最近看到好多APP开屏广告有倒计时圆圈，比如智联招聘，搜狐新闻等。来模仿一波~~
1. 先来看自定义圆圈view：CountdownCircleProgressBar
package com.example.mywelcomeapp; 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.support.annotation.Nullable; import android.util.AttributeSet; import android.util.TypedValue; import android.view.View; public class CountdownCircleProgressBar extends View {/** * 圆圈的颜色 */ private int mCircleColor; /** * 圆圈的宽度 */ private int mCircleWith; /** * 画笔 */ private Paint mPaint; /** * 当前进度 */ private int mProgress; /** * 是否正在运行 */ public boolean isRunning = true; public CountdownCircleProgressBar(Context context) { this(context, null); }public CountdownCircleProgressBar(Context context, @Nullable AttributeSet attrs) { this(context, attrs, 0); }/** * 必要的初始化，获得一些自定义的值 * * @param context上下文 * @param attrsattrs * @param defStyleAttr defStyleAttr */ public CountdownCircleProgressBar(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); TypedArray array = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CountdownCircleProgressBar, defStyleAttr, 0); int n = array.getIndexCount(); for (int i = 0; i < n; i++) { int attr = array.getIndex(i); switch (attr) { case R.styleable.CountdownCircleProgressBar_circleColor: mCircleColor = array.getColor(attr, Color.GREEN); break; case R.styleable.CountdownCircleProgressBar_circleWith: mCircleWith = array.getDimensionPixelSize(attr, (int) TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_PX, 20, getResources().getDisplayMetrics())); break; default: break; } } array.recycle(); mPaint = new Paint(); }@Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); }@Override protected void onDraw(Canvas canvas) { //获取圆心坐标 int centre = getWidth() / 2; //半径 int radius = centre - mCircleWith / 2; //设置圆环宽度 mPaint.setStrokeWidth(mCircleWith); //消除锯齿 mPaint.setAntiAlias(true); //设置空心 mPaint.setStyle(Paint.Style.STROKE); //用于定义的圆弧的形状和大小的界限 RectF oval = new RectF(centre - radius, centre - radius, centre + radius, centre + radius); //canvas.drawCircle(centre, centre, radius, mPaint); //换出圆环 //设置圆环的颜色 mPaint.setColor(mCircleColor); //根据进度画圆弧: 顺时针画圆弧 canvas.drawArc(oval, -90, mProgress, false, mPaint); //根据进度画圆弧 : 逆时针画圆弧 //canvas.drawArc(oval, -90, -mProgress, false, mPaint); }/** * 播放倒计时动画 */ public void play() { //绘制线程 new Thread() { @Override public void run() { while (isRunning) { mProgress++; postInvalidate(); try { Thread.sleep(timeMillis / 360); } catch (InterruptedException e) { e.printStackTrace(); } } } }.start(); }/** * 倒计时时间 */ private long timeMillis = 3000; /** * 设置倒计时时间 */ public void setTimeMillis(long timeMillis) { this.timeMillis = timeMillis; invalidate(); }
【Android APP开屏界面倒计时圆圈的实现】}
定义属性：attrs.xml
