自定义View（通过ViewGroup实现，Textview长度根据字数的多少而定的）

一、布局

1.1、Drawable文件布局
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">

<solid android:color="#5522ff"/>
<corners android:radius="10dp"/>

<padding
android:left="5dp"
android:right="5dp"
android:top="5dp"
android:bottom="5dp"
/>
</shape>

1.2、Main文件布局

<com.baway.www.custom_viewdemo.FlowLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/flowlayot">
</com.baway.www.custom_viewdemo.FlowLayout>

二、帮助类

public class FlowLayout extends ViewGroup {

//存储所有子View
private List<List<View>> mlistView = new ArrayList<>();
//每一行的高度
private List<Integer> mlistHigth = new ArrayList<>();

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

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

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

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
//如果当前ViewGroup的宽高为wrap_content的情况 ,自己测量的宽高
int width = 0;
int hight = 0;
//每一行线的宽度
int linWidth = 0;
int linHight = 0;
//父控件传进来的宽度和高度以及对应的测量模式
int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
int modeHight = MeasureSpec.getMode(heightMeasureSpec);
int sizeHight = MeasureSpec.getSize(heightMeasureSpec);

//获取子View的个数
int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
View child = getChildAt(i);
//测量子view的宽高
measureChild(child,widthMeasureSpec,heightMeasureSpec);
MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
//子view占得宽度
int childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
//子VIew的高度
int childHight = child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;
//换行判断
if ((linWidth + childWidth) > sizeWidth){
//对比得到最大的宽度
width = Math.max(width,linWidth);
linWidth = childWidth;
//记录行高
hight += linHight;
linHight = childHight;
}else{
//不换行的情况
linWidth += childWidth;
//得到最大行高
linHight = Math.max(linHight,childHight);
}
//处理最后一个子View的情况
if (i == childCount -1){
width = Math.max(width,linWidth);
hight += linHight;
}
}
setMeasuredDimension(modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width ,
modeHight == MeasureSpec.EXACTLY ? sizeHight : hight);

}

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
mlistView.clear();
mlistHigth.clear();
//获取当前ViewGroup的宽度
int width = getWidth();
int linWidth = 0;
int linHight = 0;
//记录当前行的view
List<View> lineViews = new ArrayList<View>();
int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
View child = getChildAt(i);
MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
int childWidth = child.getMeasuredWidth();
int childHight = child.getMeasuredHeight();
//需要换行
if (childWidth + linWidth + lp.leftMargin + lp.rightMargin > width){
//记录LineHeight
mlistHigth.add(linHight);
//记录当前的Views
mlistView.add(lineViews);
linWidth = 0;
linHight = childHight + lp.topMargin + lp.bottomMargin;
lineViews = new ArrayList();
}
linWidth += childWidth + lp.leftMargin + lp.rightMargin;
linHight = Math.max(linHight,childHight + lp.topMargin + lp.bottomMargin);
lineViews.add(child);
}
//处理最后一行
mlistHigth.add(linHight);
mlistView.add(lineViews);
//设置VIew的位置
int left = 0;
int top = 0;
//获取行数
int lineCount = mlistView.size();
for (int i = 0; i < lineCount; i++) {
lineViews = mlistView.get(i);
linHight = mlistHigth.get(i);
for (int j = 0; j < lineViews.size(); j++) {
View child = lineViews.get(j);
if (child.getVisibility() == View.GONE){
continue;
}
MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
int cLeft = left + lp.leftMargin;
int cTop = top + lp.topMargin;
int cRight = cLeft + child.getMeasuredWidth();
int cBottom = cTop + child.getMeasuredHeight();

child.layout(cLeft,cTop,cRight,cBottom);
left += child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
}
left = 0;
top += linHight;
}

}

//
@Override
public LayoutParams generateLayoutParams(AttributeSet attrs) {
return new MarginLayoutParams(getContext(), attrs);
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
}

}

三、主方法MainActivity

public class MainActivity extends AppCompatActivity {

//设置数据的个数
private String mName[] = {"xListView","XUtils","PullToRefresh","ImageLoader","RecycleView","自定义View","ViewGroup","TextView","Button","ImageButton",
"ImageView","ProgressBar","SeekBar","Model","View","Presenter","大磨叽","艳艳"};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

initChildViews();
}

private void initChildViews() {
FlowLayout mFlowLayout = (FlowLayout) findViewById(R.id.flowlayot);
int wrapContent = LayoutParams.WRAP_CONTENT;
MarginLayoutParams lp = new MarginLayoutParams(wrapContent,wrapContent);
lp.leftMargin = 5;
lp.rightMargin = 5;
lp.topMargin = 5;
lp.bottomMargin = 5;
for (int i = 0; i < mName.length; i++) {
TextView view = new TextView(this);
view.setText(mName[i]);
view.setTextColor(Color.WHITE);
//view.setBackgroundDrawable(getResources().getDrawable(R.drawable.textview_bg));
view.setBackgroundDrawable(getResources().getDrawable(R.drawable.twos));
mFlowLayout.addView(view,lp);
}

}

}

“`