因此,我已经阅读了该站点(和其他站点)上的许多问题,但找不到适合我的代码的有效解决方案,因此我认为下一步是将其发布在此处。我正在做一个迷宫游戏。我有一个生成活动和一个播放活动,我正在尝试将生成的 Maze 对象传递给 PlayActivity。迷宫是可序列化的,但是当我尝试从 PlayActivity 中的意图中获取迷宫时,它返回一个空指针异常。任何想法都会很棒。
Maze:
public class Maze implements Serializable {
private static final long serialVersionUID = 1L;
然后生成活动:
Intent playIntent = new Intent(this , PlayActivity.class);
playIntent.putExtra("MadeMaze" , maze);
startActivity(playIntent);
最后是 PlayActivity:
maze = (Maze) getIntent().getSerializableExtra("MadeMaze");
System.out.print(maze.mazecells.toString());
System.out.print("here");
我知道有人可能会建议使用 Parcelable,但我的 Maze 类有太多的数据字段,看起来并不值得(除非有人有充分的理由)。
编辑:这是日志:
FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{edu.wm.cs.cs301.jesavino/edu.wm.cs.cs301.jesavino.UI.PlayActivity}: java.lang.NullPointerException
11-20 21:46:37.614: E/AndroidRuntime(1940): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
11-20 21:46:37.614: E/AndroidRuntime(1940): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
11-20 21:46:37.614: E/AndroidRuntime(1940): at android.app.ActivityThread.access$600(ActivityThread.java:141)
11-20 21:46:37.614: E/AndroidRuntime(1940): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
11-20 21:46:37.614: E/AndroidRuntime(1940): at android.os.Handler.dispatchMessage(Handler.java:99)
11-20 21:46:37.614: E/AndroidRuntime(1940): at android.os.Looper.loop(Looper.java:137)
11-20 21:46:37.614: E/AndroidRuntime(1940): at android.app.ActivityThread.main(ActivityThread.java:5103)
11-20 21:46:37.614: E/AndroidRuntime(1940): at java.lang.reflect.Method.invokeNative(Native Method)
11-20 21:46:37.614: E/AndroidRuntime(1940): at java.lang.reflect.Method.invoke(Method.java:525)
11-20 21:46:37.614: E/AndroidRuntime(1940): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
11-20 21:46:37.614: E/AndroidRuntime(1940): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
11-20 21:46:37.614: E/AndroidRuntime(1940): at dalvik.system.NativeStart.main(Native Method)
11-20 21:46:37.614: E/AndroidRuntime(1940): Caused by: java.lang.NullPointerException
11-20 21:46:37.614: E/AndroidRuntime(1940): at edu.wm.cs.cs301.jesavino.UI.PlayActivity.onCreate(PlayActivity.java:36)
11-20 21:46:37.614: E/AndroidRuntime(1940): at android.app.Activity.performCreate(Activity.java:5133)
11-20 21:46:37.614: E/AndroidRuntime(1940): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
11-20 21:46:37.614: E/AndroidRuntime(1940): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
11-20 21:46:37.614: E/AndroidRuntime(1940): ... 11 more