我的Android进阶之旅------>android中getLocationInWindow 和 getLocationOnScreen的差别

Posted 2020-09-26 yangykaifa

View.getLocationInWindow(int[] location)

一个控件在其父窗体中的坐标位置

View.getLocationOnScreen(int[] location)

一个控件在其整个屏幕上的坐标位置

getLocationInWindow是以B为原点的C的坐标

getLocationOnScreen以A为原点。

以下是getLocationOnScreen演示样例

start = (Button) findViewById(R.id.start);
		int []location=new int[2];
		start.getLocationOnScreen(location);
		int x=location[0];//获取当前位置的横坐标
		int y=location[1];//获取当前位置的纵坐标

以下是getLocationInWindow演示样例

start = (Button) findViewById(R.id.start);
		int []location=new int[2];
		start.getLocationInWindow(location);
		int x=location[0];//获取当前位置的横坐标
		int y=location[1];//获取当前位置的纵坐标

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 附上源码

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View.getLocationInWindow(int[] location)

/**
     * <p>Computes the coordinates of this view in its window. The argument
     * must be an array of two integers. After the method returns, the array
     * contains the x and y location in that order.</p>
     *
     * @param location an array of two integers in which to hold the coordinates
     */
    public void getLocationInWindow(int[] location) {
        if (location == null || location.length < 2) {
            throw new IllegalArgumentException("location must be an array of two integers");
        }

        if (mAttachInfo == null) {
            // When the view is not attached to a window, this method does not make sense
            location[0] = location[1] = 0;
            return;
        }

        float[] position = mAttachInfo.mTmpTransformLocation;
        position[0] = position[1] = 0.0f;

        if (!hasIdentityMatrix()) {
            getMatrix().mapPoints(position);
        }

        position[0] += mLeft;
        position[1] += mTop;

        ViewParent viewParent = mParent;
        while (viewParent instanceof View) {
            final View view = (View) viewParent;

            position[0] -= view.mScrollX;
            position[1] -= view.mScrollY;

            if (!view.hasIdentityMatrix()) {
                view.getMatrix().mapPoints(position);
            }

            position[0] += view.mLeft;
            position[1] += view.mTop;

            viewParent = view.mParent;
         }

        if (viewParent instanceof ViewRootImpl) {
            // *cough*
            final ViewRootImpl vr = (ViewRootImpl) viewParent;
            position[1] -= vr.mCurScrollY;
        }

        location[0] = (int) (position[0] + 0.5f);
        location[1] = (int) (position[1] + 0.5f);
    }

View.getLocationOnScreen(int[] location)

  /**
     * <p>Computes the coordinates of this view on the screen. The argument
     * must be an array of two integers. After the method returns, the array
     * contains the x and y location in that order.</p>
     *
     * @param location an array of two integers in which to hold the coordinates
     */
    public void getLocationOnScreen(int[] location) {
        getLocationInWindow(location);

        final AttachInfo info = mAttachInfo;
        if (info != null) {
            location[0] += info.mWindowLeft;
            location[1] += info.mWindowTop;
        }
    }

 

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  作者：欧阳鹏  欢迎转载，与人分享是进步的源泉！

  转载请保留原文地址：http://blog.csdn.net/ouyang_peng

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