Android自定義屬性的使用

 在android中我們習慣了在XML佈局文件中，進行控件屬性的設置，由於控件默認提供的屬性數量有限，爲了增加屬性我們可以給控件添加一些自定義的屬性，下面來講一下爲控件添加自定義屬性的幾個步驟。

1>在res/values文件下添加一個attrs.xml文件(沒有的話)如下:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <!--添加了一個ImageTextButton的屬性集  -->
    <declare-styleable name="ImageTextButton">
        <attr format="reference" name="iconImage" />
        <attr format="reference" name="bkImage" />
        <attr format="integer" name="borderLeft" />
        <attr format="integer" name="borderRight" />
        <attr format="integer" name="borderTop" />
        <attr format="integer" name="borderBottom" />
        <attr format="integer" name="buttonstate" />
        <attr name="iconLocation">
            <enum name="center" value="0" />
            <enum name="left" value="1" />
            <enum name="right" value="2" />
        </attr>
    </declare-styleable>
</resources>

2>在相關的XML佈局文件中使用自定義的屬性:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:mux="http://schemas.android.com/apk/res/com.shareboard"
    android:layout_width="530dp"
    android:layout_height="320dp"
    android:background="@color/dlgBg"
    android:orientation="vertical" >
<!--com.shareboard 爲工程所在包  -->
            <com.shareboard.uicontrols.ImageTextButton
                android:id="@+id/btnCancel"
                android:layout_width="100sp"
                android:layout_height="wrap_content"
                android:layout_alignParentRight="true"
                android:layout_marginRight="20dp"
                mux:bkImage="@drawable/cell_bkgnd"
                mux:buttonstate="2"
                android:text="@string/btn_cancel"
                android:textColor="@color/btnText"
                android:textSize="@dimen/btnText" />

          <com.shareboard.uicontrols.ImageTextButton
                android:id="@+id/btnDone"
                android:layout_width="100sp"
                android:layout_height="wrap_content"
                android:layout_alignParentLeft="true"
                android:layout_marginLeft="@dimen/btnMargin"
                mux:bkImage="@drawable/cell_bkgnd"
                mux:buttonstate="2"
                android:text="@string/btn_done"
                android:textColor="@color/btnText"
                android:textSize="@dimen/btnText" />
</LinearLayout>

3>在代碼中獲取自定義的屬性值: 

public final class ImageTextButton extends Button {
    private int mIconId;
    private int mBkimgId;
    private int mBorderLeft = 10;
    private int mBorderRight = 10;
    private int mBorderTop = 10;
    private int mBorderBottom = 10;
    private int mnButtonState = 4;
    private int mIconLocation = 0;
    private boolean mbChecked = false;

    public ImageTextButton(Context context) {
        super(context);
        setClickable(true);
    }

    public ImageTextButton(Context context, AttributeSet attrs) {
        super(context, attrs);
        readAttrs(context, attrs);
        setClickable(true);
    }

    private void readAttrs(Context context, AttributeSet attrs) {
        TypedArray types = context.obtainStyledAttributes(attrs,
                R.styleable.ImageTextButton);
        final int count = types.getIndexCount();
        for (int i = 0; i < count; ++i) {
            int attr = types.getIndex(i);
            switch (attr) {
            case R.styleable.ImageTextButton_iconImage:
                mIconId = types.getResourceId(attr, 0);
                break;
            case R.styleable.ImageTextButton_bkImage:
                mBkimgId = types.getResourceId(attr, 0);
                break;
            case R.styleable.ImageTextButton_borderLeft:
                mBorderLeft = types.getInteger(attr, 10);
                break;
            case R.styleable.ImageTextButton_borderRight:
                mBorderRight = types.getInteger(attr, 10);
                break;
            case R.styleable.ImageTextButton_borderTop:
                mBorderTop = types.getInteger(attr, 10);
                break;
            case R.styleable.ImageTextButton_borderBottom:
                mBorderBottom = types.getInteger(attr, 10);
                break;
            case R.styleable.ImageTextButton_iconLocation:
                mIconLocation = types.getInteger(attr, 0);
                break;
            case R.styleable.ImageTextButton_buttonstate:
                mnButtonState = types.getInteger(attr, 4);
                break;
            }
        }
        types.recycle();
    }
}

好了這就完成了自定義屬性的定義和使用。