android 横向滚动条

/*** * 横向滚动条，修改版，从左向右滚动，支持html代码和html里面的网络图片 */public class MarqueeView extends LinearLayout {

    private Context context ;

    private TextView mTextField;

    private ScrollView mScrollView;

    private static final int TEXT_VIEW_VIRTUAL_WIDTH = 2000;

    private Animation mMoveTextOut = null;    //private Animation mMoveTextIn = null;

    private Paint mPaint;

    private boolean mMarqueeNeeded = false;

    private static final String TAG = MarqueeView.class.getSimpleName();

    private float mTextDifference;

    private  Drawable drawable ;

    /**     * Control the speed. The lower this value, the faster it will scroll.     */    private static final int DEFAULT_SPEED = 60;

    /**     * Control the pause between the animations. Also, after starting this activity.     */    private static final int DEFAULT_ANIMATION_PAUSE = 2000;

    private int mSpeed = DEFAULT_SPEED;

    private int mAnimationPause = DEFAULT_ANIMATION_PAUSE;

    private boolean mAutoStart = false;

    private Interpolator mInterpolator = new LinearInterpolator();

    private boolean mCancelled = false;    private Runnable mAnimationStartRunnable;

    private boolean mStarted;

    private NetworkImageGetter mImageGetter;

    /**     * Sets the animation speed.     * The lower the value, the faster the animation will be displayed.     *     * @param speed Milliseconds per PX.     */    public void setSpeed(int speed) {        this.mSpeed = speed;    }

    /**     * Sets the pause between animations     *     * @param pause In milliseconds.     */    public void setPauseBetweenAnimations(int pause) {        this.mAnimationPause = pause;    }

    /**     * Sets a custom interpolator for the animation.     *     * @param interpolator Animation interpolator.     */    public void setInterpolator(Interpolator interpolator) {        this.mInterpolator = interpolator;    }

    @SuppressWarnings({"UnusedDeclaration"})    public MarqueeView(Context context) {        super(context);        this.context = context ;        init(context);    }

    @SuppressWarnings({"UnusedDeclaration"})    public MarqueeView(Context context, AttributeSet attrs) {        super(context, attrs);        this.context = context ;        init(context);        extractAttributes(attrs);    }

    @TargetApi(Build.VERSION_CODES.HONEYCOMB)    public MarqueeView(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        this.context = context ;        init(context);        extractAttributes(attrs);    }

    private void extractAttributes(AttributeSet attrs) {        if (getContext() == null) {            return;        }

        TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.asia_ivity_android_marqueeview_MarqueeView);

        if (a == null) {            return;        }

        mSpeed = a.getInteger(R.styleable.asia_ivity_android_marqueeview_MarqueeView_speed, DEFAULT_SPEED);        mAnimationPause = a.getInteger(R.styleable.asia_ivity_android_marqueeview_MarqueeView_pause, DEFAULT_ANIMATION_PAUSE);        mAutoStart = a.getBoolean(R.styleable.asia_ivity_android_marqueeview_MarqueeView_autoStart, false);

        a.recycle();    }

    private void init(Context context) {        // init helper        mPaint = new Paint();        mPaint.setAntiAlias(true);        mPaint.setStrokeWidth(1);        mPaint.setStrokeCap(Paint.Cap.ROUND);

        mInterpolator = new LinearInterpolator();    }

    @Override    protected void onLayout(boolean changed, int l, int t, int r, int b) {        super.onLayout(changed, l, t, r, b);

        if (getChildCount() == 0 || getChildCount() > 1) {            throw new RuntimeException("MarqueeView must have exactly one child element.");        }

        if (changed && mScrollView == null) {            View v = getChildAt(0);            // Fixes #1: Exception when using android:layout_width="fill_parent". There seems to be an additional ScrollView parent.            if (v instanceof ScrollView && ((ScrollView) v).getChildCount() == 1) {                v = ((ScrollView) v).getChildAt(0);            }

            if (!(v instanceof TextView)) {                throw new RuntimeException("The child view of this MarqueeView must be a TextView instance.");            }

            initView(getContext());

            prepareAnimation();

            if (mAutoStart) {                startMarquee();            }        }    }

    private String message ;    private boolean startScroll = true ;

    /***     * 开始滚动     * @param _message     */    public void startScrollView(String _message){

        if(message.equals(_message)) return;

        this.message = _message ;        if(startScroll){            mTextField.setText(Html.fromHtml(message ,mImageGetter ,null));            startMarquee();        }    }

    /**     * Starts the configured marquee effect.     */    public void startMarquee() {        if (mMarqueeNeeded) {            startScroll = false ;            startTextFieldAnimation();        }

        mCancelled = false;        mStarted = true;    }

    private void startTextFieldAnimation() {        mAnimationStartRunnable = new Runnable() {            public void run() {                mTextField.startAnimation(mMoveTextOut);            }        };        postDelayed(mAnimationStartRunnable, mAnimationPause);    }

    /**     * Disables the animations.     */    public void reset() {        mCancelled = true;

        if (mAnimationStartRunnable != null) {            removeCallbacks(mAnimationStartRunnable);        }

        mTextField.clearAnimation();        mStarted = false;        mTextField.setVisibility(INVISIBLE);        mMoveTextOut.reset();        //   mMoveTextIn.reset();

//        mScrollView.removeView(mTextField);//        mScrollView.addView(mTextField);

        invalidate();    }

    private void prepareAnimation() {        // Measure        mPaint.setTextSize(mTextField.getTextSize());        mPaint.setTypeface(mTextField.getTypeface());        final float mTextWidth = mPaint.measureText(mTextField.getText().toString());

        // See how much functions are needed at all        mMarqueeNeeded = mTextWidth > getMeasuredWidth();

        if(drawable != null){            //当html有图片时，不能获取到图片长度，我这里滚动条有15长图片，所以需要单独加上            mTextDifference = Math.abs(mTextWidth) + drawable.getIntrinsicWidth() * 15 + 5;        }else {            mTextDifference = Math.abs(mTextWidth) + 5;        }//获取滚动条长度，根据滚动速度和长度计算滚动时间（滚动动画持续时间）

//        if (true) {//            Log.d(TAG, "mTextWidth       : " + mTextWidth);//            Log.d(TAG, "measuredWidth    : " + getMeasuredWidth());//            Log.d(TAG, "mMarqueeNeeded   : " + mMarqueeNeeded);//            Log.d(TAG, "mTextDifference  : " + mTextDifference);//        }

        final int duration = (int) (mTextDifference * mSpeed);

        mMoveTextOut = new TranslateAnimation(getMeasuredWidth(), -mTextDifference, 0, 0);        mMoveTextOut.setDuration(duration);        mMoveTextOut.setInterpolator(mInterpolator);

        mMoveTextOut.setAnimationListener(new Animation.AnimationListener() {            public void onAnimationStart(Animation animation) {                expandTextView(mTextWidth);                mTextField.setVisibility(VISIBLE);            }

            public void onAnimationEnd(Animation animation) {                //    mTextField.setText(Html.fromHtml(message));                mTextField.setText(Html.fromHtml(message ,mImageGetter ,null));

                if (mCancelled) {                    return;                }                mTextField.startAnimation(mMoveTextOut);            }

            public void onAnimationRepeat(Animation animation) {            }

        });

    }

    private void initView(Context context) {        mImageGetter = new NetworkImageGetter();        // Scroll View        LayoutParams sv1lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);        sv1lp.gravity = Gravity.CENTER_HORIZONTAL;        mScrollView = new ScrollView(context);

        // Scroll View 1 - Text Field        mTextField = (TextView) getChildAt(0);        removeView(mTextField);

        mScrollView.addView(mTextField, new ScrollView.LayoutParams(TEXT_VIEW_VIRTUAL_WIDTH, LayoutParams.WRAP_CONTENT));

        mTextField.addTextChangedListener(new TextWatcher() {            @Override            public void beforeTextChanged(CharSequence charSequence, int i, int i2, int i3) {

            }

            @Override            public void onTextChanged(CharSequence charSequence, int i, int i2, int i3) {

            }

            @Override            public void afterTextChanged(Editable editable) {                final boolean continueAnimation = mStarted;                reset();                prepareAnimation();                cutTextView();                post(new Runnable() {                    @Override                    public void run() {                        if (continueAnimation) {                            startScroll = true ;                            startMarquee();                        }                    }                });            }        });

        addView(mScrollView, sv1lp);    }

    private void expandTextView(float width) {        ViewGroup.LayoutParams lp = mTextField.getLayoutParams();        if(drawable != null){            //当html有图片时，不能获取到图片长度，我这里滚动条有15长图片，所以需要单独加上            lp.width =(int)width + drawable.getIntrinsicWidth() * 15 +1;        }else {            lp.width =(int)width +1;        }//设置滚动长度，滚动的内部其实是一个textView，滚动其实是textView向左做移动        mTextField.setLayoutParams(lp);    }

    private void cutTextView() {        if (mTextField.getWidth() != getMeasuredWidth()) {            ViewGroup.LayoutParams lp = mTextField.getLayoutParams();            lp.width = getMeasuredWidth();            mTextField.setLayoutParams(lp);        }    }

    /***     * 根据html里面的图片地址获取网络图片存储到本地     */    class NetworkImageGetter implements Html.ImageGetter{

        @Override        public Drawable getDrawable(String source) {            // 封装路径            File file = StorageUtils.getCacheFile(context,"jpg" ,source);//获取图片是否在本地SD卡中

            final Uri uri = Uri.parse(file.getAbsolutePath());            final String path = uri.getPath();

            drawable = Drawable.createFromPath(path);

            // 判断是否以http开头            if(source.startsWith("http")) {                // 判断路径是否存在                if(file.exists() && file.length() > 0) {                    // 存在即获取drawable                    drawable = Drawable.createFromPath(file.getAbsolutePath());                    drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());                } else {                    // 不存在即开启异步任务加载网络图片                    toastService(context,source ,"jpg");                }            }            return drawable;        }    }

    /**     * 本地的下载图片服务     * @param context     * @param url     * @param extension     */    private  void toastService(Context context,String url,String extension) {        Intent intent = new Intent(context,HtmlCacheService.class);        intent.putExtra(HtmlCacheService.DOWN_URL,url);        intent.putExtra(HtmlCacheService.EXTENSION,extension);        context.startService(intent);

    }

}