轻量级GridView -- CellLayout

　　这是一个模仿Android Luncher的CellLayout布局， 可以设置固定的行数和列数， 继承自ViewGroup，故不需要使用Adapter。 只需要使用addView（）方法就可以将子View添加到布局，并实现按从左到右，从上到下顺序排序view。还可以设置行间距和列间距

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

public class CellLayout extends ViewGroup {
	
	private int lineNum;
	private int columnNum;
	private int vecitcalSpace;
	private int horizontalSpace;
	
	public CellLayout(Context context) {
		super(context);
	}
	
	public CellLayout(Context context, AttributeSet attrs) {
		super(context,attrs);
	}

	public CellLayout(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		// TODO Auto-generated constructor stub
	}
	
    @Override
    protected void dispatchDraw(Canvas canvas) {
        final long drawingTime = getDrawingTime();
        final int count = getChildCount();
        for (int i = 0; i < count; i++) {
            drawChild(canvas, getChildAt(i), drawingTime);
        }

    }
	
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        if (widthMode != MeasureSpec.EXACTLY) {
            throw new IllegalStateException("Workspace can only be used in EXACTLY mode.");
        }

        final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        if (heightMode != MeasureSpec.EXACTLY) {
            throw new IllegalStateException("Workspace can only be used in EXACTLY mode.");
        }

        // The children are given the same width and height as the workspace
        final int count = getChildCount();
        for (int i = 0; i < count; i++) {
            getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
        }
    }

	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {
		// TODO Auto-generated method stub
		
		int layoutWidth = this.getWidth();
		int layoutHeight = this.getHeight();
		int count = getChildCount();
		int index = 0;
		int cellWidth  = 0;
		int cellHeight = 0;
		if(this.columnNum > 0) {
			//cellWidth = layoutWidth/this.columnNum - (this.columnNum + 1) * this.horizontalSpace;
			cellWidth = (layoutWidth - (this.columnNum + 1 ) * this.horizontalSpace)/this.columnNum ;
			Toast.makeText(getContext(), " layoutWidth/this.columnNum=" +layoutWidth/this.columnNum, Toast.LENGTH_SHORT).show();
		}
		if(this.lineNum > 0) {
			cellHeight = (layoutHeight - (this.lineNum + 1) * this.vecitcalSpace) / this.lineNum;
		}
		for(int i = 0; i < this.lineNum; i++) {
			for(int j = 0; j < this.columnNum; j++) {
				if(index >= count){
					break;
				}
				
				int x = j * cellWidth + (j+1) * this.horizontalSpace;
				int y = i * cellHeight + (i+1) * this.vecitcalSpace;
				int width = cellWidth;
				int height = cellHeight;
				
				final View child = getChildAt(index);
				
				if(child.getVisibility() != View.GONE) {
					child.layout(x, y, x + width, y + height);
				}
				
				index ++;
			}
		}
	}
	
	public void setHorizontalSpace(int space) {
		this.horizontalSpace = space;
	}
	
	public void setVecticalSpace(int space) {
		this.vecitcalSpace = space;
	}

	public int getLineNum() {
		return lineNum;
	}

	public void setLineNum(int lineNum) {
		this.lineNum = lineNum;
	}

	public int getColumnNum() {
		return columnNum;
	}

	public void setColumnNum(int columnNum) {
		this.columnNum = columnNum;
	}

}