android TextView 垂直自动滚动字幕实现

参考网上一些做法然后进行了修改，

首先继承TextView

/** * VerticalScrollTextView.java * 版权所有(C) 2013 * 创建者:cuiran 2013-12-9 下午2:48:55 */package com.cayden.videodemo.view;import java.util.ArrayList;import java.util.List;import android.content.Context;import android.graphics.Canvas;import android.graphics.Paint;import android.util.AttributeSet;import android.util.Log;import android.widget.TextView;/** * TODO  * @author cuiran * @version 1.0.0 */public class VerticalScrollTextView extends TextView {private float step =0f;       private Paint mPaint=new Paint(); ;     private String text;     private float width;     private List<String> textList = new ArrayList<String>();    //分行保存textview的显示信息。      public VerticalScrollTextView(Context context, AttributeSet attrs) {         super(context, attrs);             }           public VerticalScrollTextView(Context context) {         super(context);             }          @Override     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {                 super.onMeasure(widthMeasureSpec, heightMeasureSpec);         width = MeasureSpec.getSize(widthMeasureSpec);            final int widthMode = MeasureSpec.getMode(widthMeasureSpec);           if (widthMode != MeasureSpec.EXACTLY) {                throw new IllegalStateException("ScrollLayout only canmCurScreen run at EXACTLY mode!");         }                      text=getText().toString();        if(text==null|text.length()==0){                        return ;         }                       //下面的代码是根据宽度和字体大小，来计算textview显示的行数。          textList.clear();         StringBuilder builder =null;        for(int i=0;i<text.length();i++){        if(i%12==0){        builder = new StringBuilder();         }         if(i%12<=11){          builder.append(text.charAt(i));          }         if(i%12==11){          textList.add(builder.toString());          }                 }        Log.e("textviewscroll",""+textList.size());            }       //下面代码是利用上面计算的显示行数，将文字画在画布上，实时更新。      @Override     public void onDraw(Canvas canvas) {        if(textList.size()==0)  return;               mPaint.setTextSize(40f);//设置字体大小        for(int i = 0; i < textList.size(); i++) {             canvas.drawText(textList.get(i), 0, this.getHeight()+(i+1)*mPaint.getTextSize()-step+30, mPaint);         }         invalidate();                    step = step+0.3f;         if (step >= this.getHeight()+textList.size()*mPaint.getTextSize()) {             step = 0;         }             }  }

然后写布局文件

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="#eee"    android:orientation="vertical" >    <com.cayden.videodemo.view.VerticalScrollTextView                  android:layout_width="fill_parent"             android:layout_height="fill_parent"                android:textSize="20dp"             android:text="好雨知时节,当春乃发生.随风潜入夜,润物细无声.野径云俱黑,江船火独明.晓看红湿处,花重锦官城."/> </LinearLayout>

然后自己写个Activity就可以了。

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