Android 添加setOnclickListener后，将发生nullPointerException错误

我刚开始安卓编程。我是靠书本学习的，只是照本宣科。 但是错误发生了。我认为错误发生在serOnClickListener方法中。因为添加此方法后，不要运行应用程序（在设备上）。我搜索nullpointerException，但没有得到答案。。请帮帮我

我想知道碎片的布局。书籍仅用activity_xml解释布局代码，但我的 eclipse有两个xml文件fragment.xml，activity.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.bignerdranch.android.geoquiz.QuizActivity"
    tools:ignore="MergeRootFrame" />

---

代码

---问题方法

    mTrueButton.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

        }
    });

    mFalseButton.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

        }
    });

---

---

fragment.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical">


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="24dp"
        android:text="@string/question_text" />

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

            <Button
                android:id="@+id/true_button"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/true_button"
                />
            <Button
                android:id="@+id/false_button"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/false_button"
                />          


        </LinearLayout>

</LinearLayout>

---

按钮属于片段的视图层次结构。您应该将它们的初始化移动到
Fragment.onViewCreated
setContentView（R.layout.activity\u）中R.layout.activity\u测验！=R.layout.Fragments Fragment.onViewCreated的位置可能存在重复？请像对onCreateView所做的那样覆盖它
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical">


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="24dp"
        android:text="@string/question_text" />

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

            <Button
                android:id="@+id/true_button"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/true_button"
                />
            <Button
                android:id="@+id/false_button"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/false_button"
                />          


        </LinearLayout>

</LinearLayout>

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.bignerdranch.android.geoquiz.QuizActivity"
    tools:ignore="MergeRootFrame" />

03-16 21:35:44.177: E/Trace(19811): error opening trace file: No such file or directory (2)
03-16 21:35:44.177: D/ActivityThread(19811): setTargetHeapUtilization:0.25
03-16 21:35:44.177: D/ActivityThread(19811): setTargetHeapIdealFree:8388608
03-16 21:35:44.187: D/ActivityThread(19811): setTargetHeapConcurrentStart:2097152
03-16 21:35:44.197: V/ActivityThread(19811): Class path: /data/app/com.bignerdranch.android.geoquiz-1.apk, JNI path: /data/data/com.bignerdranch.android.geoquiz/lib
03-16 21:35:44.277: I/ActionBarImpl(19811): mActivity.getLocalClassName : QuizActivityid : 0
03-16 21:35:44.287: I/ActionBarImpl(19811): mContext.getPackageName : com.bignerdranch.android.geoquizid : 0
03-16 21:35:44.287: W/dalvikvm(19811): threadid=1: thread exiting with uncaught exception (group=0x41252438)
03-16 21:35:44.307: E/AndroidRuntime(19811): FATAL EXCEPTION: main
03-16 21:35:44.307: E/AndroidRuntime(19811): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.bignerdranch.android.geoquiz/com.bignerdranch.android.geoquiz.QuizActivity}: java.lang.NullPointerException
03-16 21:35:44.307: E/AndroidRuntime(19811):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2081)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2106)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at android.app.ActivityThread.access$600(ActivityThread.java:138)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1204)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at android.os.Handler.dispatchMessage(Handler.java:99)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at android.os.Looper.loop(Looper.java:137)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at android.app.ActivityThread.main(ActivityThread.java:4929)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at java.lang.reflect.Method.invokeNative(Native Method)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at java.lang.reflect.Method.invoke(Method.java:511)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at dalvik.system.NativeStart.main(Native Method)
03-16 21:35:44.307: E/AndroidRuntime(19811): Caused by: java.lang.NullPointerException
03-16 21:35:44.307: E/AndroidRuntime(19811):    at com.bignerdranch.android.geoquiz.QuizActivity.onCreate(QuizActivity.java:28)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at android.app.Activity.performCreate(Activity.java:5238)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1082)
03-16 21:35:44.307: E/AndroidRuntime(19811):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2045)
03-16 21:35:44.307: E/AndroidRuntime(19811):    ... 11 more