android_TextView_垂直自动滚动.doc

android TextView 垂直自动滚动2011-12-06 19:34:00 我来说两句 收藏 我要投稿 字体：小 大 在做android 应用的开发的时候,横向滚动或者要做出跑马灯的效果很简单,textview本身的属性就支持,只要设置准确就会滚动,开发起来比较简单,但是textview 不支持垂直滚动,那么垂直滚动就需要自己来实现了,很多网友提供的垂直滚 动方案都是千篇一律,使用ScrollView来进行滚动,但是都不完美,做起来有些别扭有一位网友给出的歌词的滚动思路明确,能从根本上解决问题,因此我实现的这个滚动是在这位网友的基础上实现,封装了一个View,view继承自TextView先看看实现的效果:实现图中效果的关键点是:1重写onDrow方法,计算每次的滚动的距离2计算view的Y轴的重点,让当前显示的处于高亮显示状态3定时的刷新View使其界面不断的刷先,出现滚动的效果4实现数据结构,将数据传给view下面看看主要代码:1创建一个类继承TextView/* author xushilin* 垂直滚动的TextView Widget*/public class VerticalScrollTextView extends TextView2实现构造函数:public VerticalScrollTextView(Context context) super(context); init(); public VerticalScrollTextView(Context context, AttributeSet attr) super(context, attr); init(); public VerticalScrollTextView(Context context, AttributeSet attr, int i) super(context, attr, i); init(); private void init() setFocusable(true); /这里主要处理如果没有传入内容显示的默认值 if(list=null) list=new ArrayList(); Notice sen=new Notice(0,暂时没有通知公告); list.add(0, sen); /普通文字的字号,以及画笔颜色的设置 mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setTextSize(16); mPaint.setColor(Color.BLACK); mPaint.setTypeface(Typeface.SERIF); /高亮文字的字号,以及画笔颜色的设置 mPathPaint = new Paint(); mPathPaint.setAntiAlias(true); mPathPaint.setColor(Color.RED); mPathPaint.setTextSize(16); mPathPaint.setTypeface(Typeface.SANS_SERIF); 3从写onDraw方法,并计算文字的行距,并且将将普通文字和高亮文字,在这个方法中绘制出来protected void onDraw(Canvas canvas) super.onDraw(canvas); canvas.drawColor(0xEFeffff); Paint p = mPaint; Paint p2 = mPathPaint; p.setTextAlign(Paint.Align.CENTER); if (index = -1) return; p2.setTextAlign(Paint.Align.CENTER); canvas.drawText(list.get(index).getName(), mX, middleY, p2); float tempY = middleY; for (int i = index - 1; i = 0; i-) tempY = tempY - DY; if (tempY 0) break; canvas.drawText(list.get(i).getName(), mX, tempY, p); tempY = middleY; for (int i = index + 1; i mY) break; canvas.drawText(list.get(i).getName(), mX, tempY, p); 4计算Y轴中值以及更新索引protected void onSizeChanged(int w, int h, int ow, int oh) super.onSizeChanged(w, h, ow, oh); mX = w * 0.5f; mY = h; middleY = h * 0.5f; private long updateIndex(int index) if (index = -1) return -1; this.index=index; return index; 5定时更新view,并将接口暴露给客户程序调用public void updateUI() new Thread(new updateThread().start(); class updateThread implements Runnable long time = 1000; int i=0; public void run() while (true) long sleeptime = updateIndex(i); time += sleeptime; mHandler.post(mUpdateResults); if (sleeptime = -1) return; try Thread.sleep(time); i+; if(i=getList().size() i=0; catch (InterruptedException e) e.printStackTrace(); Handler mHandler = new Handler(); Runnable mUpdateResults = new Runnable() public void run() invalidate(); ;6xml布局文件中调用: 7java代码中调用,传递数据:package com.demo.xsl.text;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.os.Bundle;import android.os.Handler;public class VerticalScrollTextActivity extends Activity SampleView mSampleView; Override public void onCreate(Bundle savedInstanceState) super.onCreate(savedInstanceState); setContentView(R.layout.main); mSampleView = (SampleView) findViewById(R.id.sampleView1); List lst=new ArrayList(); for(int i=0;i30;i+) if(i%2=0) Sentence sen=new Sentence(i,i+金球奖三甲揭晓C罗