自定义view实现开关按钮并监听（有滑动效果）

自定义view实现开关按钮并监听（有滑动效果）

原理：其实是首先得有两张图片，一张是背景图，左开右关，第二张其实说白了就是挡住某一边的图，所以这张图的宽度就只有第一张的一半，这样就可以让用户辨别按钮是开还是关。然后监听view的点击事件，从而调用invalidate（）方法来重绘来产生滑动效果。

难点：得从点击事件获取滑动的坐标然后调整第二张图片离左边的距离。

@Override
	protected void onDraw(Canvas canvas) {
		// TODO Auto-generated method stub
		maxLeft = toggleBackground.getWidth() - toggleSolide.getWidth();
		canvas.drawBitmap(toggleBackground, 0, 0, paint);
		switch (state) {
		case STATE_DOWN:
		case STATE_MOVE:
			if (currentX > toggleSolide.getWidth() / 2f) {
				// 让滑块向右移动（重新绘制滑块的位置）
				left = currentX - toggleSolide.getWidth() / 2f;
				if (left > maxLeft)
					left = maxLeft;
				canvas.drawBitmap(toggleSolide, left, 0, paint);
			} else if (currentX <= toggleSolide.getWidth() / 2f) {
				// 让滑块不动就可以
				canvas.drawBitmap(toggleSolide, 0, 0, paint);
			}
			break;
		case STATE_NONE:
			if (toggleBackground != null) {
				canvas.drawBitmap(toggleBackground, 0, 0, paint);
			}
			if (toggleSolide != null) {
				canvas.drawBitmap(toggleSolide, 0, 0, paint);
			}
			break;
		case STATE_UP:
			if (isOpen) {
				canvas.drawBitmap(toggleSolide, maxLeft, 0, paint);
			} else {
				canvas.drawBitmap(toggleSolide, 0, 0, paint);
			}
			if(onUpActionListenter!=null){
				onUpActionListenter.OnUp(isOpen);
			}
			break;
		default:
			canvas.drawBitmap(toggleSolide, 0, 0, paint);
			break;
		}
	}

开关的监听：通过自定义接口来实现对开关的监听，并在点击事件调用接口方法

private OnUpActionListenter onUpActionListenter;

public interface OnUpActionListenter{
	public void OnUp(boolean isOpen);
}
public void setOnUpActionListenter(OnUpActionListenter listenter){
	this.onUpActionListenter = listenter;
}