AchartEngine得到触摸点位置 [英] AchartEngine get position of touched point

问题描述

我用achartengine绘制折线图。我用这个code来获得当前点sellected
`view.setOnClickListener（新View.OnClickListener（）{
            公共无效的onClick（视图v）{
                //图表上处理click事件，

I use achartengine to draw a line chart. I use this code to get current point sellected `view.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { // handle the click event on the chart

            quickAction.show(v);
            SeriesSelection seriesSelection = view.getCurrentSeriesAndPoint();
            if (seriesSelection != null) {
                if(mToast == null){
                    Toast.makeText( mContext  , "" , Toast.LENGTH_SHORT );
                }
                mToast.setText( "" + seriesSelection.getValue() + "mg/dL");
                mToast.setGravity(Gravity.TOP|Gravity.CENTER_HORIZONTAL, 0, 0);
                mToast.show();
            } else {
                Log.i(this.toString(), "OnClickListener" + v.getX() + "y:" + v.getY());
            }
        }
    });`

现在我想这点或触摸的位置的位置显示一个气泡显示细节点，为帮助任何想法
对于examp

Now i want to get position of this point or position of touch to display a bubble to show detail point, any idea for help for examp

https://dl.dropboxusercontent.com/u/5860710/Untitled.jpg

推荐答案

你试过吗？

SeriesSelection seriesSelection = view.getCurrentSeriesAndPoint();
double[] xy = view.toRealPoint(0); 
Log.i(this.toString(), "OnClickListener" + xy[0] + "y:" + xy[1]);

或<一个更好看href=\"http://$c$c.google.com/p/achartengine/source/browse/trunk/achartengine/demo/org/achartengine/chartdemo/demo/chart/XYChartBuilder.java\"相对=nofollow>这个例子的行：167-172

or much better look at this example rows: 167-172

好吧，试试这个，对于数据集中的每个点：

Ok, try this, for each point in your dataset:

1. 变换真正点到屏幕上点


2. 从触摸事件计算距离


3. 如果该距离小于指定量
   （2 *的pointsize在这个例子中），然后抓住价值，并显示您的弹出

我不喜欢这里要说的是，在最坏的情况下，你已经遍历所有的点...但我希望这会给你一些提示。

What I don't like here is that, in the worst case, you've to iterate all the points...but i hope that this will give you some hints.

final XYChart chart = new LineChart(mDataset, mRenderer);
mChartView = new GraphicalView(this, chart);
mChartView.setOnTouchListener(new View.OnTouchListener() {
  @Override
  public boolean onTouch(View v, MotionEvent event) {
     XYSeries series = mDataset.getSeriesAt(0);
     for(int i = 0; i < series.getItemCount(); i++) {
       double[] xy = chart.toScreenPoint(new double[] { series.getX(i), series.getY(i) }, 0);

       double dx = (xy[0] - event.getX());
       double dy = (xy[1] - event.getY());
       double distance = Math.sqrt(dx*dx + dy*dy);
       if (distance <= 2*pointSize) {  //.pointSize that you've specified in your renderer
          SeriesSelection sel = 
            chart.getSeriesAndPointForScreenCoordinate(new Point((float)xy[0], (float)xy[1]));
          if (sel != null) {
             Toast.makeText(XYChartBuilder.this, "Touched: " + sel.getValue(), Toast.LENGTH_SHORT).show();
          }
          break;
       }
       Log.i("LuS", "dist: " + distance);
     }

     return true;
  }
});

这篇关于AchartEngine得到触摸点位置的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！