Android自定义之TextView跑马灯的监听

TextView都有跑马灯的效果，如果说让你去监听跑马灯效果的执行，我觉得这个需求有点二了，但是也要实现。思路：1.自定义View 继承TextView 这种方法过于麻烦，只是监听一个跑马灯而已。2.自定义SPan。简单好用，扩展TextView的功能。
关键代码如下：

@Override
	public void draw(Canvas canvas, CharSequence text, int start, int end,
	float x, int top, int y, int bottom, Paint paint) {
	canvas.save();
	canvas.drawText( text.toString(), x - startX, y, paint);
	canvas.restore();
	int measureText = (int) paint.measureText(text, 0, text.length());
	if (valueAnimator == null ) {
	initAnimator(measureText - mView.getWidth());
	}
	}
	private int startX = 0 ;
	private final static int DEFULT_DURATION = 2000 ;
	private int duration = DEFULT_DURATION ;
	@Override
	public int getSize(Paint paint, CharSequence text, int start, int end,
	FontMetricsInt fm) {
	return 40;
	}
	private void initAnimator(int width ){
	valueAnimator = ValueAnimator.ofInt(0, width , 0 );
	valueAnimator.addUpdateListener(new AnimatorUpdateListener() {
	@Override
	public void onAnimationUpdate(ValueAnimator animation) {
	startX = (Integer) animation.getAnimatedValue() ;
	mView.invalidate();
	}
	});
	valueAnimator.setInterpolator(new LinearInterpolator());
	valueAnimator.setDuration(duration);
	valueAnimator.addListener(new AnimatorListenerAdapter() {
	@Override
	public void onAnimationRepeat(Animator animation) {
	if (mEasySpanListener != null ) {
	mEasySpanListener.over();
	}
	}
	});
	valueAnimator.setRepeatCount(Integer.MAX_VALUE);
	valueAnimator.start();
	}

Span本身就是对TextView的一个功能增强。使用： String text = "这个是用来测试的，TextView的跑马灯效果，想要监听他的跑完的事件用的。" ; SpannableString spannableString = new SpannableString(text); EasySpan easySpan =new EasySpan(MainActivity.this,test); easySpan.setDuration(10000); easySpan.setEasySpanListener(new EasySpanListener() { @Override public void over() { Log.i("Test", "over") ; } }); spannableString.setSpan(easySpan, 0, text.length(), Spannable.SPAN_INCLUSIVE_INCLUSIVE); test.setText(spannableString);来源： <https://github.com/flyme2012/EasyListenerSpan/blob/master/src/com/example/easylistenerspan/MainActivity.java>
很简单的小功能，大家就看代码吧。 源码下载地址： https://github.com/flyme2012/EasyListenerSpan

来自为知笔记(Wiz)