一、代码实现
1. 自动换行控件：AutoLinefeedView.java
package com.stackdump.autolinefeed.widget;
import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.stackdump.autolinefeed.R;
/**
*
* @author stackdump
* @date 2018-07-03
*/
public class AutoLinefeedView extends ViewGroup {
private static String TAG = "AutoLinefeedView";
private final static int VIEW_MARGIN = 0;
public AutoLinefeedView(Context context) {
super(context);
}
public AutoLinefeedView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public AutoLinefeedView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public View addView(final String text) {
View pathView = LayoutInflater.from(getContext()).inflate(R.layout.item_path, null);
TextView tv = (TextView) pathView.findViewById(R.id.path);
tv.setText(text);
tv.setPadding(15, 0, 35, 0);
addView(pathView);
return tv;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
//将所有的子View进行测量，这会触发每个子View的onMeasure函数
//注意要与measureChild区分，measureChild是对单个view进行测量
measureChildren(widthMeasureSpec, heightMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int childCount = getChildCount();
if (childCount == 0) {//如果没有子View,当前ViewGroup没有存在的意义，不用占用空间
setMeasuredDimension(0, 0);
} else {
//如果宽高都是包裹内容
if (heightMode == MeasureSpec.AT_MOST) {//如果只有高度是包裹内容
//宽度设置为ViewGroup自己的测量宽度，高度设置为所有子View的高度总和
setMeasuredDimension(widthSize, getTotleHeight());
}
}
}
@Override
protected void onLayout(boolean arg0, int left, int top, int right, int bottom) {
//add by stackdump
final int count = getChildCount();
int row = 0;// which row lay you view relative to parent
int lengthX = left; // right position of child relative to parent
int lengthY = top; // bottom position of child relative to parent
for (int i = 0; i < count; i++) {
final View child = this.getChildAt(i);
int width = child.getMeasuredWidth();
int height = child.getMeasuredHeight();
lengthX += width + VIEW_MARGIN;
lengthY = row * (height + VIEW_MARGIN) + VIEW_MARGIN + height
+ top;
// if it can't drawing on a same line , skip to next line
if (lengthX > right) {
lengthX = width + VIEW_MARGIN + left;
row++;
lengthY = row * (height + VIEW_MARGIN) + VIEW_MARGIN + height
+ top;
}
child.layout(lengthX - width, lengthY - height, lengthX, lengthY);
}
}
//根据子控件个数计算父布局的高度
private int getTotleHeight() {
//add by stackdump
final int count = getChildCount();
int row = 0;// which row lay you view relative to parent
int left = getLeft();
int lengthX = left; // right position of child relative to parent
int top = getTop();
int lengthY = top; // bottom position of child relative to parent
int right = getMeasuredWidth();
for (int i = 0; i < count; i++) {
final View child = this.getChildAt(i);
int width = child.getMeasuredWidth();
int height = child.getMeasuredHeight();
lengthX += width + VIEW_MARGIN;
lengthY = row * (height + VIEW_MARGIN) + VIEW_MARGIN + height
+ top;
// if it can't drawing on a same line , skip to next line
if (lengthX > right) {
lengthX = width + VIEW_MARGIN + left;
row++;
lengthY = row * (height + VIEW_MARGIN) + VIEW_MARGIN + height
+ top;
}
}
return lengthY;
}
}
2. 控件调用：MainActivity.java
package com.stackdump.autolinefeed;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import com.stackdump.autolinefeed.widget.AutoLinefeedView;
public class MainActivity extends AppCompatActivity {
private LinearLayout mLayoutPath;
private AutoLinefeedView mAutoLinefeedView;
private Button mAddBtn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mAddBtn = (Button)findViewById(R.id.add_btn);
//导航
mLayoutPath = (LinearLayout) findViewById(R.id.layout_path);
mAutoLinefeedView = new AutoLinefeedView(this);
mLayoutPath.addView(mAutoLinefeedView);
mAddBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String departmentName = "department";
View tv = mAutoLinefeedView.addView(departmentName);
}
});
}
}
3. 布局文件：activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<!--显示目录层级-->
<LinearLayout
android:id="@+id/layout_path"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginBottom="20dp"
android:background="#bfbfbf">
</LinearLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:layout_below="@+id/layout_path"
android:background="#bfbfbf">
<Button
android:id="@+id/add_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:gravity="center"
android:text="Add"
android:textSize="30sp"
android:background="@drawable/select_first_button_bg"/>
</RelativeLayout>
</RelativeLayout>
二、效果图
1.初始界面只有一个Button,每点击一下button，新增一个子控件
2.最终效果图
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