precondition for each tutorial is at least one instruction and one task

src/components/Tutorial/Builder/Builder.js

@@ -19,11 +19,15 @@ import Button from '@material-ui/core/Button';
 import Backdrop from '@material-ui/core/Backdrop';
 import CircularProgress from '@material-ui/core/CircularProgress';
 import Divider from '@material-ui/core/Divider';
+import FormHelperText from '@material-ui/core/FormHelperText';
 
 const styles = (theme) => ({
   backdrop: {
     zIndex: theme.zIndex.drawer + 1,
     color: '#fff',
+  },
+  errorColor: {
+    color: theme.palette.error.dark
   }
 });
 
@@ -138,9 +142,12 @@ class Builder extends Component {
           </label>
           <Button style={{marginRight: '10px', marginBottom: '10px'}} variant='contained' color='primary' onClick={() => this.uploadJsonString()}>String laden</Button>
         </div>
-        <Divider variant='fullWidth' style={{margin: '10px 0 30px 0'}}/>
+        <Divider variant='fullWidth' style={{margin: '10px 0 15px 0'}}/>
 
         {/*Tutorial-Builder-Form*/}
+        {this.props.error.type ?
+          <FormHelperText style={{lineHeight: 'initial'}} className={this.props.classes.errorColor}>{`Ein Tutorial muss mindestens jeweils eine Instruktion und eine Aufgabe enthalten.`}</FormHelperText>
+        : null}
         <Id error={this.props.error.id} value={this.props.id}/>
         <Textfield value={this.props.title} property={'title'} label={'Titel'} error={this.props.error.title}/>
 

src/components/Tutorial/Builder/Id.js

@@ -58,7 +58,7 @@ class Id extends Component {
 
   render() {
     return (
-      <div style={{display: 'inline-flex'}}>
+      <div style={{display: 'inline-flex', marginTop: '15px'}}>
       <FormControl variant="outlined" style={{marginBottom: '10px', width: '250px'}}>
         <InputLabel
           htmlFor="id"

src/components/Tutorial/Builder/StepType.js

@@ -1,7 +1,7 @@
 import React, { Component } from 'react';
 import PropTypes from 'prop-types';
 import { connect } from 'react-redux';
-import { changeContent, deleteProperty } from '../../../actions/tutorialBuilderActions';
+import { changeContent, deleteProperty, deleteError } from '../../../actions/tutorialBuilderActions';
 
 import Radio from '@material-ui/core/Radio';
 import RadioGroup from '@material-ui/core/RadioGroup';
@@ -13,6 +13,9 @@ class StepType extends Component {
     this.props.changeContent(this.props.index, 'type', value);
     // delete property 'xml', so that all used blocks are reset
     this.props.deleteProperty(this.props.index, 'xml');
+    if(value === 'task'){
+      this.props.deleteError(undefined, 'type');
+    }
   }
 
   render() {
@@ -38,7 +41,8 @@ class StepType extends Component {
 
 StepType.propTypes = {
   changeContent: PropTypes.func.isRequired,
-  deleteProperty: PropTypes.func.isRequired
+  deleteProperty: PropTypes.func.isRequired,
+  deleteError: PropTypes.func.isRequired
 };
 
-export default connect(null, { changeContent, deleteProperty })(StepType);
+export default connect(null, { changeContent, deleteProperty, deleteError })(StepType);