Android Api Demos登顶之路（105）View-->Date widgets-->dialog

/*这个demo演示了DatePickerDialog和时间对话框TimePickerDialog的用法*/
public class MainActivity extends Activity {
    private TextView mDateDisplay;
    private String mText;

    private int mYear;
    private int mMonth;
    private int mDay;
    private int mHour;
    private int mMinute;

    //定义Dialog的Id
    private static final int TIME_12_DIALOG_ID=0;
    private static final int TIME_24_DIALOG_ID=1;
    private static final int DATE_DIALOG_ID=2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mDateDisplay=(TextView) findViewById(R.id.displayDate);

        //点击对应按钮显示对话框
        setDialogOnClickListener(R.id.pickDate,DATE_DIALOG_ID);
        setDialogOnClickListener(R.id.pickTime12,TIME_12_DIALOG_ID);
        setDialogOnClickListener(R.id.pickTime24,TIME_24_DIALOG_ID);

        //获取到当前日期和时间
        Calendar c=Calendar.getInstance();
        mYear=c.get(Calendar.YEAR);
        mMonth=c.get(Calendar.MONTH);
        mDay=c.get(Calendar.DAY_OF_MONTH);
        mHour=c.get(Calendar.HOUR_OF_DAY);
        mMinute=c.get(Calendar.MINUTE);

        updateText();
    }

    private void setDialogOnClickListener(int buttonId, final int dialogId) {
        Button bt=(Button) findViewById(buttonId);
        bt.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                //在4.2后就不推荐使用showDialog了，而是推荐使用DialogFragment；
                //因此我们需要对代码进行一下修改
                //showDialog(dialogId);
                FragDialog frag=new FragDialog(dialogId);
                frag.show(getFragmentManager(), String.valueOf(dialogId));
            }
        });
    }


    private class FragDialog extends DialogFragment{

        public FragDialog(int dialogId) {
            super();
            Bundle args = new Bundle();
            args.putInt("dialogId", dialogId);
            setArguments(args);
        }

        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            switch (getArguments().getInt("dialogId")) {
            case TIME_12_DIALOG_ID:
                return new TimePickerDialog(getActivity(), mTimeSetListener, mHour,
                        mMinute, false);
            case TIME_24_DIALOG_ID:
                return new TimePickerDialog(getActivity(), mTimeSetListener, mHour,
                        mMinute, true);
            case DATE_DIALOG_ID:
                return new DatePickerDialog(getActivity(), mDateSetListener, mYear,
                        mMonth, mDay);
            }
            return null;
        }


        private OnDateSetListener mDateSetListener=new OnDateSetListener() {
            @Override
            public void onDateSet(DatePicker view, int year, int monthOfYear,
                    int dayOfMonth) {
                mYear=year;
                mMonth=monthOfYear;
                mDay=dayOfMonth;
                updateText();
            }
        };

        private OnTimeSetListener mTimeSetListener = new OnTimeSetListener() {
            @Override
            public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
                mHour=hourOfDay;
                mMinute=minute;
                updateText();
            }
        };
    }

    public void updateText(){
        mText= new StringBuilder()
        //因为月基于0开始，所以月需要加1
        .append(mMonth+1).append("-")
        .append(mDay).append("-")
        .append(mYear).append("-")
        .append(pad(mHour)).append(":")
        .append(pad(mMinute)).toString();
        mDateDisplay.setText(mText);
    }

    private String pad(int c) {
        if(c>=10){
            return String.valueOf(c);
        }
        return "0"+c;
    }


}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/displayDate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         />
    <Button 
        android:id="@+id/pickDate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Change the date"/>
    <Button 
        android:id="@+id/pickTime12"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Change the time(12 Hours)"/>
    <Button 
        android:id="@+id/pickTime24"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Change the time(24 Hours)"/>

</LinearLayout>