怎么在Android 应用中实现一个九宫格手势锁

怎么在Android 应用中实现一个九宫格手势锁？很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。

主要的方法是重写View.onTouchEvent( MotionEvent event ) , 常用的三个操作：ACTION_DOWN 手指触摸屏幕 ; ACTION_UP 手指离开屏幕;

ACTION_MOVE手指在屏幕滑动。

如果该方法返回true ，表示该事件已经被View处理，不再向上层的View或Activity传递 ； 如果返回false， 表示事件未处理，继续传递。

实现代码如下:

package com.ninegrid;import android.content.Context;import android.graphics.canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;public class SuduView extends View {  //定义默认常量  private static final int DEFAULT_CELL_WIDTH = 200 ;  private static final int DEFAULT_CELL_STROKE_WIDTH = 10 ;  private static final int DEFAULT_SPACE = 100 ;  //九宫格数组  private Cell mCells[] = new Cell[9] ;  //直径  private int mCellWidth;  //半径  private int mCellRadius;  //边框宽度  private int mCellStrokeWidth;  //空白部分  private int mSpace ;  //定义画笔  private Paint mPaintNORMal ;  private Paint mPaintSelected ;  private float mCurrentX ;  private float mCurrentY ;  //判断是否结束的标识  private boolean mFinish = false ;  private StringBuffer mSbSelected = new StringBuffer(20);  public SuduView(Context context) {    super(context);    init();  }  public SuduView(Context context, AttributeSet attrs) {    super(context, attrs);    init();  }  public SuduView(Context context, AttributeSet attrs, int defStyleAttr) {    super(context, attrs, defStyleAttr);    init();  }  private void init(){    //初始化画笔    mCellWidth = DEFAULT_CELL_WIDTH ;    mCellRadius = DEFAULT_CELL_WIDTH >> 1 ;    mCellStrokeWidth = DEFAULT_CELL_STROKE_WIDTH ;    mSpace = DEFAULT_SPACE ;    mPaintNormal = new Paint();    mPaintNormal.setColor(Color.WHITE);    mPaintNormal.setStrokeWidth(mCellStrokeWidth);    mPaintNormal.setStyle(Paint.Style.STROKE);    mPaintNormal.setAntiAlias(true);    mPaintSelected = new Paint();    mPaintSelected.setColor(Color.CYAN);    mPaintSelected.setStrokeWidth(mCellStrokeWidth);    mPaintSelected.setStyle(Paint.Style.STROKE);    mPaintSelected.setAntiAlias(true);    Cell cell ;    float x;    float y;    //计算每个格子的坐标    for( int i = 0 ; i < 9 ; i ++ ){      x = mSpace * ( i%3 + 1 ) + mCellRadius + mCellWidth * ( i%3 ) ;      y = mSpace * ( i/3 + 1 ) + mCellRadius + mCellWidth * ( i/3 ) ;      cell = new Cell(x , y);      mCells[i] = cell ;    }  }  @Override  protected void onDraw(Canvas canvas) {    super.onDraw(canvas);    drawCell(canvas);    drawLine(canvas);  }  //绘制连接线  private void drawLine( Canvas canvas ){    if("".equals(mSbSelected.toString())){      return;    }    String[] selectedIndexs = mSbSelected.toString().split(",");    Cell cell = mCells[Integer.valueOf(selectedIndexs[0])];    Cell nextCell ;    //绘制每两个格子中心点之间的连接线    if( selectedIndexs.length > 1) {      for (int i = 1; i < selectedIndexs.length; i++) {        nextCell = mCells[Integer.valueOf(selectedIndexs[i])];        canvas.drawLine(cell.getCenterX(), cell.getCenterY(), nextCell.getCenterX(), nextCell.getCenterY(), mPaintSelected);        cell = nextCell;      }    }    //绘制格子到其他空白位置的连接线    if( !mFinish ) {      canvas.drawLine(cell.getCenterX(), cell.getCenterY(), mCurrentX, mCurrentY, mPaintSelected);    }  }  private void drawCell( Canvas canvas ){    for ( int i = 0 ; i < 9 ; i ++ ){      canvas.drawCircle(mCells[i].getCenterX(), mCells[i].getCenterY() , mCellRadius ,          mCells[i].isSelected() &#63; mPaintSelected : mPaintNormal );    }  }  //处理点击事件  @Override  public boolean onTouchEvent(MotionEvent event) {    switch ( event.getAction()){      case MotionEvent.ACTION_DOWN:        //如果手指已经松开，则所有格子变为初始状态        if( mFinish ){          for ( int i = 0 ; i < 9 ; i ++ ){            mCells[i].setSelected(false);          }          mFinish = false ;          mSbSelected.delete(0,mSbSelected.length());          invalidate();          return false;        }        handleDownEvent(event);        break;      //松开则结束      case MotionEvent.ACTION_UP:        mFinish = true ;        break;      case MotionEvent.ACTION_MOVE:        handleMoveEvent(event);        break;    }    //表示已处理，不向上传递    return true ;  }  //处理手指移动的事件  private void handleMoveEvent( MotionEvent event ){    int index = findCellIndex(event.getX(),event.getY());    if( index != -1 ){      mCells[index].setSelected(true);      mSbSelected.append(index).append(",");    }    invalidate();    mCurrentX = event.getX();    mCurrentY = event.getY();  }  //处理手指按下的事件  private void handleDownEvent( MotionEvent event){    int index = findCellIndex(event.getX(),event.getY());    if( index != -1 ){      mCells[index].setSelected(true);      mSbSelected.append(index).append(",");      invalidate();    }    mCurrentX = event.getX();    mCurrentY = event.getY();  }  //根据坐标判断点击的哪个格子  private int findCellIndex( float x , float y){    float cellX ;    float cellY ;    int result = -1 ;    for( int i = 0 ; i < 9 ; i ++ ){      if( mCells[i].isSelected()){        continue;      }      //获取每个格子的坐标      cellX = mCells[i].getCenterX();      cellY = mCells[i].getCenterY();      //计算按下的点到每个格子的距离      float tempX = cellX - x ;      float tempY = cellY - y ;      float distance = (float) Math.sqrt(tempX * tempX + tempY * tempY);      //如果点击的位置在某个格子的圆内      if( distance < mCellRadius ){        result = i ;        break;      }    }    //返回该格子的位置    return result ;  }}