Question

我正在尝试迭代值的映射并将预定义布局的文本设置为地图的值我在地图上第一次迭代后得到一个NullPointerException，我不知道为什么。

对此的任何帮助将不胜感激。

片段

    Set keys = pairedValues.keySet();

    View summaryCell = inflater.inflate(R.layout.summary_list_cell, null);

    cellTitle = (TextView) view.findViewById(R.id.summaryListItemTitle);
    cellText = (TextView) view.findViewById(R.id.summaryListItemText);

    for(Iterator i = keys.iterator(); i.hasNext();) {
        String key = (String) i.next();

        switch(key) {
            case "eventCode": cellTitle.setText("Event Code");
                cellText.setText(pairedValues.get(key).second);
                break;
            case "accountId": cellTitle.setText(pairedValues.get(key).first);
                cellText.setText(pairedValues.get(key).second);
                break;
        }

        linearLayout.addView(summaryCell);

    }

布局这个片段位于RelativeLayout内部，其中包含大量其他内容。

<ScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/summaryScrollView"
    android:layout_below="@+id/summaryFragback"
    android:layout_above="@+id/summarySaveEventButton">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@+id/summaryFragback"
        android:id="@+id/summaryVerticalView"
        android:padding="10dp"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_above="@+id/summarySaveEventButton">

    </LinearLayout>
</ScrollView>

将预定义的布局添加到LinearLayout

<?xml version="1.0" encoding="utf-8"?>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:text="Medium Text"
    android:textColor="@color/Black"
    android:layout_marginLeft="10dp"
    android:layout_marginTop="10dp"
    android:id="@+id/summaryListItemTitle"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

<TextView
    android:layout_width="match_parent"
    android:layout_height="40dp"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:background="@color/White"
    android:paddingTop="5dp"
    android:paddingLeft="5dp"
    android:layout_marginTop="10dp"
    android:layout_marginLeft="20dp"
    android:layout_marginRight="20dp"
    android:text="Text"
    android:textColor="@color/Dark_Background"
    android:id="@+id/summaryListItemText"
    android:layout_below="@+id/summaryListItemTitle"
    android:layout_alignLeft="@+id/summaryListItemTitle"
    android:layout_alignStart="@+id/summaryListItemTitle" />

（最后但并非最不重要）LogCat

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at com.koodoocreative.isnapshot.fragments.SummaryFragment.onCreateView(SummaryFragment.java:79)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at android.support.v4.app.Fragment.performCreateView(Fragment.java:1789)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:955)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1138)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:740)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1501)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:458)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at android.os.Handler.handleCallback(Handler.java:739)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:95)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:135)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5257)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:372)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
11-17 18:33:47.571 6527-6527/com.koodoocreative.isnapshot E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

Answer 1

既然你得到了你的视图：

View summaryCell = inflater.inflate(R.layout.summary_list_cell, null);

您必须使用那个（summaryCell）来检索其子女：

cellTitle = (TextView) summaryCell.findViewById(R.id.summaryListItemTitle);
cellText = (TextView) summaryCell.findViewById(R.id.summaryListItemText);

设置TextView的文本时出现NullPointerException

1 个答案: