achartengine动态加载数据

现在项目有个需求就是利用achartengine动态的加载数据，当拖动图表时会下载几条数据，拖动的轨迹越长，加载的数据就越多。网上查了些资料，找不到这样的例子。于是自己写了个package com.cng;

import java.util.ArrayList;
import java.util.List;

import org.achartengine.ChartFactory;
import org.achartengine.chart.PointStyle;
import org.achartengine.model.XYMultipleSeriesDataset;
import org.achartengine.model.XYSeries;
import org.achartengine.renderer.XYMultipleSeriesRenderer;
import org.achartengine.renderer.XYSeriesRenderer;

import android.R.integer;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.Paint.Align;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.LinearLayout;

public class DynLoadActivity extends Activity {
    /** Called when the activity is first created. */
	 private  XYMultipleSeriesDataset mDataset=new XYMultipleSeriesDataset();;
	 private  XYSeries mAtentionSeries=new XYSeries("哈哈哈");
	 //全局变量  ， 记录条数
	 private int total=0;
    @Override
    public void onCreate(Bundle savedInstanceState) {
    	super.onCreate(savedInstanceState);
    	 setContentView(R.layout.main);
    	String[] titles = new String[] { "Crete"};
        int[] colors = new int[] { Color.BLUE};
        PointStyle[] styles = new PointStyle[] { PointStyle.CIRCLE};
        XYMultipleSeriesRenderer renderer = buildRenderer(colors, styles);
        int length = renderer.getSeriesRendererCount(); 
        for (int i = 0; i < length; i++) {
          ((XYSeriesRenderer) renderer.getSeriesRendererAt(i)).setFillPoints(true);
        }
        setChartSettings(renderer, "Average temperature", "Month", "Temperature", 0.5, 12.5, -10, 2000,
            Color.LTGRAY, Color.LTGRAY);
//        renderer.setXAxisMin(0);
//        renderer.setXAxisMax(100);
        renderer.setXLabels(12);
        renderer.setYLabels(10); 
        renderer.setShowGrid(true); 
        renderer.setXLabelsAlign(Align.RIGHT);
        renderer.setYLabelsAlign(Align.RIGHT); 
        renderer.setZoomButtonsVisible(true);
        renderer.setPanLimits(new double[] { -10, 2000, -10, 2000 });
        renderer.setZoomLimits(new double[] { -10, 2000, -10, 2000 });
        LinearLayout linearLayout=(LinearLayout)findViewById(R.id.linear);
        total++;
        mAtentionSeries.add(1, 11);
        
        mDataset.addSeries(mAtentionSeries);
        View view = ChartFactory.getLineChartView(this,mDataset ,
            renderer); 
        linearLayout.addView(view);
        view.setOnTouchListener(new OnTouchListener() { 
        	int x=0;
    		int x2=0;
        	public boolean onTouch(View v, MotionEvent event) { 
        		
                switch (event.getAction()) { 

                  case MotionEvent.ACTION_DOWN: {
                        //按下时触发
                	  //判断是否向做移动
                	  if(x-x2>0)
                	  {
                		  //获取要从服务器获取的条数
                		  int length=(x-x2)/20;
                		  //添加数据至图标中
                		  for(int i=0;i<length;i++)
                		  {
                			  /** toatal可当做参数传至服务器上来获取数据
                			   *  因为获取数据时必须获取的是少量的中间的连续数据
                			   *  可从for循环外面将参数total,total+length传入获取数据库中的第total到total+length数据
                			   */
                			  total++;
                			  Log.e(total+"", total+"");
                			  mAtentionSeries.add(total, total);
                		  }
                	  }
                	  //将触摸式按下的横坐标记住
                	  x=(int) event.getX();
                  } 

                  case MotionEvent.ACTION_MOVE: {
                         //移动时触发
                	  //将触摸时手指离开时的横坐标记录
                	  x2=(int) event.getX();
                  } 

                  case MotionEvent.ACTION_UP: {
                          //触摸后触发 
                  } 
                }
				return false;
            }
        });

    }
    
    
    private XYMultipleSeriesRenderer buildRenderer(int[] colors,
			PointStyle[] styles)
	{
		XYMultipleSeriesRenderer renderer = new XYMultipleSeriesRenderer();
		// 控制横纵轴的属性字大小
		renderer.setAxisTitleTextSize(15);
		// 控制横纵轴的值大小
		renderer.setChartTitleTextSize(20);
		renderer.setLabelsTextSize(15);
		renderer.setLegendTextSize(15);
		renderer.setPointSize(5f);
		renderer.setMargins(new int[]
		{ 20, 30, 15, 0 });
		int length = colors.length;
		for (int i = 0; i < length; i++)
		{
			XYSeriesRenderer r = new XYSeriesRenderer();
			r.setColor(colors[i]);
			r.setPointStyle(styles[i]);
			renderer.addSeriesRenderer(r);
		}
		return renderer;
	}

	private void setChartSettings(XYMultipleSeriesRenderer renderer,
			String title, String xTitle, String yTitle, double xMin,
			double xMax, double yMin, double yMax, int axesColor,
			int labelsColor)
	{
		renderer.setChartTitle(title);
		renderer.setXTitle(xTitle);
		renderer.setYTitle(yTitle);
		renderer.setXAxisMin(xMin);
		renderer.setXAxisMax(xMax);
		renderer.setYAxisMin(yMin);
		renderer.setYAxisMax(yMax);
		renderer.setAxesColor(axesColor);
		renderer.setLabelsColor(labelsColor);
	}

	private XYMultipleSeriesDataset buildDataset(String[] titles,
			List<double[]> xValues, List<double[]> yValues)
	{
		XYMultipleSeriesDataset dataset = new XYMultipleSeriesDataset();
		int length = titles.length;
		for (int i = 0; i < length; i++)
		{
			XYSeries series = new XYSeries(titles[i]);
			double[] xV = xValues.get(i);
			double[] yV = yValues.get(i);
			int seriesLength = xV.length;
			for (int k = 0; k < seriesLength; k++)
			{
				series.add(xV[k], yV[k]);
			}
			dataset.addSeries(series);
		}
		return dataset;
	}
}

 

其实原理很简单  就是捕获ontouch事件的ACTION_DOWN ，ACTION_UP事件，记下他们的x坐标。在下一次ACTION_DOWN 时出发加载数据事件，我这里没有调用访问webservice事件，

只是模拟了几个数据。

这代码很水，望指教