iOS 图表工具charts之BarChartView

关于charts的系列视图介绍传送门：
iOS 图表工具charts介绍
iOS 图表工具charts之LineChartView
iOS 图表工具charts之BarChartView
iOS 图表工具charts之PieChartView
iOS 图表工具charts之CandleStickChartView
iOS 图表工具charts之CombinedChartView

BarChartView在charts中可以用来绘制柱状图,由于charts是基于swift开发的，如果需要和objective-C混编(通过pod的方式不用管)，可以参考我的上几篇文章《iOS OC中桥接swift第三方库》，这里主要讲的是LineChartView的一些常用属性和一些基本用法，实际情况以开发为准

chartView的更加细节的属性设置 请查看我的上篇文章《iOS 图表工具charts之LineChartView》，因为BarChartView大部分基础属性都差不多，这里就不详细写注释了
BarChartView的基础设置

-(void)setupUI{
    //BarChartView默认纵向展示柱状图， 如果需要横向展示 则创建HorizontalBarChartView即可
    BarChartView *chartView = [[BarChartView alloc] init];
    //设置偏移
    [chartView setExtraOffsetsWithLeft:10 top:10 right:10 bottom:10];
    //开启border
    chartView.drawBordersEnabled = YES;
    chartView.borderLineWidth = .5f;
    chartView.borderColor = UIColor.blackColor;
    //设置背景
    chartView.drawGridBackgroundEnabled = NO;
    chartView.gridBackgroundColor = [UIColor grayColor];
    //无内容显示
    chartView.noDataText = @"";
    //关闭描述
    chartView.chartDescription.enabled = NO;
    chartView.chartDescription.text = @"tiny`s barChart demo";
    //关闭图例
    chartView.legend.enabled = NO;
    //缩放
    chartView.scaleXEnabled = NO;
    chartView.scaleYEnabled = NO;
    chartView.autoScaleMinMaxEnabled = YES;
    chartView.highlightPerTapEnabled = NO;
    chartView.highlightPerDragEnabled = NO;
    chartView.pinchZoomEnabled = NO;  //手势捏合
    chartView.dragEnabled = YES;
    chartView.dragDecelerationFrictionCoef = 0.5;  //0 1 惯性
    //代理
    chartView.delegate = self;
    
    //leftAxis
    ChartYAxis *leftAxis = chartView.leftAxis;
    leftAxis.enabled = YES;
    leftAxis.labelPosition = YAxisLabelPositionOutsideChart;
    leftAxis.drawGridLinesEnabled = YES;
    leftAxis.gridLineDashLengths = @[@2,@4];
    leftAxis.labelTextColor = UIColor.blackColor;
    leftAxis.labelFont = [UIFont systemFontOfSize:10];
    leftAxis.decimals = 2;
    //设置样式
    LeftAxisFormatter *leftFormatter = [LeftAxisFormatter new];
    leftAxis.valueFormatter = leftFormatter;
    
    //rightAxis
    ChartYAxis *rightAxis = chartView.rightAxis;
    rightAxis.enabled = NO;
    
    //xAxis
    ChartXAxis *xAxis = chartView.xAxis;
    xAxis.enabled = YES;
    xAxis.labelPosition = XAxisLabelPositionBottom;
    //不画线
    xAxis.drawGridLinesEnabled = NO;
    BarxAxisFormatter *xFormatter = [BarxAxisFormatter new];
    xAxis.valueFormatter = xFormatter;
    xFormatter.titles = @[@"语文",@"数学",@"外语",@"物理"];
    self.charView = chartView;
    [self addSubview:self.charView];
    [self.charView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.edges.mas_offset(0);
    }];
    
    //draw
    [self drawData];
    //执行动画
    [self.charView animateWithYAxisDuration:1.f];
}


-(void)drawData{
    NSArray *datas = @[@100,@90,@76,@55,@45,@77,@98,@62];
    NSMutableArray *array = [NSMutableArray array];
    for (int i = 0; i < datas.count; i++) {
        BarChartDataEntry *entry = [[BarChartDataEntry alloc] initWithX:i y:[datas[i] integerValue]];
        [array addObject:entry];
    }
    //set
    BarChartDataSet *set = [[BarChartDataSet alloc] initWithEntries:array label:@"Bar DataSet"];
    [set setColors:@[UIColor.redColor,UIColor.blueColor,UIColor.blueColor,UIColor.blackColor,UIColor.cyanColor,UIColor.grayColor,UIColor.greenColor,UIColor.cyanColor]];
    //显示柱图值并格式化
    NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
    numberFormatter.positiveSuffix = @"分";
    ChartDefaultValueFormatter *formatter = [[ChartDefaultValueFormatter alloc] initWithFormatter:numberFormatter];
    [set setValueFormatter:formatter];
    set.highlightEnabled = NO;
    BarChartData *data = [[BarChartData alloc] initWithDataSet:set];
    self.charView.data = data;
}

#pragma mark - ChartViewDelegate
#pragma mark 图表中数值被选中
-(void)chartValueSelected:(ChartViewBase *)chartView entry:(ChartDataEntry *)entry highlight:(ChartHighlight *)highlight{
    
//    NSLog(@"图表中数值被选中");
}

#pragma mark 图表中的空白区域被选中
-(void)chartValueNothingSelected:(ChartViewBase *)chartView{
//    NSLog(@"空白区域被选中");
}

#pragma mark 图表被缩放
-(void)chartScaled:(ChartViewBase *)chartView scaleX:(CGFloat)scaleX scaleY:(CGFloat)scaleY{
//    NSLog(@"图表被缩放");
}

#pragma mark 图表被移动
-(void)chartTranslated:(ChartViewBase *)chartView dX:(CGFloat)dX dY:(CGFloat)dY{
//    NSLog(@"图表被移动");
}

一些需要注意的点：
1.如果需要给每个bar显示的数字格式化比如 100分, 100t，100g等等添加前缀或者后缀，则可以设置BarChartDataSet属性

    NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
    numberFormatter.positiveSuffix = @"分";
    ChartDefaultValueFormatter *formatter = [[ChartDefaultValueFormatter alloc] initWithFormatter:numberFormatter];
    [set setValueFormatter:formatter];

2.柱状图动画效果

    //执行动画
    [self.charView animateWithYAxisDuration:1.f];

3.颜色可以没每个柱子设置颜色

    [set setColors:@[UIColor.redColor,UIColor.blueColor,UIColor.blueColor,UIColor.blackColor,UIColor.cyanColor,UIColor.grayColor,UIColor.greenColor,UIColor.cyanColor]];

4.每个点的数值要显示出来

    set.drawValuesEnabled = YES;

5.柱状图横向显示，只需要将BarChartView换成HorizontalBarChartView即可，其他不变 效果图如下：

6.BarChartData可以添加多个柱子

 BarChartData *data = [[BarChartData alloc] init]
 [data addDataSet:set]

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