波浪动画实现方法的改进——用自定义SurfaceView实现

来源：互联网发布：手机精确定位软件编辑：程序博客网时间：2024/06/05 14:53
由于之前实现WaveView需要大量的重绘，用SurfaceView实现能有效提升性能。代码如下：
public class WaveSurfaceView extends SurfaceView implements SurfaceHolder.Callback {    private int width;    private int height;    private float[] y;    private float[] y2;    private float waveLength;    private Paint paint;    private Paint paint2;    private Canvas canvas;    private boolean isDraw = false;    private float vScale;    SurfaceHolder holder;    public WaveSurfaceView(Context context) {        this(context, null);    }    public WaveSurfaceView(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public WaveSurfaceView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        paint = new Paint();        paint.setARGB(80, 0, 137, 228);        paint.setAntiAlias(true);        paint2 = new Paint();        paint2.setARGB(150, 0, 137, 228);        paint2.setAntiAlias(true);        holder = getHolder();        holder.addCallback(this);    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        width = MeasureSpec.getSize(widthMeasureSpec);        height = MeasureSpec.getSize(heightMeasureSpec);        /*以720*1280分辨率屏幕为基准得出速度和振幅的放大因子（由于控件不一定占满屏幕，以width和height计算是不严谨的）*/        vScale = (float) (width / 720.0);        float aScale = (float) (height / 1280.0);        /*振幅*/        int a = (int) (25 * aScale);        /*初相位*/        int b = 0;        /*人为设定的波长*/        waveLength = (float) (3.0 / 2 * width);        /*波长确定后计算出的频率*/        float w = (float) (4.0 / 3 * Math.PI / width);        /*存储y坐标的数组（横坐标为0的点+波长的长度）*/        y = new float[(int) (waveLength + 1)];        /*为每一个y赋值*/        for (int i = 0; i < waveLength + 1; i++) {            y[i] = (float) (a * Math.sin(w * i + b));        }        int a2 = (int) (35 * aScale);        float b2 = (float) (Math.PI / 3);        float w2 = (float) (2 * Math.PI / width);        y2 = new float[width + 1];        for (int i = 0; i < width + 1; i++) {            y2[i] = (float) (a2 * Math.sin(w2 * i + b2));        }    }    @Override    public void surfaceCreated(final SurfaceHolder holder) {        isDraw = true;        new Thread(new Runnable() {            @Override            public void run() {                while (isDraw) {                    try {                        drawWave();                    } catch (Exception e) {                        e.printStackTrace();                    } finally {                        /*提交每次更新*/                        if (canvas != null) {                            holder.unlockCanvasAndPost(canvas);                        }                    }                }            }        }).start();    }    private void drawWave() {        /*移动速度*/        int v = (int) (4 * vScale);        int v2 = (int) (4 * vScale);        canvas = holder.lockCanvas();        /*获取到的canvas对象不是新的，所以每次更新前用drawRGB方法进行擦除以更新而不是覆盖*/        canvas.drawRGB(249, 245, 237);        for (int i = 0; i < waveLength + 1; i++) {            if (i + v <= waveLength) {                y[i] = y[i + v];            } else {                y[i] = y[((int) (i + v - waveLength))];            }            if (i <= width) {                /*细分法画出每一条竖直的线*/                canvas.drawLine(i, y[i] + height * 2 / 3, i, height, paint);            }        }        for (int i = 0; i < width + 1; i++) {            if (i + v2 <= width) {                y2[i] = y2[i + v2];            } else {                y2[i] = y2[i + v2 - width];            }            canvas.drawLine(i, y2[i] + height * 2 / 3, i, height, paint2);        }    }    @Override    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {    }    @Override    public void surfaceDestroyed(SurfaceHolder holder) {        isDraw = false;    }}
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