Android仿格瓦拉循环滚动View

来源：互联网发布：江民杀毒知乎编辑：程序博客网时间：2024/05/21 00:49

之前有同事用格瓦拉买电影票，自己下了一个看了看，App整体做的比较炫酷，看到一个效果挺不错，又在自己的能力范围之内，就模仿一下。下面是效果图：

这里写图片描述
就是一连串的电影胶片不停的向某一方向滑动，思路：
取两张背景图，同时向一个方向滑动，当超出屏幕范围时重新调整两张图的横坐标即可。
代码如下：

/** * @description 仿格瓦拉App背景自动移动View* @author rzq* @date 2015年9月29日*/public class AutomaticMoveView extends View{    /**     * 默认常量     */    private static final int DIRECTION = 1;    private static final int SPEED = 5;    private static final float ALPHA = 0.5f;    /**     * 公共变量     */    private Context mContext;    private DisplayMetrics dm;    private int screenWidth;    /**     * 背景移动方向     */    private MoveDirection mDirection;    /**     * 循环移动的背景      */    private Bitmap mBackgroundOne, mBackgroundTwo;    /**     * 遮罩层透明度百分比     */    private float mAlpha;    /**     * 循环移动的速度     */    private float mSpeed;    /**     * 两张轮播图的的横坐标     */    private float x1, x2;    private int mBgOneWidth, mBgOneHeight;    private int mBgTwoWidth;    private Handler mHandler = new Handler()    {        public void handleMessage(Message msg)        {            x1 += mSpeed;            x2 += mSpeed;            switch (mDirection)            {            case RIGHT:                if (x1 >= screenWidth)                {                    x1 = x2 - mBgOneWidth;                }                if (x2 >= screenWidth)                {                    x2 = x1 - mBgTwoWidth;                }                break;            case LEFT:                if (x1 <= -mBgOneWidth)                {                    x1 = x2 + mBgTwoWidth;                }                if (x2 <= -mBgTwoWidth)                {                    x2 = x1 + mBgOneWidth;                }                break;            }            invalidate();            mHandler.sendEmptyMessageDelayed(0, 100);        };    };    public AutomaticMoveView(Context context, AttributeSet attrs)    {        super(context, attrs);        mContext = context;        TypedArray a = mContext.obtainStyledAttributes(attrs, R.styleable.AutomicMove);        Drawable drawableOne = a.getDrawable(R.styleable.AutomicMove_auto_background_one);        Drawable drawableTwo = a.getDrawable(R.styleable.AutomicMove_auto_background_two);        if (drawableOne instanceof BitmapDrawable && drawableTwo instanceof BitmapDrawable)        {            mBackgroundOne = ((BitmapDrawable) drawableOne).getBitmap();            mBackgroundTwo = ((BitmapDrawable) drawableTwo).getBitmap();        }        mDirection = a.getInt(R.styleable.AutomicMove_auto_direction, DIRECTION) == DIRECTION ? MoveDirection.LEFT                : MoveDirection.RIGHT;        mSpeed = a.getDimension(R.styleable.AutomicMove_auto_speed, SPEED);        mAlpha = a.getFloat(R.styleable.AutomicMove_auto_alpha, ALPHA);        a.recycle();        init();    }    private void init()    {        dm = new DisplayMetrics();        WindowManager wm = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);        wm.getDefaultDisplay().getMetrics(dm);        screenWidth = dm.widthPixels;        mBgOneWidth = mBackgroundOne.getWidth();        mBgOneHeight = mBackgroundOne.getHeight();        mBgTwoWidth = mBackgroundTwo.getWidth();        switch (mDirection)        {        case RIGHT:            x1 = screenWidth - mBgOneWidth;            x2 = screenWidth - mBgOneWidth - mBgTwoWidth;            break;        case LEFT:            mSpeed *= -1;            x1 = 0;            x2 = mBgOneWidth;            break;        }        mHandler.sendEmptyMessageDelayed(0, 0);    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)    {        /**         * 指定View的宽度为屏幕宽度，高度为背景高度。         */        int viewHeight = mBgOneHeight + getPaddingTop() + getPaddingBottom();        setMeasuredDimension(screenWidth, viewHeight);    }    @Override    protected void onDraw(Canvas canvas)    {        /**         * 绘制两张背景图         */        canvas.drawBitmap(mBackgroundOne, x1, 0, null);        canvas.drawBitmap(mBackgroundTwo, x2, 0, null);        /**         * 绘制遮罩层         */        canvas.drawARGB((int) (mAlpha * 255), 0, 0, 0);    }    @Override    protected void onDetachedFromWindow()    {        super.onDetachedFromWindow();        mBackgroundOne = null;        mBackgroundTwo = null;    }    /**     * 背景移动方向枚举      */    public enum MoveDirection    {        LEFT, RIGHT;    }}

代码也不复杂，变量的作用都注释好了。有需要的可以参考。

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