如何接收用户在 DialogFragment 中所做的操作？

Question

我有一个显示联系人列表的 ListView。单击联系人时，会创建一个 DialogFragment，其中显示有关是否取消或确认的通知。根据他们是单击取消还是确认，我想更改 ListView 项的颜色。如何获取对话框的按钮单击状态。我的对话框代码：

@Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // Use the Builder class for convenient dialog construction
        String first = this.getArguments().getString("first");
        String last = this.getArguments().getString("last");
        String phone = this.getArguments().getString("phone");

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

        LayoutInflater inflater = getActivity().getLayoutInflater();

        View view = inflater.inflate(R.layout.add_contact_dialog, null);
        TextView tv = (TextView) view.findViewById(R.id.new_first);
        tv.setText(first);

        TextView tv2 = (TextView) view.findViewById(R.id.new_phone);
        tv2.setText(phone);

        TextView tv3 = (TextView) view.findViewById(R.id.new_last);
        tv3.setText(last);

        builder.setView(view);
        //builder.setTitle("Are you sure?").setMessage("Would you like to add " + name + " as a contact?");

        builder.setPositiveButton("Confirm", new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int id) {
                       // Add the contact

                   }
               })
               .setNegativeButton("Deny", new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int id) {
                       // User cancelled the dialog
                   }
               });

        // Create the AlertDialog object and return it
        return builder.create();
    }

现在我希望 setPositiveButton 或 setNegativeButton 返回一个值，我可以在我的主活动中进行比较，或者让我的 ArrayAdapter 在对话框的范围内，以便我可以对其进行更改。有什么方法可以将DialogFragment.show() 和被点击的对话框按钮联系起来？

Answer 1

有什么方法可以关联 DialogFragment.show() 和 Dialog 被点击的按钮？

使用接口将该信息传递给活动，该活动又将其传递给有可能进行更改的适配器/片段：

public interface OnSelectionMade {

     int OK = 1000;
     int CANCEL = 2000;
     doChange(int result);
}

使活动实现此接口并使用doChange() 回调在适配器中进行更改，方法是直接访问适配器（如果您使用简单的ListView）或将其传递给持有@987654324 的片段@进行更改：

public class YourActivity extends Activity implements OnSelectionMade {

     @Override
     public void doChange(int result) {
         // the result parameter will be either the OK or CANCEL constants
         // you know now what button was clicked so you can do the change
         ...
     }

}

现在您需要连接DialogFragment 以通过OnSelectionMade 传递事件，如下所示：

private OnSelectionMade mListener;

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    mListener = (OnSelectionMade) activity; // you'd want to implement a cast check here to be safe
}

//then in the onCreateDialog() method
builder.setPositiveButton("Confirm", new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int id) {
                       mListener.doChange(OnSelectionMade.OK); // do a null mListener check?
                   }
               })
               .setNegativeButton("Deny", new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int id) {
                       mListener.doChange(OnSelectionMade.CANCEL);
                   }
               });

您可能可以直接传递对 DialogFragment 的引用来传递结果，但从长远来看，这不是一个很好的解决方案。

Answer 2

确实有。在 Activity 或 Fragment 中实例化 DialogFragment，首先声明：

public static final int MY_DIALOGFRAGMENT = 123;   /* Any random int values will do. */
public static final int CONTACT_CONFIRM = 124;
public static final int CONTACT_DENY = 125;

像这样实例化你的DialogFragment：

FragmentManager fm = getSupportFragmentManager();
MyDialogFragment myDialogFragment = new MyDialogFragment();
myDialogFragment.setTargetFragment(this, MY_DIALOGFRAGMENT);
myDialogFragment.show(fm, "my_dialog_fragment");

在DialogFragment 的onCreateDialog() 方法中，

builder.setPositiveButton("Confirm", new DialogInterface.OnClickListener() {
               public void onClick(DialogInterface dialog, int id) {
                   // Add the contact
                   getTargetFragment().onActivityResult(getTargetRequestCode(), 
                       MyActivity.CONTACT_CONFIRM, getActivity().getIntent());
                   dismiss();
               }
           })
           .setNegativeButton("Deny", new DialogInterface.OnClickListener() {
               public void onClick(DialogInterface dialog, int id) {
                   // User cancelled the dialog
                   getTargetFragment().onActivityResult(getTargetRequestCode(), 
                       MyActivity.CONTACT_DENY, getActivity().getIntent());
                   dismiss();
               }
           });

最后，将以下方法添加到您的Activity 或Fragment：

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch(requestCode) {
            case MY_DIALOGFRAGMENT:

                if (resultCode == CONTACT_CONFIRM) {

                    // Change color of listview item to green

                } else if (resultCode == CONTACT_DENY){

                    // Change color of listview item to red

                }

                break;
        }
}

这应该可以。试试看。