前言
本文將通過示例代碼介紹如何自定義簡單的直方圖表，此圖表并非常見的直方圖表，而是可以分組的。此文不會過多涉及原理，比較簡單，示例圖片如下(gif圖片沒有制作好，有閃爍，請見諒)：
對于該示例的代碼實現，其實重點在于坐標軸、文字、直方圖的位置控制，需要隨滑動距離而動態更新。注意事項會在示例代碼中標注。下面貼出示例代碼
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public class MultiGroupHistogramView extends View { private int width; private int height; // 坐標軸線寬度 private int coordinateAxisWidth; // 組名稱字體大小 private int groupNameTextSize; // 小組之間間距 private int groupInterval; // 組內子直方圖間距 private int histogramInterval; private int histogramValueTextSize; // 圖表數值小數點位數 private int histogramValueDecimalCount; private int histogramHistogramWidth; private int chartPaddingTop; private int histogramPaddingStart; private int histogramPaddingEnd; // 各組名稱到X軸的距離 private int distanceFormGroupNameToAxis; // 直方圖上方數值到直方圖的距離 private int distanceFromValueToHistogram; // 直方圖最大高度 private int maxHistogramHeight; // 軸線畫筆 private Paint coordinateAxisPaint; // 組名畫筆 private Paint groupNamePaint; private Paint.FontMetrics groupNameFontMetrics; private Paint.FontMetrics histogramValueFontMetrics; // 直方圖數值畫筆 private Paint histogramValuePaint; // 直方圖畫筆 private Paint histogramPaint; // 直方圖繪制區域 private Rect histogramPaintRect; // 直方圖表視圖總寬度 private int histogramContentWidth; // 存儲組內直方圖shader color，例如，每組有3個直方圖，該SparseArray就存儲3個相對應的shader color private SparseArray<int[]> histogramShaderColorArray; private List<MultiGroupHistogramGroupData> dataList; private SparseArray<Float> childMaxValueArray; private Scroller scroller; private int minimumVelocity; private int maximumVelocity; private VelocityTracker velocityTracker; public MultiGroupHistogramView(Context context) { this(context, null); } public MultiGroupHistogramView(Context context, @Nullable AttributeSet attrs) { this(context, attrs, 0); } public MultiGroupHistogramView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(attrs); } private void init(AttributeSet attrs) { setLayerType(View.LAYER_TYPE_HARDWARE, null); TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.MultiGroupHistogramView); coordinateAxisWidth = typedArray.getDimensionPixelSize(R.styleable.MultiGroupHistogramView_coordinateAxisWidth, DisplayUtil.dp2px(2)); // 坐標軸線顏色 int coordinateAxisColor = typedArray.getColor(R.styleable.MultiGroupHistogramView_coordinateAxisColor, Color.parseColor("#434343")); // 底部小組名稱字體顏色 int groupNameTextColor = typedArray.getColor(R.styleable.MultiGroupHistogramView_groupNameTextColor, Color.parseColor("#CC202332")); groupNameTextSize = typedArray.getDimensionPixelSize(R.styleable.MultiGroupHistogramView_groupNameTextSize, DisplayUtil.dp2px(15)); groupInterval = typedArray.getDimensionPixelSize(R.styleable.MultiGroupHistogramView_groupInterval, DisplayUtil.dp2px(30)); histogramInterval = typedArray.getDimensionPixelSize(R.styleable.MultiGroupHistogramView_histogramInterval, DisplayUtil.dp2px(10)); // 直方圖數值文本顏色 int histogramValueTextColor = typedArray.getColor(R.styleable.MultiGroupHistogramView_histogramValueTextColor, Color.parseColor("#CC202332")); histogramValueTextSize = typedArray.getDimensionPixelSize(R.styleable.MultiGroupHistogramView_histogramValueTextSize, DisplayUtil.dp2px(12)); histogramValueDecimalCount = typedArray.getInt(R.styleable.MultiGroupHistogramView_histogramValueDecimalCount, 0); histogramHistogramWidth = typedArray.getDimensionPixelSize(R.styleable.MultiGroupHistogramView_histogramHistogramWidth, DisplayUtil.dp2px(20)); chartPaddingTop = typedArray.getDimensionPixelSize(R.styleable.MultiGroupHistogramView_chartPaddingTop, DisplayUtil.dp2px(10)); histogramPaddingStart = typedArray.getDimensionPixelSize(R.styleable.MultiGroupHistogramView_histogramPaddingStart, DisplayUtil.dp2px(15)); histogramPaddingEnd = typedArray.getDimensionPixelSize(R.styleable.MultiGroupHistogramView_histogramPaddingEnd, DisplayUtil.dp2px(15)); distanceFormGroupNameToAxis = typedArray.getDimensionPixelSize(R.styleable.MultiGroupHistogramView_distanceFormGroupNameToAxis, DisplayUtil.dp2px(15)); distanceFromValueToHistogram = typedArray.getDimensionPixelSize(R.styleable.MultiGroupHistogramView_distanceFromValueToHistogram, DisplayUtil.dp2px(10)); typedArray.recycle(); coordinateAxisPaint = new Paint(Paint.ANTI_ALIAS_FLAG); coordinateAxisPaint.setStyle(Paint.Style.FILL); coordinateAxisPaint.setStrokeWidth(coordinateAxisWidth); coordinateAxisPaint.setColor(coordinateAxisColor); groupNamePaint = new Paint(Paint.ANTI_ALIAS_FLAG); groupNamePaint.setTextSize(groupNameTextSize); groupNamePaint.setColor(groupNameTextColor); groupNameFontMetrics = groupNamePaint.getFontMetrics(); histogramValuePaint = new Paint(Paint.ANTI_ALIAS_FLAG); histogramValuePaint.setTextSize(histogramValueTextSize); histogramValuePaint.setColor(histogramValueTextColor); histogramValueFontMetrics = histogramValuePaint.getFontMetrics(); histogramPaintRect = new Rect(); histogramPaint = new Paint(Paint.ANTI_ALIAS_FLAG); scroller = new Scroller(getContext(), new LinearInterpolator()); ViewConfiguration configuration = ViewConfiguration.get(getContext()); minimumVelocity = configuration.getScaledMinimumFlingVelocity(); maximumVelocity = configuration.getScaledMaximumFlingVelocity(); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); width = getMeasuredWidth(); height = getMeasuredHeight(); maxHistogramHeight = height - groupNameTextSize - coordinateAxisWidth - distanceFormGroupNameToAxis - distanceFromValueToHistogram - histogramValueTextSize - chartPaddingTop; } /** * 判斷是否可以水平滑動 * @param direction 標識滑動方向 正數：右滑(手指從右至左移動)；負數：左滑(手指由左向右移動) * 您可參考ScaollView或HorizontalScrollView理解滑動方向 */ @Override public boolean canScrollHorizontally(int direction) { if (direction > 0) { return histogramContentWidth - getScrollX() - width + histogramPaddingStart + histogramPaddingEnd > 0; } else { return getScrollX() > 0; } } /** * 根據滑動方向獲取最大可滑動距離 * @param direction 標識滑動方向 正數：右滑(手指從右至左移動)；負數：左滑(手指由左向右移動) * 您可參考ScaollView或HorizontalScrollView理解滑動方向 */ private int getMaxCanScrollX(int direction) { if (direction > 0) { return histogramContentWidth - getScrollX() - width + histogramPaddingStart + histogramPaddingEnd > 0 ? histogramContentWidth - getScrollX() - width + histogramPaddingStart + histogramPaddingEnd : 0; } else if (direction < 0) { return getScrollX(); } return 0; } private float lastX; @Override public boolean onTouchEvent(MotionEvent event) { initVelocityTrackerIfNotExists(); velocityTracker.addMovement(event); switch (event.getAction()) { case MotionEvent.ACTION_DOWN: { if (!scroller.isFinished()) { scroller.abortAnimation(); } lastX = event.getX(); return true; } case MotionEvent.ACTION_MOVE: { int deltaX = (int) (event.getX() - lastX); lastX = event.getX(); // 滑動處理 if (deltaX > 0 && canScrollHorizontally(-1)) { scrollBy(-Math.min(getMaxCanScrollX(-1), deltaX), 0); } else if (deltaX < 0 && canScrollHorizontally(1)) { scrollBy(Math.min(getMaxCanScrollX(1), -deltaX), 0); } break; } case MotionEvent.ACTION_UP: { velocityTracker.computeCurrentVelocity(1000, maximumVelocity); int velocityX = (int) velocityTracker.getXVelocity(); fling(velocityX); recycleVelocityTracker(); break; } case MotionEvent.ACTION_CANCEL: { recycleVelocityTracker(); break; } } return super.onTouchEvent(event); } private void initVelocityTrackerIfNotExists() { if (velocityTracker == null) { velocityTracker = VelocityTracker.obtain(); } } private void recycleVelocityTracker() { if (velocityTracker != null) { velocityTracker.recycle(); velocityTracker = null; } } // ACTION_UP事件觸發 private void fling(int velocityX) { if (Math.abs(velocityX) > minimumVelocity) { if (Math.abs(velocityX) > maximumVelocity) { velocityX = maximumVelocity * velocityX / Math.abs(velocityX); } scroller.fling(getScrollX(), getScrollY(), -velocityX, 0, 0, histogramContentWidth + histogramPaddingStart - width, 0, 0); } } @Override public void computeScroll() { if (scroller.computeScrollOffset()) { scrollTo(scroller.getCurrX(), 0); } } public void setDataList(@NonNull List<MultiGroupHistogramGroupData> dataList) { this.dataList = dataList; if (childMaxValueArray == null) { childMaxValueArray = new SparseArray<>(); } else { childMaxValueArray.clear(); } histogramContentWidth = 0; for (MultiGroupHistogramGroupData groupData : dataList) { List<MultiGroupHistogramChildData> childDataList = groupData.getChildDataList(); if (childDataList != null && childDataList.size() > 0) { for (int i = 0; i < childDataList.size(); i++) { histogramContentWidth += histogramHistogramWidth + histogramInterval; MultiGroupHistogramChildData childData = childDataList.get(i); Float childMaxValue = childMaxValueArray.get(i); if (childMaxValue == null || childMaxValue < childData.getValue()) { childMaxValueArray.put(i, childData.getValue()); } } histogramContentWidth += groupInterval - histogramInterval; } } histogramContentWidth += -groupInterval; } /** * 設置組內直方圖顏色(并不是設置所有直方圖顏色，而是根據每組數據內直方圖數量設置) */ public void setHistogramColor(int[]... colors) { if (colors != null && colors.length > 0) { if (histogramShaderColorArray == null) { histogramShaderColorArray = new SparseArray<>(); } else { histogramShaderColorArray.clear(); } for (int i = 0; i < colors.length; i++) { histogramShaderColorArray.put(i, colors[i]); } } } @Override protected void onDraw(Canvas canvas) { if (width == 0 || height == 0) { return; } int scrollX = getScrollX(); int axisBottom = height - groupNameTextSize - distanceFormGroupNameToAxis - coordinateAxisWidth / 2; canvas.drawLine(coordinateAxisWidth / 2 + scrollX, 0, coordinateAxisWidth / 2 + scrollX, axisBottom, coordinateAxisPaint); canvas.drawLine(scrollX, axisBottom, width + scrollX, axisBottom, coordinateAxisPaint); if (dataList != null && dataList.size() > 0) { int xAxisOffset = histogramPaddingStart; // 每個直方圖在x軸的偏移量 for (MultiGroupHistogramGroupData groupData : dataList) { List<MultiGroupHistogramChildData> childDataList = groupData.getChildDataList(); if (childDataList != null && childDataList.size() > 0) { int groupWidth = 0; for (int i = 0; i < childDataList.size(); i++) { MultiGroupHistogramChildData childData = childDataList.get(i); histogramPaintRect.left = xAxisOffset; histogramPaintRect.right = histogramPaintRect.left + histogramHistogramWidth; int childHistogramHeight; if (childData.getValue() <= 0 || childMaxValueArray.get(i) <= 0) { childHistogramHeight = 0; } else { childHistogramHeight = (int) (childData.getValue() / childMaxValueArray.get(i) * maxHistogramHeight); } histogramPaintRect.top = height - childHistogramHeight - coordinateAxisWidth - distanceFormGroupNameToAxis - groupNameTextSize; histogramPaintRect.bottom = histogramPaintRect.top + childHistogramHeight; int[] histogramShaderColor = histogramShaderColorArray.get(i); LinearGradient shader = null; if (histogramShaderColor != null && histogramShaderColor.length > 0) { shader = getHistogramShader(histogramPaintRect.left, chartPaddingTop + distanceFromValueToHistogram + histogramValueTextSize, histogramPaintRect.right, histogramPaintRect.bottom, histogramShaderColor); } histogramPaint.setShader(shader); canvas.drawRect(histogramPaintRect, histogramPaint); String childHistogramHeightValue = StringUtil.NumericScaleByFloor(String.valueOf(childData.getValue()), histogramValueDecimalCount) + childData.getSuffix(); float valueTextX = xAxisOffset + (histogramHistogramWidth - histogramValuePaint.measureText(childHistogramHeightValue)) / 2; // 數值繪制Y軸位置特別處理 float valueTextY = histogramPaintRect.top - distanceFormGroupNameToAxis + (histogramValueFontMetrics.bottom) / 2; canvas.drawText(childHistogramHeightValue, valueTextX, valueTextY, histogramValuePaint); int deltaX = i < childDataList.size() - 1 ? histogramHistogramWidth + histogramInterval : histogramHistogramWidth; groupWidth += deltaX; // 注意此處偏移量累加 xAxisOffset += i == childDataList.size() - 1 ? deltaX + groupInterval : deltaX; } String groupName = groupData.getGroupName(); float groupNameTextWidth = groupNamePaint.measureText(groupName); float groupNameTextX = xAxisOffset - groupWidth - groupInterval + (groupWidth - groupNameTextWidth) / 2; // 組名繪制Y軸位置特別處理 float groupNameTextY = (height - groupNameFontMetrics.bottom / 2); canvas.drawText(groupName, groupNameTextX, groupNameTextY, groupNamePaint); } } } } private LinearGradient getHistogramShader(float x0, float y0, float x1, float y1, int[] colors) { return new LinearGradient(x0, y0, x1, y1, colors, null, Shader.TileMode.CLAMP); }} |
代碼就這一點，閱讀起來應該不難，如有疑問歡迎留言
自定義屬性如下：
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<declare-styleable name="MultiGroupHistogramView"> <attr name="coordinateAxisWidth" format="dimension" /> <attr name="coordinateAxisColor" format="color" /> <attr name="groupNameTextColor" format="color" /> <attr name="groupNameTextSize" format="dimension" /> <attr name="groupInterval" format="dimension" /> <attr name="histogramInterval" format="dimension" /> <attr name="histogramValueTextColor" format="color" /> <attr name="histogramValueTextSize" format="dimension" /> <attr name="histogramHistogramWidth" format="dimension" /> <attr name="histogramPaddingStart" format="dimension" /> <attr name="histogramPaddingEnd" format="dimension" /> <attr name="chartPaddingTop" format="dimension" /> <attr name="distanceFormGroupNameToAxis" format="dimension" /> <attr name="distanceFromValueToHistogram" format="dimension" /> <!--圖表數值小數點位數--> <attr name="histogramValueDecimalCount"> <enum name="ZERO" value="0" /> <enum name="ONE" value="1" /> <enum name="TWO" value="2" /> </attr></declare-styleable> |
下面貼出使用方法：
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private void initMultiGroupHistogramView() { Random random = new Random(); int groupSize = random.nextInt(5) + 10; List<MultiGroupHistogramGroupData> groupDataList = new ArrayList<>(); // 生成測試數據 for (int i = 0; i < groupSize; i++) { List<MultiGroupHistogramChildData> childDataList = new ArrayList<>(); MultiGroupHistogramGroupData groupData = new MultiGroupHistogramGroupData(); groupData.setGroupName("第" + (i + 1) + "組"); MultiGroupHistogramChildData childData1 = new MultiGroupHistogramChildData(); childData1.setSuffix("分"); childData1.setValue(random.nextInt(50) + 51); childDataList.add(childData1); MultiGroupHistogramChildData childData2 = new MultiGroupHistogramChildData(); childData2.setSuffix("%"); childData2.setValue(random.nextInt(50) + 51); childDataList.add(childData2); groupData.setChildDataList(childDataList); groupDataList.add(groupData); } multiGroupHistogramView.setDataList(groupDataList); int[] color1 = new int[]{getResources().getColor(R.color.color_orange), getResources().getColor(R.color.colorPrimary)}; int[] color2 = new int[]{getResources().getColor(R.color.color_supper_tip_normal), getResources().getColor(R.color.bg_supper_selected)}; // 設置直方圖顏色 multiGroupHistogramView.setHistogramColor(color1, color2);} |
完整示例：https://github.com/670832188/TestApp
總結
以上就是這篇文章的全部內容了，希望本文的內容對大家的學習或者工作具有一定的參考學習價值，如果有疑問大家可以留言交流，謝謝大家對服務器之家的支持。
原文鏈接：https://www.jianshu.com/p/1595ce6aa3a7
