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上面是采用adapter模式实现的一个自定义标签效果，传入的是一个集合数据，同时可以灵活的设置标签的背景以及给标签设置相应的点击事件。
代码实现：
/**
* Created by Administrator on 2017/7/3.
* 流式布局的适配器
*/
public abstract class TagAdapter {
//有多少个条目
public abstract int getCount();
//getView通过position
public abstract View getView(int position, ViewGroup parent);
//观察者模式通知更新
public void unregisterDataSetObserver(DataSetObserver observer){
};
public void registerDataSetObserver(DataSetObserver observer){
}
}
public class TagLayout extends ViewGroup {
private List<List<View>> mChildViews = new ArrayList<>();
private TagAdapter mAdapter;
public TagLayout(Context context) {
super(context);
}
public TagLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public TagLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
// 清空集合
mChildViews.clear();
int childCount = getChildCount();
// 获取到宽度
int width = MeasureSpec.getSize(widthMeasureSpec);
// 高度需要计算
int height = getPaddingTop() + getPaddingBottom();
// 一行的宽度
int lineWidth = getPaddingLeft();
ArrayList<View> childViews = new ArrayList<>();
mChildViews.add(childViews);
// 子View高度不一致的情况下
int maxHeight = 0;
for (int i = 0; i < childCount; i++) {
// 2.1.1 for循环测量子View
View childView = getChildAt(i);
if(childView.getVisibility() == GONE){
continue;
}
// 这段话执行之后就可以获取子View的宽高，因为会调用子View的onMeasure
measureChild(childView, widthMeasureSpec, heightMeasureSpec);
// margin值 ViewGroup.LayoutParams 没有 就用系统的MarginLayoutParams
// 想想 LinearLayout为什么有？
// LinearLayout有自己的 LayoutParams 会复写一个非常重要的方法
MarginLayoutParams params = (MarginLayoutParams) childView.getLayoutParams();
// 什么时候需要换行，一行不够的情况下 考虑 margin
if (lineWidth + (childView.getMeasuredWidth() + params.rightMargin + params.leftMargin) > width) {
// 换行,累加高度 加上一行条目中最大的高度
height += maxHeight;
lineWidth = childView.getMeasuredWidth() + params.rightMargin + params.leftMargin;
childViews = new ArrayList<>();
mChildViews.add(childViews);
} else {
lineWidth += childView.getMeasuredWidth() + params.rightMargin + params.leftMargin;
maxHeight = Math.max(childView.getMeasuredHeight() + params.bottomMargin + params.topMargin, maxHeight);
}
childViews.add(childView);
}
height += maxHeight;
Log.e("TAG", "width -> " + width + " height-> " + height);
// 2.1.2 根据子View计算和指定自己的宽高
setMeasuredDimension(width, height);
}
@Override
protected LayoutParams generateLayoutParams(LayoutParams p) {
return super.generateLayoutParams(p);
}
@Override
public LayoutParams generateLayoutParams(AttributeSet attrs) {
return new MarginLayoutParams(getContext(), attrs);
}
/**
* 摆放
*
* @param changed
* @param l
* @param t
* @param r
* @param b
*/
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int left, top = getPaddingTop(), right, bottom;
for (List<View> childViews : mChildViews) {
left = getPaddingLeft();
int maxHeight = 0;
for (View childView : childViews) {
if(childView.getVisibility() == GONE){
continue;
}
MarginLayoutParams params = (MarginLayoutParams) childView.getLayoutParams();
left += params.leftMargin;
int childTop = top + params.topMargin;
right = left + childView.getMeasuredWidth();
bottom = childTop + childView.getMeasuredHeight();
Log.e("TAG", childView.toString());
Log.e("TAG", "left -> " + left + " top-> " + childTop + " right -> " + right + " bottom-> " + bottom);
// 摆放
childView.layout(left, childTop, right, bottom);
// left 叠加
left += childView.getMeasuredWidth() + params.rightMargin;
// 不断的叠加top值
int childHeight = childView.getMeasuredHeight()+ params.topMargin+params.bottomMargin;
maxHeight = Math.max(maxHeight,childHeight);
}
top += maxHeight;
}
}
public void setAdapter(TagAdapter adapter){
if(adapter==null){
//控制针异常
throw new NullPointerException("adapter is null");
}
//清空所有子view
removeAllViews();
mAdapter=adapter;
//获取数量
int childCount=mAdapter.getCount();
for(int i=0;i<childCount;i++){
View childView = mAdapter.getView(i,this);
addView(childView);
}
}
}
这里extends ViewGroup，其实自定义的TabLayout也就是一个布局容器，这里主要涉及到的就是字view的测量和摆放，所以肯定要重写onMeasure和OnLayout，在测量和摆放的时要根据子view的情况去计算每行的高度和宽度，根据计算的宽度和父布局的宽度进行对比是否要换行；经过测量和摆放后，差不多就实现了，在布局文件中直接使用就可以了。
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.viewday08.MainActivity">
<com.viewday08.TagLayout
android:id="@+id/tag_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</com.viewday08.TagLayout>
</LinearLayout>
获取自定义的TagLayout并设置adapter
public class MainActivity extends AppCompatActivity {
private TagLayout tagLayout;
private List<String> mItems;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tagLayout = (TagLayout) findViewById(R.id.tag_layout);
mItems=new ArrayList<>();
mItems.add("111111111111111111111");
mItems.add("222");
mItems.add("3333333333");
mItems.add("666677");
mItems.add("000009989");
mItems.add("1111111");
mItems.add("222");
mItems.add("3333333333");
mItems.add("666677");
mItems.add("000009989111111111111111111111");
mItems.add("1111111");
mItems.add("222");
mItems.add("3333333333");
mItems.add("666677");
mItems.add("000009989");
tagLayout.setAdapter(new TagAdapter() {
@Override
public int getCount() {
return mItems.size();
}
@Override
public View getView(int position, ViewGroup parent) {
TextView tagTv = (TextView) LayoutInflater.from(MainActivity.this).inflate(R.layout.item_tag, parent, false);
final String s = mItems.get(position);
tagTv.setText(s);
tagTv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this,s,Toast.LENGTH_LONG).show();
}
});
return tagTv;
}
});
}
}
这样子效果就实现了。
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