Android实现歌曲播放时歌词同步显示具体思路

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Iterator;
import java.util.TreeMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
public class LyricView extends View{
private static TreeMap<Integer, LyricObject> lrc_map;
private float mX; //屏幕X轴的中点，此值固定，保持歌词在X中间显示
private float offsetY; //歌词在Y轴上的偏移量，此值会根据歌词的滚动变小
private static boolean blLrc=false;
private float touchY; //当触摸歌词View时，保存为当前触点的Y轴坐标
private float touchX;
private boolean blScrollView=false;
private int lrcIndex=0; //保存歌词TreeMap的下标
private int SIZEWORD=0;//显示歌词文字的大小值
private int INTERVAL=45;//歌词每行的间隔
Paint paint=new Paint();//画笔，用于画不是高亮的歌词
Paint paintHL=new Paint(); //画笔，用于画高亮的歌词，即当前唱到这句歌词
public LyricView(Context context){
super(context);
init();
}
public LyricView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}

@Override
protected void onDraw(Canvas canvas) {
if(blLrc){
paintHL.setTextSize(SIZEWORD);
paint.setTextSize(SIZEWORD);
LyricObject temp=lrc_map.get(lrcIndex);
canvas.drawText(temp.lrc, mX, offsetY+(SIZEWORD+INTERVAL)*lrcIndex, paintHL);
// 画当前歌词之前的歌词
for(int i=lrcIndex-1;i>=0;i--){
temp=lrc_map.get(i);
if(offsetY+(SIZEWORD+INTERVAL)*i<0){
break;
}
canvas.drawText(temp.lrc, mX, offsetY+(SIZEWORD+INTERVAL)*i, paint);
}
// 画当前歌词之后的歌词
for(int i=lrcIndex+1;i<lrc_map.size();i++){
temp=lrc_map.get(i);
if(offsetY+(SIZEWORD+INTERVAL)*i>600){
break;
}
canvas.drawText(temp.lrc, mX, offsetY+(SIZEWORD+INTERVAL)*i, paint);
}
}
else{
paint.setTextSize(25);
canvas.drawText("找不到歌词", mX, 310, paint);
}
super.onDraw(canvas);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
System.out.println("bllll==="+blScrollView);
float tt=event.getY();
if(!blLrc){
//return super.onTouchEvent(event);
return super.onTouchEvent(event);
}
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
touchX=event.getX();
break;
case MotionEvent.ACTION_MOVE:
touchY=tt-touchY;
offsetY=offsetY+touchY;
break;
case MotionEvent.ACTION_UP:
blScrollView=false;
break;
}
touchY=tt;
return true;
}
public void init(){
lrc_map=new TreeMap<Integer, LyricObject>();
offsetY=320;
paint=new Paint();
paint.setTextAlign(Paint.Align.CENTER);
paint.setColor(Color.GREEN);
paint.setAntiAlias(true);
paint.setDither(true);
paint.setAlpha(180);
paintHL=new Paint();
paintHL.setTextAlign(Paint.Align.CENTER);
paintHL.setColor(Color.RED);
paintHL.setAntiAlias(true);
paintHL.setAlpha(255);
}

public void SetTextSize(){
if(!blLrc){
return;
}
int max=lrc_map.get(0).lrc.length();
for(int i=1;i<lrc_map.size();i++){
LyricObject lrcStrLength=lrc_map.get(i);
if(max<lrcStrLength.lrc.length()){
max=lrcStrLength.lrc.length();
}
}
SIZEWORD=320/max;
}
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
mX=w * 0.5f;
super.onSizeChanged(w, h, oldw, oldh);
}

public Float SpeedLrc(){
float speed=0;
if(offsetY+(SIZEWORD+INTERVAL)*lrcIndex>220){
speed=((offsetY+(SIZEWORD+INTERVAL)*lrcIndex-220)/20);
} else if(offsetY+(SIZEWORD+INTERVAL)*lrcIndex < 120){
Log.i("speed", "speed is too fast!!!");
speed=0;
}
// if(speed<0.2){
// speed=0.2f;
// }
return speed;
}

public int SelectIndex(int time){
if(!blLrc){
return 0;
}
int index=0;
for(int i=0;i<lrc_map.size();i++){
LyricObject temp=lrc_map.get(i);
if(temp.begintime<time){
++index;
}
}
lrcIndex=index-1;
if(lrcIndex<0){
lrcIndex=0;
}
return lrcIndex;
}

public static void read(String file) {
TreeMap<Integer, LyricObject> lrc_read=new TreeMap<Integer, LyricObject>();
String data="";
try {
File saveFile=new File(file);
// System.out.println("是否有歌词文件"+saveFile.isFile());
if(!saveFile.isFile()){
blLrc=false;
return;
}
blLrc=true;
//System.out.println("bllrc==="+blLrc);
FileInputStream stream=new FileInputStream(saveFile);// context.openFileInput(file);
BufferedReader br=new BufferedReader(new InputStreamReader(stream,"GB2312"));
int i=0;
Pattern pattern=Pattern.compile("\\d{2}");
while ((data=br.readLine()) !=null) {
// System.out.println("++++++++++++>>"+data);
data=data.replace("[","");//将前面的替换成后面的
data=data.replace("]","@");
String splitdata[]=data.split("@");//分隔
if(data.endsWith("@")){
for(int k=0;k<splitdata.length;k++){
String str=splitdata[k];
str=str.replace(":",".");
str=str.replace(".","@");
String timedata[]=str.split("@");
Matcher matcher=pattern.matcher(timedata[0]);
if(timedata.length==3 && matcher.matches()){
int m=Integer.parseInt(timedata[0]); //分
int s=Integer.parseInt(timedata[1]); //秒
int ms=Integer.parseInt(timedata[2]); //毫秒
int currTime=(m*60+s)*1000+ms*10;
LyricObject item1=new LyricObject();
item1.begintime=currTime;
item1.lrc="";
lrc_read.put(currTime,item1);
}
}
}
else{
String lrcContenet=splitdata[splitdata.length-1];
for (int j=0;j<splitdata.length-1;j++)
{
String tmpstr=splitdata[j];
tmpstr=tmpstr.replace(":",".");
tmpstr=tmpstr.replace(".","@");
String timedata[]=tmpstr.split("@");
Matcher matcher=pattern.matcher(timedata[0]);
if(timedata.length==3 && matcher.matches()){
int m=Integer.parseInt(timedata[0]); //分
int s=Integer.parseInt(timedata[1]); //秒
int ms=Integer.parseInt(timedata[2]); //毫秒
int currTime=(m*60+s)*1000+ms*10;
LyricObject item1=new LyricObject();
item1.begintime=currTime;
item1.lrc=lrcContenet;
lrc_read.put(currTime,item1);// 将currTime当标签 item1当数据 插入TreeMap里
i++;
}
}
}
}
stream.close();
}
catch (FileNotFoundException e) {
}
catch (IOException e) {
}

lrc_map.clear();
data="";
Iterator<Integer> iterator=lrc_read.keySet().iterator();
LyricObject oldval=null;
int i=0;
while(iterator.hasNext()) {
Object ob=iterator.next();
LyricObject val=(LyricObject)lrc_read.get(ob);
if (oldval==null)
oldval=val;
else
{
LyricObject item1=new LyricObject();
item1=oldval;
item1.timeline=val.begintime-oldval.begintime;
lrc_map.put(new Integer(i), item1);
i++;
oldval=val;
}
if (!iterator.hasNext()) {
lrc_map.put(new Integer(i), val);
}
}
}

public static boolean isBlLrc() {
return blLrc;
}

public float getOffsetY() {
return offsetY;
}

public void setOffsetY(float offsetY) {
this.offsetY=offsetY;
}

public int getSIZEWORD() {
return SIZEWORD;
}

public void setSIZEWORD(int sIZEWORD) {
SIZEWORD=sIZEWORD;
}
}