本文實例講述了Android編程實現類似于圓形ProgressBar的進度條效果。分享給大家供大家參考，具體如下：
我們要實現一個類似于小米分享中的圓形播放進度條，android自帶的圓形ProgressBar是默認自動旋轉的，所以無法實現，于是我們想到了使用自定義一個View，來實現這種效果。
首先來看看自己定義的View
package cn.easymobi.application.bell.common;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.RectF;import android.util.AttributeSet;import android.view.View;public class ProgressView extends View{ private float fArcNum; private float fMax; private float density; public float getDensity() { return density; } public void setDensity(float density) { this.density = density; } public ProgressView(Context context) { super(context); } public ProgressView(Context context,AttributeSet attrs) { super(context,attrs); } protected void onDraw(Canvas canvas) { // TODO Auto-generated method stub super.onDraw(canvas); Paint paint=new Paint(); if(fArcNum>0) { paint.setColor(Color.GRAY); paint.setFlags(Paint.ANTI_ALIAS_FLAG); canvas.drawCircle(40*density/2, 40*density/2, 40*density/2, paint); } paint.setColor(Color.YELLOW); paint.setFlags(Paint.ANTI_ALIAS_FLAG); //paint.setStrokeWidth(2); RectF rect=new RectF(0, 0, 40*density, 40*density); canvas.drawArc(rect, -90, fArcNum,true, paint); paint.setColor(Color.BLACK); paint.setFlags(Paint.ANTI_ALIAS_FLAG); canvas.drawCircle(40*density/2, 40*density/2, 40*density/2-5, paint); } public void setProgress(float num) { fArcNum = (num/fMax) * 360; } public float getfArcNum() { return fArcNum; } public void setfArcNum(float fArcNum) { this.fArcNum = fArcNum; } public float getfMax() { return fMax; } public void setfMax(float fMax) { this.fMax = fMax; }}我們通過重寫View的onDraw方法，根據fArcNum好fMax來判斷當前播放到的位置，然后不停的刷新改View就實現了這個效果。至于畫弧，是采用了drawArc方法，然后通過在其內部畫圓遮蓋多余部分實現。
下面是MediaPlayer與該View的同步處理，核心代碼如下
// *******************************************************************// Func: playAudio//// by: Sun// 2011.9.1// *******************************************************************public void playAudio(final String path, final ProgressBar pb) { Thread thread = new Thread(new Runnable() { public void run() { try { if (mpMediaPlayer != null) { mpMediaPlayer.stop(); mpMediaPlayer.release(); mpMediaPlayer = null; } mpMediaPlayer = new MediaPlayer(); mpMediaPlayer.setDataSource(path); mpMediaPlayer.prepare(); mpMediaPlayer.setOnPreparedListener(new OnPreparedListener() { public void onPrepared(MediaPlayer mp) { pb.setVisibility(ProgressBar.GONE); frontPv.setfMax(mpMediaPlayer.getDuration()); frontPv.setProgress(0); mpMediaPlayer.start(); refrash = new Thread(new Runnable() { public void run() { try { while (frontPv.getfArcNum() <= 360 && mpMediaPlayer.isPlaying()) { if (bIsOver) break; frontPv.setProgress(mpMediaPlayer.getCurrentPosition()); Thread.sleep(1000); mHandle.sendEmptyMessage(MSG_REFRESH_UI); } mHandle.sendEmptyMessage(MSG_PLAY_OVER); } catch (Exception e) { e.printStackTrace(); } } }); refrash.start(); } }); } catch (Exception e) { e.printStackTrace(); } } }); thread.start();}其中frontPv是我們自己定義的view,最后發送handler是調用invalidate方法刷新該 view,mpMediaPlayers是我們定義的MediaPlayer對象。我們通過在進程中每隔一秒更新frontPv當中的fArcNum并且 刷新實現轉動的動畫效果。
希望本文所述對大家Android程序設計有所幫助。
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