好久沒有寫部落格了，趁著年末，總結了下最近一年所遇到的一些技術問題，還有一些自定義控制元件，比如倒計時功能

首先倒計時的實現方式

1.Handler
2.Timer
3.RxJava
4.ValueAnimator
5.其他

這些方式中，我選擇了ValueAnimator,主要是它的API比較友好，不需要我們去封裝太多東西,具體的使用方式我就不單獨寫了，下面的程式碼都有備註

專案地址

專案圖片

程式碼實現：

package com.example.countdownview;
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ValueAnimator;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.LinearInterpolator;
public class CountDownView extends View {
  //圓輪顏色
  private int mRingColor;
  //圓輪寬度
  private float mRingWidth;
  //寬度
  private int mWidth;
  //高度
  private int mHeight;
  private Paint mPaint;
  //圓環的矩形區域
  private RectF mRectF;
  //
  private int mCountdownTime;
  private float mCurrentProgress;
  private OnCountDownFinishListener mListener;
  ValueAnimator valueAnimator;
  public CountDownView(Context context) {
    this(context,null);
  }
  public CountDownView(Context context,AttributeSet attrs) {
    this(context,attrs,0);
  }
  public CountDownView(Context context,AttributeSet attrs,int defStyleAttr) {
    super(context,defStyleAttr);
    TypedArray a = context.obtainStyledAttributes(attrs,R.styleable.CountDownView);
    mRingColor = a.getColor(R.styleable.CountDownView_ringColor,Color.RED);
    mCountdownTime = a.getInteger(R.styleable.CountDownView_countdownTime,10);
    mRingWidth=a.getDimension(R.styleable.CountDownView_ringWidth,2);
    a.recycle();
    mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    /**
     *圓環
     */
    //顏色
    mPaint.setColor(mRingColor);
    //空心
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setAntiAlias(true); // 消除鋸齒
    //寬度
    mPaint.setStrokeWidth(mRingWidth);
  }
  public void setCountdownTime(int mCountdownTime) {
    this.mCountdownTime = mCountdownTime;
  }
  @Override
  protected void onLayout(boolean changed,int left,int top,int right,int bottom) {
    super.onLayout(changed,left,top,right,bottom);
    mWidth = getMeasuredWidth();
    mHeight = getMeasuredHeight();
    mRectF = new RectF(0 + mRingWidth / 2,0 + mRingWidth / 2,mWidth - mRingWidth / 2,mHeight - mRingWidth / 2);
  }
  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    canvas.drawArc(mRectF,-90,mCurrentProgress,false,mPaint);
  }
  private ValueAnimator getValA(long countdownTime) {
    ValueAnimator valueAnimator = ValueAnimator.ofFloat(0,100);
    valueAnimator.setDuration(countdownTime);
    valueAnimator.setInterpolator(new LinearInterpolator());
    valueAnimator.setRepeatCount(0);
    return valueAnimator;
  }
  /**
   * 開始倒計時
   */
  public void startCountDown() {
    setClickable(false);
    valueAnimator = getValA(mCountdownTime * 1000);
    //狀態更新監聽
    valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
      @Override
      public void onAnimationUpdate(ValueAnimator animation) {
        float i = Float.valueOf(String.valueOf(animation.getAnimatedValue()));
        mCurrentProgress = (int) (360 * (i / 100f));
        invalidate();
      }
    });
    valueAnimator.start();
    //狀態變化結束監聽
    valueAnimator.addListener(new AnimatorListenerAdapter() {
      @Override
      public void onAnimationEnd(Animator animation) {
        super.onAnimationEnd(animation);
        //倒計時結束回撥
        if (mListener != null) {
          mListener.countDownFinished();
        }
        setClickable(true);
      }
    });
  }
  /**
   * 恢復
   */
  public void resumeCountDown(){
    if (valueAnimator!=null){
      valueAnimator.resume();
    }
  }
  /**
   * 暫停
   */
  public void pauseCountDown(){
    if (valueAnimator!=null){
        valueAnimator.pause();
    }
  }
  /**
   * 停止倒計時
   */
  public void stopCountDown(){
    if (valueAnimator!=null){
      valueAnimator.cancel();
    }
  }
  public void setCountDownFinishListener(OnCountDownFinishListener mListener) {
    this.mListener = mListener;
  }
  public interface OnCountDownFinishListener {
    void countDownFinished();
  }
}

總結

以上所述是小編給大家介紹的Android倒計時功能的實現程式碼，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回覆大家的。在此也非常感謝大家對我們網站的支援！
如果你覺得本文對你有幫助，歡迎轉載，煩請註明出處，謝謝！