关于重写RelativeLayout布局

最新推荐文章于 2022-09-07 20:32:36 发布

原创最新推荐文章于 2022-09-07 20:32:36 发布 · 751 阅读

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#onMeasure

本文介绍两种在Android中实现视图高度自动调整为宽度一定比例的方法。一种是通过覆写onMeasure方法并使用MeasureSpec来设置视图的高度；另一种是直接设置测量尺寸，但可能导致子View无法正常显示。

1 布局height=width*ratio

@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		 int widthMode = MeasureSpec.getMode(widthMeasureSpec);
		 int widthSize = MeasureSpec.getSize(widthMeasureSpec);
		 super.onMeasure(MeasureSpec.makeMeasureSpec(widthSize, widthMode), MeasureSpec.makeMeasureSpec((int) (widthSize * ratio), widthMode));
	}

2 height=width*ratio(注：子View无法显示)

@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		int width = measureWidth(widthMeasureSpec);
		setMeasuredDimension(width, (int) (width * ratio));
	}

	private int measureWidth(int widthMeasureSpec) {
		int result = 0;
		int mode = MeasureSpec.getMode(widthMeasureSpec);
		int size = MeasureSpec.getSize(widthMeasureSpec);
		if (mode == MeasureSpec.EXACTLY) {
			result = size;
		} else {
			result = 200;
		}
		if (mode == MeasureSpec.AT_MOST) {
			result = Math.min(result, size);
		}
		return result;
	}