如何从 TabHost 活动返回结果 (startActivityForResult)? [英] How to return a result (startActivityForResult) from a TabHost Activity?

问题描述

我的示例中有 3 个类:A类，主要活动.A 类调用一个 startActivityForResult:

I have 3 classes in my example: Class A, the main activity. Class A calls a startActivityForResult:

Intent intent = new Intent(this, ClassB.class);
startActivityForResult(intent, "STRING");

B 类，这个类是一个 TabActivity:

Class B, this class is a TabActivity:

Intent intent = new Intent(this, ClassC.class);
tabHost.addTab...

C班，这个班是一个常规的Activity:

Class C, this class is a regular Activity:

Intent intent = this.getIntent();
intent.putExtra("SOMETHING", "EXTRAS");
this.setResult(RESULT_OK, intent);
finish();

onActivityResult 在 Class A 中被调用，但是 resultCode 是 RESULT_CANCELED 而不是 RESULT_OK 并且返回的 Intent 为 null.如何从 TabHost 内的 Activity 返回某些内容?

onActivityResult is called in Class A, but the resultCode is RESULT_CANCELED instead of RESULT_OK and the returned intent is null. How do I return something from the Activity inside a TabHost?

我意识到问题是我的 C 类实际上在 B 类内部运行，而 B 类是将 RESULT_CANCELED 返回到 A 类的原因.我只是不知道有什么工作还在附近.

I realize that the problem is that my Class C is actually running inside of Class B, and Class B is what is returning the RESULT_CANCELED back to Class A. I just don't know a work around yet.

推荐答案

天哪！花了几个小时下载了安卓源，终于找到了解决办法.

Oh, god! After spending several hours and downloading the Android sources, I have finally come to a solution.

如果您查看 Activity 类，您会看到 finish() 方法仅在 mParent 属性设置为 时才将结果发回空.否则结果丢失.

If you look at the Activity class, you will see, that finish() method only sends back the result if there is a mParent property set to null. Otherwise the result is lost.

public void finish() {
    if (mParent == null) {
        int resultCode;
        Intent resultData;
        synchronized (this) {
            resultCode = mResultCode;
            resultData = mResultData;
        }
        if (Config.LOGV) Log.v(TAG, "Finishing self: token=" + mToken);
        try {
            if (ActivityManagerNative.getDefault()
                .finishActivity(mToken, resultCode, resultData)) {
                mFinished = true;
            }
        } catch (RemoteException e) {
            // Empty
        }
    } else {
        mParent.finishFromChild(this);
    }
}

所以我的解决方案是将结果设置为父活动(如果存在)，如下所示:

So my solution is to set result to the parent activity if present, like that:

Intent data = new Intent();
 [...]
if (getParent() == null) {
    setResult(Activity.RESULT_OK, data);
} else {
    getParent().setResult(Activity.RESULT_OK, data);
}
finish();

如果有人再次寻找此问题的解决方法，我希望这会有所帮助.

I hope that will be helpful if someone looks for this problem workaround again.

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