本文實例講述了Android編程使用自定義View實現水波進度效果。分享給大家供大家參考，具體如下：
首先上效果圖：
簡介：
1.自動適應屏幕大?。?br />2.水波自動橫向滾動；
3.各種繪制參數可通過修改常量進行控制。
代碼不多，注釋也比較詳細，全部貼上：
（一）自定義組件：
/** * 水波進度效果. */public class WaterWaveView extends View { //邊框寬度 private int STROKE_WIDTH; //組件的寬，高 private int width, height; /** * 進度條最大值和當前進度值 */ private float max, progress; /** * 繪制波浪的畫筆 */ private Paint progressPaint; //波紋振幅與半徑之比。(建議設置：<0.1) private static final float A = 0.05f; //繪制文字的畫筆 private Paint textPaint; //繪制邊框的畫筆 private Paint circlePaint; /** * 圓弧圓心位置 */ private int centerX, centerY; //內圓所在的矩形 private RectF circleRectF; public WaterWaveView(Context context) { super(context); init(); } public WaterWaveView(Context context, AttributeSet attrs) { super(context, attrs); init(); } public WaterWaveView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(); } //初始化 private void init() { progressPaint = new Paint(); progressPaint.setColor(Color.parseColor("#77cccc88")); progressPaint.setAntiAlias(true); textPaint = new Paint(); textPaint.setColor(Color.WHITE); textPaint.setAntiAlias(true); circlePaint = new Paint(); circlePaint.setStyle(Paint.Style.STROKE); circlePaint.setAntiAlias(true); circlePaint.setColor(Color.parseColor("#33333333")); autoRefresh(); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (width == 0 || height == 0) { width = getWidth(); height = getHeight(); //計算圓弧半徑和圓心點 int circleRadius = Math.min(width, height) >> 1; STROKE_WIDTH = circleRadius / 10; circlePaint.setStrokeWidth(STROKE_WIDTH); centerX = width / 2; centerY = height / 2; VALID_RADIUS = circleRadius - STROKE_WIDTH; RADIANS_PER_X = (float) (Math.PI / VALID_RADIUS); circleRectF = new RectF(centerX - VALID_RADIUS, centerY - VALID_RADIUS, centerX + VALID_RADIUS, centerY + VALID_RADIUS); } } private Rect textBounds = new Rect(); //x方向偏移量 private int xOffset; @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); //繪制圓形邊框 canvas.drawCircle(centerX, centerY, VALID_RADIUS + (STROKE_WIDTH >> 1), circlePaint); //繪制水波曲線 canvas.drawPath(getWavePath(xOffset), progressPaint); //繪制文字 textPaint.setTextSize(VALID_RADIUS >> 1); String text1 = String.valueOf(progress); //測量文字長度 float w1 = textPaint.measureText(text1); //測量文字高度 textPaint.getTextBounds("8", 0, 1, textBounds); float h1 = textBounds.height(); float extraW = textPaint.measureText("8") / 3; canvas.drawText(text1, centerX - w1 / 2 - extraW, centerY + h1 / 2, textPaint); textPaint.setTextSize(VALID_RADIUS / 6); textPaint.getTextBounds("M", 0, 1, textBounds); float h2 = textBounds.height(); canvas.drawText("M", centerX + w1 / 2 - extraW + 5, centerY - (h1 / 2 - h2), textPaint); String text3 = "共" + String.valueOf(max) + "M"; float w3 = textPaint.measureText(text3, 0, text3.length()); textPaint.getTextBounds("M", 0, 1, textBounds); float h3 = textBounds.height(); canvas.drawText(text3, centerX - w3 / 2, centerY + (VALID_RADIUS >> 1) + h3 / 2, textPaint); String text4 = "流量剩余"; float w4 = textPaint.measureText(text4, 0, text4.length()); textPaint.getTextBounds(text4, 0, text4.length(), textBounds); float h4 = textBounds.height(); canvas.drawText(text4, centerX - w4 / 2, centerY - (VALID_RADIUS >> 1) + h4 / 2, textPaint); } //繪制水波的路徑 private Path wavePath; //每一個像素對應的弧度數 private float RADIANS_PER_X; //去除邊框后的半徑（即內圓半徑） private int VALID_RADIUS; /** * 獲取水波曲線（包含圓弧部分）的Path. * * @param xOffset x方向像素偏移量. */ private Path getWavePath(int xOffset) { if (wavePath == null) { wavePath = new Path(); } else { wavePath.reset(); } float[] startPoint = new float[2]; //波浪線起點 float[] endPoint = new float[2]; //波浪線終點 for (int i = 0; i <= VALID_RADIUS * 2; i += 2) { float x = centerX - VALID_RADIUS + i; float y = (float) (centerY + VALID_RADIUS * (1.0f + A) * 2 * (0.5f - progress / max) + VALID_RADIUS * A * Math.sin((xOffset + i) * RADIANS_PER_X)); //只計算內圓內部的點，邊框上的忽略 if (calDistance(x, y, centerX, centerY) > VALID_RADIUS) { if (x < centerX) { continue; //左邊框,繼續循環 } else { break; //右邊框,結束循環 } } //第1個點 if (wavePath.isEmpty()) { startPoint[0] = x; startPoint[1] = y; wavePath.moveTo(x, y); } else { wavePath.lineTo(x, y); } endPoint[0] = x; endPoint[1] = y; } if (wavePath.isEmpty()) { if (progress / max >= 0.5f) { //滿格 wavePath.moveTo(centerX, centerY - VALID_RADIUS); wavePath.addCircle(centerX, centerY, VALID_RADIUS, Path.Direction.CW); } else { //空格 return wavePath; } } else { //添加圓弧部分 float startDegree = calDegreeByPosition(startPoint[0], startPoint[1]); //0~180 float endDegree = calDegreeByPosition(endPoint[0], endPoint[1]); //180~360 wavePath.arcTo(circleRectF, endDegree - 360, startDegree - (endDegree - 360)); } return wavePath; } private float calDistance(float x1, float y1, float x2, float y2) { return (float) Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2)); } //根據當前位置，計算出進度條已經轉過的角度。 private float calDegreeByPosition(float currentX, float currentY) { float a1 = (float) (Math.atan(1.0f * (centerX - currentX) / (currentY - centerY)) / Math.PI * 180); if (currentY < centerY) { a1 += 180; } else if (currentY > centerY && currentX > centerX) { a1 += 360; } return a1 + 90; } public void setMax(int max) { this.max = max; invalidate(); } //直接設置進度值（同步） public void setProgressSync(float progress) { this.progress = progress; invalidate(); } /** * 自動刷新頁面，創造水波效果。組件銷毀后該線城將自動停止。 */ private void autoRefresh() { new Thread(new Runnable() { @Override public void run() { while (!detached) { xOffset += (VALID_RADIUS >> 4); SystemClock.sleep(100); postInvalidate(); } } }).start(); } //標記View是否已經銷毀 private boolean detached = false; @Override protected void onDetachedFromWindow() { super.onDetachedFromWindow(); detached = true; }}（二）使用方法：
在xml布局中引入上述組件，然后在activity或fragment中設置屬性：
WaterWaveView bar = (WaterWaveView) getActivity().findViewById(R.id.water_wave_view); bar.setMax(500); bar.setProgressSync(361.8f);
更多關于Android相關內容感興趣的讀者可查看本站專題：《Android開發動畫技巧匯總》、《Android編程之activity操作技巧總結》、《Android視圖View技巧總結》、《Android布局layout技巧總結》、《Android開發入門與進階教程》、《Android資源操作技巧匯總》及《Android控件用法總結》
希望本文所述對大家Android程序設計有所幫助。
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