安卓getIntent（）。getExtras（）返回null [英] Android getIntent().getExtras() returns null

问题描述

我想传递两个活动之间的字符串。我在用同样的方法等项目做到了这一点，但由于某种原因，我得到一个NullPointerException异常时，我呼吁intent.getStringExtra（字符串）。我也曾尝试通过

I'm trying to pass a string between two activities. I've done this in other projects using the same method, but for some reason I'm getting a NullPointerException when I call intent.getStringExtra(String). I have also tried creating a Bundle for the extras via

Bundle b = getIntent().getExtras();

但也返回null。下面是code，我目前正在尝试使用。

but that also returned null. Below is the code that I am currently trying to use.

活动答：

Intent myIntent = null; 
    String select = "";
            if (selection.equals("Chandelle")) {
                myIntent = new Intent(Commercial.this, Chandelle.class);
                select = "Chandelle";
            } else if (selection.equals("Eights on Pylons")) {
                myIntent = new Intent(Commercial.this, EightsOnPylons.class);
                select = "Eights on Pylons";
            }
 // Start the activity
    if (myIntent != null) {
        myIntent.putExtra("selection", select);
        Log.d("*** OUTBOUND INTENT: ", "" + myIntent.getExtras().get("selection"));
        startActivity(myIntent);
    }

这里的code在b活动，试图拉多余的：

Here's the code in activity B that tries to pull the extra:

    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState); 

    Intent i = getIntent();

    if (i == null) 
        Log.d("***DEBUG****", "Intent was null");
    else
        Log.d("**** DEBUG ***", "Intent OK");

    String MANEUVER_ID  = i.getStringExtra("selection"); //Exception points to this line
    Log.d("*** DEBUG", rec + " " + MANEUVER_ID);

我已经试过pretty的传球额外的每得多另一种方式，但他们似乎都表现得这样。我在想什么？

I've tried pretty much every alternative way of passing extras, but they all seem to behave this way. What am I missing?

推荐答案

添加的ToString（）到 myIntent.putExtra（选择，选择）; ，使其 myIntent.putExtra（选择，select.ToString（））;

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