Android TextView上下滚动

我们经常看到一个软件的首页会有上下循环滚动的TextView，我们可以用来作为标题，或者活动信息展示，那么怎么实现的呢，废话不说，请看代码:

第一步，我们先写一个自定义view来继承TextSwitcher

public class AutoTextView extends TextSwitcher implements ViewFactory {

    private float mHeight;
    private Context mContext;
    //mInUp,mOutUp分别构成向下翻页的进出动
    private Rotate3dAnimation mInUp;
    private Rotate3dAnimation mOutUp;
    final int[] auto3d = {
            0x7f010000
        };
    //mInDown,mOutDown分别构成向下翻页的进出动
    private Rotate3dAnimation mInDown;
    private Rotate3dAnimation mOutDown;

    public AutoTextView(Context context) {
        this(context, null);
    }

    public AutoTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        TypedArray a = context.obtainStyledAttributes(attrs, auto3d);
        mHeight = a.getDimension(0, 15);
        a.recycle();
        mContext = context;
        init();
    }

    private void init() {
        setFactory(this);
        mInUp = createAnim(-90, 0, true, true);
        mOutUp = createAnim(0, 90, false, true);
        mInDown = createAnim(90, 0, true, false);
        mOutDown = createAnim(0, -90, false, false);
        //TextSwitcher主要用于文件切换，比�? 从文字A 切换�? 文字 B�?
        //setInAnimation()后，A将执行inAnimation�?
        //setOutAnimation()后，B将执行OutAnimation
        setInAnimation(mInUp);
        setOutAnimation(mOutUp);
    }

    private Rotate3dAnimation createAnim(float start, float end, boolean turnIn, boolean turnUp) {
        final Rotate3dAnimation rotation = new Rotate3dAnimation(start, end, turnIn, turnUp);
        rotation.setDuration(300);
        rotation.setFillAfter(false);
        rotation.setInterpolator(new AccelerateInterpolator());
        return rotation;
    }

    //这里返回的TextView，就是我们看到的View
    @Override
    public View makeView() {
        TextView t = new TextView(mContext);
        t.setGravity(Gravity.CENTER);
        t.setTextSize(mHeight);
        t.setSingleLine(true);
        t.setTextColor(R.color.black);
        return t;
    }

    //定义动作，向下滚动翻�?
    public void previous() {
        if (getInAnimation() != mInDown) {
            setInAnimation(mInDown);
        }
        if (getOutAnimation() != mOutDown) {
            setOutAnimation(mOutDown);
        }
    }

    //定义动作，向上滚动翻�?
    public void next() {
        if (getInAnimation() != mInUp) {
            setInAnimation(mInUp);
        }
        if (getOutAnimation() != mOutUp) {
            setOutAnimation(mOutUp);
        }
    }

    class Rotate3dAnimation extends Animation {
        private final float mFromDegrees;
        private final float mToDegrees;
        private final boolean mTurnIn;
        private final boolean mTurnUp;
        private float mCenterX;
        private float mCenterY;
        private Camera mCamera;

        public Rotate3dAnimation(float fromDegrees, float toDegrees, boolean turnIn, boolean turnUp) {
            mFromDegrees = fromDegrees;
            mToDegrees = toDegrees;
            mTurnIn = turnIn;
            mTurnUp = turnUp;
        }

        @Override
        public void initialize(int width, int height, int parentWidth, int parentHeight) {
            super.initialize(width, height, parentWidth, parentHeight);
            mCamera = new Camera();
            mCenterY = getHeight() / 2;
            mCenterX = getWidth() / 2;
        }

        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            final float fromDegrees = mFromDegrees;
            float degrees = fromDegrees + ((mToDegrees - fromDegrees) * interpolatedTime);

            final float centerX = mCenterX;
            final float centerY = mCenterY;
            final Camera camera = mCamera;
            final int derection = mTurnUp ? 1 : -1;

            final Matrix matrix = t.getMatrix();

            camera.save();
            if (mTurnIn) {
                camera.translate(0.0f, derection * mCenterY * (interpolatedTime - 1.0f), 0.0f);
            } else {
                camera.translate(0.0f, derection * mCenterY * (interpolatedTime), 0.0f);
            }
            camera.rotateX(degrees);
            camera.getMatrix(matrix);
            camera.restore();

            matrix.preTranslate(-centerX, -centerY);
            matrix.postTranslate(centerX, centerY);
        }
    }
}

第二步，这里写个Handler来循环滚动TextView内容

private Handler handler = new Handler() {
		public void handleMessage(android.os.Message msg) {
		
			switch (msg.what) {
			case 1001:
				handler.sendEmptyMessageDelayed(1001, 4000);
				mStringArray = new ArrayList<>();
				mStringArray.add("滚动字体一");
				mStringArray.add("滚动字体二");
				if (mStringArray.size() != 0) {
					int i = mLoopCount % mStringArray.size();
					tv_main_inform.next();
					tv_main_inform.setText(mStringArray.get(i));
					mLoopCount++;
					// handler.sendEmptyMessageDelayed(FLAG, 5000);
				}
				break;
			}
		};
	};

这里写的这个handler有点麻烦了，后面我用了一个新写法：

  		mStringArray = new ArrayList<>();
		mStringArray.add("滚动字体一");
		mStringArray.add("滚动字体二");
  Observable.interval(0, 4, TimeUnit.SECONDS).subscribe { 

				if (mStringArray.size() != 0) {
					int i = mLoopCount % mStringArray.size();
					tv_main_inform.next();
					tv_main_inform.setText(mStringArray.get(i));
					mLoopCount++;
					// handler.sendEmptyMessageDelayed(FLAG, 5000);
				}}

以上就是到这里了，不当之处还望大家指教，不明白的地方可以留言