一个简单的倒计时控件的实现

好久没有写博客了,本来想当做自己的知识库来着,但是有时候不能坚持下来,今天有时间就再来更新下,就写一个简单的倒计时实现,其实没啥难点,Handler+Timer就可以实现.

原理就是:启动一个定时器,每个1秒钟利用handler发送一个请求,然后到handleMessage处理,判断小时,分钟,秒是多少,最后显示到页面上(没有特别难理解的,代码里面就没有写注释,ps:貌似好像也是借鉴的别人的,但是时间有点久远,忘记了)
下面直接上代码吧:
布局文件:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context="com.jiuair.booking.activity.Djs">
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:paddingTop="5dp">

        <TextView
            android:id="@+id/tv_hour"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/icon_special_tv"
            android:gravity="center"
            android:text="48"
            android:textColor="@color/white"
            android:textSize="11sp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:paddingLeft="2dp"
            android:text="h"
            android:textColor="@color/black" />

        <TextView
            android:id="@+id/tv_min"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="2dp"
            android:background="@drawable/icon_special_tv"
            android:gravity="center"
            android:text="48"
            android:textColor="@color/white"
            android:textSize="11sp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:paddingLeft="2dp"
            android:text="m"
            android:textColor="@color/black" />

        <TextView
            android:id="@+id/tv_second"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="2dp"
            android:background="@drawable/icon_special_tv"
            android:gravity="center"
            android:text="48"
            android:textColor="@color/white"
            android:textSize="11sp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:paddingLeft="2dp"
            android:text="s"
            android:textColor="@color/black" />
    </LinearLayout>
</RelativeLayout>

activity的代码:

package com.jiuair.booking.activity;

import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.jiuair.booking.R;

import java.util.ArrayList;
import java.util.Timer;
import java.util.TimerTask;

public class Djs extends AppCompatActivity {

    private Handler handler;
    private int hour;
    private int min;
    private int second;
    private LinearLayout ll_package;
    private TextView tv_hour;
    private TextView tv_second;
    private TextView tv_min;
    private Timer timer;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_djs);
        handler = new Handler() {
            @Override
            public void handleMessage(Message msg) {
                computeTime();
                if (hour <= 0 && min <= 0 && second < 0){
                    if (timer != null){
                        timer.cancel();
                    }
                    handler.removeCallbacks(null);
                }else{
                    tv_hour.setText(hour+"");
                    tv_min.setText(min+"");
                    tv_second.setText(second+"");
                }

            }
        };
        tv_hour = (TextView)findViewById(R.id.tv_hour);
        tv_min = (TextView)findViewById(R.id.tv_min);
        tv_second = (TextView)findViewById(R.id.tv_second);
        ArrayList<Integer> list = new ArrayList<>();
        list.add(1);
        list.add(1);
        list.add(10);
        hour = list.get(0);
        min = list.get(1);
        second = list.get(2);
        tv_hour.setText(hour+"");
        tv_min.setText(min+"");
        tv_second.setText(second+"");

        timer = new Timer(true);
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                Message message = new Message();
                handler.sendMessage(message);
            }
        },100,1000);
    }
    private void computeTime() {
        second--;
        if (second < 0) {
            min--;
            second = 59;
            if (min < 0) {
                min = 59;
                hour--;
            }
        }
    }
    @Override
    public void onDestroy() {
        handler.removeCallbacks(null);
        if (timer != null){
            timer.cancel();
        }
        super.onDestroy();
    }
}