关于onActivityResult的一些细节

1. onActivityResult是比onResume先调用的，而且如果onActivityResult中的code比较耗时的话，会阻塞onResume，可以通过如下的code进行测试：

public void onActivityResult(int requestCode, int resultCode, Intent data) {
    Log.w(TAG, "on activity result start to deal with: " + requestCode);

    try {
        Thread.sleep(1000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    Log.w(TAG, "on activity result end");
}

public void onResume() {
    super.onResume();
    Log.w(TAG, "on resume start");
}

 

打印的次序应该是

MainActivity: on activity result start to deal with: 13

MainActivity: on activity result end

MainActivity: on resume start

 

refer onActivityResult() & onResume()

 

2. 在activity和fragment并存的时候startActivityForResult

如果在host activity中重写了onActivityResult，那么应该调用super.onActivityResult，这样才能保证fragment中的onActivityResult会被调用

通过如下片段测试：

host activity中有一个fragment，fragment通过两种方式startActivityForResult

1)

Intent intent = new Intent(getContext(), SecondActivity.class);
startActivityForResult(intent, 12);

 

2)

Intent intent = new Intent(getContext(), SecondActivity.class);
getActivity().startActivityForResult(intent, 13);

 

注意两者之间的区别，第二个显示调用了getActivity

 

并且在fragment中设置onActivityResult

public void onActivityResult(int requestCode, int resultCode, Intent data) {
    Log.w(TAG, "on activity result start to deal with: " + requestCode);

    try {
        Thread.sleep(1000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    Log.w(TAG, "on activity result end");
}

public void onResume() {
    super.onResume();
    Log.w(TAG, "on resume start");
}

 

在host activity中

public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    Log.w(TAG, "on activity result start to deal with: " + requestCode);

    try {
        Thread.sleep(1000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    Log.w(TAG, "on activity result end");
}

public void onResume() {
    super.onResume();
    Log.w(TAG, "on resume start");
}

 

结果，如果通过方式1 startActivityForResult，会发现fragment中的onActivityResult先被调用，然后到host activity中的onActivityResult，但是host activity中获取的requestCode是一个随机值：

FirstFragment: on activity result start to deal with: 12

FirstFragment: on activity result end

MainActivity: on activity result start to deal with: 196620

MainActivity: on activity result end

MainActivity: on resume start

FirstFragment: on resume start

 

如果是方式2，fragment中的onActivityResult不会被调用，host activity中获取到的requestCode是准确的：

MainActivity: on activity result start to deal with: 13

MainActivity: on activity result end

MainActivity: on resume start

FirstFragment: on resume start

 

refer onActivityResult not being called in Fragment

 

这样的问题也需要在androidannotations中引起注意，

ProcessActivity_.intent(this).startForResult(12)

这边intent中用this，还是getActivity()，onActivityResult的响应是不一样的