android怎样写一个循环文字滚动的TextView

效果图:

在layout中这样来声明:

	<com.kaixin001.view.ScrollText android:id="@+id/news_statustxt"
		    android:layout_width="wrap_content"
			android:layout_height="wrap_content"
			android:paddingLeft="10dp"
			android:paddingRight="10dp"
			android:layout_gravity="center_vertical"
			android:textColor="#000000"
			android:textSize="16sp"
			android:hint="@string/news_state_hint"
			android:inputType="text"/>

activity这样来调用:

   private void initStatus(){
    	ivState = (ImageView) findViewById(R.id.news_statusinput);
    	//必须使text长度比控件的宽度大
    	String s = "dsafsdfsdf(#开心)fsgfdg(#闭嘴)fdgdfgdfgdfgdfgdfgfdgfdgfdgfdgdfg";
    	newsModel.setStatus(s);
    	String strModel = newsModel.getStatus();
        setStateText(strModel);

	}

	private void setStateText(String strModel){
		if(!TextUtils.isEmpty(strModel)){
			tvState.setStateList(newsModel.getStateList());
			tvState.setText(strModel);
            tvState.init(getWindowManager(), handler);
            tvState.startScroll();
            tvState.start();
        }
	}
	<pre name="code" class="java"> <span style="white-space:pre">	</span> public void setStatus(String status){
    	this.status = status;
    	if(!TextUtils.isEmpty(status)){
    		stateList = ParseNewsInfoUtil.parseStr(status);
    	}
   <span style="white-space:pre">	</span>}

private Handler handler = new Handler() {@Overridepublic void handleMessage(Message msg) {switch (msg.what) {case ScrollText.TEXT_TIMER:if(tvState != null){tvState.scrollText();}break;default:break;}}};

import java.util.ArrayList;
import java.util.Timer;
import java.util.TimerTask;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.FontMetrics;
import android.graphics.Paint.Style;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.WindowManager;
import android.widget.TextView;
import com.kaixin001.item.LinkInfo;
import com.kaixin001.model.StateFaceModel;

public class ScrollText extends TextView {

	public static final int TEXT_TIMER = 100;
	private float textLength = 0f;// 文本长度
	private float viewWidth = 0f;
	private float step = 0f;// 文字的横坐标
	private float y = 0f;// 文字的纵坐标
	private float temp_view_plus_text_length = 0.0f;// 用于计算的暂时变量
	private float temp_view_plus_two_text_length = 0.0f;// 用于计算的暂时变量
	private boolean isStarting = false;// 是否開始滚动
	private int left = 0;
	private int right = 0;
	private Paint paint = null;// 画图样式
	private String text = "";// 文本内容
	private Bitmap txtBmp;
	private Canvas txtCanvas;
	private FontMetrics fontMetrics;
	private Timer timer = new Timer();
	private ArrayList<LinkInfo> stateList;

	Handler handler;

	TimerTask task = new TimerTask() {
		public void run() {
			if (handler != null && isStarting) {
				Message msg = Message.obtain();
				msg.what = TEXT_TIMER;
				handler.sendMessage(msg);
			}
		}
	};

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

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

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

	/** */
	/**
	 * 文本初始化，每次更改文本内容或者文本效果等之后都须要又一次初始化一下
	 */
	public void init(WindowManager windowManager, Handler handler) {
		try {
			this.handler = handler;
			paint = new Paint();
			paint.setAntiAlias(true);
			paint.setStyle(Style.STROKE);
			paint.setTextSize(getTextSize());
			paint.setColor(getCurrentTextColor());
			text = getText().toString();
			textLength = 0;
			// textLength = paint.measureText(text);
			int len = stateList.size();
			for (int i = 0; i < len; i++) {
				LinkInfo info = stateList.get(i);
				if (info.isFace()) {// 表情符排版
					Bitmap faceBmp = StateFaceModel.getInstance()
							.getSmallFaceIcon(info.getContent());
					int xLen = faceBmp.getWidth();
					textLength += xLen + 4;
					continue;
				}
				String strContent = info.getContent();
				float xLen = paint.measureText(strContent);
				textLength += xLen;
			}
			left = this.getPaddingLeft();
			right = this.getPaddingRight();
			step = textLength;
			fontMetrics = paint.getFontMetrics();

			y = getPaddingTop();// getTextSize() + getPaddingTop();
			txtBmp = null;
		} catch (Exception ex) {
			ex.printStackTrace();
		}
	}

	public void scrollText() {
		if (!isStarting) {
			return;
		}
		invalidate();
		if (viewWidth < textLength) {
			step += 0.5;
			if (step > temp_view_plus_two_text_length) {
				step = textLength;
			}
		}
	}

	public void setStateList(ArrayList<LinkInfo> stateList) {
		this.stateList = stateList;
	}

	private void setTxtBmp() {
		if (txtBmp == null && fontMetrics != null) {
			y = -paint.ascent();// fontMetrics.bottom -
								// fontMetrics.ascent;//(this.getHeight() -
								// (int)fontMetrics.ascent)/2;
			viewWidth = getWidth() - left - right;
			temp_view_plus_text_length = viewWidth + textLength;
			temp_view_plus_two_text_length = viewWidth + textLength * 2;
			txtCanvas = new Canvas();

			int width = (int) viewWidth;
			float height = getHeight();
			txtBmp = Bitmap.createBitmap(width, (int) height, Config.ARGB_8888);
			txtCanvas.setBitmap(txtBmp);

		}
	}

	/** */
	/**
	 * 開始滚动
	 */
	public void startScroll() {
		isStarting = true;
	}

	/** */
	/**
	 * 停止滚动
	 */
	public void stopScroll() {
		isStarting = false;
		// invalidate();
	}

	public void start() {
		timer.schedule(task, 10, 20);
	}

	public void stop() {
		timer.cancel();
	}

	@Override
	public void onDraw(Canvas canvas) {
		try {
			setTxtBmp();
			if (txtBmp == null) {
				return;
			}
			Paint txtPaint = new Paint();
			txtPaint.setColor(Color.WHITE);
			txtPaint.setStyle(Style.FILL);
			txtCanvas.drawRect(0, 0, txtBmp.getWidth(), txtBmp.getHeight(),
					txtPaint);
			txtPaint.setAntiAlias(true);
			txtPaint.setStyle(Style.STROKE);
			txtPaint.setTextSize(getTextSize());
			txtPaint.setColor(getCurrentTextColor());
			float x = 0;
			// step为text的宽度
			if (viewWidth < textLength) {
				x = temp_view_plus_text_length - step;
			}
			int len = stateList.size();
			float curLen = x;
			for (int i = 0; i < len; i++) {
				LinkInfo info = stateList.get(i);
				if (info.isFace()) {// 表情符排版
					Bitmap faceBmp = StateFaceModel.getInstance()
							.getSmallFaceIcon(info.getContent());
					int xLen = faceBmp.getWidth();
					txtCanvas.drawBitmap(faceBmp, curLen + 2, 0, txtPaint);
					curLen += xLen + 4;
					continue;
				}
				String strContent = info.getContent();
				strContent = strContent.replaceAll("\n", " ");
				float xLen = txtPaint.measureText(strContent);
				//由于x的值一直降低，所以文字能够滚动
				txtCanvas.drawText(strContent, curLen, y, txtPaint); //<span style="font-family: Arial, Helvetica, sans-serif;">txtCanvas早drawtext.txtBmp上也自然也带有这些text</span>

				curLen += xLen;
			}
			canvas.drawBitmap(txtBmp, left, 0, paint);
		} catch (Exception ex) {
			ex.printStackTrace();
		}
	}

	@Override
	protected void onSizeChanged(int w, int h, int oldw, int oldh) {
		super.onSizeChanged(w, h, oldw, oldh);
		txtBmp = null;
		setTxtBmp();
	}
}

代码:http://download.csdn.net/detail/baidu_nod/7736733