直播系統原始碼，圖片一直滾動，迴圈滾動，豎向和橫向實現的相關程式碼

豎向：

public class LoopScrollView extends View {
  private final int speed;
  private final Bitmap bitmap;

  private Rect clipBounds = new Rect();
  private float offset = 0;

  private boolean isStarted;

  public LoopScrollView(Context context, AttributeSet attrs) {
    super(context, attrs);
    TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.ParallaxView, 0, 0);
    try {
      speed = ta.getDimensionPixelSize(R.styleable.ParallaxView_speed, 10);
      bitmap = BitmapFactory.decodeResource(getResources(), ta.getResourceId(R.styleable.ParallaxView_src, 0));
    } finally {
      ta.recycle();
    }
//    start();
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    setMeasuredDimension(bitmap.getWidth(), MeasureSpec.getSize(heightMeasureSpec));
  }

  @Override
  public void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    if (canvas == null) {
      return;
    }

    canvas.getClipBounds(clipBounds);

    float normalizedOffset = offset;
    float layerHeight = bitmap.getHeight();

    if (offset <= -layerHeight) {
      offset += (floor(abs(normalizedOffset) / layerHeight) * layerHeight);
    }

    float top = offset;
    while (top < clipBounds.height()) {
      canvas.drawBitmap(bitmap, 0, getBitmapTop(layerHeight, top), null);
      top += layerHeight;
    }

    if (isStarted) {
      offset -= speed;
      postInvalidateOnAnimation();
    }
  }

  private float getBitmapTop(float layerHeight, float top) {
    float bitmapTop = top;
    if (speed < 0) {
      bitmapTop = clipBounds.height() - layerHeight - top;
    }
    return bitmapTop;
  }

  /**
  * Start the animation
  */
  public void start() {
    if (!isStarted) {
      isStarted = true;
      postInvalidateOnAnimation();
    }
  }

  /**
  * Stop the animation
  */
  public void stop() {
    if (isStarted) {
      isStarted = false;
      invalidate();
    }
  }
}

​

橫向：

public class LoopScrollView extends View {
  private final int speed;
  private final Bitmap bitmap;

  private Rect clipBounds = new Rect();
  private int offset = 0;

  private boolean isStarted;

  public LoopScrollView(Context context, AttributeSet attrs) {
    super(context, attrs);
    TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.ParallaxView, 0, 0);
    try {
      speed = ta.getDimensionPixelSize(R.styleable.ParallaxView_speed, 10);
      bitmap = BitmapFactory.decodeResource(getResources(), ta.getResourceId(R.styleable.ParallaxView_src, 0));
    } finally {
      ta.recycle();
    }
    start();
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec), bitmap.getHeight());
  }

  @Override
  public void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    if (canvas == null) {
      return;
    }

    canvas.getClipBounds(clipBounds);

    int normalizedOffset = offset;
    int layerWidth = bitmap.getWidth();
    if (offset < -layerWidth) {
      offset += (int) (floor(abs(normalizedOffset) / (float) layerWidth) * layerWidth);
    }

    int left = offset;
    while (left < clipBounds.width()) {
      canvas.drawBitmap(bitmap, getBitmapLeft(layerWidth, left), 0, null);
      left += layerWidth;
    }

    if (isStarted) {
      offset -= speed;
      postInvalidateOnAnimation();
    }
  }

  private float getBitmapLeft(int layerWidth, int left) {
    float bitmapLeft = left;
    if (speed < 0) {
      bitmapLeft = clipBounds.width() - layerWidth - left;
    }
    return bitmapLeft;
  }

  /**
  * Start the animation
  */
  public void start() {
    if (!isStarted) {
      isStarted = true;
      postInvalidateOnAnimation();
    }
  }

  /**
  * Stop the animation
  */
  public void stop() {
    if (isStarted) {
      isStarted = false;
      invalidate();
    }
  }
}

以上就是直播系統原始碼，圖片一直滾動，迴圈滾動，豎向和橫向實現的相關程式碼， 更多內容歡迎關注之後的文章