如何使用 onPause（后退按钮）发送结果 Intent

Question

我有一个 Activity，其中包含一个 Recycler 视图，并使用一个额外的字符串从主 activity 调用。然后用户会做一些改变字符串的事情，我想将它发送回 Main activity。有没有办法只使用 phone 上的后退按钮来做到这一点？我有结果意图在我的第二个 activity 的 "onPause" 方法中设置结果，但是主要的 activity 一直说结果被取消了。请帮忙！

主要Activity代码：


    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if(requestCode == 1){
            if(resultCode == RESULT_OK){
                pantryJson = data.getStringExtra("newPantryContents");
                pantry = new ArrayList<>(Arrays.asList(new Gson().fromJson(pantryJson,
                        Ingredient[].class)));
                System.out.println("onActivityResult says: " + pantryJson);
                savePantry();
            }
            if(resultCode == RESULT_CANCELED){
                System.out.println("onActivityResult says: result canceled");
                return;
            }
        }
    }

我的第二个Activity:

@Override
    protected void onDestroy() {
        super.onDestroy();

        String pantryJsonArray = new Gson().toJson(pantry);
        System.out.println("ViewPantry onDestroy says: " + pantryJsonArray);
        Intent intent = new Intent(ViewPantryActivity.this,MainActivity.class);
        intent.putExtra("newPantryContents",pantryJsonArray);
        setResult(RESULT_OK,intent);
        finish();
    }

    @Override
    protected void onPause() {
        String pantryJsonArray = new Gson().toJson(pantry);
        System.out.println("ViewPantry onPause Says" + pantryJsonArray);
        Intent resultIntent = new Intent(ViewPantryActivity.this,MainActivity.class);
        resultIntent.putExtra("newPantryContents",pantryJsonArray);
        setResult(ViewPantryActivity.RESULT_OK,resultIntent);
        super.onPause();

    }

LogCat System.Out:

2019-11-02 22:05:42.068 566-566/com.example.myapplication I/System.out: ViewPantry onPause Says[{"barcode":{"cornerPoints":[{"x":181,"y":360},{"x":193,"y":356},{"x":193,"y":479},{"x":181,"y":483}],"displayValue":"04904500","format":1024,"rawValue":"04904500","valueFormat":5},"image":{"mHeight":300,"mNativePtr":497431990208,"mWidth":300},"name":"Clicked","quantityInPantry":1},{"barcode":{"cornerPoints":[{"x":157,"y":359},{"x":229,"y":335},{"x":229,"y":461},{"x":157,"y":487}],"displayValue":"04904500","format":1024,"rawValue":"04904500","valueFormat":5},"image":{"mHeight":300,"mNativePtr":497433345344,"mWidth":300},"name":"Diet Coca-cola","quantityInPantry":3}]
2019-11-02 22:05:42.073 566-566/com.example.myapplication I/System.out: onActivityResult says: result canceled
2019-11-02 22:05:42.516 566-566/com.example.myapplication I/System.out: ViewPantry onDestroy says: [{"barcode":{"cornerPoints":[{"x":181,"y":360},{"x":193,"y":356},{"x":193,"y":479},{"x":181,"y":483}],"displayValue":"04904500","format":1024,"rawValue":"04904500","valueFormat":5},"image":{"mHeight":300,"mNativePtr":497431990208,"mWidth":300},"name":"Clicked","quantityInPantry":1},{"barcode":{"cornerPoints":[{"x":157,"y":359},{"x":229,"y":335},{"x":229,"y":461},{"x":157,"y":487}],"displayValue":"04904500","format":1024,"rawValue":"04904500","valueFormat":5},"image":{"mHeight":300,"mNativePtr":497433345344,"mWidth":300},"name":"Diet Coca-cola","quantityInPantry":3}]

Answer 1

欢迎来到代码派对

首先我必须说一下你的问题的逻辑：

您想将某些东西传递给 activity，这是有意为之的。当您使用 Back btn 回到 activity 时，您会调用它的 onResume。

现在的解决方案：

您可以使用意图覆盖 onBackedPressed，这样您就可以在 onResult 中收到您想要的内容...

2.you 可以将代码的位置从 onResult 更改为 onResume。

您可以使用下面的 link 了解有关 android

中生命周期的更多信息

Life Cycling in android

在评论中更新我

如何使用 onPause（后退按钮）发送结果 Intent

How to send result Intent using onPause (back button)

android

android-intent

onactivityresult

onpause

android-ondestroy