<span style="font-size:18px;">package com.example.textviewpao;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.widget.TextView;

public class MyTextView extends TextView{
	public static final String TAG = "MyTextView";

	/** 字幕滾動的速度 快，普通，慢 */
	public static final int SCROLL_SLOW = 0;
	public static final int SCROLL_NORM = 1;
	public static final int SCROLL_FAST = 2;

	/** 字幕內容 */
	private String mText;

	/** 字幕字型顏色 */
	private int mTextColor;

	/** 字幕字型大小 */
	private float mTextSize;

	private float offX = 0f;

	private float mStep = 0.5f;

	private Rect mRect = new Rect();

	private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);;


	public MyTextView(Context context) {
		super(context);
		setSingleLine(true);
		
	}
	public MyTextView(Context context, AttributeSet attrs) {
		super(context, attrs);
		setSingleLine(true);
	
	}
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);
		// TODO Auto-generated method stub
		mText = getText().toString();
		mTextColor = getCurrentTextColor();
		mTextSize = getTextSize();
		mPaint.setColor(mTextColor);
		mPaint.setTextSize(mTextSize);
		mPaint.getTextBounds(mText, 0, mText.length(), mRect);
		
	}
	@Override
	protected void onDraw(Canvas canvas) {
		float x, y;
		x = getMeasuredWidth() - offX;
		y = getMeasuredHeight() / 2 + (mPaint.descent() - mPaint.ascent()) / 2;
		canvas.drawText(mText, x, y, mPaint);
		offX += mStep;
		if (offX >= getMeasuredWidth() + mRect.width()) {
			offX = 0f;
		}
		invalidate();
	}
	/**
	 * 設定字幕滾動的速度
	 */
	public void setScrollMode(int scrollMod) {
		if (scrollMod == SCROLL_SLOW) {
			mStep = 0.5f;
		} else if (scrollMod == SCROLL_NORM) {
			mStep = 1f;
		} else {
			mStep = 1.5f;
		}
	}

	

}
</span>