Android进阶之使用时间戳计算时间差

package com.bakheet.effect.time;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class MainActivity extends AppCompatActivity {

 private SimpleDateFormat format;
 public String oldtime ;
 public String newtime;
 private TextView mContent;
 private TextView mCount;
 private TextView mBtnNow;
 private TextView mBtn;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

  mBtn = (TextView) findViewById(R.id.btn);
  mBtnNow = (TextView) findViewById(R.id.btn_now);
  mCount = (TextView) findViewById(R.id.count);
  mContent = (TextView) findViewById(R.id.content);

  //Csdn内一篇博主的博文
  mBtn.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View view) {
    Toast.makeText(MainActivity.this,"Csdn博友事件触发",Toast.LENGTH_SHORT).show();
    try {
    Date d1 = format.parse("2012-11-05 12:00:00");//后的时间
    Date d2 = format.parse("2012-11-04 11:10:00"); //前的时间
    Long diff = d1.getTime() - d2.getTime(); //两时间差，精确到毫秒

    Long day = diff / (1000 * 60 * 60 * 24);   //以天数为单位取整
    Long hour=(diff/(60*60*1000)-day*24);    //以小时为单位取整
    Long min=((diff/(60*1000))-day*24*60-hour*60); //以分钟为单位取整
    Long second=(diff/1000-day*24*60*60-hour*60*60-min*60);//秒

     Log.e("tag","day =" +day);
     Log.e("tag","hour =" +hour);
     Log.e("tag","min =" +min);
     Log.e("tag","second =" +second);

     mContent.setText("day = "+day+"，hour = "+hour+"，min = "+min+"，second = "+second);
    } catch (Exception e) {
     e.printStackTrace();
    }
   }
  });

  //获取当前的时间戳和时间转译 - 这里同时用存储老的时间
  mBtnNow.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View view) {
    Toast.makeText(MainActivity.this,"获取当前时间",Toast.LENGTH_SHORT).show();
    long timeMillis = System.currentTimeMillis();
    Log.e("tag timeMillis =",""+timeMillis);
    //将时间戳转为日期格式
    String time = stampToDate(timeMillis);
    Log.e("tag time = ",time);
    oldtime=time;
    Log.e("tag newtime = ",oldtime);
    try {
     //将日期格式转回为时间戳的格式
     String what = dateToStamp(time);
     Log.e("tag what = ",what);
    } catch (ParseException e) {
     e.printStackTrace();
    }

   }
  });

  //This is my code - - 主要作用与计算时间差 （会用到之前我们的记录的时间，所以使用的时候，无比先执行上面的逻辑）
  mCount.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View view) {
    //思维方式，使用最新的时间减去之前我们的老时间进行运算

    Toast.makeText(MainActivity.this,"新老时间触发",Toast.LENGTH_SHORT).show();
    long timeMillis = System.currentTimeMillis();
    Log.e("tag timeMillis =",""+timeMillis);
    String time = stampToDate(timeMillis);
    Log.e("tag time = ",time);
    newtime=time;
    Log.e("tag newtime = ",newtime);
    try {
    //严格来讲，在使用中这里需要判断的，尤其是null的判断，这里我们使用的了 try catch

    Date d1 = format.parse(newtime); //当前时间
    Date d2 = format.parse(oldtime); //之前记录的时间

    Long diff = d1.getTime() - d2.getTime(); //两时间差，精确到毫秒
     //以天数为单位取整
     Long day = diff / (1000 * 60 * 60 * 24);
     //以小时为单位取整
     Long hour=(diff/(60*60*1000)-day*24);
     //以分钟为单位取整
     Long min=((diff/(60*1000))-day*24*60-hour*60);
     //以秒为单位
     Long second=(diff/1000-day*24*60*60-hour*60*60-min*60);

     Log.e("tag","day =" +day);
     Log.e("tag","hour =" +hour);
     Log.e("tag","min =" +min);
     Log.e("tag","second =" +second);
     mContent.setText("day = "+day+"，hour = "+hour+"，min = "+min+"，second = "+second);
    } catch (Exception e) {
     //建议抛出总异常
     e.printStackTrace();
    }
   }
  });
 }


  /**
  * 将时间转换为时间戳
  */
 public String dateToStamp(String time) throws ParseException {
  SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  Date date = simpleDateFormat.parse(time);
  long ts = date.getTime();
  return String.valueOf(ts);
 }

  /**
  * 将时间戳转换为时间
  */
 public String stampToDate(long timeMillis){
  SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  Date date = new Date(timeMillis);
  return simpleDateFormat.format(date);
 }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/activity_main"
 android:orientation="vertical"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context="com.bakheet.effect.time.MainActivity">

 <TextView
  android:layout_marginTop="10dp"
  android:layout_width="match_parent"
  android:padding="5dp"
  android:layout_height="wrap_content"
  android:text="csdn博友时间差算法"
  android:gravity="center"
  android:id="@+id/btn"
  />

 <TextView
  android:layout_marginTop="10dp"
  android:layout_width="match_parent"
  android:padding="5dp"
  android:layout_height="wrap_content"
  android:gravity="center"
  android:text="当前时间"
  android:id="@+id/btn_now"
  />

 <TextView
  android:layout_marginTop="10dp"
  android:layout_width="match_parent"
  android:padding="5dp"
  android:layout_height="wrap_content"
  android:gravity="center"
  android:id="@+id/count"
  android:text="新老时间计算"
  />
 <TextView
  android:layout_marginTop="10dp"
  android:layout_width="match_parent"
  android:padding="5dp"
  android:layout_height="wrap_content"
  android:gravity="center"
  android:id="@+id/content"
  android:text=""
  />
</LinearLayout>