FlowLayout流式布局

FlowLayout

效果图

每个textview根据里面文字的多少,自动调整大小.当一行被填满或者无法再填充一个单独的textview的时候,就换行.



使用方法

在activity的onCreate()方法中添加initData()方法

public void initData(){
LayoutInflater mInflater = LayoutInflater.from(this);
//我忘了为什么了,但是一定要用这种加载布局的方式.使用View.inflate()会报错. (我现在很尴尬 --')
for (int i = 0; i < mVals.length; i++)
{
TextView tv = (TextView) mInflater.inflate(R.layout.tv,
mFlowLayout, false);
tv.setText(mVals[i]);
mFlowLayout.addView(tv);
}
}

其中,mFlowLayout就是我们下面代码的FlowLayout.

其在Activity中的布局文件中长这个样子(很普通的自定义控件的写法 : 包名+类名)

<包名.FlowLayout
android:id="@+id/flowlayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>

FlowLayout的代码

public class FlowLayout extends ViewGroup
{

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

public FlowLayout(Context context, AttributeSet attrs)
{
this(context, attrs, 0);
}

public FlowLayout(Context context)
{
this(context, null);
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
int modeHeight = MeasureSpec.getMode(heightMeasureSpec);

// wrap_content
int width = 0;
int height = 0;

// 记录每一行的宽度与高度
int lineWidth = 0;
int lineHeight = 0;

// 得到内部元素的个数
int cCount = getChildCount();

for (int i = 0; i < cCount; i++)
{
View child = getChildAt(i);
// 测量子View的宽和高
measureChild(child, widthMeasureSpec, heightMeasureSpec);
// 得到LayoutParams
MarginLayoutParams lp = (MarginLayoutParams) child
.getLayoutParams();

// 子View占据的宽度
int childWidth = child.getMeasuredWidth() + lp.leftMargin
+ lp.rightMargin;
// 子View占据的高度
int childHeight = child.getMeasuredHeight() + lp.topMargin
+ lp.bottomMargin;

// 换行
if (lineWidth + childWidth > sizeWidth - getPaddingLeft() - getPaddingRight())
{
// 对比得到最大的宽度
width = Math.max(width, lineWidth);
// 重置lineWidth
lineWidth = childWidth;
// 记录行高
height += lineHeight;
lineHeight = childHeight;
} else
// 未换行
{
// 叠加行宽
lineWidth += childWidth;
// 得到当前行最大的高度
lineHeight = Math.max(lineHeight, childHeight);
}
// 最后一个控件
if (i == cCount - 1)
{
width = Math.max(lineWidth, width);
height += lineHeight;
}
}

Log.e("TAG", "sizeWidth = " + sizeWidth);
Log.e("TAG", "sizeHeight = " + sizeHeight);

setMeasuredDimension(
//
modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width + getPaddingLeft() + getPaddingRight(),
modeHeight == MeasureSpec.EXACTLY ? sizeHeight : height + getPaddingTop()+ getPaddingBottom()//
);

}

/**
* 存储所有的View
*/
private List<List<View>> mAllViews = new ArrayList<List<View>>();
/**
* 每一行的高度
*/
private List<Integer> mLineHeight = new ArrayList<Integer>();

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b)
{
mAllViews.clear();
mLineHeight.clear();

// 当前ViewGroup的宽度
int width = getWidth();

int lineWidth = 0;
int lineHeight = 0;

List<View> lineViews = new ArrayList<View>();

int cCount = getChildCount();

for (int i = 0; i < cCount; i++)
{
View child = getChildAt(i);
MarginLayoutParams lp = (MarginLayoutParams) child
.getLayoutParams();

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

// 如果需要换行
if (childWidth + lineWidth + lp.leftMargin + lp.rightMargin > width - getPaddingLeft() - getPaddingRight())
{
// 记录LineHeight
mLineHeight.add(lineHeight);
// 记录当前行的Views
mAllViews.add(lineViews);

// 重置我们的行宽和行高
lineWidth = 0;
lineHeight = childHeight + lp.topMargin + lp.bottomMargin;
// 重置我们的View集合
lineViews = new ArrayList<View>();
}
lineWidth += childWidth + lp.leftMargin + lp.rightMargin;
lineHeight = Math.max(lineHeight, childHeight + lp.topMargin
+ lp.bottomMargin);
lineViews.add(child);

}// for end
// 处理最后一行
mLineHeight.add(lineHeight);
mAllViews.add(lineViews);

// 设置子View的位置
int left = getPaddingLeft();
int top = getPaddingTop();

// 行数
int lineNum = mAllViews.size();

for (int i = 0; i < lineNum; i++)
{
// 当前行的所有的View
lineViews = mAllViews.get(i);
lineHeight = mLineHeight.get(i);

for (int j = 0; j < lineViews.size(); j++)
{
View child = lineViews.get(j);
// 判断child的状态
if (child.getVisibility() == View.GONE)
{
continue;
}

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

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

// 为子View进行布局
child.layout(lc, tc, rc, bc);

left += child.getMeasuredWidth() + lp.leftMargin
+ lp.rightMargin;
}
left = getPaddingLeft() ;
top += lineHeight ;
}

}

/**
* 与当前ViewGroup对应的LayoutParams
*/
@Override
public LayoutParams generateLayoutParams(AttributeSet attrs)
{
return new MarginLayoutParams(getContext(), attrs);
}

}