android.util.TypedValue.applyDimension

標籤：

先看一個例子：

int size = (int)TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 3,　　context.getResources().getDisplayMetrics());

這行代碼是把在當前螢幕解析度的狀態下將dip為3的值轉換成單位為px值　　

 

下面是API介紹：

public static float applyDimension (int unit, float value, DisplayMetrics metrics) Since: API Level 1

Converts an unpacked complex data value holding a dimension to its final floating point value. The two parameters unit and value are as in TYPE_DIMENSION.

Parameters

unit	The unit to convert from.
value	The value to apply the unit to.
metrics	Current display metrics to use in the conversion -- supplies display density and scaling information.

Returns

• The complex floating point value multiplied by the appropriate metrics depending on its unit. 

 

查看其在framework中的源碼

    public static float applyDimension(int unit, float value,                                       DisplayMetrics metrics)    {        switch (unit) {        case COMPLEX_UNIT_PX:            return value;        case COMPLEX_UNIT_DIP:            return value * metrics.density;        case COMPLEX_UNIT_SP:            return value * metrics.scaledDensity;        case COMPLEX_UNIT_PT:            return value * metrics.xdpi * (1.0f/72);        case COMPLEX_UNIT_IN:            return value * metrics.xdpi;        case COMPLEX_UNIT_MM:            return value * metrics.xdpi * (1.0f/25.4f);        }        return 0;    }

如果傳入的unit為COMPLIEX_UNIT_PX，則傳回值與傳入的value值保持一致；反之會根據一定的計算方式轉換成px並返回。

 

android.util.TypedValue.applyDimension