Question

我希望第二项活动是ShowActivity当我按回它时会返回ArrayList，但我无法得到它。在调试setResult()方法中显示数组，但在activityResult数据的下一个点为空为什么？在第一个活动中，onActivityResult数据为空。

MainActivity.java：

btnShow.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
                Intent show=new Intent(MainActivity.this,ShowActivity.class);
                // Create a Bundle and Put Bundle in to it
                Bundle bundleObject = new Bundle();
                bundleObject.putSerializable("key", showImagelist);
                show.putExtras(bundleObject);
                //startActivity(show);
                startActivityForResult(show,COUNTER_ARRAY_LIST);
        }
    });

   protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if(requestCode==SELECT_IMAGE){
        if(resultCode==RESULT_OK && null!=data){
          for (int i=0,c=0,r=0;i<count;i++,c++){
              if(c==coloumn){
                    c=0;
                    r++;
               }

          }

            ImageUri=data.getData();
            imageItemBin=new ImageItemBin();
            imageItemBin.setImage(ImageUri.toString());
            publicSelectedImage.add(imageItemBin);

            gridAdaptor=new CustomAdapter(MainActivity.this,publicSelectedImage,this);
            gridview.setAdapter(gridAdaptor);

        }
    }
    if(requestCode==REQUEST_CAMERA)
    {
        if(resultCode==RESULT_OK && data!=null){
            Bitmap mphoto = (Bitmap) data.getExtras().get("data");

            String stringImage=BitMapToString(mphoto);

            imageItemBin=new ImageItemBin();
            imageItemBin.setImage(stringImage);
            //imageItemBin.setImage(picturePth.toString());
            publicSelectedImage.add(imageItemBin);
            gridAdaptor=new CustomAdapter(MainActivity.this,publicSelectedImage,this);
            gridview.setAdapter(gridAdaptor);
            //gridAdaptor.notifyDataSetChanged();

           // tvcounter.setText(counter);
            //publicSelectedImage=selectedImage;
        }
    }
    if(requestCode==COUNTER_ARRAY_LIST){
        //if(resultCode==RESULT_OK && data!=null){
            Bundle bundle=getIntent().getExtras();
            showImagelist=(ArrayList<ImageItemBin>)bundle.getSerializable("BackArrayList");
            int sizeOfArrry=showImagelist.size();
            btnShow.setText("Show ( " + Integer.toString(sizeOfArrry) + " ) ");
            showImagelist.notifyAll();
        //}
    }


}

ShowActivity.java：

 @Override
public void onBackPressed() {
    super.onBackPressed();
    Intent back=new Intent();
    Bundle b=new Bundle();
    b.putSerializable("BackArrayList",showlist1);
    back.putExtras(b);
    //startActivity(back,b);
    setResult(2,back);
    finish();
    //startActivityForResult(back,MainActivity.COUNTER_ARRAY_LIST,b);
}

Answer 1

为什么必须在方法super.onBackPressed()执行之前设置结果：

查看grepcode.com

处onBackPressed()的代码

如果backstack上没有可用的片段，则此方法将调用方法finishAfterTransition()。在finishAfterTransition()方法中，您会看到对finish()的调用。因此，在您在代码中设置结果之前，系统会将活动移至状态＆＃34;已完成＆＃34;然后忽略后面的设置结果。因此，您必须确保在调用super.onBackPressed()之前设置结果，以确保在活动结束之前设置结果。

我无法从setResult方法获取数据，而调试显示它有额外的...？

1 个答案: