FlowLayout
package org.apmem.tools.layouts;
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;
import org.apmem.tools.R;
/**
* 注意：这个东西并未把左边、上边、下边、右边这两块区域给计算进去，所以它的水平和垂直间距对这四边是不起作用的，不过，
* 也有优点就是它不会影响周边控件，如果需要为四周写东西，则只需要手动加上即可。
*
*/
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 = true;
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.getPaddingTop() - this.getPaddingBottom();
int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
int modeHeight = MeasureSpec.getMode(heightMeasureSpec);
int size;//总宽度，也是它们所能容纳的最大宽度
int mode;
if (orientation == HORIZONTAL) {
size = sizeWidth;
mode = modeWidth;
} else {
size = sizeHeight;
mode = modeHeight;
}
int lineThicknessWithSpacing = 0;//带间隔的折线高度
int lineThickness = 0;//折线总高度
int lineLengthWithSpacing = 0;//带间隔的折线总长度，其实它只是一个中间值
int lineLength;//其实是总长度，包含了控件和间隔的长度
int prevLinePosition = 0;//表示Y轴上的位置
int controlMaxLength = 0;//控制的最大长度
int controlMaxThickness = 0;//控制的最大高度
final int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() == GONE) {
continue;
}
child.measure(
//如果确切知道大小的话就让其自适应，否则按照最大的给它。
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);//得到水平间距
int vSpacing = this.getVerticalSpacing(lp);//得到垂直间距
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();
int childLength;//子view的长度
int childThickness;//子view的高度
int spacingLength;//子view的间距长度
int spacingThickness;//子view的间距高度
if (orientation == HORIZONTAL) {
childLength = childWidth;
childThickness = childHeight;
spacingLength = hSpacing;
spacingThickness = vSpacing;
} else {
childLength = childHeight;
childThickness = childWidth;
spacingLength = vSpacing;
spacingThickness = hSpacing;
}
// 这个lineLengthWithSpacing很精妙，每一行的第一个长度为item实际的宽度，第一个之后就是实际占用的宽度，妈的
//这个看了好久才明白
lineLength = lineLengthWithSpacing + childLength;//已占用的总长度,
lineLengthWithSpacing = lineLength + spacingLength;//带间距的已占用总长度
boolean newLine = lp.newLine || (mode != MeasureSpec.UNSPECIFIED && lineLength > size);
if (newLine) {
prevLinePosition = prevLinePosition + lineThicknessWithSpacing;
lineThickness = childThickness;
lineLength = childLength;
lineThicknessWithSpacing = childThickness + spacingThickness;
lineLengthWithSpacing = lineLength + spacingLength;
}
//带间距的总高度
lineThicknessWithSpacing = Math.max(lineThicknessWithSpacing, childThickness + spacingThickness);
//不带间距的总高度
lineThickness = Math.max(lineThickness, childThickness);
//以左上角为标准
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);
System.out.println("lineLength:"+lineLength);
controlMaxLength = Math.max(controlMaxLength, lineLength);
System.out.println("controlMaxLength:"+controlMaxLength);
System.out.println("prevLinePosition:"+prevLinePosition+" lineThickness"+lineThickness);
//这个最大高度也很精妙prevLinePosition表示包含了控件高度和间距，但是最后一个则只需要加上 控件的本来高度，正好是完整的。
controlMaxThickness = prevLinePosition + lineThickness;
}
/* need to take paddings into account */
if (orientation == HORIZONTAL) {
controlMaxLength += getPaddingLeft() + getPaddingRight();
controlMaxThickness += getPaddingBottom() + getPaddingTop();
} else {
controlMaxLength += getPaddingBottom() + getPaddingTop();
controlMaxThickness += getPaddingLeft() + getPaddingRight();
}
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;
//如果layoutParamters里面有水平间隔就用属性里面有值，如果没有就用布局里面的自定义属性，
//即，优化使用参数里面的自定义间距属性的值，否则再使用布局里面自定义属性的值
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();
}
}
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();
}
}
}
}
</pre><pre code_snippet_id="365746" snippet_file_name="blog_20140527_3_2466645" name="code" class="java">
github上搜索flowlayout
https://github.com/ApmeM/android-flowlayout
附网上能用方法，此法错误，不可取 ：
<pre name="code" class="java">package com.example.flowlayout;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
public class FlowLayout1 extends ViewGroup {
public FlowLayout1(Context context) {
super(context);
}
public FlowLayout1(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public FlowLayout1(Context context, AttributeSet attrs) {
super(context, attrs);
}
//每个View的上下间距
private int dividerLine = 20;
//每个View的左右间距
private int dividerCol = 20;
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
for (int i = 0; i < getChildCount(); i++) {
final View child = getChildAt(i);
child.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
}
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
/**
* 此方案你写在这，永远是一个Demo级别的应用，因为大小已不可改变，它只能占满两个屏幕。
* 还有，它的上下左右的距离正好是20，这个东西很神奇，你画图才能明白这些东西。
*/
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
final int count = getChildCount();
int row = 0;
int lengthX = l;//这两个表示右下角
int lengthY = t;
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
int width = child.getMeasuredWidth();
int height = child.getMeasuredHeight();
lengthX += width + dividerCol;
lengthY = t + row*(height+dividerLine)+ height + dividerLine;
if (lengthX > r) {
lengthX = width + l + dividerCol;
row++;
lengthY = row * (height+dividerLine) + t + height + dividerLine;
}
child.layout(lengthX - width , lengthY - height, lengthX, lengthY);
}
}
}