Android 滚动字幕实现

转自：http://blog.csdn.net/cupidove/article/details/38316215

最近项目需求做个循环滚动字幕功能，自己找了相关资料，根据自己的风格用两种方法实现了该功能；

(备注：本人只实现了滚动效果，对于文字的格式排版没做处理，格式可能会乱，文字排版还在研究中)

效果图：

具体如下；

方法一:横向滚动字幕继承TextView

 package com.example.playpic;

 import com.example.playpic.AutoScrollTextView.SavedState;

 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.Typeface;
 import android.graphics.Paint.FontMetrics;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.util.AttributeSet;
 import android.util.DisplayMetrics;
 import android.util.Log;
 import android.view.WindowManager;
 import android.view.View.BaseSavedState;
 import android.widget.TextView;

 public class AutoText extends TextView {

     private int width,height;
     private Paint paintText;
     private float posx,posy;
     private float speed=0.0f;
     private String text="hello haha";
     private float textWidth=0;
     private float moveDistance=0.0f;
     private boolean isStarting=false;

     public AutoText(Context context) {
         super(context);

     }

     public AutoText(Context context, AttributeSet attrs) {
         super(context, attrs);

     }

     private void initView(){
         paintText=new Paint();
         paintText.setTextSize(50.0f);
         paintText.setColor(Color.BLACK);
         paintText.setTypeface(Typeface.DEFAULT_BOLD);
         paintText.setAntiAlias(true);
         text=getText().toString();
         textWidth=paintText.measureText(text);Log.e("msg", "textWidth= "+textWidth);
         this.speed=textWidth;
         moveDistance=textWidth*2+width;
     }

     public void initDisplayMetrics(WindowManager windowManager){
            /* 取得屏幕分辨率大小 */
          DisplayMetrics dm=new DisplayMetrics();
          windowManager.getDefaultDisplay().getMetrics(dm);
          this.width=dm.widthPixels;
          this.height=dm.heightPixels;

          initView();
          this.posx=width+textWidth;
          FontMetrics fm = paintText.getFontMetrics();
          float baseline = fm.descent - fm.ascent;
          this.posy=height/2-baseline;
     }

     public void startScroll() {
         isStarting = true;
         invalidate();
     }
     public void stopScroll() {
         isStarting = false;
         invalidate();
     }

     @Override
     protected void onDraw(Canvas canvas) {
     //  super.onDraw(canvas);
         canvas.drawText(text, posx-speed, posy, paintText);
         if (!isStarting) {
             return;
         }
         speed += 2.0f;
         if (speed > moveDistance)
             speed = textWidth;
         invalidate();
     }

 }

布局文件；

 "1.0" encoding="utf-8"?>
 "http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical" >



         android:id="@+id/autoTxt"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:background="#ffffff"
         android:textColor="#00ff00"
         android:textSize="35sp" />

方法二：继承sufaceView实现纵向文字滚动功能

 package com.example.playpic;

 import java.util.ArrayList;
 import java.util.List;

 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.Paint.FontMetrics;
 import android.graphics.Rect;
 import android.graphics.Typeface;
 import android.util.AttributeSet;
 import android.util.DisplayMetrics;
 import android.view.SurfaceHolder;
 import android.view.SurfaceView;
 import android.view.WindowManager;

 public class ScrollText extends SurfaceView implements SurfaceHolder.Callback ,Runnable{

     private int width,height;
     private SurfaceHolder sfh;
     private Thread th;
     private boolean flag;
     private Paint backPaint,textPaint;
     /**文字开始出现的位置坐标*/
     private float posx,posy;
     /**每行文本 当前移动文本距离以及文本的原始移动位置*/
     private Float[] step,stepBack;
     private String txtContent;
     /**存储每行文本原始纵坐标位置*/
     private Float[] tposy;
     /**存储每行文本内容*/
     private String[] texts;

     public ScrollText(Context context) {
         super(context);
         initView();
     }

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

     private void initView(){
         sfh=this.getHolder();
         sfh.addCallback(this);
         this.setKeepScreenOn(true);
         this.setFocusable(true);
     //  this.setFocusableInTouchMode(true);
         backPaint=new Paint();
         backPaint.setColor(Color.BLACK);
         textPaint=new Paint();

         textPaint.setTextSize(30.0f);
         textPaint.setColor(Color.BLUE);
         textPaint.setTypeface(Typeface.DEFAULT_BOLD);
         textPaint.setTextAlign(Paint.Align.LEFT);
         textPaint.setAntiAlias(true);
     }

     public void initDisplayMetrics(WindowManager windowManager){
            /* 取得屏幕分辨率大小 */
         DisplayMetrics dm=new DisplayMetrics();
         windowManager.getDefaultDisplay().getMetrics(dm);
         this.width=dm.widthPixels;
         this.height=dm.heightPixels;
         this.posx=width/6;
       /*  FontMetrics fm = textPaint.getFontMetrics();
         float baseline = fm.descent - fm.ascent;*/
         this.posy=height-100;

     }

     public void setTxtContent(String txt){
         this.txtContent=txt;
     }

     @Override
     public void surfaceCreated(SurfaceHolder holder) {
         this.flag=true;

         if(th==null||!th.isAlive()){
             th=new Thread(this);
             th.start();
         }
     }

     @Override
     public void surfaceChanged(SurfaceHolder holder, int format, int width,
             int height) {

     }

     @Override
     public void surfaceDestroyed(SurfaceHolder holder) {

         this.flag=false;
     }
     /**
      * 调用所有绘制方法
      */
     private void drawAll(){
         Canvas canvas=null;
         try{
             canvas=sfh.lockCanvas();
             drawText(canvas, txtContent);

         }catch(Exception e){
             e.printStackTrace();
         }finally{
             if(canvas!=null){
                 sfh.unlockCanvasAndPost(canvas);
             }
         }
     }

     private void drawText(Canvas canvas,String text){
         //clear screen
         canvas.drawRect(new Rect(0,0,getWidth(),getHeight()), backPaint);

         initDrawText(text);

         int len=tposy.length;
         // draw text content
         for(int n=0;n
             if(texts[n]==null)
                 return;
             float ty=tposy[n]-step[n];

             canvas.drawText(texts[n], posx, ty, textPaint);
             step[n]+=5.0f;

             if(n==len-1&&ty<0){
                 step=stepBack.clone();
             }
             /*if (ty<0){ Log.e("msgreset", "back step");
                 step[n] = stepBack[n].floatValue();
             }*/
         }
         postInvalidate();
     }
     /**
      * 在文字信息绘制前对文本信息进行文字分割，文字间距，文字位置计算处理
      * @param text
      */
     private void initDrawText(String text){
         if(texts==null){
             texts=getTexts(text);
         }
         if(tposy==null){
             tposy=getTextLinePosy();
         }
         if(stepBack==null){
             stepBack=new Float[tposy.length];
             int i=0;
             float interval=0.0f;
             FontMetrics fm = textPaint.getFontMetrics();
             float baseline = fm.descent - fm.ascent;
             while(i
                 stepBack[i]=interval;
                 interval-=baseline;
                 i++;
             }
         }
         if(step==null){
             step=stepBack.clone();
         }
     }
     /**
      * 获取分割后的文本信息
      * @param text
      * @return
      */
     private String[] getTexts(String text){
         List totalList=new ArrayList(10);
         String[] str=text.split("\n");
         int len=str.length;

         for(int i=0;i
             String[] ss=autoSplit(str[i], textPaint, getWidth()/3*2);
             for(String s:ss){
                 totalList.add(s);
             }
         }
         if(texts==null)
             texts=(String[]) totalList.toArray(new String[0]);
         /*if(texts==null)
          texts = autoSplit(text, textPaint, getWidth()/3*2); */
         return texts;
     }
     /**
      * 获取每行文本的纵坐标信息
      * @return
      */
     private Float[] getTextLinePosy(){
          FontMetrics fm = textPaint.getFontMetrics();
          float baseline = fm.descent - fm.ascent;
          float y =  posy+baseline;  //由于系统基于字体的底部来绘制文本，所有需要加上字体的高度

          int len=texts.length;
          Float[] groups=new Float[len];

             for(int i=0;i
                 groups[i]=y;
                 y =y+ baseline + fm.leading; //添加字体行间距
             }
             return groups;
     }
     /**
      * 自动分割文本
      * @param content 需要分割的文本
      * @param p  画笔，用来根据字体测量文本的宽度
      * @param width 最大的可显示像素（一般为控件的宽度）
      * @return 一个字符串数组，保存每行的文本
      */
     private String[] autoSplit(String content, Paint p, float width) {


        /* String[] lineTexts = new String[1000];
         int lenStr=0;
         int lineNum=0,w=0,start=0,end=1,n=0;

             lenStr=content.length();
             for(int j=0;j
                 char ch=content.charAt(j);
                 String str_ch=String.valueOf(ch);
                 float[] ch_w=new float[1];
                 p.getTextWidths(str_ch, ch_w);

                 if(str_ch=="\n"){
                     lineNum++;
                 //  start=j+1;
                     end=j+1;
                     w=0;

                     lineTexts[n++] = (String) content.subSequence(start, end);
                     start=end;
                 }else{
                     w+=(int)(Math.ceil(ch_w[0]));
                     if(w>width){
                         lineNum++;
                 //      start=j;
                         end=j;
                         j--;
                         w=0;

                         lineTexts[n++] = (String) content.subSequence(start, end);
                         start=end;
                     }else{
                         if(j==(lenStr-1)){
                             lineNum++;
                             lineTexts[n++] = (String) content.subSequence(start, end);
                             break;
                         }
                     }
                 }
             }
             Log.e("msg", "lineNum= "+lineNum);*/


         float textWidth = p.measureText(content);
         if(textWidth <= width) {
             return new String[]{content};
         }

         int length = content.length();
         int start = 0, end = 1, i = 0;
         int lines = (int) Math.ceil(textWidth / width); //计算行数
         String[] lineTexts = new String[lines];

         while(start < length) {
             if(p.measureText(content, start, end) > width) { //文本宽度超出控件宽度时
                     lineTexts[i++] = content.substring(start, end);//(String) content.subSequence(start, end);
                     start = end;
                 }
             if(end == length) { //不足一行的文本
                 lineTexts[i] = content.substring(start, end);//(String) content.subSequence(start, end);
                 break;
             }
             end += 1;
         }

         return lineTexts;
     }

     @Override
     public void run() {
         while(flag){
             drawAll();
             try {
                 Thread.sleep(200);
             } catch (InterruptedException e) {
                 e.printStackTrace();
             }
         }
     }


 }

 package com.example.playpic;

 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.FileReader;
 import java.io.IOException;
 import java.io.InputStreamReader;

 import android.app.Activity;
 import android.os.Bundle;
 import android.os.Environment;
 import android.text.method.ScrollingMovementMethod;
 import android.util.Log;
 import android.widget.TextView;

 import com.sample.fun.R;

 public class ScrollTextActivity extends Activity{


     String str="";

     String str11="促进青年教师全面发展，\n引导广大高校青年教师为实现中华民族伟大复兴的中国梦贡献力" +"\n"+"促进青年教师全面发展，\n引导广大高校青年教师为实现中华民族伟大复兴的中国梦贡献力"+"\n"+
             "  djsdnh   kshdfjks     \n\r\t ";

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);

         scroll3();
     }

     void scroll2(){
         ScrollText v=new ScrollText(getApplicationContext());
         setContentView(v);
         v.setTxtContent(str11);
         v.initDisplayMetrics(getWindowManager());
     }

     void scroll3(){
         setContentView(R.layout.scrollview1);
         AutoText auto=(AutoText)findViewById(R.id.autoTxt);
         auto.setText(str11);
         auto.initDisplayMetrics(getWindowManager());
         auto.startScroll();
     }

 }