0

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
4

3 回答 3

0

尝试在你的 Maze 类中实现 Parcelable。</p>

Android 不太支持 Serializable,当您尝试在 android 上下文之间发送数据时,您应该首先使用 Parcelable。

于 2013-11-21T03:15:43.100 回答
0

System.out.print(maze.toString()) 不应该为空,检查一下

于 2013-11-21T03:04:18.443 回答
0

请尝试使用捆绑

Intent playIntent = new Intent(this , PlayActivity.class);
Bundle bundle = new Bundle();
bundle.putSerializable("MadeMaze", maze);
playIntent.putExtras(bundle);
startActivity(playIntent);

并在 PlayActivity

 maze = (Maze) getIntent().getExtra().getSerializable("MadeMaze");
于 2013-11-21T03:07:27.473 回答