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@vinothkannans
Created May 11, 2016 09:41
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Android Flow Layout
package com.vinkas.layout;
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;
public class FlowLayout extends ViewGroup {
private int mHorizontalSpacing;
private int mVerticalSpacing;
private Paint mPaint;
public FlowLayout(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.FlowLayout);
try {
mHorizontalSpacing = a.getDimensionPixelSize(R.styleable.FlowLayout_horizontalSpacing, 0);
mVerticalSpacing = a.getDimensionPixelSize(R.styleable.FlowLayout_verticalSpacing, 0);
} finally {
a.recycle();
}
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setColor(0xffff0000);
mPaint.setStrokeWidth(2.0f);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int widthSize = MeasureSpec.getSize(widthMeasureSpec) - getPaddingRight();
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
boolean growHeight = widthMode != MeasureSpec.UNSPECIFIED;
int width = 0;
int height = getPaddingTop();
int currentWidth = getPaddingLeft();
int currentHeight = 0;
boolean breakLine = false;
boolean newLine = false;
int spacing = 0;
final int count = getChildCount();
for (int i = 0; i < count; i++) {
View child = getChildAt(i);
measureChild(child, widthMeasureSpec, heightMeasureSpec);
LayoutParams lp = (LayoutParams) child.getLayoutParams();
spacing = mHorizontalSpacing;
if (lp.horizontalSpacing >= 0) {
spacing = lp.horizontalSpacing;
}
if (growHeight && (breakLine || currentWidth + child.getMeasuredWidth() > widthSize)) {
height += currentHeight + mVerticalSpacing;
currentHeight = 0;
width = Math.max(width, currentWidth - spacing);
currentWidth = getPaddingLeft();
newLine = true;
} else {
newLine = false;
}
lp.x = currentWidth;
lp.y = height;
currentWidth += child.getMeasuredWidth() + spacing;
currentHeight = Math.max(currentHeight, child.getMeasuredHeight());
breakLine = lp.breakLine;
}
if (!newLine) {
height += currentHeight;
width = Math.max(width, currentWidth - spacing);
}
width += getPaddingRight();
height += getPaddingBottom();
setMeasuredDimension(resolveSize(width, widthMeasureSpec),
resolveSize(height, heightMeasureSpec));
}
@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);
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 - 4.0f, x, y + 4.0f, mPaint);
canvas.drawLine(x, y, x + lp.horizontalSpacing, y, mPaint);
canvas.drawLine(x + lp.horizontalSpacing, y - 4.0f, x + lp.horizontalSpacing, y + 4.0f, mPaint);
}
if (lp.breakLine) {
float x = child.getRight();
float y = child.getTop() + child.getHeight() / 2.0f;
canvas.drawLine(x, y, x, y + 6.0f, mPaint);
canvas.drawLine(x, y + 6.0f, x + 6.0f, y + 6.0f, mPaint);
}
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 attrs) {
return new LayoutParams(getContext(), attrs);
}
@Override
protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
return new LayoutParams(p.width, p.height);
}
public static class LayoutParams extends ViewGroup.LayoutParams {
int x;
int y;
public int horizontalSpacing;
public boolean breakLine;
public LayoutParams(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.FlowLayout_LayoutParams);
try {
horizontalSpacing = a.getDimensionPixelSize(R.styleable.FlowLayout_LayoutParams_layout_horizontalSpacing, -1);
breakLine = a.getBoolean(R.styleable.FlowLayout_LayoutParams_layout_breakLine, false);
} finally {
a.recycle();
}
}
public LayoutParams(int w, int h) {
super(w, h);
}
}
}
@vinothkannans
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vinothkannans commented May 11, 2016

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="FlowLayout">
        <attr name="horizontalSpacing" format="dimension" />
        <attr name="verticalSpacing" format="dimension" />
    </declare-styleable>
    <declare-styleable name="FlowLayout_LayoutParams">
        <attr name="layout_breakLine" format="boolean" />
        <attr name="layout_horizontalSpacing" format="dimension" />
    </declare-styleable>
</resources>

@vinothkannans
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Usage

<com.vinkas.layout.FlowLayout
        xmlns:vinkas="http://schemas.android.com/apk/res/com.vinkas.layout"
        xmlns:android="http://schemas.android.com/apk/res/android"
        vinkas:horizontalSpacing="6dip"
        vinkas:verticalSpacing="12dip"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true">

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