经常有这样的需求，你的功能图标要像一个个物品，摆放在书架上，像这样：
我的思路比较简单，重载GridView，在他绘制子视图前，先把背景绘制完成
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public class RowGridView extends GridView {
private Bitmap rowBackground;
private int rowBgHeight;
private int columnNum;
public RowGridView(Context context, AttributeSet attrs){
super(context,attrs);
//获得列数
columnNum = attrs.getAttributeIntValue(NAMESPACE_ANDROID,"numColumns",3);
//获取自定义属性
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.row_bg_grid_view);
rowBgHeight = a.getDimensionPixelSize(R.styleable.row_bg_grid_view_row_bg_height,50);
int row_bg_resource = a.getResourceId(R.styleable.row_bg_grid_view_row_background,-1);
rowBackground = BitmapFactory.decodeResource(getResources(),row_bg_resource);
}
@Override
protected void dispatchDraw(Canvas canvas){
//行高
int rHeight = getChildAt(0).getHeight();
int width = getWidth();
int rowNum = (int)Math.ceil(getChildCount()/(double)columnNum);
//源绘制矩形
Rect src = new Rect(0,0,rowBackground.getWidth(),rowBackground.getHeight());
for(int i=0,y=rHeight-(rowBgHeight/2); i<rowNum; i++,y += rHeight){
//目的绘制矩形
Rect dst = new Rect(0,y,width,y+rowBgHeight);
canvas.drawBitmap(rowBackground,src,dst,null);
}
super.dispatchDraw(canvas);
}
} |
上面第11行有这样一句
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columnNum = attrs.getAttributeIntValue(NAMESPACE_ANDROID,"numColumns",3);
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为什么不用getNumColumns？因为这个函数需要api level 11（即Android 3.0以上），而且有可能返回-1
两个自定义属性：背景和背景高度，在values/attrs.xml定义如下
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<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="row_bg_grid_view">
<attr name="row_background" format="reference"/>
<attr name="row_bg_height" format="dimension" />
</declare-styleable>
</resources>
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最后使用的方法
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<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<com.best.oa.common.base.RowGridView
android:id="@+id/functions"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dip"
android:layout_weight="1"
android:numColumns="2"
oa:row_background="@drawable/grid_row_bg"
oa:row_bg_height="60dip"
android:stretchMode="columnWidth">
</com.best.oa.common.base.RowGridView>
</LinearLayout>
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