上面是採用adapter模式實現的一個自定義標籤效果，傳入的是一個集合數據，同時可以靈活的設置標籤的背景以及給標籤設置相應的點擊事件。
代碼實現：
/**
* Created by Administrator on 2017/7/3.
* 流式佈局的適配器
*/
public abstract class TagAdapter {
//有多少個條目
public abstract int getCount();
//getView通過position
public abstract View getView(int position, ViewGroup parent);
//觀察者模式通知更新
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();
// 獲取到寬度
int width = MeasureSpec.getSize(widthMeasureSpec);
// 高度需要計算
int height = getPaddingTop() + getPaddingBottom();
// 一行的寬度
int lineWidth = getPaddingLeft();
ArrayList<View> childViews = new ArrayList<>();
mChildViews.add(childViews);
// 子View高度不一致的情況下
int maxHeight = 0;
for (int i = 0; i < childCount; i++) {
// 2.1.1 for循環測量子View
View childView = getChildAt(i);
if(childView.getVisibility() == GONE){
continue;
}
// 這段話執行之後就可以獲取子View的寬高，因爲會調用子View的onMeasure
measureChild(childView, widthMeasureSpec, heightMeasureSpec);
// margin值 ViewGroup.LayoutParams 沒有 就用系統的MarginLayoutParams
// 想想 LinearLayout爲什麼有？
// LinearLayout有自己的 LayoutParams 會複寫一個非常重要的方法
MarginLayoutParams params = (MarginLayoutParams) childView.getLayoutParams();
// 什麼時候需要換行，一行不夠的情況下 考慮 margin
if (lineWidth + (childView.getMeasuredWidth() + params.rightMargin + params.leftMargin) > width) {
// 換行,累加高度 加上一行條目中最大的高度
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 根據子View計算和指定自己的寬高
setMeasuredDimension(width, height);
}
@Override
protected LayoutParams generateLayoutParams(LayoutParams p) {
return super.generateLayoutParams(p);
}
@Override
public LayoutParams generateLayoutParams(AttributeSet attrs) {
return new MarginLayoutParams(getContext(), attrs);
}
/**
* 擺放
*
* @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);
// 擺放
childView.layout(left, childTop, right, bottom);
// left 疊加
left += childView.getMeasuredWidth() + params.rightMargin;
// 不斷的疊加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){
//控制針異常
throw new NullPointerException("adapter is null");
}
//清空所有子view
removeAllViews();
mAdapter=adapter;
//獲取數量
int childCount=mAdapter.getCount();
for(int i=0;i<childCount;i++){
View childView = mAdapter.getView(i,this);
addView(childView);
}
}
}這裏extends ViewGroup，其實自定義的TabLayout也就是一個佈局容器，這裏主要涉及到的就是字view的測量和擺放，所以肯定要重寫onMeasure和OnLayout，在測量和擺放的時要根據子view的情況去計算每行的高度和寬度，根據計算的寬度和父佈局的寬度進行對比是否要換行；經過測量和擺放後，差不多就實現了，在佈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>獲取自定義的TagLayout並設置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;
}
});
}
}這樣子效果就實現了。
