这是代码。不确定是否需要更多信息。该应用程序完全按照预期和期望的方式工作，除了屏幕旋转。旋转屏幕时会发生此崩溃。我是 Android 的新手，正在努力学习，所以如果还有其他需要，请告诉我。
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.d(TAG, "onCreate(Bundle) called");
setContentView(R.layout.activity_quiz);
if(savedInstanceState != null){
mCurrentIndex = savedInstanceState.getInt(KEY_INDEX, 0);
}
mCheatButton = (Button)findViewById(R.id.cheat_button);
mCheatButton.setOnClickListener(new View.OnClickListener() {//this is line 127
@Override
public void onClick(View v) {
Intent i = new Intent(QuizActivity.this, CheatActivity.class);
boolean answerIsTrue = mQuestionBank[mCurrentIndex].isTrueQuestion();
i.putExtra(CheatActivity.EXTRA_ANSWER_IS_TRUE, answerIsTrue);
startActivityForResult(i, 0);
}
});
这是日志:
03-18 06:54:35.203: E/AndroidRuntime(5411): FATAL EXCEPTION: main
03-18 06:54:35.203: E/AndroidRuntime(5411): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.geoquiz/com.example.geoquiz.QuizActivity}: java.lang.NullPointerException
03-18 06:54:35.203: E/AndroidRuntime(5411): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
03-18 06:54:35.203: E/AndroidRuntime(5411): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
03-18 06:54:35.203: E/AndroidRuntime(5411): at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3692)
03-18 06:54:35.203: E/AndroidRuntime(5411): at android.app.ActivityThread.access$700(ActivityThread.java:141)
03-18 06:54:35.203: E/AndroidRuntime(5411): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1240)
03-18 06:54:35.203: E/AndroidRuntime(5411): at android.os.Handler.dispatchMessage(Handler.java:99)
03-18 06:54:35.203: E/AndroidRuntime(5411): at android.os.Looper.loop(Looper.java:137)
03-18 06:54:35.203: E/AndroidRuntime(5411): at android.app.ActivityThread.main(ActivityThread.java:5041)
03-18 06:54:35.203: E/AndroidRuntime(5411): at java.lang.reflect.Method.invokeNative(Native Method)
03-18 06:54:35.203: E/AndroidRuntime(5411): at java.lang.reflect.Method.invoke(Method.java:511)
03-18 06:54:35.203: E/AndroidRuntime(5411): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
03-18 06:54:35.203: E/AndroidRuntime(5411): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
03-18 06:54:35.203: E/AndroidRuntime(5411): at dalvik.system.NativeStart.main(Native Method)
03-18 06:54:35.203: E/AndroidRuntime(5411): Caused by: java.lang.NullPointerException
03-18 06:54:35.203: E/AndroidRuntime(5411): at com.example.geoquiz.QuizActivity.onCreate(QuizActivity.java:127)
03-18 06:54:35.203: E/AndroidRuntime(5411): at android.app.Activity.performCreate(Activity.java:5104)
03-18 06:54:35.203: E/AndroidRuntime(5411): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
03-18 06:54:35.203: E/AndroidRuntime(5411): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
03-18 06:54:35.203: E/AndroidRuntime(5411): ... 12 more
最佳答案
我想您有横向和纵向的替代布局。其中一个布局没有 ID 为 cheat_button 的按钮。
如果您说 NPE 是 @mCheatButton.setOnClickListener(new View.OnClickListener() 那么 mCheatButton 我们为 null。
确保布局有一个带有 id cheat_button 的按钮
关于java - 应用程序在旋转时崩溃，NullPointerException，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22472429/