读取layout属性-AttributeSet TypedArray

假如说要读取layout_height属性

两种方式，第一种

  /**
     * Returns the value of the specified attribute as a string representation.
     * 
     * @param index Index of the desired attribute, 0...count-1.
     * 
     * @return A String containing the value of the attribute, or null if the
     *         attribute cannot be found.
     */
    public String getAttributeValue(int index);

String namespace = "http://schemas.android.com/apk/res/android";
viewHeight = attrs.getAttributeIntValue(namespace, "layout_height", ViewGroup.LayoutParams.MATCH_PARENT);

layout_height=“match_parent”

 viewHeight 取到的值为 “match_parent”

layout_height=“100dip”

 viewHeight 取到的值为 “100dip”

如果用 getAttributeIntValue 读取的话, 无法正确读取到数值

/**
* Return the integer value of 'attribute'.
*
* @param namespace Namespace of attribute to retrieve.
* @param attribute The attribute to retrieve.
* @param defaultValue What to return if the attribute isn't found.
*
* @return Resulting value.
*/
public int getAttributeIntValue(String namespace, String attribute, int defaultValue);

很显然这种方式读取数值不是很爽

第二种方式: 通过TypedArray读取

int[] arr = new int[] { android.R.attr.layout_width, android.R.attr.layout_height };
TypedArray typedArray = context.obtainStyledAttributes(attrs, arr);
// MATCH_PARENT -1 WRAP_CONTENT-2
try {
// String namespace = "http://schemas.android.com/apk/res/android";
// initViewHeight = attrs.getAttributeIntValue(namespace, "layout_height", ViewGroup.LayoutParams.MATCH_PARENT);
TypedValue typeValue = typedArray.peekValue(1);
if (typeValue.type == TypedValue.TYPE_DIMENSION) {// 0x10
initViewHeight = (int) typedArray.getDimension(1, ViewGroup.LayoutParams.MATCH_PARENT);
initViewHeight = TypedValue.complexToDimensionPixelSize(typeValue.data, getResources().getDisplayMetrics());
} else if (typeValue.type == TypedValue.TYPE_FIRST_INT) {// 0x05
initViewHeight = typeValue.data;
}
} catch (Exception e) {
// java.lang.UnsupportedOperationException: Can't convert to dimension: type=0x10
e.printStackTrace();
}
typedArray.recycle();