android 獲取系統時間和日期，星期幾

final Calendar calendar = Calendar.getInstance();
calendar.setTimeZone(TimeZone.getTimeZone("GMT+8:00"));
mYear = String.valueOf(calendar.get(Calendar.YEAR));           // 獲取當前年份
mMonth = String.valueOf(calendar.get(Calendar.MONTH) + 1);     // 獲取當前月份
mDay = String.valueOf(calendar.get(Calendar.DAY_OF_MONTH));    // 獲取當前月份的日期號碼
mWay = String.valueOf(calendar.get(Calendar.DAY_OF_WEEK));     //獲取當前周幾
mHour = String.valueOf(calendar.get(Calendar.HOUR_OF_DAY));    //獲取當前小時
mMinute = String.valueOf(calendar.get(Calendar.MINUTE));       //獲取當前多少分

if("1".equals(mWay)){
    mWay ="天";
}else if("2".equals(mWay)){
    mWay ="一";
}else if("3".equals(mWay)){
    mWay ="二";
}else if("4".equals(mWay)){
    mWay ="三";
}else if("5".equals(mWay)){
    mWay ="四";
}else if("6".equals(mWay)){
    mWay ="五";
}else if("7".equals(mWay)){
    mWay ="六";
}

tvTime.setText(mHour + ":" + mMinute);
tvDate.setText(mMonth + "月"+ mDay + "日" + " 星期" + mWay);