Android自定义View之吃豆人动画（一）

- 先看效果图，但是图是没动的效果。代码的效果就是实现吃豆人一直吃豆子的效果。

自定义view的代码

• 这里view的宽高颜色都设置死了的，后面会将很多配置的东西抽到attrs.xml中。以便更多场景的使用。

package com.simple_test_android.weiget.indicator;

import com.nineoldandroids.animation.ValueAnimator;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.LinearInterpolator;

public class PcmanLoadingView extends View {

    private Paint mPcmanPaint, mCirclePaint, mEyePaint;
    private int width;
    private int height;
    protected Float translateX;
    protected Integer alpha;
    protected Float degrees1;
    protected Float degrees2;
    private boolean mHasAnimation;
    private int duration = 450;

    public PcmanLoadingView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        width = measureDimension(dp2px(70), widthMeasureSpec);
        height = measureDimension(dp2px(50), heightMeasureSpec);
        setMeasuredDimension(width, height);
    }

    /**
     * 测量方法
     */
    private int measureDimension(int defaultSize, int measureSpec) {
        int result = defaultSize;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize = MeasureSpec.getSize(measureSpec);
        if (specMode == MeasureSpec.EXACTLY) {
            result = specSize;
        } else if (specMode == MeasureSpec.AT_MOST) {
            result = Math.min(defaultSize, specSize);
        } else {
            result = defaultSize;
        }
        return result;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        drawPcman(canvas);
        drawCircle(canvas);
        // 画眼睛
        canvas.drawCircle(width / 3, height / 3, dp2px(2), mEyePaint);
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        if (!mHasAnimation) {
            mHasAnimation = true;
            createAnimation();
        }
    }

    private void init() {
        // 设置画吃豆人的画笔
        mPcmanPaint = new Paint();
        mPcmanPaint.setColor(Color.YELLOW);
        mPcmanPaint.setStyle(Paint.Style.FILL);
        mPcmanPaint.setAntiAlias(true);
        // 设置画豆子的画笔
        mCirclePaint = new Paint();
        mCirclePaint.setColor(Color.WHITE);
        mCirclePaint.setStyle(Paint.Style.FILL);
        mCirclePaint.setAntiAlias(true);
        // 设置画吃豆人眼睛的画笔
        mEyePaint = new Paint();
        mEyePaint.setColor(Color.BLACK);
        mEyePaint.setStyle(Paint.Style.FILL);
        mEyePaint.setAntiAlias(true);
    }

    /**
     * 画吃豆人
     */
    private void drawPcman(Canvas canvas) {
        float x = width / 2 - dp2px(10);
        float y = height / 2;

        canvas.save();

        canvas.translate(x, y);
        canvas.rotate(degrees1);
        mPcmanPaint.setAlpha(255);
        RectF rectF1 = new RectF(-x / 1.7f, -y / 1.7f, x / 1.7f, y / 1.7f);
        canvas.drawArc(rectF1, 0, 270, true, mPcmanPaint);

        canvas.restore();

        canvas.save();
        canvas.translate(x, y);
        canvas.rotate(degrees2);
        mPcmanPaint.setAlpha(255);
        RectF rectF2 = new RectF(-x / 1.7f, -y / 1.7f, x / 1.7f, y / 1.7f);
        canvas.drawArc(rectF2, 90, 270, true, mPcmanPaint);
        canvas.restore();

    }

    /**
     * 画豆子
     */
    private void drawCircle(Canvas canvas) {
        float radius = height / 11;
        mCirclePaint.setAlpha(alpha);
        canvas.drawCircle(translateX - (3 * radius), height / 2, radius, mCirclePaint);
        mCirclePaint.setAlpha(255);
        canvas.drawCircle(translateX, height / 2, radius, mCirclePaint);
        mCirclePaint.setAlpha(255);
        canvas.drawCircle(3 * radius + translateX, height / 2, radius, mCirclePaint);
    }

    /**
     * 创建动画
     */
    public void createAnimation() {
        float startT = width / 11;
        ValueAnimator translationAnim = ValueAnimator.ofFloat(width - startT, width / 2);
        translationAnim.setDuration(duration);// 设置动画的持续时间
        translationAnim.setInterpolator(new LinearInterpolator());// 设置动画的速率为匀速
        translationAnim.setRepeatCount(-1);// 设置动画重复播放次数，-1位一直重复
        translationAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {// 动画绘制过程的监听
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                translateX = (Float) animation.getAnimatedValue();
                postInvalidate();// 使用这个方法可以在非ui线程绘制view，当view依附在window上时，这个方法就会去调用外部线程
            }
        });
        translationAnim.start();

        ValueAnimator alphaAnim = ValueAnimator.ofInt(255, 122);
        alphaAnim.setDuration(duration);
        alphaAnim.setRepeatCount(-1);
        alphaAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                alpha = (Integer) animation.getAnimatedValue();
                postInvalidate();
            }
        });
        alphaAnim.start();
        ValueAnimator rotateAnim1 = ValueAnimator.ofFloat(0, 45, 0);
        rotateAnim1.setDuration(duration);
        rotateAnim1.setRepeatCount(-1);
        rotateAnim1.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                degrees1 = (Float) animation.getAnimatedValue();
                postInvalidate();
            }
        });
        rotateAnim1.start();

        ValueAnimator rotateAnim2 = ValueAnimator.ofFloat(0, -45, 0);
        rotateAnim2.setDuration(duration);
        rotateAnim2.setRepeatCount(-1);
        rotateAnim2.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                degrees2 = (Float) animation.getAnimatedValue();
                postInvalidate();
            }
        });
        rotateAnim2.start();
    }

    /**
     * dp转像素
     */
    private int dp2px(int dpValue) {
        return (int) (getContext().getResources().getDisplayMetrics().density * dpValue);
    }

}

布局

"http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res/com.simple_test_android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#66000000" >

    <com.simple_test_android.weiget.indicator.PcmanLoadingView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

• 还需要一个nineoldandroid.jar包，可以自行百度下载。