NativeScript/src/org/nativescript/widgets/WrapLayout.java

/**
 * 
 */
package org.nativescript.widgets;

import java.util.ArrayList;
import android.content.Context;
import android.view.View;

/**
 * @author hhristov
 *
 */
public class WrapLayout extends LayoutBase {

	private int _itemWidth = -1;
	private int _itemHeight = -1;
	private Orientation _orientation = Orientation.horzontal;
    private ArrayList<Integer> _lengths = new ArrayList<Integer>();
    
	public WrapLayout(Context context) {
		super(context);
	}	

	public Orientation getOrientation() {
	    return this._orientation;
	}
	public void setOrientation(Orientation value) {
	    this._orientation = value;
	    this.requestLayout();
	}
	
	public int getItemWidth() {
	    return this._itemWidth;
	}
	public void setItemWidth(int value) {
	    this._itemWidth = value;
	    this.requestLayout();
	}
	
	public int getItemHeight() {
	    return this._itemHeight;
	}
	public void setItemHeight(int value) {
	    this._itemHeight = value;
	    this.requestLayout();
	}
	
    private static int getViewMeasureSpec(int parentMode, int parentLength, int itemLength) {
        if (itemLength > 0) {
            return MeasureSpec.makeMeasureSpec(itemLength, MeasureSpec.EXACTLY);
        }
        else if (parentMode == MeasureSpec.UNSPECIFIED) {
            return MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
        }
        else {
            return MeasureSpec.makeMeasureSpec(parentLength, MeasureSpec.AT_MOST);
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    	
    	int measureWidth = 0;
    	int measureHeight = 0;

        int width = MeasureSpec.getSize(widthMeasureSpec);
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);

        int height = MeasureSpec.getSize(heightMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);

        boolean isVertical = this._orientation == Orientation.vertical;
        int verticalPadding = this.getPaddingTop() + this.getPaddingBottom();
        int horizontalPadding = this.getPaddingLeft() + this.getPaddingRight();

        int childWidthMeasureSpec = getViewMeasureSpec(widthMode, width, this._itemWidth);
        int childHeightMeasureSpec = getViewMeasureSpec(heightMode, height, this._itemHeight);

        int remainingWidth = widthMode == MeasureSpec.UNSPECIFIED ? Integer.MAX_VALUE : width - horizontalPadding;
        int remainingHeight = heightMode == MeasureSpec.UNSPECIFIED ? Integer.MAX_VALUE : height - verticalPadding;

        int count = this.getChildCount();
        
        this._lengths.clear();
        int rowOrColumn = 0;
        int maxLength = 0;
        
        for (int i = 0; i < count; i++) {
            View child = this.getChildAt(i);
            if (child.getVisibility() == View.GONE) {
                continue;
            }
            
            CommonLayoutParams.updateChildLayoutParams(child, widthMeasureSpec, heightMeasureSpec);
        	CommonLayoutParams.measureChild(child, childWidthMeasureSpec, childHeightMeasureSpec);
            final int childMeasuredWidth = CommonLayoutParams.getDesiredWidth(child);
            final int childMeasuredHeight = CommonLayoutParams.getDesiredHeight(child);
            
            if (isVertical) {
                if (childMeasuredHeight > remainingHeight) {
                    rowOrColumn++;
                    maxLength = Math.max(maxLength, measureHeight);
                    measureHeight = childMeasuredHeight;
                    remainingWidth = height - childMeasuredHeight;
                    this._lengths.add(rowOrColumn, childMeasuredWidth);
                }
                else {
                    remainingHeight -= childMeasuredHeight;
                    measureHeight += childMeasuredHeight;
                }
            }
            else {
                if (childMeasuredWidth > remainingWidth) {
                    rowOrColumn++;
                    maxLength = Math.max(maxLength, measureWidth);
                    measureWidth = childMeasuredWidth;
                    remainingWidth = width - childMeasuredWidth;
                    this._lengths.add(rowOrColumn, childMeasuredHeight);
                }
                else {
                    remainingWidth -= childMeasuredWidth;
                    measureWidth += childMeasuredWidth;
                }
            }
            
            if(this._lengths.size() <= rowOrColumn) {
            	this._lengths.add(rowOrColumn, isVertical ? childMeasuredWidth : childMeasuredHeight);
            }
            else {
            	this._lengths.set(rowOrColumn, Math.max(this._lengths.get(rowOrColumn), isVertical ? childMeasuredWidth : childMeasuredHeight));
            }
        }

        count = this._lengths.size();
        if (isVertical) {
            measureHeight = Math.max(maxLength, measureHeight);
            for (int i = 0; i < count; i++) {
                measureWidth += this._lengths.get(i);
            }
        }
        else {
            measureWidth = Math.max(maxLength, measureWidth);
            for (int i = 0; i < count; i++) {
                measureHeight += this._lengths.get(i);
            }
        }
        
        // Add in our padding
        measureWidth += horizontalPadding;
        measureHeight += verticalPadding;

        // Check against our minimum sizes
        measureWidth = Math.max(measureWidth, this.getSuggestedMinimumWidth());
        measureHeight = Math.max(measureHeight, this.getSuggestedMinimumHeight());

        int widthSizeAndState = resolveSizeAndState(measureWidth, widthMeasureSpec, 0);
        int heightSizeAndState = resolveSizeAndState(measureHeight, heightMeasureSpec, 0);

        this.setMeasuredDimension(widthSizeAndState, heightSizeAndState);
    }

	@Override
	protected void onLayout(boolean changed, int left, int top, int right, int bottom) {

		boolean isVertical = this._orientation == Orientation.vertical;
        int paddingLeft = this.getPaddingLeft();
        int paddingRight = this.getPaddingRight();
        int paddingTop = this.getPaddingTop();
        int paddingBottom = this.getPaddingBottom();

        int childLeft = paddingLeft;
        int childTop = paddingTop;
        int childrenLength = isVertical ? bottom - top - paddingBottom : right - left - paddingRight;

        int rowOrColumn = 0;
        int count = this.getChildCount();        
        for (int i = 0; i < count; i++) {
            View child = this.getChildAt(i);
            if (child.getVisibility() == View.GONE) {
                continue;
            }

            // Add margins because layoutChild will subtract them.
            int childWidth = CommonLayoutParams.getDesiredWidth(child);
            int childHeight = CommonLayoutParams.getDesiredHeight(child);

            int length = this._lengths.get(rowOrColumn);
            if (isVertical) {
                
                childWidth = length;
                childHeight = this._itemHeight > 0 ? this._itemHeight : childHeight;
                if (childTop + childHeight > childrenLength) {
                    // Move to top.
                    childTop = paddingTop;

                    // Move to right with current column width.
                    childLeft += length;

                    // Move to next column.
                    rowOrColumn++;

                    // Take current column width.
                    childWidth = length = this._lengths.get(rowOrColumn);
                }
            }
            else {
                childWidth = this._itemWidth > 0 ? this._itemWidth : childWidth;
                childHeight = length;
                if (childLeft + childWidth > childrenLength) {
                    // Move to left.
                    childLeft = paddingLeft;

                    // Move to bottom with current row height.
                    childTop += length;

                    // Move to next column.
                    rowOrColumn++;

                    // Take current row height.
                    childHeight = length = this._lengths.get(rowOrColumn);
                }
            }

            CommonLayoutParams.layoutChild(child, childLeft, childTop, childLeft + childWidth, childTop + childHeight);

            if (isVertical) {
                // Move next child Top position to bottom.
                childTop += childHeight;
            }
            else {
                // Move next child Left position to right.
                childLeft += childWidth;
            }
        }
    }
}