android如何寫一個循環文字滾動的TextView

效果圖:

在layout中這樣來聲明:<喎?/kf/ware/vc/" target="_blank" class="keylink">vcD4KPHA+PC9wPgo8cHJlIGNsYXNzPQ=="brush:java;">
activity這樣來調用:

   private void initStatus(){
    	ivState = (ImageView) findViewById(R.id.news_statusinput);
    	//必須使text長度比控件的寬度大
    	String s = "dsafsdfsdf(#開心)fsgfdg(#閉嘴)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();
        }
	}
	
 	 public void setStatus(String status){
    	this.status = status;
    	if(!TextUtils.isEmpty(status)){
    		stateList = ParseNewsInfoUtil.parseStr(status);
    	}
   	}


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;// 文本長度
	private float viewWidth = 0f;
	private float step = 0f;// 文字的橫坐標
	private float y = 0f;// 文字的縱坐標
	private float temp_view_plus_text_length = 0.0f;// 用於計算的臨時變量
	private float temp_view_plus_two_text_length = 0.0f;// 用於計算的臨時變量
	private boolean isStarting = false;// 是否開始滾動
	private int left = 0;
	private int right = 0;
	private Paint paint = null;// 繪圖樣式
	private String text = "";// 文本內容
	private Bitmap txtBmp;
	private Canvas txtCanvas;
	private FontMetrics fontMetrics;
	private Timer timer = new Timer();
	private ArrayList 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，每次更改文本內容或者文本效果等之後都需要重新初始化一下
	 */
	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 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);

		}
	}

	/** */
	/**
	 * 開始滾動
	 */
	public void startScroll() {
		isStarting = true;
	}

	/** */
	/**
	 * 停止滾動
	 */
	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為text的寬度
			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);
				//因為x的值一直減少，所以文字可以滾動
				txtCanvas.drawText(strContent, curLen, y, txtPaint); //txtCanvas早drawtext.txtBmp上也自然也帶有這些text

				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();
	}
}



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