTemp = cYear + "";
            String cMonthTemp = cMonth + "";
            if (cMonth >= 10) {
            } else {
                cMonthTemp = cMonthTemp.replace("0", "");
                cMonthTemp = "0" + cMonthTemp;
            }

            if (cDay > 9)   {
                podDates[ArrayMarker] = (cMonthTemp + "" + cDay + "" + cYearTemp.replace("20", ""));
            }
            if (cDay <= 9)  {
                podDates[ArrayMarker] = (cMonthTemp + "" + "0" + cDay + "" + cYearTemp.replace("20", ""));
            }
            ArrayMarker++;

        }
        if (dayOfWeek == (1|7) && (ArrayMarker > 0))    {
            ArrayMarker--;
        }
    }

    for (int buildtext = 0; buildtext < 14; buildtext++) {
        dateadapterarray.add(podDatesName[buildtext]);
    }

    fragviewPod = getLayoutInflater().inflate(R.layout.podcasts, null);
    Spinner datespinner = (Spinner) fragviewPod.findViewById(R.id.spinnerdate);
    Spinner hourspinner = (Spinner) fragviewPod.findViewById(R.id.spinnerhour);
    //Spinner hourspinner = (Spinner) mViewPager.findViewById(R.id.spinnerhour);

    ArrayAdapter<CharSequence> dateadapter = new ArrayAdapter<CharSequence>(RADIO_Live.this, android.R.layout.simple_spinner_item, dateadapterarray);
    dateadapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

    ArrayAdapter<CharSequence> houradapter = new ArrayAdapter<CharSequence>(RADIO_Live.this, android.R.layout.simple_spinner_item, R.array.hour_array);
    houradapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);


    datespinner.setAdapter(dateadapter);
    hourspinner.setAdapter(houradapter);

    // Display the current date under "Today's Date" at the top
    updateCurrentDate();
    datespinner.setOnItemSelectedListener(new DateOnItemSelectedListener());
    hourspinner.setOnItemSelectedListener(new HourOnItemSelectedListener());

    Button livebutton = (Button) fragviewLive.findViewById(R.id.button_streamstartstop);
    //livebutton.setOnClickListener((View.OnClickListener) this);

    Button podplaybutton = (Button)fragviewPod.findViewById(R.id.button_pod_play);
    //podplaybutton.setOnClickListener((View.OnClickListener) this);

}

更新：这是视图夸大的地方。我试图将两个视图膨胀到他们自己的静态LinearLayouts中，但这也不起作用。

所以在主要活动开始时：

static LinearLayout livelayout;
static LinearLayout podlayout;

然后是片段代码。它实际上是来自Android Studio的空默认应用程序的代码，其中包含我的东西：

public static class DummySectionFragment extends Fragment {
    public DummySectionFragment() {
    }

    public static final String ARG_SECTION_NUMBER = "section_number";

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        TextView textView = new TextView(getActivity());
        textView.setGravity(Gravity.CENTER);
        Bundle args = getArguments();
        int test = args.getInt(ARG_SECTION_NUMBER);

        livelayout = (LinearLayout)inflater.inflate(R.layout.live, null);
        podlayout = (LinearLayout)inflater.inflate(R.layout.podcasts, null);

        inflater.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        int resID = 0;
        switch (test) {
            case 1:
                    resID = R.layout.live;
                    break;
            case 2: 
                    resID = R.layout.podcasts;
                    break;
        }
        //textView.setText(Integer.toString(args.getInt(ARG_SECTION_NUMBER)));
        View fragview = inflater.inflate(resID, null);
        return fragview;
    }
}

因此，为了澄清，我有一个main.xml，它只是标题和页面适配器，然后是live.xml和podcast.xml。

main.xml中：

<android.support.v4.view.ViewPager         
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".RADIO_Live" >

<!--
This title strip will display the currently visible page title, as well as the page
titles for adjacent pages.
-->
<android.support.v4.view.PagerTitleStrip android:id="@+id/pager_title_strip"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="top"
    android:background="#33b5e5"
    android:textColor="#fff"
    android:paddingTop="4dp"
    android:paddingBottom="4dp" />
</android.support.v4.view.ViewPager>

Live.xml：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/tab1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#ffffff"
android:orientation="vertical" >

<LinearLayout android:id="@+id/tab1.1"
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:layout_marginTop="15sp"
        android:layout_marginBottom="10sp" android:layout_marginLeft="30sp"
        android:layout_marginRight="30sp" android:textSize="18sp"
        android:text="@string/LiveTabBlurb" />
</LinearLayout>
<Button android:id="@+id/button_streamstartstop"
    android:layout_width="fill_parent" android:layout_height="wrap_content"
    android:layout_marginTop="10sp" android:layout_marginLeft="20sp"
    android:layout_marginRight="20sp" android:textSize="28sp"
    android:textStyle="italic" android:textColor="#FFFFFF" android:text="@string/ListenLiveText" android:onClick="LiveButtonClick" />

<ProgressBar android:layout_gravity="center"
    android:layout_height="100dp" android:layout_width="wrap_content"
    android:id="@+id/liveProgress" android:paddingTop="30dp"
    android:indeterminateBehavior="cycle" android:indeterminate="true"
    android:visibility="gone">
</ProgressBar>

<ProgressBar
    android:id="@+id/liveProgress"
    style="?android:attr/progressBarStyleLarge"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingTop="20dp"
    android:visibility="gone" />

</LinearLayout>

Podcasts.xml：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/tab2" android:orientation="vertical"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:background="#ffffff">

<LinearLayout android:orientation="horizontal" android:layout_width="wrap_content"
    android:layout_height="wrap_content">
    <LinearLayout android:orientation="vertical" android:layout_width="160dp"
        android:layout_height="wrap_content">
        <TextView android:id="@+id/currentdateDescription"
            android:layout_width="wrap_content" android:layout_height="wrap_content"
            android:paddingTop="5px" android:text="Today's Date:" />
        <TextView android:id="@+id/currentdateDisplay"
            android:layout_width="wrap_content" android:layout_height="wrap_content"
            android:paddingBottom="5px" android:text="" />
    </LinearLayout>
    <LinearLayout android:orientation="vertical" android:layout_width="160dp"
        android:layout_height="wrap_content">
        <TextView android:id="@+id/selecteddateDescription"
            android:layout_width="wrap_content" android:layout_height="wrap_content"
            android:paddingTop="5px" android:text="Selected Date:" />
        <TextView android:id="@+id/selecteddateDisplay"
            android:layout_width="wrap_content" android:layout_height="wrap_content"
            android:paddingBottom="5px" android:text="None Selected" />
    </LinearLayout>
</LinearLayout>
<LinearLayout android:orientation="horizontal" android:layout_width="fill_parent"
    android:layout_height="wrap_content">
    <Spinner android:id="@+id/spinnerdate" android:layout_width="160dp"
        android:layout_height="wrap_content" android:prompt="@string/date_prompt" />
    <Spinner android:id="@+id/spinnerhour" android:layout_width="160dp"
        android:layout_height="wrap_content" android:prompt="@string/hour_prompt" />
</LinearLayout>
<Button android:id="@+id/button_pod_play"
    android:layout_width="fill_parent" android:layout_height="wrap_content"
    android:layout_marginLeft="20sp" android:layout_marginRight="20sp"
    android:paddingTop="5sp" android:layout_marginTop="10sp"
    android:textSize="28sp" android:textColor="#FFFFFF" android:textStyle="italic"
    android:text="@string/PlayPodText" android:onClick="PodButtonClick"/>
<SeekBar android:layout_width="fill_parent"
    android:layout_height="wrap_content" android:paddingTop="5dp"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_margin="10dp" android:id="@+id/seekBar" android:max="100"
    android:progress="0" />

<LinearLayout android:orientation="horizontal" android:layout_width="fill_parent"
    android:layout_height="wrap_content">

    <TextView android:id="@+id/CurrentTimeText"
        android:layout_width="60dp" android:layout_height="wrap_content"
        android:paddingTop="5px" android:textSize="18px" android:text="0:00" />
    <ProgressBar android:layout_gravity="center"
        android:layout_height="wrap_content" android:layout_width="fill_parent"
        android:id="@+id/podProgress" android:paddingTop="10px"
        android:indeterminateBehavior="cycle" android:indeterminate="true"
        android:visibility="gone">
    </ProgressBar>
    <TextView android:id="@+id/TotalTimeText"
        android:layout_width="fill_parent" android:layout_height="wrap_content"
        android:paddingTop="5px" android:gravity="right" android:textSize="18px"
        android:text="0:00" />
</LinearLayout>

</LinearLayout>

稍微多一点的背景。这个应用程序实际上是100％工作，但我使用了一个丑陋的Android 2.0天标签界面，并希望更新与一个漂亮的Holo界面与页面视图适配器。在我尝试之前没有这样做过，我遇到了这些问题。

更新：我有一些工作（有点）。调试时，我的两个微调器不再为null，至少根据调试器。但是，只要活动访问任何布局对象，应用程序仍然会崩溃。如果我尝试设置任何文本视图或微调器，它似乎崩溃，或者只是不更新内容。

片段代码：

public class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int i) {
        //Fragment fragment = new DummySectionFragment();

        Fragment fragment;
        Bundle args = new Bundle();
        switch(i){
            case 0:
                fragment = new fragLive();
                args.putInt(fragLive.ARG_SECTION_NUMBER, i + 1);
                break;
            case 1:
                fragment = new fragPod();
                args.putInt(fragPod.ARG_SECTION_NUMBER, i + 1);
                break;
            default:
                fragment = new fragLive();
                args.putInt(fragLive.ARG_SECTION_NUMBER, i + 1);
                break;
        }

        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public int getCount() {
        return 2;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0: return getString(R.string.title_section1).toUpperCase();
            case 1: return getString(R.string.title_section2).toUpperCase();
        }
        return null;
    }
}

/**
 * Two classes for the two layout fragments
 */
public class fragLive extends Fragment {
    public fragLive() {
    }

    public static final String ARG_SECTION_NUMBER = "section_number";

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        TextView textView = new TextView(getActivity());
        textView.setGravity(Gravity.CENTER);
        Bundle args = getArguments();
        int test = args.getInt(ARG_SECTION_NUMBER);

        inflater.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        //textView.setText(Integer.toString(args.getInt(ARG_SECTION_NUMBER)));
        fragviewLive = inflater.inflate(R.layout.live, null);
        return fragviewLive;
    }
}

public class fragPod extends Fragment {
    public fragPod() {
    }

    public static final String ARG_SECTION_NUMBER = "section_number";

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        TextView textView = new TextView(getActivity());
        textView.setGravity(Gravity.CENTER);
        Bundle args = getArguments();
        int test = args.getInt(ARG_SECTION_NUMBER);

        inflater.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        //textView.setText(Integer.toString(args.getInt(ARG_SECTION_NUMBER)));
        fragviewPod = inflater.inflate(R.layout.podcasts, null);
        return fragviewPod;
    }
}

Answer 1

首先检查你的main.xml布局中是否有R.id.spinnerdate 如果是这种情况，请尝试以下方法：

由于您使用的是FragmentActivity，请先扩充您的布局。

 private View myView;

 .....

myView = getLayoutInflater().inflate(R.layout.main, null);

并将datespinner引用更改为：

Spinner datespinner = (Spinner) myView.findViewById(R.id.spinnerdate);

Answer 2

您需要在片段视图中调用findViewById()：

Spinner datespinner = (Spinner) fragmentThatContainsSpinner.getView().findViewById(R.id.spinnerdate);

Answer 3

问题在于语境化，这在某种程度上是一个特殊的问题。应该平衡上下文问题，并且在没有任何上下文或范围问题的情况下提供对象。但在等待此类更新之前，我们可以使用下面显示的解决方案。

即。当你在Button -inside-a片段上点击监听器设置鼠标时......

示例（null）片段代码：

MyButton.setOnClickListener(new View.OnClickListener(){

  @Override 
  public void onClick(View MyClickViewer) {

    //here the spinner is null?
    Spinner MySpinner = null; 

    //it is so result is null...
    MyClickViewer.findViewById(R.id.a_spinner);

  }

}

MyClickViewer位于Click View的-context-内。
MySpinner位于Root View的-context-里面。

示例（非空）微调器检索：

//not null anymore...
Spinner MySpinner = 
  (Spinner)MyClickViewer.getRootView().findViewById(R.id.a_spinner);

方法 getRootView（）允许您制作'fragment.xml'文件，而无需在任何'main.xml'文件中重新定义对象。最重要的是，您可以从Spinner获取任何值，因为它现在被引用而不再为null。

示例（非空）微调位置：

MySpinner.getSelectedItemPosition()

Android微调器为null

3 个答案: