使用Bundle传递数据时出现空指针异常 [英] Null pointer exception when using Bundle to pass data

问题描述

我有一个浮点数组 camObjCoord 声明为..

I've got a float array camObjCoord declared as..

public static float camObjCoord[] = new float[8000];

然后我在一个类中填充它的索引，该类执行如下操作..

I'm then filling it's indexes in a class that does something like the following..

camObjCoord[1] = 2.5;

然后我调用 makeview()

       public void makeview() {
    Intent myIntent = new Intent(this, GLCamTest.class);
    this.startActivity(myIntent);
    Bundle b = new Bundle();
    b.putFloatArray("tweets", camObjCoord);
}

然后在新班级中它正在做...

and then in the new class it's doing...

               public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Bundle b = this.getIntent().getExtras();
    float original[] = b.getFloatArray("tweets");
    camObjCoord = original;
    counter++;
}   

但是...我在 float original[] = b.getFloatArray("tweets"); 处得到一个空指针异常，我不知道为什么.我在调用意图等之前尝试过捆绑，但我没有解决问题.有人知道为什么吗?

But... I'm getting a Null pointer Exception at float original[] = b.getFloatArray("tweets"); and I don't know why. I've tried bundling before calling the intent etc. but I've had no luck at a fix. Anyone know why?

我还包含了一些错误，以防大家有兴趣.

I've also included some of the error incase any of you are interested.

            07-14 11:14:35.592: ERROR/AndroidRuntime(7886): Caused by:  java.lang.NullPointerException
            07-14 11:14:35.592: ERROR/AndroidRuntime(7886):     at  org.digital.com.GLCamTest.onCreate(GLCamTest.java:41)
            07-14 11:14:35.592: ERROR/AndroidRuntime(7886):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
            07-14 11:14:35.592: ERROR/AndroidRuntime(7886):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
            07-14 11:14:35.592: ERROR/AndroidRuntime(7886):     ... 11 more

谢谢！

推荐答案

好的，所以这表明 this.getIntent().getExtras() 返回了 null.请注意，在 makeview 中，您在创建包之后还没有做任何事情.你需要做什么:

Okay, so that suggests that this.getIntent().getExtras() has returned null. Note that in makeview you haven't done anything after creating the bundle. Do you need to do:

myIntent.putExtras(b);

也许在最后?(我不是 Android 开发人员，所以我不知道 API，但这听起来很可能...)

at the end perhaps? (I'm not an Android developer so I don't know the API, but that sounds likely...)

正如其他人所指出的，您可能应该将 startActivity 调用 after 设置为意图.

As others have pointed out, you should potentially put the startActivity call after setting everything on the intent.

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