Android自定义之流式布局

来源：互联网发布：中科院软件所招聘编辑：程序博客网时间：2024/05/01 16:08

流式布局，好处就是父类布局可以自动的判断子孩子是不是需要换行，什么时候需要换行，可以做到网页版的标签的效果。今天就是简单的做了自定义的流式布局。

具体效果：

原理：
其实很简单，Measure Layout。只需要这两个步骤就可以搞定了。完全的手动去Measure Layout。
我们看一下代码。
解释就在代码里面做注释了，因为使用为知笔记写的博客，格式不符合代码格式。大家可以看具体的源码。最后又源码下载地址。
1.Measure 测量

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

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

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

int lineHeight = 0 ;
int lineWidth = 0 ;

int width = 0 ;
int height = 0 ;

int childCount = getChildCount();

Log.i("Test", getPaddingLeft() + "==right=" +getPaddingRight());

for (int i = 0; i < childCount; i++) {
View childView = getChildAt(i);
measureChild(childView, widthMeasureSpec, heightMeasureSpec);
MarginLayoutParams params = (MarginLayoutParams) childView.getLayoutParams();

int childWidth = childView.getMeasuredWidth() + params.leftMargin + params.rightMargin ;

int childHeight = childView.getMeasuredHeight() + params.topMargin + params.bottomMargin ;


if ((lineWidth + childWidth ) > widthSize - getPaddingLeft() - getPaddingRight() ) {
width = Math.max(width, lineWidth);
lineWidth = childWidth ;
height += lineHeight ;
lineHeight = childHeight;
}else {
lineWidth += childWidth ;
lineHeight = Math.max(lineHeight, childHeight);
}


if (i == childCount-1) {
width = Math.max(width, lineWidth);
height += lineHeight ;
}
}

height += getPaddingTop() + getPaddingBottom() ;

setMeasuredDimension(widthMode == MeasureSpec.EXACTLY?widthSize:width,
heightMode == MeasureSpec.EXACTLY?heightSize:height);
}

2.onLayout 布局
@Override
protected void onLayout(boolean a, int l, int t, int r, int b) {

childViewList.clear();

int childCount = getChildCount() ;
int width = getWidth();
int lineWidth = 0 ;
int lineHeight = 0 ;

List<View> lineViews = new ArrayList<View>();
for (int i = 0; i < childCount; i++) {
View childView = getChildAt(i);
MarginLayoutParams params = (MarginLayoutParams) childView.getLayoutParams();

int childWidth = childView.getMeasuredWidth() + params.leftMargin + params.rightMargin ;
int childHeight = childView.getMeasuredHeight() + params.topMargin + params.bottomMargin ;

if (lineWidth + childWidth > width - getPaddingLeft() - getPaddingRight()) {

childViewList.add(lineViews);
lineViews = new ArrayList<View>();

if (i == 0 ) {
lineHeight += getPaddingTop() ;
}else if (i== childCount - 1) {
lineHeight += getPaddingBottom() ;
}
this.lineHeight.add(lineHeight);

lineHeight = 0 ;
lineWidth = 0 ;
}

lineWidth += childWidth;
lineHeight = Math.max(lineHeight, childHeight) ;

lineViews.add(childView);
}

childViewList.add(lineViews);
this.lineHeight.add(lineHeight);

int left = getPaddingLeft() ;
int top = getPaddingTop();

for (int i = 0; i < childViewList.size(); i++) {
lineViews = childViewList.get(i);
for (int j = 0; j < lineViews.size(); j++) {
View childView = lineViews.get(j);

MarginLayoutParams params = (MarginLayoutParams) childView.getLayoutParams();

int lc = left + params.leftMargin ;
int tc = top + params.topMargin ;
int rc = lc + childView.getMeasuredWidth() ;
int bc = tc + childView.getMeasuredHeight() ;

childView.layout(lc,tc,rc,bc);

left += params.leftMargin + childView.getMeasuredWidth() + params.rightMargin ;
}

left = getPaddingLeft() ;
top += this.lineHeight.get(i) ;
}
}

代码下载地址：
百度网盘： http://pan.baidu.com/s/1hqH1kFU

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