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  • Android手势锁实现

    最终效果如下

    整体思路

    a、自定义了一个RelativeLayout(GestureLockViewGroup)在里面会根据传入的每行的个数,生成多个GestureLockView(就是上面一个个小圈圈),然后会自动进行布局,里面的宽度,间距,内圆的直径,箭头的大小神马的都是百分比实现的,所以大胆的设置你喜欢的个数,只要你没有密集恐惧症~

    b、GestureLockView有三个状态,没有手指触碰、手指触碰、和手指抬起,会根据这三个状态绘制不同的效果,以及抬起时的小箭头需要旋转的角度,会根据用户选择的GestureLockView,进行计算,在GestureLockViewGroup为每个GestureLockView设置

    c、GestureLockViewGroup主要就是判断用户ACTION_MOVE,ACTION_DOWN , ACTION_UP时改变选中的GestureLockView的状态,并且记录下来,提供一定的回调。

    自定义属性

    <?xml version="1.0" encoding="utf-8"?>
    <resources>
    
        <attr name="color_no_finger_inner_circle" format="color" />
        <attr name="color_no_finger_outer_circle" format="color" />
        <attr name="color_finger_on" format="color" />
        <attr name="color_finger_up" format="color" />
        <attr name="count" format="integer" />
        <attr name="tryTimes" format="integer" />
    
        <declare-styleable name="GestureLockViewGroup">
            <attr name="color_no_finger_inner_circle" />
            <attr name="color_no_finger_outer_circle" />
            <attr name="color_finger_on" />
            <attr name="color_finger_up" />
            <attr name="count" />
            <attr name="tryTimes" />
        </declare-styleable>
    
    </resources>

    GestureLockView

    package com.zhy.zhy_gesturelockview.view;
    
    import android.content.Context;
    import android.graphics.Canvas;
    import android.graphics.Paint;
    import android.graphics.Paint.Style;
    import android.graphics.Path;
    import android.view.View;
    
    public class GestureLockView extends View
    {
        private static final String TAG = "GestureLockView";
        /**
         * GestureLockView的三种状态
         */
        enum Mode
        {
            STATUS_NO_FINGER, STATUS_FINGER_ON, STATUS_FINGER_UP;
        }
    
        /**
         * GestureLockView的当前状态
         */
        private Mode mCurrentStatus = Mode.STATUS_NO_FINGER;
    
        /**
         * 宽度
         */
        private int mWidth;
        /**
         * 高度
         */
        private int mHeight;
        /**
         * 外圆半径
         */
        private int mRadius;
        /**
         * 画笔的宽度
         */
        private int mStrokeWidth = 2;
    
        /**
         * 圆心坐标
         */
        private int mCenterX;
        private int mCenterY;
        private Paint mPaint;
    
        /**
         * 箭头(小三角最长边的一半长度 = mArrawRate * mWidth / 2 )
         */
        private float mArrowRate = 0.333f;
        private int mArrowDegree = -1;
        private Path mArrowPath;
        /**
         * 内圆的半径 = mInnerCircleRadiusRate * mRadus
         * 
         */
        private float mInnerCircleRadiusRate = 0.3F;
    
        /**
         * 四个颜色,可由用户自定义,初始化时由GestureLockViewGroup传入
         */
        private int mColorNoFingerInner;
        private int mColorNoFingerOutter;
        private int mColorFingerOn;
        private int mColorFingerUp;
    
        public GestureLockView(Context context , int colorNoFingerInner , int colorNoFingerOutter , int colorFingerOn , int colorFingerUp )
        {
            super(context);
            this.mColorNoFingerInner = colorNoFingerInner;
            this.mColorNoFingerOutter = colorNoFingerOutter;
            this.mColorFingerOn = colorFingerOn;
            this.mColorFingerUp = colorFingerUp;
            mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
            mArrowPath = new Path();
    
        }
    
        @Override
        protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
        {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    
            mWidth = MeasureSpec.getSize(widthMeasureSpec);
            mHeight = MeasureSpec.getSize(heightMeasureSpec);
    
            // 取长和宽中的小值
            mWidth = mWidth < mHeight ? mWidth : mHeight;
            mRadius = mCenterX = mCenterY = mWidth / 2;
            mRadius -= mStrokeWidth / 2;
    
            // 绘制三角形,初始时是个默认箭头朝上的一个等腰三角形,用户绘制结束后,根据由两个GestureLockView决定需要旋转多少度
            float mArrowLength = mWidth / 2 * mArrowRate;
            mArrowPath.moveTo(mWidth / 2, mStrokeWidth + 2);
            mArrowPath.lineTo(mWidth / 2 - mArrowLength, mStrokeWidth + 2
                    + mArrowLength);
            mArrowPath.lineTo(mWidth / 2 + mArrowLength, mStrokeWidth + 2
                    + mArrowLength);
            mArrowPath.close();
            mArrowPath.setFillType(Path.FillType.WINDING);
    
        }
    
        @Override
        protected void onDraw(Canvas canvas)
        {
    
            switch (mCurrentStatus)
            {
            case STATUS_FINGER_ON:
    
                // 绘制外圆
                mPaint.setStyle(Style.STROKE);
                mPaint.setColor(mColorFingerOn);
                mPaint.setStrokeWidth(2);
                canvas.drawCircle(mCenterX, mCenterY, mRadius, mPaint);
                // 绘制内圆
                mPaint.setStyle(Style.FILL);
                canvas.drawCircle(mCenterX, mCenterY, mRadius
                        * mInnerCircleRadiusRate, mPaint);
                break;
            case STATUS_FINGER_UP:
                // 绘制外圆
                mPaint.setColor(mColorFingerUp);
                mPaint.setStyle(Style.STROKE);
                mPaint.setStrokeWidth(2);
                canvas.drawCircle(mCenterX, mCenterY, mRadius, mPaint);
                // 绘制内圆
                mPaint.setStyle(Style.FILL);
                canvas.drawCircle(mCenterX, mCenterY, mRadius
                        * mInnerCircleRadiusRate, mPaint);
    
                drawArrow(canvas);
    
                break;
    
            case STATUS_NO_FINGER:
    
                // 绘制外圆
                mPaint.setStyle(Style.FILL);
                mPaint.setColor(mColorNoFingerOutter);
                canvas.drawCircle(mCenterX, mCenterY, mRadius, mPaint);
                // 绘制内圆
                mPaint.setColor(mColorNoFingerInner);
                canvas.drawCircle(mCenterX, mCenterY, mRadius
                        * mInnerCircleRadiusRate, mPaint);
                break;
    
            }
    
        }
    
        /**
         * 绘制箭头
         * @param canvas
         */
        private void drawArrow(Canvas canvas)
        {
            if (mArrowDegree != -1)
            {
                mPaint.setStyle(Paint.Style.FILL);
    
                canvas.save();
                canvas.rotate(mArrowDegree, mCenterX, mCenterY);
                canvas.drawPath(mArrowPath, mPaint);
    
                canvas.restore();
            }
    
        }
    
        /**
         * 设置当前模式并重绘界面
         * 
         * @param mode
         */
        public void setMode(Mode mode)
        {
            this.mCurrentStatus = mode;
            invalidate();
        }
    
        public void setArrowDegree(int degree)
        {
            this.mArrowDegree = degree;
        }
    
        public int getArrowDegree()
        {
            return this.mArrowDegree;
        }
    }
    

    GestureLockViewGroup

    package com.zhy.zhy_gesturelockview.view;
    
    import java.util.ArrayList;
    import java.util.List;
    
    import android.content.Context;
    import android.content.res.TypedArray;
    import android.graphics.Canvas;
    import android.graphics.Color;
    import android.graphics.Paint;
    import android.graphics.Path;
    import android.graphics.Point;
    import android.util.AttributeSet;
    import android.util.Log;
    import android.view.MotionEvent;
    import android.view.View;
    import android.widget.RelativeLayout;
    
    import com.zhy.zhy_gesturelockview.R;
    import com.zhy.zhy_gesturelockview.view.GestureLockView.Mode;
    
    /**
     * 整体包含n*n个GestureLockView,每个GestureLockView间间隔mMarginBetweenLockView,
     * 最外层的GestureLockView与容器存在mMarginBetweenLockView的外边距
     * 
     * 关于GestureLockView的边长(n*n): n * mGestureLockViewWidth + ( n + 1 ) *
     * mMarginBetweenLockView = mWidth ; 得:mGestureLockViewWidth = 4 * mWidth / ( 5
     * * mCount + 1 ) 注:mMarginBetweenLockView = mGestureLockViewWidth * 0.25 ;
     * 
     * @author zhy
     * 
     */
    public class GestureLockViewGroup extends RelativeLayout
    {
    
        private static final String TAG = "GestureLockViewGroup";
        /**
         * 保存所有的GestureLockView
         */
        private GestureLockView[] mGestureLockViews;
        /**
         * 每个边上的GestureLockView的个数
         */
        private int mCount = 3;
        /**
         * 存储答案
         */
        private int[] mAnswer = { 0, 1, 2, 5, 8 };
        /**
         * 保存用户选中的GestureLockView的id
         */
        private List<Integer> mChoose = new ArrayList<Integer>();
    
        private Paint mPaint;
        /**
         * 每个GestureLockView中间的间距 设置为:mGestureLockViewWidth * 25%
         */
        private int mMarginBetweenLockView = 30;
        /**
         * GestureLockView的边长 4 * mWidth / ( 5 * mCount + 1 )
         */
        private int mGestureLockViewWidth;
    
        /**
         * GestureLockView无手指触摸的状态下内圆的颜色
         */
        private int mNoFingerInnerCircleColor = 0xFF939090;
        /**
         * GestureLockView无手指触摸的状态下外圆的颜色
         */
        private int mNoFingerOuterCircleColor = 0xFFE0DBDB;
        /**
         * GestureLockView手指触摸的状态下内圆和外圆的颜色
         */
        private int mFingerOnColor = 0xFF378FC9;
        /**
         * GestureLockView手指抬起的状态下内圆和外圆的颜色
         */
        private int mFingerUpColor = 0xFFFF0000;
    
        /**
         * 宽度
         */
        private int mWidth;
        /**
         * 高度
         */
        private int mHeight;
    
        private Path mPath;
        /**
         * 指引线的开始位置x
         */
        private int mLastPathX;
        /**
         * 指引线的开始位置y
         */
        private int mLastPathY;
        /**
         * 指引下的结束位置
         */
        private Point mTmpTarget = new Point();
    
        /**
         * 最大尝试次数
         */
        private int mTryTimes = 4;
        /**
         * 回调接口
         */
        private OnGestureLockViewListener mOnGestureLockViewListener;
    
        public GestureLockViewGroup(Context context, AttributeSet attrs)
        {
            this(context, attrs, 0);
        }
    
        public GestureLockViewGroup(Context context, AttributeSet attrs,
                int defStyle)
        {
            super(context, attrs, defStyle);
            /**
             * 获得所有自定义的参数的值
             */
            TypedArray a = context.getTheme().obtainStyledAttributes(attrs,
                    R.styleable.GestureLockViewGroup, defStyle, 0);
            int n = a.getIndexCount();
    
            for (int i = 0; i < n; i++)
            {
                int attr = a.getIndex(i);
                switch (attr)
                {
                case R.styleable.GestureLockViewGroup_color_no_finger_inner_circle:
                    mNoFingerInnerCircleColor = a.getColor(attr,
                            mNoFingerInnerCircleColor);
                    break;
                case R.styleable.GestureLockViewGroup_color_no_finger_outer_circle:
                    mNoFingerOuterCircleColor = a.getColor(attr,
                            mNoFingerOuterCircleColor);
                    break;
                case R.styleable.GestureLockViewGroup_color_finger_on:
                    mFingerOnColor = a.getColor(attr, mFingerOnColor);
                    break;
                case R.styleable.GestureLockViewGroup_color_finger_up:
                    mFingerUpColor = a.getColor(attr, mFingerUpColor);
                    break;
                case R.styleable.GestureLockViewGroup_count:
                    mCount = a.getInt(attr, 3);
                    break;
                case R.styleable.GestureLockViewGroup_tryTimes:
                    mTryTimes = a.getInt(attr, 5);
                default:
                    break;
                }
            }
    
            a.recycle();
    
            // 初始化画笔
            mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
            mPaint.setStyle(Paint.Style.STROKE);
            // mPaint.setStrokeWidth(20);
            mPaint.setStrokeCap(Paint.Cap.ROUND);
            mPaint.setStrokeJoin(Paint.Join.ROUND);
            // mPaint.setColor(Color.parseColor("#aaffffff"));
            mPath = new Path();
        }
    
        @Override
        protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
        {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    
            mWidth = MeasureSpec.getSize(widthMeasureSpec);
            mHeight = MeasureSpec.getSize(heightMeasureSpec);
    
            // Log.e(TAG, mWidth + "");
            // Log.e(TAG, mHeight + "");
    
            mHeight = mWidth = mWidth < mHeight ? mWidth : mHeight;
    
            // setMeasuredDimension(mWidth, mHeight);
    
            // 初始化mGestureLockViews
            if (mGestureLockViews == null)
            {
                mGestureLockViews = new GestureLockView[mCount * mCount];
                // 计算每个GestureLockView的宽度
                mGestureLockViewWidth = (int) (4 * mWidth * 1.0f / (5 * mCount + 1));
                //计算每个GestureLockView的间距
                mMarginBetweenLockView = (int) (mGestureLockViewWidth * 0.25);
                // 设置画笔的宽度为GestureLockView的内圆直径稍微小点(不喜欢的话,随便设)
                mPaint.setStrokeWidth(mGestureLockViewWidth * 0.29f);
    
                for (int i = 0; i < mGestureLockViews.length; i++)
                {
                    //初始化每个GestureLockView
                    mGestureLockViews[i] = new GestureLockView(getContext(),
                            mNoFingerInnerCircleColor, mNoFingerOuterCircleColor,
                            mFingerOnColor, mFingerUpColor);
                    mGestureLockViews[i].setId(i + 1);
                    //设置参数,主要是定位GestureLockView间的位置
                    RelativeLayout.LayoutParams lockerParams = new RelativeLayout.LayoutParams(
                            mGestureLockViewWidth, mGestureLockViewWidth);
    
                    // 不是每行的第一个,则设置位置为前一个的右边
                    if (i % mCount != 0)
                    {
                        lockerParams.addRule(RelativeLayout.RIGHT_OF,
                                mGestureLockViews[i - 1].getId());
                    }
                    // 从第二行开始,设置为上一行同一位置View的下面
                    if (i > mCount - 1)
                    {
                        lockerParams.addRule(RelativeLayout.BELOW,
                                mGestureLockViews[i - mCount].getId());
                    }
                    //设置右下左上的边距
                    int rightMargin = mMarginBetweenLockView;
                    int bottomMargin = mMarginBetweenLockView;
                    int leftMagin = 0;
                    int topMargin = 0;
                    /**
                     * 每个View都有右外边距和底外边距 第一行的有上外边距 第一列的有左外边距
                     */
                    if (i >= 0 && i < mCount)// 第一行
                    {
                        topMargin = mMarginBetweenLockView;
                    }
                    if (i % mCount == 0)// 第一列
                    {
                        leftMagin = mMarginBetweenLockView;
                    }
    
                    lockerParams.setMargins(leftMagin, topMargin, rightMargin,
                            bottomMargin);
                    mGestureLockViews[i].setMode(Mode.STATUS_NO_FINGER);
                    addView(mGestureLockViews[i], lockerParams);
                }
    
                Log.e(TAG, "mWidth = " + mWidth + " ,  mGestureViewWidth = "
                        + mGestureLockViewWidth + " , mMarginBetweenLockView = "
                        + mMarginBetweenLockView);
    
            }
        }
    
        @Override
        public boolean onTouchEvent(MotionEvent event)
        {
            int action = event.getAction();
            int x = (int) event.getX();
            int y = (int) event.getY();
    
            switch (action)
            {
            case MotionEvent.ACTION_DOWN:
                // 重置
                reset();
                break;
            case MotionEvent.ACTION_MOVE:
                mPaint.setColor(mFingerOnColor);
                mPaint.setAlpha(50);
                GestureLockView child = getChildIdByPos(x, y);
                if (child != null)
                {
                    int cId = child.getId();
                    if (!mChoose.contains(cId))
                    {
                        mChoose.add(cId);
                        child.setMode(Mode.STATUS_FINGER_ON);
                        if (mOnGestureLockViewListener != null)
                            mOnGestureLockViewListener.onBlockSelected(cId);
                        // 设置指引线的起点
                        mLastPathX = child.getLeft() / 2 + child.getRight() / 2;
                        mLastPathY = child.getTop() / 2 + child.getBottom() / 2;
    
                        if (mChoose.size() == 1)// 当前添加为第一个
                        {
                            mPath.moveTo(mLastPathX, mLastPathY);
                        } else
                        // 非第一个,将两者使用线连上
                        {
                            mPath.lineTo(mLastPathX, mLastPathY);
                        }
    
                    }
                }
                // 指引线的终点
                mTmpTarget.x = x;
                mTmpTarget.y = y;
                break;
            case MotionEvent.ACTION_UP:
    
                mPaint.setColor(mFingerUpColor);
                mPaint.setAlpha(50);
                this.mTryTimes--;
    
                // 回调是否成功
                if (mOnGestureLockViewListener != null && mChoose.size() > 0)
                {
                    mOnGestureLockViewListener.onGestureEvent(checkAnswer());
                    if (this.mTryTimes == 0)
                    {
                        mOnGestureLockViewListener.onUnmatchedExceedBoundary();
                    }
                }
    
                Log.e(TAG, "mUnMatchExceedBoundary = " + mTryTimes);
                Log.e(TAG, "mChoose = " + mChoose);
                // 将终点设置位置为起点,即取消指引线
                mTmpTarget.x = mLastPathX;
                mTmpTarget.y = mLastPathY;
    
                // 改变子元素的状态为UP
                changeItemMode();
    
                // 计算每个元素中箭头需要旋转的角度
                for (int i = 0; i + 1 < mChoose.size(); i++)
                {
                    int childId = mChoose.get(i);
                    int nextChildId = mChoose.get(i + 1);
    
                    GestureLockView startChild = (GestureLockView) findViewById(childId);
                    GestureLockView nextChild = (GestureLockView) findViewById(nextChildId);
    
                    int dx = nextChild.getLeft() - startChild.getLeft();
                    int dy = nextChild.getTop() - startChild.getTop();
                    // 计算角度
                    int angle = (int) Math.toDegrees(Math.atan2(dy, dx)) + 90;
                    startChild.setArrowDegree(angle);
                }
                //reset();
                break;
    
            }
            invalidate();
            return true;
        }
    
        private void changeItemMode()
        {
            for (GestureLockView gestureLockView : mGestureLockViews)
            {
                if (mChoose.contains(gestureLockView.getId()))
                {
                    gestureLockView.setMode(Mode.STATUS_FINGER_UP);
                }
            }
        }
    
        /**
         * 
         * 做一些必要的重置
         */
        private void reset()
        {
            mChoose.clear();
            mPath.reset();
            for (GestureLockView gestureLockView : mGestureLockViews)
            {
                gestureLockView.setMode(Mode.STATUS_NO_FINGER);
                gestureLockView.setArrowDegree(-1);
            }
        }
        /**
         * 检查用户绘制的手势是否正确
         * @return
         */
        private boolean checkAnswer()
        {
            if (mAnswer.length != mChoose.size())
                return false;
    
            for (int i = 0; i < mAnswer.length; i++)
            {
                if (mAnswer[i] != mChoose.get(i))
                    return false;
            }
    
            return true;
        }
    
        /**
         * 检查当前左边是否在child中
         * @param child
         * @param x
         * @param y
         * @return
         */
        private boolean checkPositionInChild(View child, int x, int y)
        {
    
            //设置了内边距,即x,y必须落入下GestureLockView的内部中间的小区域中,可以通过调整padding使得x,y落入范围不变大,或者不设置padding
            int padding = (int) (mGestureLockViewWidth * 0.15);
    
            if (x >= child.getLeft() + padding && x <= child.getRight() - padding
                    && y >= child.getTop() + padding
                    && y <= child.getBottom() - padding)
            {
                return true;
            }
            return false;
        }
    
        /**
         * 通过x,y获得落入的GestureLockView
         * @param x
         * @param y
         * @return
         */
        private GestureLockView getChildIdByPos(int x, int y)
        {
            for (GestureLockView gestureLockView : mGestureLockViews)
            {
                if (checkPositionInChild(gestureLockView, x, y))
                {
                    return gestureLockView;
                }
            }
    
            return null;
    
        }
    
        /**
         * 设置回调接口
         * 
         * @param listener
         */
        public void setOnGestureLockViewListener(OnGestureLockViewListener listener)
        {
            this.mOnGestureLockViewListener = listener;
        }
    
        /**
         * 对外公布设置答案的方法
         * 
         * @param answer
         */
        public void setAnswer(int[] answer)
        {
            this.mAnswer = answer;
        }
    
        /**
         * 设置最大实验次数
         * 
         * @param boundary
         */
        public void setUnMatchExceedBoundary(int boundary)
        {
            this.mTryTimes = boundary;
        }
    
        @Override
        public void dispatchDraw(Canvas canvas)
        {
            super.dispatchDraw(canvas);
            //绘制GestureLockView间的连线
            if (mPath != null)
            {
                canvas.drawPath(mPath, mPaint);
            }
            //绘制指引线
            if (mChoose.size() > 0)
            {
                if (mLastPathX != 0 && mLastPathY != 0)
                    canvas.drawLine(mLastPathX, mLastPathY, mTmpTarget.x,
                            mTmpTarget.y, mPaint);
            }
    
        }
    
        public interface OnGestureLockViewListener
        {
            /**
             * 单独选中元素的Id
             * 
             * @param position
             */
            public void onBlockSelected(int cId);
    
            /**
             * 是否匹配
             * 
             * @param matched
             */
            public void onGestureEvent(boolean matched);
    
            /**
             * 超过尝试次数
             */
            public void onUnmatchedExceedBoundary();
        }
    }
    

    布局文件

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:zhy="http://schemas.android.com/apk/res/com.zhy.zhy_gesturelockview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    
        <com.zhy.zhy_gesturelockview.view.GestureLockViewGroup
            android:id="@+id/id_gestureLockViewGroup"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#F2F2F7"
            android:gravity="center_vertical"
            zhy:count="3"
            zhy:tryTimes="5" />
    <!--   zhy:color_no_finger_inner_circle="#ff085D58"
            zhy:color_no_finger_outer_circle="#ff08F0E0"
            zhy:color_finger_on="#FF1734BF" -->
    
    </RelativeLayout>

    调用

    package com.zhy.zhy_gesturelockview;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.widget.Toast;
    
    import com.zhy.zhy_gesturelockview.view.GestureLockViewGroup;
    import com.zhy.zhy_gesturelockview.view.GestureLockViewGroup.OnGestureLockViewListener;
    
    public class MainActivity extends Activity
    {
    
        private GestureLockViewGroup mGestureLockViewGroup;
    
        @Override
        protected void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            mGestureLockViewGroup = (GestureLockViewGroup) findViewById(R.id.id_gestureLockViewGroup);
            mGestureLockViewGroup.setAnswer(new int[] { 1, 2, 3 });
            mGestureLockViewGroup
                    .setOnGestureLockViewListener(new OnGestureLockViewListener()
                    {
    
                        @Override
                        public void onUnmatchedExceedBoundary()
                        {
                            Toast.makeText(MainActivity.this, "错误5次...",
                                    Toast.LENGTH_SHORT).show();
                            mGestureLockViewGroup.setUnMatchExceedBoundary(5);
                        }
    
                        @Override
                        public void onGestureEvent(boolean matched)
                        {
                            Toast.makeText(MainActivity.this, matched+"",
                                    Toast.LENGTH_SHORT).show();
                        }
    
                        @Override
                        public void onBlockSelected(int cId)
                        {
                        }
                    });
        }
    
    }

    ondraw() 和dispatchdraw()的区别

    本文中用到了dispatchdraw,
    绘制VIew本身的内容,通过调用View.onDraw(canvas)函数实现

    绘制自己的孩子通过dispatchDraw(canvas)实现

    参考链接

    ondraw() 和dispatchdraw()的区别 - scorplopan的专栏 - 博客频道 - CSDN.NET

    在计算箭头应该转化的角度时用到了atan2

    atan2 返回的是方位角,也可以理解为计算复数 x+yi 的辐角

    参考链接

    atan2_百度百科

    本文主要参考链接

    Android 手势锁的实现 让自己的应用更加安全吧 - Hongyang - 博客频道 - CSDN.NET

    源代码下载

    源代码下载

    完成

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  • 原文地址:https://www.cnblogs.com/jjx2013/p/6223661.html
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