固定纵横比查看 [英] Fixed aspect ratio View

问题描述

我将如何去实现一个固定纵横比查看？我想有1项：在的GridView 1纵横比。我认为这是最好的子类的儿童比的GridView ？

How would I go implementing a fixed aspect ratio View? I'd like to have items with 1:1 aspect ratio in a GridView. I think it's better to subclass the children than the GridView?

编辑：我想这需要通过编程完成，那也没问题。另外，我不想限制的大小，只宽高比。

I assume this needs to be done programmatically, that's no problem. Also, I don't want to limit the size, only the aspect ratio.

推荐答案

我实现FixedAspectRatioFrameLayout，这样我就可以重新使用它，有什么看法托管与固定纵横比：

I implemented FixedAspectRatioFrameLayout, so I can reuse it and have any hosted view be with fixed aspect ratio:

public class FixedAspectRatioFrameLayout extends FrameLayout
{
    private int mAspectRatioWidth;
    private int mAspectRatioHeight;

    public FixedAspectRatioFrameLayout(Context context)
    {
        super(context);
    }

    public FixedAspectRatioFrameLayout(Context context, AttributeSet attrs)
    {
        super(context, attrs);

        Init(context, attrs);
    }

    public FixedAspectRatioFrameLayout(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);

        Init(context, attrs);
    }

    private void Init(Context context, AttributeSet attrs)
    {
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.FixedAspectRatioFrameLayout);

        mAspectRatioWidth = a.getInt(R.styleable.FixedAspectRatioFrameLayout_aspectRatioWidth, 4);
        mAspectRatioHeight = a.getInt(R.styleable.FixedAspectRatioFrameLayout_aspectRatioHeight, 3);

        a.recycle();
    }
    // **overrides**

    @Override protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)
    {
        int originalWidth = MeasureSpec.getSize(widthMeasureSpec);

        int originalHeight = MeasureSpec.getSize(heightMeasureSpec);

        int calculatedHeight = originalWidth * mAspectRatioHeight / mAspectRatioWidth;

        int finalWidth, finalHeight;

        if (calculatedHeight > originalHeight)
        {
            finalWidth = originalHeight * mAspectRatioWidth / mAspectRatioHeight; 
            finalHeight = originalHeight;
        }
        else
        {
            finalWidth = originalWidth;
            finalHeight = calculatedHeight;
        }

        super.onMeasure(
                MeasureSpec.makeMeasureSpec(finalWidth, MeasureSpec.EXACTLY), 
                MeasureSpec.makeMeasureSpec(finalHeight, MeasureSpec.EXACTLY));
    }
}

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