FlowLayout浮动布局

package com.bitcare.view;

import com.bitcareV2.activity.R;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;

/**
 * User: Romain Guy
 * <p/>
 * Using example:
 * <?xml version="4.0" encoding="utf-8"?>
 * <com.example.android.layout.FlowLayout
 * xmlns:f="http://schemas.android.com/apk/res/org.apmem.android"
 * xmlns:android="http://schemas.android.com/apk/res/android"
 * f:horizontalSpacing="6dip"
 * f:verticalSpacing="12dip"
 * android:layout_width="wrap_content"
 * android:layout_height="wrap_content"
 * android:paddingLeft="6dip"
 * android:paddingTop="6dip"
 * android:paddingRight="12dip">
 * <Button
 * android:layout_width="wrap_content"
 * android:layout_height="wrap_content"
 * f:layout_horizontalSpacing="32dip"
 * f:layout_breakLine="true"
 * android:text="Cancel" />
 * <p/>
 * </com.example.android.layout.FlowLayout>
 */
public class FlowLayout extends ViewGroup {
    public static final int HORIZONTAL = 0;
    public static final int VERTICAL = 1;

    private int horizontalSpacing = 0;
    private int verticalSpacing = 0;
    private int orientation = 0;
    private boolean debugDraw = false;

    public FlowLayout(Context context) {
        super(context);

        this.readStyleParameters(context, null);
    }

    public FlowLayout(Context context, AttributeSet attributeSet) {
        super(context, attributeSet);

        this.readStyleParameters(context, attributeSet);
    }

    public FlowLayout(Context context, AttributeSet attributeSet, int defStyle) {
        super(context, attributeSet, defStyle);

        this.readStyleParameters(context, attributeSet);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int sizeWidth = MeasureSpec.getSize(widthMeasureSpec) - this.getPaddingRight() - this.getPaddingLeft();
        int sizeHeight = MeasureSpec.getSize(heightMeasureSpec) - this.getPaddingRight() - this.getPaddingLeft();

        int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
        int modeHeight = MeasureSpec.getMode(heightMeasureSpec);

        int size;
        int mode;

        if (orientation == HORIZONTAL) {
            size = sizeWidth;
            mode = modeWidth;
        } else {
            size = sizeHeight;
            mode = modeHeight;
        }

        int lineThicknessWithSpacing = 0;
        int lineThickness = 0;
        int lineLengthWithSpacing = 0;
        int lineLength;

        int prevLinePosition = 0;

        int controlMaxLength = 0;
        int controlMaxThickness = 0;

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

            child.measure(
                    MeasureSpec.makeMeasureSpec(sizeWidth, modeWidth == MeasureSpec.EXACTLY ? MeasureSpec.AT_MOST : modeWidth),
                    MeasureSpec.makeMeasureSpec(sizeHeight, modeHeight == MeasureSpec.EXACTLY ? MeasureSpec.AT_MOST : modeHeight)
            );

            LayoutParams lp = (LayoutParams) child.getLayoutParams();

            int hSpacing = this.getHorizontalSpacing(lp);
            int vSpacing = this.getVerticalSpacing(lp);

            int childWidth = child.getMeasuredWidth();
            int childHeight = child.getMeasuredHeight();

            int childLength;
            int childThickness;
            int spacingLength;
            int spacingThickness;

            if (orientation == HORIZONTAL) {
                childLength = childWidth;
                childThickness = childHeight;
                spacingLength = hSpacing;
                spacingThickness = vSpacing;
            } else {
                childLength = childHeight;
                childThickness = childWidth;
                spacingLength = vSpacing;
                spacingThickness = hSpacing;
            }

            lineLength = lineLengthWithSpacing + childLength;
            lineLengthWithSpacing = lineLength + spacingLength;

            boolean newLine = lp.newLine || (mode != MeasureSpec.UNSPECIFIED && lineLength > size);
            if (newLine) {
                prevLinePosition = prevLinePosition + lineThicknessWithSpacing;

                lineThickness = childThickness;
                lineLength = childLength;
                lineThicknessWithSpacing = childThickness + spacingThickness;
                lineLengthWithSpacing = lineLength + spacingLength;
            }

            lineThicknessWithSpacing = Math.max(lineThicknessWithSpacing, childThickness + spacingThickness);
            lineThickness = Math.max(lineThickness, childThickness);

            int posX;
            int posY;
            if (orientation == HORIZONTAL) {
                posX = getPaddingLeft() + lineLength - childLength;
                posY = getPaddingTop() + prevLinePosition;
            } else {
                posX = getPaddingLeft() + prevLinePosition;
                posY = getPaddingTop() + lineLength - childHeight;
            }
            lp.setPosition(posX, posY);

            controlMaxLength = Math.max(controlMaxLength, lineLength);
            controlMaxThickness = prevLinePosition + lineThickness;
        }

        if (orientation == HORIZONTAL) {
            this.setMeasuredDimension(resolveSize(controlMaxLength, widthMeasureSpec), resolveSize(controlMaxThickness, heightMeasureSpec));
        } else {
            this.setMeasuredDimension(resolveSize(controlMaxThickness, widthMeasureSpec), resolveSize(controlMaxLength, heightMeasureSpec));
        }
    }

    private int getVerticalSpacing(LayoutParams lp) {
        int vSpacing;
        if (lp.verticalSpacingSpecified()) {
            vSpacing = lp.verticalSpacing;
        } else {
            vSpacing = this.verticalSpacing;
        }
        return vSpacing;
    }

    private int getHorizontalSpacing(LayoutParams lp) {
        int hSpacing;
        if (lp.horizontalSpacingSpecified()) {
            hSpacing = lp.horizontalSpacing;
        } else {
            hSpacing = this.horizontalSpacing;
        }
        return hSpacing;
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        final int count = getChildCount();
        for (int i = 0; i < count; i++) {
            View child = getChildAt(i);
            LayoutParams lp = (LayoutParams) child.getLayoutParams();
            child.layout(lp.x, lp.y, lp.x + child.getMeasuredWidth(), lp.y + child.getMeasuredHeight());
        }
    }

    @Override
    protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
        boolean more = super.drawChild(canvas, child, drawingTime);
        this.drawDebugInfo(canvas, child);
        return more;
    }

    @Override
    protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
        return p instanceof LayoutParams;
    }

    @Override
    protected LayoutParams generateDefaultLayoutParams() {
        return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    }

    @Override
    public LayoutParams generateLayoutParams(AttributeSet attributeSet) {
        return new LayoutParams(getContext(), attributeSet);
    }

    @Override
    protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
        return new LayoutParams(p);
    }

    private void readStyleParameters(Context context, AttributeSet attributeSet) {
        TypedArray a = context.obtainStyledAttributes(attributeSet, R.styleable.FlowLayout);
        try {
            horizontalSpacing = a.getDimensionPixelSize(R.styleable.FlowLayout_horizontalSpacing, 0);
            verticalSpacing = a.getDimensionPixelSize(R.styleable.FlowLayout_verticalSpacing, 0);
            orientation = a.getInteger(R.styleable.FlowLayout_orientation, HORIZONTAL);
            debugDraw = a.getBoolean(R.styleable.FlowLayout_debugDraw, false);
        } finally {
            a.recycle();
        }
    }

    private void drawDebugInfo(Canvas canvas, View child) {
        if (!debugDraw) {
            return;
        }

        Paint childPaint = this.createPaint(0xffffff00);
        Paint layoutPaint = this.createPaint(0xff00ff00);
        Paint newLinePaint = this.createPaint(0xffff0000);

        LayoutParams lp = (LayoutParams) child.getLayoutParams();

        if (lp.horizontalSpacing > 0) {
            float x = child.getRight();
            float y = child.getTop() + child.getHeight() / 2.0f;
            canvas.drawLine(x, y, x + lp.horizontalSpacing, y, childPaint);
            canvas.drawLine(x + lp.horizontalSpacing - 4.0f, y - 4.0f, x + lp.horizontalSpacing, y, childPaint);
            canvas.drawLine(x + lp.horizontalSpacing - 4.0f, y + 4.0f, x + lp.horizontalSpacing, y, childPaint);
        } else if (this.horizontalSpacing > 0) {
            float x = child.getRight();
            float y = child.getTop() + child.getHeight() / 2.0f;
            canvas.drawLine(x, y, x + this.horizontalSpacing, y, layoutPaint);
            canvas.drawLine(x + this.horizontalSpacing - 4.0f, y - 4.0f, x + this.horizontalSpacing, y, layoutPaint);
            canvas.drawLine(x + this.horizontalSpacing - 4.0f, y + 4.0f, x + this.horizontalSpacing, y, layoutPaint);
        }

        if (lp.verticalSpacing > 0) {
            float x = child.getLeft() + child.getWidth() / 2.0f;
            float y = child.getBottom();
            canvas.drawLine(x, y, x, y + lp.verticalSpacing, childPaint);
            canvas.drawLine(x - 4.0f, y + lp.verticalSpacing - 4.0f, x, y + lp.verticalSpacing, childPaint);
            canvas.drawLine(x + 4.0f, y + lp.verticalSpacing - 4.0f, x, y + lp.verticalSpacing, childPaint);
        } else if (this.verticalSpacing > 0) {
            float x = child.getLeft() + child.getWidth() / 2.0f;
            float y = child.getBottom();
            canvas.drawLine(x, y, x, y + this.verticalSpacing, layoutPaint);
            canvas.drawLine(x - 4.0f, y + this.verticalSpacing - 4.0f, x, y + this.verticalSpacing, layoutPaint);
            canvas.drawLine(x + 4.0f, y + this.verticalSpacing - 4.0f, x, y + this.verticalSpacing, layoutPaint);
        }

        if (lp.newLine) {
            if (orientation == HORIZONTAL) {
                float x = child.getLeft();
                float y = child.getTop() + child.getHeight() / 2.0f;
                canvas.drawLine(x, y - 6.0f, x, y + 6.0f, newLinePaint);
            } else {
                float x = child.getLeft() + child.getWidth() / 2.0f;
                float y = child.getTop();
                canvas.drawLine(x - 6.0f, y, x + 6.0f, y, newLinePaint);
            }
        }
    }

    private Paint createPaint(int color) {
        Paint paint = new Paint();
        paint.setAntiAlias(true);
        paint.setColor(color);
        paint.setStrokeWidth(2.0f);
        return paint;
    }

    public static class LayoutParams extends ViewGroup.LayoutParams {
        private static int NO_SPACING = -1;

        private int x;
        private int y;
        private int horizontalSpacing = NO_SPACING;
        private int verticalSpacing = NO_SPACING;
        private boolean newLine = false;

        public LayoutParams(Context context, AttributeSet attributeSet) {
            super(context, attributeSet);
            this.readStyleParameters(context, attributeSet);
        }

        public LayoutParams(int width, int height) {
            super(width, height);
        }

        public LayoutParams(ViewGroup.LayoutParams layoutParams) {
            super(layoutParams);
        }

        public boolean horizontalSpacingSpecified() {
            return horizontalSpacing != NO_SPACING;
        }

        public boolean verticalSpacingSpecified() {
            return verticalSpacing != NO_SPACING;
        }

        public void setPosition(int x, int y) {
            this.x = x;
            this.y = y;
        }

        private void readStyleParameters(Context context, AttributeSet attributeSet) {
            TypedArray a = context.obtainStyledAttributes(attributeSet, R.styleable.FlowLayout_LayoutParams);
            try {
                horizontalSpacing = a.getDimensionPixelSize(R.styleable.FlowLayout_LayoutParams_layout_horizontalSpacing, NO_SPACING);
                verticalSpacing = a.getDimensionPixelSize(R.styleable.FlowLayout_LayoutParams_layout_verticalSpacing, NO_SPACING);
                newLine = a.getBoolean(R.styleable.FlowLayout_LayoutParams_layout_newLine, false);
            } finally {
                a.recycle();
            }
        }
    }
}

<resources>
    <declare-styleable name="FlowLayout">
        <attr name="horizontalSpacing" format="dimension"/>
        <attr name="verticalSpacing" format="dimension"/>
        <attr name="orientation" format="enum">
            <enum name="horizontal" value="0"/>
            <enum name="vertical" value="1"/>
        </attr>
        <attr name="debugDraw" format="boolean" />
    </declare-styleable>
    <declare-styleable name="FlowLayout_LayoutParams">
        <attr name="layout_newLine" format="boolean"/>
        <attr name="layout_horizontalSpacing" format="dimension"/>
        <attr name="layout_verticalSpacing" format="dimension"/>
    </declare-styleable>
</resources>

xmlns:f="http://schemas.android.com/apk/res/your.namespace"
f:horizontalSpacing="6dip"
f:verticalSpacing="12dip"

f:orientation="vertical"