Android动绘图标——I am not a gif maker,I am a developer

最早在git上发现一个非常酷眩的动绘图标效果：

https://github.com/xuyisheng/tickplusdrawable

不得不说，国外的程序猿在细节的考虑上，确实比我们要好非常多，ok，今天我们就来模仿下这个：

现来看看我们的效果，别喷我，就写了个把小时，非常多细节还没考虑全，代码也还没重构，希望大家能提出改动意见，thx～

gif效果不一定好，大家能够參考github的gif。

代码例如以下：

首先我们要来了解下原理：

1、我们首先来确定一些关键点的坐标，也就是我们要显示的图形的全部出现的顶点

2、线条的移动效果，我们使用属性动画来控制，不熟悉的朋友能够看看http://blog.csdn.net/eclipsexys/article/details/38401641，通过这个样例大家应该会对属性动画有更深的理解了

3、对于没有提供get、set方法的属性，我们通过重写Property来帮助这个属性添加get、set方法

了解了以上内容，就能够来看详细的代码了：

package com.example.yishengxu.canvas;

import android.animation.ObjectAnimator;
import android.animation.TypeEvaluator;
import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.util.Property;
import android.view.MotionEvent;
import android.view.View;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by yisheng.xu on 10/30/14.
 */
public class CanvasView extends View {

    private float mPaddingW;
    private float mPaddingH;

    private float mRotation;

    private List<PointF> mAllPoints = new ArrayList<PointF>();

    private PointF mPoint0;
    private PointF mPoint1;
    private PointF mPoint2;
    private PointF mPoint3;
    private PointF mPoint4;
    private PointF mPoint5;
    private PointF mPoint6;
    private PointF mPoint7;

    private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

    private int touchFlag = 0;

    public CanvasView(Context context) {
        super(context);
    }

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

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

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        mPaddingW = w / 4;
        mPaddingH = h / 4;

        mAllPoints.add(new PointF(mPaddingW, mPaddingH));
        mAllPoints.add(new PointF(mPaddingW * 3, mPaddingH));
        mAllPoints.add(new PointF(mPaddingW, mPaddingH * 2));
        mAllPoints.add(new PointF(mPaddingW * 3, mPaddingH * 2));
        mAllPoints.add(new PointF(mPaddingW, mPaddingH * 3));
        mAllPoints.add(new PointF(mPaddingW * 3, mPaddingH * 3));
        mAllPoints.add(new PointF(mPaddingW * 2, mPaddingH));
        mAllPoints.add(new PointF(mPaddingW * 2, mPaddingH * 3));

        initPoints();

        mPaint.setColor(Color.BLUE);
        mPaint.setStrokeWidth(20);
        mPaint.setStrokeCap(Paint.Cap.ROUND);
        super.onSizeChanged(w, h, oldw, oldh);
    }

    private void initPoints() {
        mPoint0 = new PointF(mAllPoints.get(0).x, mAllPoints.get(0).y);
        mPoint1 = new PointF(mAllPoints.get(1).x, mAllPoints.get(1).y);
        mPoint2 = new PointF(mAllPoints.get(2).x, mAllPoints.get(2).y);
        mPoint3 = new PointF(mAllPoints.get(3).x, mAllPoints.get(3).y);
        mPoint4 = new PointF(mAllPoints.get(4).x, mAllPoints.get(4).y);
        mPoint5 = new PointF(mAllPoints.get(5).x, mAllPoints.get(5).y);
        mPoint6 = new PointF();
        mPoint7 = new PointF();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.save();
        canvas.rotate(180 * mRotation, mPaddingW * 2, mPaddingH * 2);
        drawLine(canvas, mPoint0, mPoint1);
        drawLine(canvas, mPoint2, mPoint3);
        drawLine(canvas, mPoint4, mPoint5);
        drawLine(canvas, mPoint6, mPoint7);
        canvas.restore();
    }

    private void drawLine(Canvas canvas,PointF start,PointF end) {
        if (start.x!=0 && end.x !=0) {
            canvas.drawLine(start.x, start.y, end.x, end.y, mPaint);
        }
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (touchFlag == 0) {
            animPoints(mPoint0, mAllPoints.get(2));
            animPoints(mPoint4, mAllPoints.get(2));
            animPoints(mPoint1, mAllPoints.get(6));
            animPoints(mPoint5, mAllPoints.get(7));
            touchFlag += 1;
        }else if (touchFlag == 1) {
            resetPoints();
            touchFlag += 1;
        }else if (touchFlag == 2) {
            animPoints(mPoint0, mAllPoints.get(4));
            animPoints(mPoint4, mAllPoints.get(0));
            mPoint2 = new PointF(0, 0);
            mPoint3 = new PointF(0, 0);
            invalidate();
            touchFlag += 1;
        } else if (touchFlag == 3) {
            resetPoints();
            touchFlag += 1;
        } else {
            animPoints(mPoint0, mAllPoints.get(6));
            animPoints(mPoint1, mAllPoints.get(3));
            animPoints(mPoint5, mAllPoints.get(6));
            mPoint2 = new PointF(0, 0);
            mPoint3 = new PointF(0, 0);
            invalidate();
            touchFlag = 1;
        }

        return super.onTouchEvent(event);
    }

    private void resetPoints() {
        animPoints(mPoint0, mAllPoints.get(0));
        animPoints(mPoint1, mAllPoints.get(1));
        animPoints(mPoint2, mAllPoints.get(2));
        animPoints(mPoint3, mAllPoints.get(3));
        animPoints(mPoint4, mAllPoints.get(4));
        animPoints(mPoint5, mAllPoints.get(5));
    }

    private void animPoints(final PointF start, final PointF end) {
        ValueAnimator animator = ValueAnimator.ofObject(new TypeEvaluator<PointF>() {
            @Override
            public PointF evaluate(float v, PointF o, PointF o2) {
                start.x = start.x + (end.x - start.x) * v;
                start.y = start.y + (end.y - start.y) * v;
                invalidate();
                return null;
            }
        }, start, end);
        animator.setDuration(1000);
        animator.start();
        ObjectAnimator animator1 = ObjectAnimator.ofFloat(this, mRotationProperty, 0, 1F);
        animator1.setDuration(500);
        animator1.start();
    }

    private Property<CanvasView, Float> mRotationProperty = new Property<CanvasView, Float>(Float.class, "rotation") {
        @Override
        public Float get(CanvasView object) {
            return object.mRotation;
        }

        @Override
        public void set(CanvasView object, Float value) {
            object.mRotation = value;
        }
    };
}

布局文件和主文件非常easy：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="50dp"
    android:paddingRight="50dp"
    android:paddingTop="150dp"
    android:paddingBottom="150dp"
    tools:context=".MainActivity">

    <view
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        class="com.example.yishengxu.canvas.CanvasView"
        android:id="@+id/view"
        android:layout_alignParentStart="true" />
</RelativeLayout>

package com.example.yishengxu.canvas;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

OK，关键还是要有脑子，有idea，在现有知识的基础上，加工、创造。

如今，5.0来了，新增了Vector Drawable，以及对SVG的支持，让我们对实现更复杂的路径轨迹动画效果，有了更强大的工具。

最后，打个广告——友情链接 HZTalk~非常好的，说科技、聊电影、游戏，真独立，非客观，第三方.

以上。