常用计时器实现

• • 两种实现方式
    • 1定义一个计时类
    • 2使用handler-message

项目开发中常常会用到计时器

例如，获取验证码的时候，商城类应用的限时抢购，考试类应用的考试计时

两种实现方式：

1，定义一个计时类

提供以下方法：

开始倒计时–startTime()

刷新计时–refreshTime(long second)

停止计时–stopTime()

获取现在时间–getNowTime()

获取message.what的TAG –getTAG()

  /**
 * 计时器不使用内部类的时候一定要注意生命周期管理
 * 传入的时间用秒做单位
 * Created by Administrator on 2017/3/29.
 */

public class ClockUtils extends Activity {
private long time ;
private Handler mHandler;
private TextView mView;
private int REFRESH_LIMIT = 2017;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
    }

public ClockUtils(long second, Handler handler, TextView view) {
this.time = second;
this.mHandler = handler;
this.mView = view;
    }

public void startTime(){
        runnable.run();
    }

public void refreshTime(long second){
this.time = second;
        runnable.run();
    }

public long getNowTime(){
return time<0?0:time;
    }

public void stopTime(){
        timeHandler.removeCallbacks(runnable);
    }

public int getTAG(){
return REFRESH_LIMIT;
    }

    Handler timeHandler = new Handler();
    Runnable runnable = new Runnable() {
@Override
public void run() {
if (time>0){
                time--;
                timeHandler.postDelayed(this, 1000);
//需要显示小时的倒计时
// long hour = (time / (60 * 60));
// long minute = ((time / 60 ) - hour * 60);
// long second = (time - (hour * 60 * 60 )- (minute * 60));
// mView.setText(timeFormatting(hour) + ":" + timeFormatting(minute) + ":" + timeFormatting(second));
//只需要从分钟开始显示的倒计时
long minute = ((time / 60 ));
long second = (time - (minute * 60));
                mView.setText(timeFormatting(minute) + ":" + timeFormatting(second));
            }else
if (time == 0){
//时间走完，告知activity处理
                Message message = new Message();
                message.what = REFRESH_LIMIT;
                mHandler.sendMessage(message);
            }
        }
    };

@Override
protected void onDestroy() {
super.onDestroy();
        timeHandler.removeCallbacks(runnable);
    }

// 时间格式化，在小于10的情况下前面自动补0
private String timeFormatting(long number) {
        String str = String.valueOf(number);
if (str.length() < 2) {
            str = "0" + str;
        }
return str;
    }
}

特别重要的一点，不可见的时候要停止计时

2，使用handler-message

以获取验证码的倒计时为例

 private void getVerifyCode() {
        phone = etPhoneVerify.getText().toString();
boolean b = CommUtils.isPhoneValid(phone);
if (b) {
if (recLen == 60){
                getVerify(phone);
                showTime();
            }else {
                ToastUtil.showShort(RegisterActivity.this,"正在请求，请稍后", Gravity.CENTER);
            }
        } else {
            ToastUtil.showShort(this,"请检查手机号是否有误", Gravity.CENTER);
        }
    }

//显示验证码有效时间倒计时
private void showTime() {
        handler.postDelayed(runnable, 1000);
    }

private int recLen = 60;//设置有效时间
    Handler handler = new Handler();
    Runnable runnable = new Runnable() {
@Override
public void run() {
            recLen--;
            tvGetVerify.setText("有效时间:" + recLen);
            handler.postDelayed(this, 1000);
if (recLen <= 0) {
                recLen = 60;//重置
                Message message = new Message();
                message.what = 1;
                handlerStop.sendMessage(message);
                tvGetVerify.setText("获取验证码");
            }
        }
    };

final Handler handlerStop = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case 1:
                    handler.removeCallbacks(runnable);
break;
            }
super.handleMessage(msg);
        }

    };

@Override
protected void onDestroy() {
super.onDestroy();
        handler.removeCallbacks(runnable);
    }