Android特殊碎片 —— DialogFragment

       顾名思义，DialogFragment就是一个浮动在Activity上面的Fragment。当需要用户的反馈时，它就会派上用场。下面将会展示如何使用DialogFragment，与使用ListFragment类似，需要继承DialogFragment基类。

1、创建一个工程：DialogFragmentExample
2、在包路径下面新建一个类Fragment1

public class Fragment1 extends DialogFragment {
        static Fragment1 newInstance(String title) {
            Fragment1 fragment = new Fragment1();
            Bundle args = new Bundle();
            args.putString("title", title);
            fragment.setArguments(args);
            return fragment;
        }

        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            String title = getArguments().getString("title");
            return new AlertDialog.Builder(getActivity())
            .setIcon(R.drawable.ic_launcher)
            .setTitle(title)
            .setPositiveButton("OK",
                    new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog,
                        int whichButton) {
                    ((DialogFragmentExampleActivity)
                            getActivity()).doPositiveClick();
                }
            })
            .setNegativeButton("Cancel",
                    new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog,
                        int whichButton) {
                    ((DialogFragmentExampleActivity)
                            getActivity()).doNegativeClick();
                }
            }).create();
        }
    }

3、DialogFragmentExampleActivity.java中的代码

public class DialogFragmentExampleActivity extends Activity {
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);

            Fragment1 dialogFragment = Fragment1.newInstance(
                    "Are you sure you want to do this?");
                dialogFragment.show(getFragmentManager(), "dialog");
        }

        public void doPositiveClick() {
            //---perform steps when user clicks on OK---
            Log.d("DialogFragmentExample", "User clicks on OK");
        }

        public void doNegativeClick() {
            //---perform steps when user clicks on Cancel---
            Log.d("DialogFragmentExample", "User clicks on Cancel");
        }

    }

4、按F11在模拟器上调试，会看到一个对话框，点击OK或Cancel按钮会弹出消息。


注：在Android 4.0版本以后，官方推荐使用DialogFragment去替换Dialog。大家可以看看Android 4.0的Launcher等源码，这些源码中大量使用了Fragment类。