FlowLayout.java

package cn.mutils.app.ui;

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

import cn.mutils.app.R;
import cn.mutils.core.event.IListener;

@SuppressWarnings({"UnnecessaryInterfaceModifier", "unused"})
public class FlowLayout extends ViewGroup {

    public static interface OnLinesChangeListener extends IListener {

        void onChanged(FlowLayout v, int lines);

    }

    protected int mHorizontalGap;
    protected int mVerticalGap;

    protected int mMaxLines = -1;
    protected int mMeasuredLines;

    protected OnLinesChangeListener mOnLinesChangeListener;

    public FlowLayout(Context context) {
        super(context);
        init(context, null);
    }

    public FlowLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs);
    }

    public FlowLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context, attrs);
    }

    protected void init(Context context, AttributeSet attrs) {
        if (attrs != null) {
            TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.FlowLayout);
            mHorizontalGap = typedArray.getDimensionPixelSize(R.styleable.FlowLayout_android_horizontalGap, 10);
            mVerticalGap = typedArray.getDimensionPixelSize(R.styleable.FlowLayout_android_verticalGap, 10);
            mMaxLines = typedArray.getInt(R.styleable.FlowLayout_android_maxLines, -1);
            typedArray.recycle();
        }
    }

    public void setOnLinesChangeListener(OnLinesChangeListener listener) {
        mOnLinesChangeListener = listener;
    }

    public int getMaxLines() {
        return mMaxLines;
    }

    public void setMaxLines(int maxLines) {
        if (mMaxLines == maxLines) {
            return;
        }
        mMaxLines = maxLines;
        this.requestLayout();
        this.invalidate();
    }

    public int getMeasuredLines() {
        return mMeasuredLines;
    }

    public void setMeasuredLines(int measuredLines) {
        mMeasuredLines = measuredLines;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int w = MeasureSpec.getSize(widthMeasureSpec) - getPaddingLeft() - getPaddingRight();
        int h = MeasureSpec.getSize(heightMeasureSpec) - getPaddingTop() - getPaddingBottom();
        int childHeightMeasureSpec;
        if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST) {
            childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(h, MeasureSpec.AT_MOST);
        } else {
            childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
        }
        int x = getPaddingLeft();
        int y = getPaddingTop();
        int rowHeight = 0;
        int maxHeight = 0;
        int lines = 1;
        boolean linesInvalidate = false;
        for (int i = 0, size = this.getChildCount(); i < size; i++) {
            View child = getChildAt(i);
            if (child.getVisibility() == View.GONE) {
                continue;
            }
            if (linesInvalidate) {
                linesInvalidate = false;
                rowHeight = 0;
            }
            child.measure(MeasureSpec.makeMeasureSpec(w, MeasureSpec.AT_MOST), childHeightMeasureSpec);
            rowHeight = Math.max(rowHeight, child.getMeasuredHeight() + mVerticalGap);
            if (x + child.getMeasuredWidth() > w) {
                if (x > getPaddingLeft()) {
                    x = getPaddingLeft();
                    y += rowHeight;
                    if (lines == mMaxLines) {
                        maxHeight = y;
                    }
                    lines++;
                    linesInvalidate = true;
                }
            }
            LayoutParams lp = (LayoutParams) child.getLayoutParams();
            lp.mX = x;
            lp.mY = y;
            x += child.getMeasuredWidth() + mHorizontalGap;
        }
        if (maxHeight != 0) {// 固定高度
            h = maxHeight;
        } else {
            if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.UNSPECIFIED) {
                h = y + rowHeight;
            } else if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST) {
                if (y + rowHeight < h) {
                    h = y + rowHeight;
                }
            }
        }
        setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec), h + getPaddingBottom());
        if (mMeasuredLines != lines) {
            mMeasuredLines = lines;
            if (mOnLinesChangeListener != null) {
                mOnLinesChangeListener.onChanged(this, lines);
            }
        }
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        for (int i = this.getChildCount() - 1; i >= 0; i--) {
            View child = this.getChildAt(i);
            if (child.getVisibility() == View.GONE) {
                continue;
            }
            LayoutParams lp = (LayoutParams) child.getLayoutParams();
            child.layout(lp.mX, lp.mY, lp.mX + child.getMeasuredWidth(), lp.mY + child.getMeasuredHeight());
        }
    }

    @Override
    protected boolean checkLayoutParams(android.view.ViewGroup.LayoutParams p) {
        return p != null && (p instanceof LayoutParams);
    }

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

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

    @Override
    protected LayoutParams generateLayoutParams(android.view.ViewGroup.LayoutParams p) {
        return new LayoutParams(p.width, p.height);
    }

    public static class LayoutParams extends ViewGroup.LayoutParams {

        protected int mX;
        protected int mY;

        public LayoutParams(Context c, AttributeSet attrs) {
            super(c, attrs);
        }

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

        public LayoutParams(LayoutParams source) {
            super(source);
        }
    }

}