DialogFragment類介紹

DialogFragment是Android 3.0新增的Fragment子類，他的Package在android.app.DialogFragment 中，Dialog和android常規的Dialog是不同的實現方法。

  一、常規對話框

public static class MyDialogFragment extends DialogFragment {
    int mNum;

    static MyDialogFragment newInstance(int num) {
        MyDialogFragment f = new MyDialogFragment();

        Bundle args = new Bundle();
        args.putInt("num", num);
        f.setArguments(args);

        return f;
    }

   下面是Fragment的onCreate方法，需要注意的是，設置布局不在這裡，和Activity有些不同。

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mNum = getArguments().getInt("num");

        int style = DialogFragment.STYLE_NORMAL, theme = 0;
        switch ((mNum-1)%6) {
            case 1: style = DialogFragment.STYLE_NO_TITLE; break;
            case 2: style = DialogFragment.STYLE_NO_FRAME; break;
            case 3: style = DialogFragment.STYLE_NO_INPUT; break;
            case 4: style = DialogFragment.STYLE_NORMAL; break;
            case 5: style = DialogFragment.STYLE_NORMAL; break;
        }
        switch ((mNum-1)%6) {
            case 4: theme = android.R.style.Theme_Light; break;
            case 5: theme = android.R.style.Theme; break;
        }
        setStyle(style, theme);
    }

   在Fragment設置布局在onCreateVIEw中，使用inflater可以映射一個XML方式布局的layout文件。

    @Override
    public VIEw onCreateVIEw(LayoutInflater inflater, VIEwGroup container,
            Bundle savedInstanceState) {
        VIEw v = inflater.inflate(R.layout.fragment_dialog, container, false);
        View tv = v.findVIEwById(R.id.text);
        ((TextVIEw)tv).setText("Dialog #" + mNum + ": using style "
                + getNameForNum(mNum));

        Button button = (Button)v.findVIEwById(R.id.show);
        button.setOnClickListener(new OnClickListener() {
            public void onClick(VIEw v) {
                ((FragmentDialog)getActivity()).showDialog(); //顯示fragmentdialog
            }
        });

        return v;
    }
}

  上面的showDialog方法在Activity中的定義如下:

  void showDialog() {
    mStackLevel++;

    FragmentTransaction ft = getFragmentManager().beginTransaction();
    Fragment prev = getFragmentManager().findFragmentByTag("dialog");
    if (prev != null) {
        ft.remove(prev);
    }
    ft.addToBackStack(null);

    DialogFragment newFragment = MyDialogFragment.newInstance(mStackLevel);
    newFragment.show(ft, "dialog");
}

 二、警告對話框，類似AlertDialog

  public static class MyAlertDialogFragment extends DialogFragment {
 
    public static MyAlertDialogFragment newInstance(int title) {
        MyAlertDialogFragment frag = new MyAlertDialogFragment();
        Bundle args = new Bundle();
        args.putInt("title", title);
        frag.setArguments(args);
        return frag;
    }

   這裡android開發網提示大家，下面重寫了onCreateDialog方法，而不是onCreateVIEw，希望大家注意:

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        int title = getArguments().getInt("title");
 
        return new AlertDialog.Builder(getActivity())
                .setIcon(R.drawable.alert_dialog_icon)
                .setTitle(title)
                .setPositiveButton(R.string.alert_dialog_ok,
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int whichButton) {
                            ((FragmentAlertDialog)getActivity()).doPositiveClick();
                        }
                    }
                )
                .setNegativeButton(R.string.alert_dialog_cancel,
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int whichButton) {
                            ((FragmentAlertDialog)getActivity()).doNegativeClick();
                        }
                    }
                )
                .create();
    }
}

顯示Alert的Fragment類似AlertDialog，下面是Activity中使用的showDialog的實現代碼，如下

void showDialog() {
    DialogFragment newFragment = MyAlertDialogFragment.newInstance(
            R.string.alert_dialog_two_buttons_title);
    newFragment.show(getFragmentManager(), "dialog");
}
 
public void doPositiveClick() {
    // Do stuff here.
    Log.i("FragmentAlertDialog", "Positive click!");
}
 
public void doNegativeClick() {
    // Do stuff here.
    Log.i("FragmentAlertDialog", "Negative click!");
}

 如果你不了解Fragment，可以查看android Fragment使用詳解一文