WaveView.java

package com.lcodecore.tkrefreshlayout.header.bezierlayout;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PixelFormat;
import android.graphics.drawable.Drawable;
import android.support.annotation.ColorInt;
import android.util.AttributeSet;
import android.view.View;

/**
 * Created by cjj on 2015/8/5.
 * 绘制贝塞尔来绘制波浪形
 */
public class WaveView extends View {
    private int waveHeight;
    private int headHeight;
    Path path;
    Paint paint;

    public WaveView(Context context) {
        this(context, null, 0);
    }

    public WaveView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public WaveView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        path = new Path();
        paint = new Paint();
        paint.setColor(0xff1F2426);
        paint.setAntiAlias(true);
    }

    public int getHeadHeight() {
        return headHeight;
    }

    public void setHeadHeight(int headHeight) {
        this.headHeight = headHeight;
    }

    public int getWaveHeight() {
        return waveHeight;
    }

    public void setWaveHeight(int waveHeight) {
        this.waveHeight = waveHeight;
    }

    public void setWaveColor(@ColorInt int color) {
        if (paint != null) paint.setColor(color);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //重置画笔
        path.reset();
        path.lineTo(0, headHeight);
        //绘制贝塞尔曲线
        path.quadTo(getMeasuredWidth() / 2, headHeight + waveHeight, getMeasuredWidth(), headHeight);
        path.lineTo(getMeasuredWidth(), 0);
        canvas.drawPath(path, paint);
    }


    static Bitmap drawableToBitmap(Drawable drawable) // drawable 转换成bitmap
    {
        int width = drawable.getIntrinsicWidth();// 取drawable的长宽
        int height = drawable.getIntrinsicHeight();
        Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565;// 取drawable的颜色格式
        Bitmap bitmap = Bitmap.createBitmap(width, height, config);// 建立对应bitmap
        Canvas canvas = new Canvas(bitmap);// 建立对应bitmap的画布
        drawable.setBounds(0, 0, width, height);
        drawable.draw(canvas);// 把drawable内容画到画布中
        return bitmap;
    }

}