本文概述：

 滑动解锁九宫格的分析：

1、需要自定义控件；
2、需要重写事件onTouchEvent();
3、需要给九个点设置序号和坐标，这里用Map类就行；
4、需要判断是否到滑到过九点之一，并存储滑到过的点的序号，而且需要一个方法可以返回它们，这里用List类就行；

滑动解锁当前还是比较流行的，今天写了个简单的滑动解锁九宫格的例程，分享出来让初学者看看。

我的是这样的：

Demo

首先，自定义一个View

/**
 * 九宫格
 */
public class NineGridView extends View {
  private int width;//该控件的宽
  private int height;//该控件的高
  private Paint mPaintBigCircle;//用于画外圆
  private Paint mPaintSmallCircle;//用于画内圆
  private Paint mPaintLine;//用于画线
  private Paint mPaintText;//用于画文本
  private Path path;//手势划线时需要用到它
  private Map<Integer, Float[]> pointContainer;//存储九个点的坐标
  private List<Integer> pointerSlipped;//存储得到的九宫格密码
  public List<Integer> getPointerSlipped() {
    return pointerSlipped;
  }
  public void setPointerSlipped(List<Integer> pointerSlipped) {
    this.pointerSlipped = pointerSlipped;
  }
  public NineGridView(Context context) {
    super(context);
  }
  public NineGridView(Context context, AttributeSet attrs) {
    super(context, attrs);
    mPaintBigCircle = new Paint();
    mPaintBigCircle.setColor(Color.BLUE);
    mPaintBigCircle.setStyle(Paint.Style.STROKE);//不充满
    mPaintBigCircle.setAntiAlias(true);//抗锯齿打开
    mPaintSmallCircle = new Paint();
    mPaintSmallCircle.setColor(Color.GREEN);
    mPaintSmallCircle.setStyle(Paint.Style.FILL);//充满，即画的几何体为实心
    mPaintSmallCircle.setAntiAlias(true);
    mPaintLine = new Paint();
    mPaintLine.setColor(Color.GREEN);
    mPaintLine.setStyle(Paint.Style.STROKE);
    mPaintLine.setStrokeWidth(20);
    mPaintLine.setAntiAlias(true);
    mPaintText = new Paint();
    mPaintText.setColor(Color.WHITE);
    mPaintText.setTextAlign(Paint.Align.CENTER);//向中央对齐
    mPaintText.setTextSize(50);
    mPaintText.setAntiAlias(true);
    path = new Path();
    pointContainer = new HashMap<>();
    pointerSlipped = new ArrayList<>();
  }
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    width = getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec);
    height = getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec);
  }
  private float pivotX;//触屏得到的x坐标
  private float pivotY;//触屏得到的y坐标
  private float selectedX;//当前选中的圆点的x坐标
  private float selectedY;//当前选中的圆点的y坐标
  private float selectedXOld;//从前选中的圆点的x坐标
  private float selectedYOld;//从前选中的圆点的y坐标
  private boolean isHasMoved = false;//用于判断path是否调用过moveTo()方法
  @Override
  public boolean onTouchEvent(MotionEvent event) {
    switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
        pivotX = event.getX();
        pivotY = event.getY();
        //每次触屏时需要清空一下pointerSlipped，即重置密码
        pointerSlipped.clear();
        Log.d("pointTouched", pivotX + "," + pivotY);
        getSelectedPointIndex(pivotX, pivotY);
        invalidate();//重绘
        break;
      case MotionEvent.ACTION_MOVE:
        pivotX = event.getX();
        pivotY = event.getY();
        getSelectedPointIndex(pivotX, pivotY);
        invalidate();
        break;
      case MotionEvent.ACTION_UP:
        /**
         * 当手指离开屏幕时，重置path
         */
        path.reset();
        isHasMoved = false;
        String indexSequence = "";
        //打印出上一次手势密码的值
        for(int index:pointerSlipped){
          indexSequence += "/"+index;
        }
        Log.d("index",indexSequence);
        break;
    }
    invalidate();
    return true;
  }
  /**
   * 得到并存储经过的圆点的序号
   * @param pivotX
   * @param pivotY
   */
  private void getSelectedPointIndex(float pivotX, float pivotY) {
    int index = 0;
    if (pivotX > patternMargin && pivotX < patternMargin + bigCircleRadius * 2) {
      if (pivotY > height / 2 && pivotY < height / 2 + bigCircleRadius * 2) {
        selectedX = pointContainer.get(1)[0];
        selectedY = pointContainer.get(1)[1];
        index = 1;
        Log.d("selectedPoint", selectedX + "," + selectedY);
      } else if (pivotY > height / 2 + added && pivotY < height / 2 + added + bigCircleRadius * 2) {
        selectedX = pointContainer.get(4)[0];
        selectedY = pointContainer.get(4)[1];
        index = 4;
      } else if (pivotY > height / 2 + added * 2 && pivotY < height / 2 + added * 2 + bigCircleRadius * 2) {
        selectedX = pointContainer.get(7)[0];
        selectedY = pointContainer.get(7)[1];
        index = 7;
      }
    } else if (pivotX > patternMargin + added && pivotX < patternMargin + added + bigCircleRadius * 2) {
      if (pivotY > height / 2 && pivotY < height / 2 + bigCircleRadius * 2) {
        selectedX = pointContainer.get(2)[0];
        selectedY = pointContainer.get(2)[1];
        index = 2;
      } else if (pivotY > height / 2 + added && pivotY < height / 2 + added + bigCircleRadius * 2) {
        selectedX = pointContainer.get(5)[0];
        selectedY = pointContainer.get(5)[1];
        index = 5;
      } else if (pivotY > height / 2 + added * 2 && pivotY <height / 2 + added * 2 + bigCircleRadius * 2) {
        selectedX = pointContainer.get(8)[0];
        selectedY = pointContainer.get(8)[1];
        index = 8;
      }
    } else if (pivotX > patternMargin + added * 2 && pivotX < patternMargin + added * 2 + bigCircleRadius * 2) {
      if (pivotY > height / 2 && pivotY < height / 2 + bigCircleRadius * 2) {
        selectedX = pointContainer.get(3)[0];
        selectedY = pointContainer.get(3)[1];
        index = 3;
      } else if (pivotY > height / 2 + added && pivotY < height / 2 + added + bigCircleRadius * 2) {
        selectedX = pointContainer.get(6)[0];
        selectedY = pointContainer.get(6)[1];
        index = 6;
      } else if (pivotY > height / 2 + added * 2 && pivotY < height / 2 + added * 2 + bigCircleRadius * 2) {
        selectedX = pointContainer.get(9)[0];
        selectedY = pointContainer.get(9)[1];
        index = 9;
      }
    }
    if (selectedX!=selectedXOld||selectedY!=selectedYOld){
      //当这次的坐标与上次的坐标不同时存储这次点序号
      pointerSlipped.add(index);
      selectedXOld = selectedX;
      selectedYOld = selectedY;
      if (!isHasMoved){
        //当第一次触碰到九个点之一时，path调用moveTo;
        path.moveTo(selectedX,selectedY);
        isHasMoved = true;
      }else{
        //path移动至当前圆点坐标
        path.lineTo(selectedX,selectedY);
      }
    }
  }
  private String text = "请绘制解锁图案";
  private float x;//绘制的圆形的x坐标
  private float y;//绘制圆形的纵坐标
  private float added;//水平竖直方向每个圆点中心间距
  private float patternMargin = 100;//九宫格距离边界距离
  private float bigCircleRadius = 90;//外圆半径
  private float smallCircleRadius = 25;//内圆半径
  private int index;//圆点的序号
  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    added = (width - patternMargin * 2) / 3;
    x = patternMargin + added / 2;
    y = added / 2 + height / 2;
    index = 1;
    canvas.drawColor(Color.BLACK);
    canvas.drawText(text, width / 2, height / 4, mPaintText);
    /**
     * 绘制九个圆点图案
     */
    for (int column = 0; column < 3; column++) {
      for (int row = 0; row < 3; row++) {
        canvas.drawCircle(x, y, bigCircleRadius, mPaintBigCircle);
        canvas.drawCircle(x, y, smallCircleRadius, mPaintSmallCircle);
        pointContainer.put(index, new Float[]{x, y});
        index++;
        x += added;
      }
      y += added;
      x = patternMargin + added / 2;
    }
    x = patternMargin + added / 2;
    y = added / 2 + height / 2;
    canvas.drawPath(path, mPaintLine);
  }
}

为什么要规避重复？

因为在触屏时，会调用很多次onTouchEvent()方法，这样存储的手势密码肯定会不准确，我在以上代码中作出了处理，已经避免了重复，看打印信息：

这里写图片描述

显然，密码没有相邻数重复，当然还有一种情况就是手指在两个点之间来回等问题，这种状况也需要避免，这里没有作处理。当然，我做得还不够。。。

自定义view中用到的dp和px互相转换的工具类：

public class SizeConvert {
  /**
   * 将dp转换为sp
   */
  public static int dip2px(Context context, float dipValue){
    final float scale = context.getResources().getDisplayMetrics().density;
    return (int)(dipValue * scale + 0.5f);
  }
  /**
   * sp转dp
   */
  public static int px2dip(Context context, float pxValue){
    final float scale = context.getResources().getDisplayMetrics().density;
    return (int)(pxValue / scale + 0.5f);
  }
}

主活动：

public class NineGridActivity extends BaseActivity{
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.view_nine_grid);
  }
}

layout中的布局文件view_nine_grid：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
       android:orientation="vertical"
       android:layout_width="match_parent"
       android:layout_height="match_parent">
  <com.test.shiweiwei.myproject.selfish_view.NineGridView
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>
</LinearLayout>

总结

我写的只是最基本的九宫格滑动解密项目，实际用的九宫格解密比这个要复杂，有许多特效和其他更严谨的处理，事件的处理也不是这样草草了事，如果想写得漂亮，还得多花工夫。