[Android]HelloCharts实现动态加载数据

最近项目中用到了折线图,找了几个.最后还是选择了hellocharts.需求要加载八万个点,这么多直接就卡死了,所以做了修改,实现边滑动边加载点.

hellocharts里的ChartScroller.class里有用来计算滚动时x轴可见距离的方法,那么可以在这里设置回调函数,将当前屏幕可见的x轴位置获取出来,然后在list中取对应位置的点去加载.

1.在ChartScroller类中中加入回调函数,分别在测量距离和滑动的方法中,即computeScrollOffset和scroll方法中使用回调

 

private onScrollListener onScrollListener;
   /**
     * 设置回调接口
     */
    public void setOnScrollListener(onScrollListener onScrollListener)
    {
        this.onScrollListener = onScrollListener;
    }

    public interface onScrollListener
    {
        /**
         * 当进行滑动时,将x点坐标记录
         */
	public void onScroll(float x,float y);
    }//曲线滑动过程中
	public boolean computeScrollOffset(ChartComputator computator) {
		if (scroller.computeScrollOffset()) {
			// The scroller isn't finished, meaning a fling or programmatic pan
			// operation is
			// currently active.
			computator.computeScrollSurfaceSize(surfaceSizeBuffer);
			scrollerStartViewport.set(computator.getCurrentViewport());
//			Log.e("computeScrollOffset", "x--" + scrollerStartViewport.left
//					+ " :y--" + scrollerStartViewport.right);
			//计算时回调
			if(onScrollListener !=null){
				onScrollListener.onScroll(scrollerStartViewport.right,scrollerStartViewport.left);
			}
			final Viewport maxViewport = computator.getMaximumViewport();

			computator.computeScrollSurfaceSize(surfaceSizeBuffer);

			final float currXRange = maxViewport.left + maxViewport.width()
					* scroller.getCurrX() / surfaceSizeBuffer.x;
			final float currYRange = maxViewport.top - maxViewport.height()
					* scroller.getCurrY() / surfaceSizeBuffer.y;

			computator.setViewportTopLeft(currXRange, currYRange);

			return true;
		}

		return false;
	}

 

2.在ChartTouchHandler类中同样设置回调,并在computeTouch方法中的move事件中接收回调         

 private onChartScrollListener onChartScrollListener;
	 /**
    * 设置回调接口
    */
   public void setOnChartScrollListener(onChartScrollListener onChartScrollListener)
   {
       this.onChartScrollListener = onChartScrollListener;
   }

   public interface onChartScrollListener
   {
       /**
        * 当进行滑动时,将x点坐标记录
        */
		public void onChartScroll(float x,float y);
   }case MotionEvent.ACTION_MOVE:
                // If value was touched and now touch point is outside of value area - clear touch and invalidate, user
                // probably moved finger away from given chart value.
            	//滑动时设置回调
            	 chartScroller.setOnScrollListener(new onScrollListener() {
         			
         			@Override
         			public void onScroll(float right, float left) {
         				if(onChartScrollListener !=null){
         					onChartScrollListener.onChartScroll(right,left);
         				}
         			}
         		});
            	if (renderer.isTouched()) {
                    if (!checkTouch(event.getX(), event.getY())) {
                        renderer.clearTouch();
                        needInvalidate = true;
                    }
                }

                break;

3.在AbstractChartView类中也设置回调函数,并在onTouchEvent方法中接收回调

 

private onScrollListener onScrollListener;

	/**
	 * 设置回调接口
	 */
	public void setOnScrollListener(onScrollListener onScrollListener) {
		this.onScrollListener = onScrollListener;
	}

	public interface onScrollListener {
		/**
		 * 当进行滑动时,将x点坐标记录
		 */
		public void onChartScroll(float x, float y);
	}@Override
	public boolean onTouchEvent(MotionEvent event) {
		super.onTouchEvent(event);
		touchHandler.setOnChartScrollListener(new onChartScrollListener() {

			@Override
			public void onChartScroll(float right, float left) {
				if (onScrollListener != null) {
					onScrollListener.onChartScroll(right, left);
				}
			}
		});
		if (isInteractive) {

			boolean needInvalidate;

			if (isContainerScrollEnabled) {
				needInvalidate = touchHandler.handleTouchEvent(event,
						getParent(), containerScrollType);
			} else {
				needInvalidate = touchHandler.handleTouchEvent(event);
			}

			if (needInvalidate) {
				ViewCompat.postInvalidateOnAnimation(this);
			}

			return true;
		} else {

			return false;
		}
	}

 

4.然后就可以在我们的页面中接收回调了,实现滑动加载数据

//滑动回调
		chart.setOnScrollListener(new onScrollListener() {
			@Override
			public void onChartScroll(float right, float left) {
				// TODO Auto-generated method stub
				Log.e("xy", right + ":" + left);
				//是否滑动
				isfill = true;
				xList.clear();
				labels.clear();
				for (int i = (int) left; i < right; i++) {
					//当前可见的点加入list
					xList.add(dayList.get(i));
					//同可见的点名称加入list
					labels.add(dayList.get(i).getTime());
				}
//				List mList = new ArrayList();
//				mList.clear();
//				//特殊点的过滤算法
//				ArrayList fList = new ArrayList();
//				fList.clear();
//				int len = xList.size();
//				int i = 0;
//				//加入可见范围的第一个点
//				if (Collections.frequency(fList, xList.get(0)) < 1) {
//					fList.add(xList.get(0));
//				}
//				for (i = 0; i < len; i++) {
//					if (i > 0 && i < len - 2) {
//						if ((Math.abs(xList.get(i).getPointY()
//								- xList.get(i + 1).getPointY())) > 10
//								&& Collections.frequency(mList, xList.get(i)) < 1) {
//							fList.add(xList.get(i));
//						}
//						// if(i!=0&&Collections.frequency(fList,
//						// xList.get(len/(i*10)))<1){
//						// fList.add(xList.get(len/(i*10)));
//						// }
//					}
//				}
//				//加入可见范围的最后一个点
//				if (Collections.frequency(fList, xList.get(len - 1)) < 1) {
//					fList.add(xList.get(len - 1));
//				}
				//加载曲线数据
				generateData(xList);
			}
		}); mList = new ArrayList();
//				mList.clear();
//				//特殊点的过滤算法
//				ArrayList fList = new ArrayList();
//				fList.clear();
//				int len = xList.size();
//				int i = 0;
//				//加入可见范围的第一个点
//				if (Collections.frequency(fList, xList.get(0)) < 1) {
//					fList.add(xList.get(0));
//				}
//				for (i = 0; i < len; i++) {
//					if (i > 0 && i < len - 2) {
//						if ((Math.abs(xList.get(i).getPointY()
//								- xList.get(i + 1).getPointY())) > 10
//								&& Collections.frequency(mList, xList.get(i)) < 1) {
//							fList.add(xList.get(i));
//						}
//						// if(i!=0&&Collections.frequency(fList,
//						// xList.get(len/(i*10)))<1){
//						// fList.add(xList.get(len/(i*10)));
//						// }
//					}
//				}
//				//加入可见范围的最后一个点
//				if (Collections.frequency(fList, xList.get(len - 1)) < 1) {
//					fList.add(xList.get(len - 1));
//				}
				//加载曲线数据
				generateData(xList);
			}
		});