package com.example.test.view;

import com.example.test.R;

import android.content.Context;

import android.content.res.TypedArray;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.os.Handler;

import android.os.Message;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

/**

 * Focus View

 * @author xp.chen

 */

public class FocusView extends View {

    public FocusView(Context context) {

        super(context);

    }

    public FocusView(Context context, AttributeSet attrs) {

        super(context, attrs);

        init(context,attrs);

    }

    private Paint mPaint;

    private void init(Context context, AttributeSet attrs) {

        // init paint

        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.FocusView);

        int count = typedArray.getIndexCount();

        for (int i = 0; i < count; i++) {

            int id = typedArray.getIndex(i);

            switch (id) {

            case R.styleable.FocusView_focusColor:

                paintColor = typedArray.getColor(id, Color.WHITE);

                break;

            case R.styleable.FocusView_focusDefaultRadius:

                radius = typedArray.getFloat(id, 20);

                break;

            case R.styleable.FocusView_focusMaxRadius:

                maxRadius = typedArray.getFloat(id, 100);

                break;

            default:

                break;

            }

        }

        typedArray.recycle();

        mPaint = new Paint();

        mPaint.setAntiAlias(true);

        mPaint.setStyle(Paint.Style.STROKE);

        mPaint.setStrokeWidth(3);

        mPaint.setColor(paintColor);

    }

    // addGestureRecognizer UITapGestureRecognizer

    @Override

    public boolean onTouchEvent(MotionEvent event) {

        switch (event.getAction()) {

        case MotionEvent.ACTION_DOWN: // UIGestureRecognizerStateBegan

            if (!isStart) {

                centerX = event.getX();

                centerY = event.getY();

                // 重量选框参数

                isStart = true;

                isNeedDismiss = false;

                paintAlpha = 255;

                mPaint.setAlpha(paintAlpha);

                radius = 20;

                invalidate();

                mHandler.obtainMessage(0).sendToTarget();

            }

            break;

        case MotionEvent.ACTION_MOVE: // UIGestureRecognizerStateChange

            break;

        case MotionEvent.ACTION_UP: // UIGestureRecognizerStateEnd

            break;

        default:

            break;

        }

        return super.onTouchEvent(event);

    }

    private Handler mHandler = new Handler() {

        @Override

        public void handleMessage(Message msg) {

            super.handleMessage(msg);

            switch (msg.what) {

            case 0: // update size

                radius += 5;

                if (radius >= maxRadius) { // 若将要绘制的尺寸大于约束的最大尺寸,则将该尺寸还原

                    radius -= 5;

                    mHandler.sendEmptyMessageDelayed(1, 1000); // 使选框停留1s后逐渐消失

                } else {

                    mHandler.sendEmptyMessageDelayed(0, (long)(200f/radius));

                    invalidate(); // setNeedDisplay

                }

                break;

            case 1: // update alpha

                paintAlpha -= 20; // 当选框达到最大后,就不断改变其透明度，直至透明度为0，本次绘制过程结束

                if (paintAlpha <=0) {

                    isNeedDismiss = true;

                    invalidate();

                    isStart = false;

                } else {

                    mPaint.setAlpha(paintAlpha);

                    invalidate();

                    mHandler.sendEmptyMessageDelayed(1,15);

                }

                break;

            default:

                break;

            }

        }

    };

    @Override

    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        // CGSize

//        setMeasuredDimension(measuredWidth, measuredHeight);

    }

    private float centerX; // 焦点中心点X

    private float centerY; // 焦点中心点Y

    private float radius = 20; // 焦点选框的最小半径

    private float maxRadius = 100; // 焦点选框的最大半径

    private int paintAlpha = 255; // 焦点选框的最大透明度

    private int paintColor = Color.WHITE;

    /**

     * 设置焦点选框的初始半径

     * @param radius

     */

    public void setFocusCircleRadius(float radius) {

        this.radius = radius;

    }

    /**

     * 设置焦点选框的最大半径

     * @param radius

     */

    public void setFocusCircleMaxRadius(float radius) {

        this.maxRadius = radius;

    }

    /**

     * 设置焦点选框的颜色

     * @param color

     */

    public void setFocusCircleColor(int color) {

        this.paintColor = color;

        mPaint.setColor(color);

    }

    /**

     * 焦点选框是否需要消失

     */

    private boolean isNeedDismiss = true; 

    /**

     * 是否已经开始绘制的标志位。如果已经开始绘制，则拒绝下一次点击绘制请求

     */

    private boolean isStart = false;

    // drawRect

    @Override

    protected void onDraw(Canvas canvas) {

        if (!isNeedDismiss) { // 若绘制过程结束,则清除焦点框

            canvas.drawCircle(centerX, centerY, radius, mPaint);

        }

    }

}

    <declare-styleable name="FocusView">

        <attr name="focusDefaultRadius" format="float"/>

        <attr name="focusMaxRadius" format="float"/>

        <attr name="focusColor" format="color"/>

    </declare-styleable>

<RelativeLayout

    xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:app="http://schemas.android.com/apk/res/com.example.test"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:background="#000"

    >

    <com.example.test.view.FocusView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        app:focusColor = "#fff"

        app:focusMaxRadius = "100"

        />

</RelativeLayout>