导航回到先前的活动，一起携带数据

Question

I have a MainActivity that has a list storing my objects:

private List<House> houses;

When the user clicks an ADD button, it calls another activity:

addButton.setOnClickListener(new Button.OnClickListener()
{
    public void onClick(View v)
    {
        Intent intent = new Intent(MainActivity.this, HouseDetails.class);
        startActivity(intent);
    }
};

This new activity provides a screen where the user fills the data for the new object. Here he has to options: cancel (go back and nothing is created) or accept (go back with the newly created object).

How do I go back to the MainActivity with the newly created object? Should I start MainActicity again or is there any way to go back to the original main activity that was running before and bring together the new data?

Answer 1

//Global variable
private string request_code = 1000;

and Start new activity by calling in MainActivity

Intent intent = new Intent(MainActivity.this, HouseDetails.class); 
startActivityForResult(intent , request_code );

and override method onActivityResult

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode == request_code){
            if(resultCode == RESULT_OK){
                //put  your stuff here
            }else if(resultCode == RESULT_CANCEL){
                //put  your stuff here
            }
        }
    }

in HouseDetails activity override method finish of activity

    @Override
    public void finish() {
        Intent data = new Intent();
        Bundle extra = new Bundle();
        //put your data in bundle
        data.putExtras(extra);
        if(cancel){
             setResult(RESULT_CANCEL , data);
        }else{
               setResult(RESULT_OK,data);
         }
        super.finish();
    }

Answer 2

您的列表应该是静态的，并且您可以从第二个活动中添加一个新对象，例如

MainActivity.houses.add(House house);