结束当前Activity时将值传给上一个Activity

A Activity 启动 B Activity ： Intent intent = new Intent(this,B.class); startActivityForResult(intent,1);B Activity 传值，并关闭B Activity：Intent intent = new Intent();intent.putExtra("KEY",value);setResult(RESULT_OK,intent);finish();A Activity 接收值：重新写 onActivityResultpublic
void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); String construction = data.getStringExtra("KEY");}