无法理解的onMeasure(int widthMeasureSpec, int heightMeasureSpec)

Sodino 2012-01-13 12:00:49

自己继承ViewGroup实现一个视图。重写protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
发现执行该函数时widthMeasureSpec值为1073742304，heightMeasureSpec值为-2147482923。

这两个值是什么意思？

谢谢。

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Sodino 2012-01-13

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嗯，是的。只是View的宽高，与分辨率无直接关系。

BadPattern 2012-01-13

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原来我搞错了,那是窗口的大小+MeasureSpec类中的specMode的值

BadPattern 2012-01-13

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那是多少呐?

Sodino 2012-01-13

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[Quote=引用 4 楼 dr8737010 的回复:]

楼主得到的两个值其实就是屏幕的长宽+MeasureSpec类中的specMode的值.
由此推断楼主设备的屏幕分辨率为:725*480
[/Quote]

错！

BadPattern 2012-01-13

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恭喜楼主解决问题

BadPattern 2012-01-13

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楼主得到的两个值其实就是屏幕的长宽+MeasureSpec类中的specMode的值.
由此推断楼主设备的屏幕分辨率为:725*480

Sodino 2012-01-13

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详见源代码：
http://www.google.com/codesearch/p?hl=en#uX1GffpyOZk/core/java/android/view/View.java&l=9019

Sodino 2012-01-13

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已解决：

Log.d("ANDROID_LAB",
"onMeasure w_mode=" + MeasureSpec.getMode(widthMeasureSpec) + " w_size="
+ MeasureSpec.getSize(widthMeasureSpec) + " h_mode=" + MeasureSpec.getMode(heightMeasureSpec)
+ " h_size=" + MeasureSpec.getSize(heightMeasureSpec));

其中getMode()返回值为：EXACTLY。

BadPattern 2012-01-13

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/**
* Measure specification mode: The parent has determined an exact size
* for the child. The child is going to be given those bounds regardless
* of how big it wants to be.
*/
public static final int EXACTLY = 1 << MODE_SHIFT;

/**
* Measure specification mode: The child can be as large as it wants up
* to the specified size.
*/
public static final int AT_MOST = 2 << MODE_SHIFT;
private static final int MODE_SHIFT = 30;

那两个值是出自这个函数:

       private int getRootMeasureSpec(int windowSize, int rootDimension) {

        int measureSpec;

        switch (rootDimension) {



        case ViewGroup.LayoutParams.FILL_PARENT:

            // Window can't resize. Force root view to be windowSize.

            measureSpec = MeasureSpec.makeMeasureSpec(windowSize, MeasureSpec.EXACTLY);

            break;

        case ViewGroup.LayoutParams.WRAP_CONTENT:

            // Window can resize. Set max size for root view.

            measureSpec = MeasureSpec.makeMeasureSpec(windowSize, MeasureSpec.AT_MOST);

            break;

        default:

            // Window wants to be an exact size. Force root view to be that size.

            measureSpec = MeasureSpec.makeMeasureSpec(rootDimension, MeasureSpec.EXACTLY);

            break;

        }

        return measureSpec;

    }