从活动A-> B-> C导航-如何在onBackPressed()中将数据从C传递到A? [英] Navigating from Activity A->B->C - How to pass data from C to A in onBackPressed()?

问题描述

1. 从Activity A呼叫Activity B
2. 从B到C并同时调用Activity C
3. 我为Activity B调用完成，(从堆栈历史记录Activity B中清除)
在
4. 和Activity B onBackPressed()中，我通过setResult()从Activity B到Activity A传递数据，但是在Activity A中，数据是null和resultCode 0.

1. From Activity A call Activity B
2. from B to C and while calling Activity C
3. I call finish for Activity B, (to clear from stack history Activity B)
4. and in Activity B onBackPressed(), I pass data via setResult() from Activity B to Activity A, but in Activity A the data is null and resultCode 0.

如何从Activity A中的Activity B获取数据?

推荐答案

打开C时不要从B调用finish().相反，请使用startActivityforResult()调用C，然后在onActivityResult()时将数据通过B传回.在B中被触发.像这样:

Don't call finish() from B when opening C. Instead, call C with startActivityforResult() and then pass the data back through B when onActivityResult() in B is triggered. Something like:

ActivityB {
    onCreate(Bundle) {
        startActivityForResult(ActivityC, 0);
    }

    onActivityResult(int, int, Intent){
        setResult(resultCode, data);
        finish();
    }
}

显然，在调用B时添加标记Intent.FLAG_ACTIVITY_FORWARD_RESULT实际上也应该达到您想要的结果.

Apparently adding the flag Intent.FLAG_ACTIVITY_FORWARD_RESULT when calling B should actually achieve your desired result as well.

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