与findViewById的NullPointerError

Question

我试图遍历EditText id的数组以获取所有文本并将它们添加到单个邮件中。我理解NullPointers是如何工作的，但是如果我像以前一样初始化它们，我就无法理解temp和temp2是如何NullPointers的，只是这次它处于循环中。这是我得到的错误：

Process: com.example.brandon.netflixcalculator, PID: 6369
java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
at com.example.brandon.netflixcalculator.Exact_Activity.getInfo(Exact_Activity.java:152)
at com.example.brandon.netflixcalculator.Exact_Activity.updateFile(Exact_Activity.java:125)
at com.example.brandon.netflixcalculator.Exact_Activity$Listener.onClick(Exact_Activity.java:76)
at android.view.View.performClick(View.java:5254)
at android.view.View$PerformClick.run(View.java:21179)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6895)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)

以下是方法：

int[] editTextIds = {R.id.editTextMon, R.id.editTextTues, R.id.editTextWed, R.id.editTextThurs, R.id.editTextFri,
R.id.editTextSat, R.id.editTextSun};
int[] spinnerIds = {R.id.spinnerMon, R.id.spinnerTues, R.id.spinnerWed, R.id.spinnerThurs, R.id.spinnerFri,
       R.id.spinnerSat, R.id.spinnerSun};


public String getInfo(){
    String msg = "";
    StringBuffer sb = new StringBuffer();
    for(int i = 0; i < editTextIds.length; i++){
        EditText temp = (EditText)findViewById(editTextIds[i]);
        Spinner temp2 = (Spinner)findViewById(spinnerIds[i]);
        sb.append(temp.getText().toString());
        sb.append(".");
        sb.append(temp2.getSelectedItem().toString());
        sb.append("\n");
    }
    msg = sb.toString();
    return msg;
}

这是我的布局。一周中的每一天都是它自己的片段，所以这里是星期一（除了每个组件的id之外它们都是一样的）：

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.brandon.netflixcalculator.Monday"
style="@style/Main">

<!-- TODO: Update blank fragment layout -->

<LinearLayout
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center_horizontal|top">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/editTextMon"
        android:layout_gravity="center_horizontal"
        android:background="@drawable/apptheme_edit_text_holo_light"
        android:hint="Average number of available viewing minutes on Monday"
        android:numeric="integer"
        android:layout_marginTop="15dp" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Probability of above viewing time on Monday"
        android:id="@+id/textView"
        android:layout_gravity="center_horizontal"
        android:textAlignment="center"
        android:layout_marginTop="15dp" />

    <Spinner
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/spinnerMon"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="15dp" />
</LinearLayout>