水波灵纹

来源：互联网发布：java api接口测试工具编辑：程序博客网时间：2024/04/28 15:15

1、自定义一个类用来画图

package com.bwei.waterwave;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Random;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class WaterWaveViewWithMove extends View {

   private Wave wave;
    private List<Wave> wavesList;
    private boolean isRunning;
    private int xSlop = 10, ySlop = 10;

    public WaterWaveViewWithMove(Context context) {
        super(context);
        wavesList = new ArrayList<WaterWaveViewWithMove.Wave>();
    }

    public WaterWaveViewWithMove(Context context, AttributeSet attrs) {
        super(context, attrs);
        wavesList = new ArrayList<WaterWaveViewWithMove.Wave>();
    }

    private Handler handler = new Handler() {
        public void handleMessage(android.os.Message msg) {
            for (Iterator iterator = wavesList.iterator(); iterator.hasNext();) {
                Wave wave = (Wave) iterator.next();

                //透明度越低越透明
                int alpha = wave.paint.getAlpha() - 5;
                if (alpha < 0) {
                    iterator.remove();
                    continue;
                }

                //圆的半径变大
                wave.radius += 10;

                //圆环的半径变小
                wave.paint.setStrokeWidth(wave.radius / 6); //轮廓宽度
                wave.paint.setAlpha(alpha);

            }
            if (wavesList.size() == 0) {
                isRunning = false;
            }

            invalidate();
            if (isRunning) {
                handler.sendEmptyMessageDelayed(0, 50);
            }
        };
    };

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        for (Iterator iterator = wavesList.iterator(); iterator.hasNext();) {
            Wave wave = (Wave) iterator.next();
            if (wave.paint.getAlpha() > 0) { //透明度大>0 才绘制
                canvas.drawCircle(wave.x, wave.y, wave.radius, wave.paint);
            }
        }
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
        case MotionEvent.ACTION_MOVE:
            if (wavesList.size() == 0) {
                isRunning = true;
                handler.sendEmptyMessageDelayed(0, 50); //发送消息后，handler遍历wavesList 循环更新
            }
            //若不在上面的if里发送msg，会：手指down|move时都会更新一下view
//          handler.sendEmptyMessageDelayed(0, 50);

            float x = event.getX();
            float y = event.getY();
            //当前点的x或y与最后有效点的x或y距离大于slop值才添加新的wave
            if (wavesList.size() > 0) {
                if (Math.abs(x - wavesList.get(wavesList.size() - 1).x) > xSlop
                        || Math.abs(y - wavesList.get(wavesList.size() - 1).y) > ySlop) {
                    wave = new Wave();
                    wave.x = x;
                    wave.y = y;
                    wave.resetPaint();//重写设置一次画笔
                    wavesList.add(wave);
                }
            } else {
                wave = new Wave();
                wave.x = x;
                wave.y = y;
                wave.resetPaint();//重写设置一次画笔
                wavesList.add(wave);
            }

            break;
        case MotionEvent.ACTION_UP:

            break;

        default:
            break;
        }
        return true;
    }


    /**
     * 随机颜色
     * @return
     */
    private int getColor() {
        StringBuilder sb = new StringBuilder();
        Random random = new Random();
        String temp;
        for (int i = 0; i < 3; i++) {
            temp = Integer.toHexString(random.nextInt(0xFF));
            if (temp.length() == 1) {
                temp = "0" + temp;
            }
            sb.append(temp);
        }
        return Color.parseColor("#" + sb.toString());
    }

    private class Wave {
        private float x, y, radius;
        private Paint paint;

        private void resetPaint() {
            paint = new Paint();
            paint.setAntiAlias(true);//抗锯齿
            paint.setStyle(Style.STROKE);//绘制轮廓
            paint.setColor(getColor());//随机颜色
        }
    }

}

2、布局文件中引用一下

<com.bwei.waterwave.WaterWaveViewWithMove
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>

3、MainActivity中不用写东西

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