java - onActivityResult wont work after onBackPressed

Question

I created an app with 2 screens: Activity A (main) and Activity B.

When the user clicks on the search button in activity A it opens a ListView named Activity B.

In this ListView the user has CheckBoxes that he clicks and once he clicks Done, the results are returned to Activity A by using onActivityResult.

For some reason, if let say I do the following:

1) clicked the search button in activity A. 2) chose 1 item in Activity B but didn't click done. Instead, I clicked the return button. 3) re-enter again to activity B 4) choose items + click done

Then my app crashes because it says the result is null.

It seems like after I'm clicking on the return button, that the onActivity result is not working between activity A and B.

My code is:

  @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == 1) {
            if(resultCode == ChatActivity.RESULT_OK){

                new CountDownTimer(1000, 500) {
                    @Override
                    public void onTick(long millisUntilFinished) {
                    }
                    @Override
                    public void onFinish() {
                        confirmedBooks = (ArrayList<DiscoverBooks>)data.getSerializableExtra("confirmedItems");
                        DateInMillis = data.getLongExtra( "dateInMillis", System.currentTimeMillis());
                    }

                }.start();

            }
            if (resultCode == ChatActivity.RESULT_CANCELED) {

            }
        }
    }

and:

Btn_Done.setOnClickListener( new View.OnClickListener() {
    @Override
    public void onClick(View v) {

        Intent confirmedData = new Intent();
        confirmedData.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
        confirmedData.putExtra( "confirmedItems", (Serializable) itemsSelected );
        confirmedData.putExtra( "dateInMillis",DateInMillis );
        setResult(ChatActivity.RESULT_OK,confirmedData);

        finish();
    }
} );

NOTE:

I added the line confirmedData.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK); because I was hoping that it will clear the data from the previous choose however it also seems to work not so well.

If I do these actions without clicking on the return button everything works correctly.

Any reason for this?

Thank you!

标签： javaandroidonactivityresult

Answer 1

请检查您是否使用活动 A调用了活动 BstartActivityforResult

而且您不需要在设置结果上设置标志。您需要像这样更新它：

Btn_Done.setOnClickListener( new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Intent confirmedData = new Intent();
        confirmedData.putExtra( "confirmedItems", (Serializable) itemsSelected );
        confirmedData.putExtra( "dateInMillis",DateInMillis );
        setResult(ChatActivity.RESULT_OK,confirmedData);    
        finish();
    }
} );