Android自定义控件之自定义倒计时按钮

自定义的倒计时按钮应该很多人都做过，我想最常见的实现方式应该就是开启一个子线程，然后通过Handler去更新UI实现，

这里我自定义了一个按钮，通过在handler中发送handler的方式，也同样实现了计时器的效果，而且也不需要开子线程，是代码的内存消耗更小更具有操作性

实现效果如下

直接上代码：

package com.fizzer.doraemon.localdemo.Animation.View;

import android.content.Context;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.widget.Button;
import android.widget.Chronometer;

/**
 * Created by Fizzer on 2016/12/13.
 * Email: doraemonmqq@sina.com
 * 倒计时控件
 */

public class CountDownButton extends Button {

    private boolean isRunning = false;

    private int startTime = 10;

    private int changeTime;

    private int TASK_RUNNING = 1;

    public CountDownButton(Context context) {
        super(context);
    }

    public CountDownButton(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CountDownButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }


    public void start() {
        isRunning = true;
        changeTime = startTime;
        setText(changeTime + "秒");
        updateRunning();
    }

    public void stop() {
        isRunning = false;
        updateRunning();
    }

    /**
     * 设置倒计时时间
     * @param time  time
     */
    public void setStartTime(int time) {
        this.startTime = time;
    }

    private void updateRunning() {
        if (isRunning) {
            mHandler.sendMessageDelayed(Message.obtain(mHandler, TASK_RUNNING), 1000);
        } else {
            mHandler.removeMessages(TASK_RUNNING);
        }
    }

    Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            changeTime--;
            setText(changeTime + "秒");
            setClickable(false);
            if (changeTime >= 0) {
                mHandler.sendMessageDelayed(Message.obtain(mHandler, TASK_RUNNING), 1000);
            } else {
                changeTime = startTime;
                mHandler.removeMessages(TASK_RUNNING);
                setText("重新开始");
                setClickable(true);
            }
        }
    };

    /**
     * 界面关闭的时候，停止发送handler
     */
    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        isRunning = false;
        updateRunning();
    }
}

在使用的类中调用一下start方法就行了

mMyButton.start();