解决Android Studio xml 格式化不自动换行的问题

今天把Android Studio 2.3 更新为了3.0 遇到一个蛋疼的问题

如图：

格式化完代码后发现不会自动换行了，看着真心不爽。

后来发现其实是设置问题,如图：

只要把这里打上√就可以了。

在此记录一下，希望可以帮到后面的小伙伴

补充知识：Android实现控件内自动换行（比如LinearLayout内部实现子控件换行 ）

一、创建类AntoLineUtil（换行操作主要在这里实现）

package com.inpor.fmctv.util;
import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import com.inpor.fmctv.R;

public class AntoLineUtil extends ViewGroup {

/**
  * 子view左右间距
  */
 private int mHorizontalSpacing;
 /**
  * 子view上下行距离
  */
 private int mVerticalSpacing;

private Context context;

public AntoLineUtil(Context context) {
   this(context, null);
   this.context = context;
 }

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

public AntoLineUtil(Context context, AttributeSet attrs, int defStyleAttr) {
   super(context, attrs, defStyleAttr);
   if (attrs != null) {
     TypedArray array = context.obtainStyledAttributes(attrs,
         R.styleable.AntoLineUtil);

mHorizontalSpacing = array.getDimensionPixelOffset(
         R.styleable.AntoLineUtil_horizontalSpacing, 0);
     mVerticalSpacing = array.getDimensionPixelOffset(
         R.styleable.AntoLineUtil_verticalSpacing, 0);
     array.recycle();

if (mHorizontalSpacing < 0) mHorizontalSpacing = 0;
     if (mVerticalSpacing < 0) mVerticalSpacing = 0;
   }
 }

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

int width = MeasureSpec.getSize(widthMeasureSpec);
   int count = getChildCount();
   for (int i = 0; i < count; i++) {
     measureChild(getChildAt(i), widthMeasureSpec, heightMeasureSpec);
   }

int widthMode = MeasureSpec.getMode(widthMeasureSpec);
   if (widthMode != MeasureSpec.EXACTLY) {
     widthMeasureSpec = MeasureSpec.makeMeasureSpec(
         getAutoLinefeedWidth(width), widthMode);
   }

int heightMode = MeasureSpec.getMode(heightMeasureSpec);
   if (heightMode != MeasureSpec.EXACTLY) {
     heightMeasureSpec = MeasureSpec.makeMeasureSpec(
         getAutoLinefeedHeight(width), heightMode);
   }
   super.onMeasure(widthMeasureSpec, heightMeasureSpec);
 }

/**
  * 自动换行 计算需要的宽度
  *
  * @param width 可用宽度
  * @return 需要的宽度
  */
 private int getAutoLinefeedWidth(int width) {
   int totalWidth = getPaddingLeft() + getPaddingRight();

for (int i = 0; i < getChildCount(); i++) {
     if (i > 0) totalWidth += mHorizontalSpacing;
     View child = getChildAt(i);
     int childWidth = child.getMeasuredWidth();
     totalWidth += childWidth;
     if (totalWidth >= width) {
       totalWidth = width;
       break;
     }
   }

return totalWidth;
 }

/**
  * 自动换行 计算需要的高度
  *
  * @param width 可用宽度
  * @return 需要的高度
  */
 private int getAutoLinefeedHeight(int width) {

//一行最大可用宽度
   int lineWidth = width - getPaddingLeft() - getPaddingRight();
   //剩余可用宽度
   int availableLineWidth = lineWidth;
   //需要的高度
   int totalHeight = getPaddingTop() + getPaddingBottom();
   int lineChildIndex = 0;
   //本行最大高度
   int lineMaxHeight = 0;
   for (int i = 0; i < getChildCount(); i++) {
     View child = getChildAt(i);
     int childWidth = child.getMeasuredWidth();
     int childHeight = child.getMeasuredHeight();
     //这个child需要的宽度 如果不是第一位的 那么需要加上间距
     //这里是用来判断需不需要换行
     int needWidth = i == 0 ? childWidth : (childWidth + mHorizontalSpacing);
     //如果剩余可用宽度小于需要的长度 那么换行
     if (availableLineWidth < needWidth) {
       totalHeight = totalHeight + lineMaxHeight;
       if (i > 0) totalHeight += mVerticalSpacing;
       availableLineWidth = lineWidth;
       lineMaxHeight = 0;
       lineChildIndex = 0;
     }
     //这个child需要的宽度 如果不是第一位的 那么需要加上间距
     int realNeedWidth = lineChildIndex == 0 ? childWidth : (childWidth + mHorizontalSpacing);
     lineMaxHeight = Math.max(childHeight, lineMaxHeight);
     availableLineWidth = availableLineWidth - realNeedWidth;
     lineChildIndex++;
   }

totalHeight = totalHeight + lineMaxHeight;
   return totalHeight;
 }

@Override
 protected void onLayout(boolean changed, int l, int t, int r, int b) {
   layout();
 }

private void layout() {

int count = getChildCount();
   int childLeft = getPaddingLeft();
   int childTop = getPaddingTop();
   int lineWidth = getMeasuredWidth() - getPaddingRight() - getPaddingLeft();
   int availableLineWidth = lineWidth;
   int lineChildIndex = 0;
   //一行的最大高度
   int lineMaxHeight = 0;
   for (int i = 0; i < count; i++) {

View child = getChildAt(i);

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

int needWidth = i == 0 ? childWidth : (childWidth + mHorizontalSpacing);

if (availableLineWidth < needWidth) {
       availableLineWidth = lineWidth;
       childTop += lineMaxHeight;
       if (i > 0) childTop += mVerticalSpacing;
       lineMaxHeight = 0;
       childLeft = getPaddingLeft();
       lineChildIndex = 0;
     }

int realNeedWidth = lineChildIndex == 0 ? childWidth : (childWidth + mHorizontalSpacing);

lineMaxHeight = Math.max(lineMaxHeight, childHeight);
     child.layout(childLeft + realNeedWidth - childWidth, childTop, childLeft + realNeedWidth, childTop + childHeight);
     availableLineWidth -= realNeedWidth;
     childLeft += realNeedWidth;
     lineChildIndex++;
   }
 }

public int getHorizontalSpacing() {
   return mHorizontalSpacing;
 }

public void setHorizontalSpacing(int horizontalSpacing) {
   mHorizontalSpacing = horizontalSpacing;
 }

public int getVerticalSpacing() {
   return mVerticalSpacing;
 }

public void setVerticalSpacing(int verticalSpacing) {
   mVerticalSpacing = verticalSpacing;
 }
}

二、在values中的attrs.xml中添加以下代码（实现子控件的边距）：

<declare-styleable name="AntoLineUtil">
   <attr name="horizontalSpacing" format="dimension"/>
   <attr name="verticalSpacing" format="dimension"/>
 </declare-styleable>

三、添加固定的xml布局父控件，事先写好，布局activity_video_preview.xml ：

<com.inpor.fmctv.util.AntoLineUtil
   android:id="@+id/camera_group"
   android:layout_width="@dimen/size_dp_630"
   android:layout_height="@dimen/size_dp_138"
   android:layout_marginTop="@dimen/size_dp_18"
   android:orientation="horizontal"
   app:horizontalSpacing="@dimen/size_dp_18"
   app:verticalSpacing="@dimen/size_dp_18">
</com.inpor.fmctv.util.AntoLineUtil>

四、添加固定的xml布局子控件，事先写好，动态添加进去，布局item_camera_info.xml ：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:id="@+id/video_preview_item"
 android:layout_width="@dimen/size_dp_198"
 android:layout_height="@dimen/size_dp_60"
 android:orientation="horizontal"
 android:paddingLeft="@dimen/size_dp_18"
 android:paddingRight="@dimen/size_dp_18"
 android:gravity="center_vertical"
 android:background="@color/textcolor_395878">
 <TextView
   android:id="@+id/video_preview_item_tv"
   android:layout_width="@dimen/size_dp_120"
   android:layout_height="wrap_content"
   android:textSize="@dimen/size_sp_24"
   android:textColor="@color/white"/>
 <CheckBox
   android:id="@+id/video_previ"
   android:layout_width="@dimen/size_dp_24"
   android:layout_height="@dimen/size_dp_24"
   android:button="@null"
   android:background="@drawable/radio_button_select_ico" />
</LinearLayout>

五、在其他方法中动态添加子控件：

AntoLineUtil cameraGroup = (AntoLineUitl) findViewById(R.id.camera_group); // 此处是找到父控件LinearLayout
for (int i = 0; i<6; i++) {
// 用以下方法将layout布局文件换成view
LayoutInflater inflater = getLayoutInflater();
View view = inflater.inflate(R.layout.item_camera_info,null);
TextView textView = view.findViewById(R.id.video_preview_item_tv);
textView.setText("摄像头"+ (cameraId+1));
cameraGroup.addView(view);
}

六、效果图：

来源：https://blog.csdn.net/qq_41818634/article/details/79510382