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。
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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; /** * Created by Administrator on 2017/6/24. */ 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() ? 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 ; } }
最后在布局文件中引用该View即可,若想实现更高的定制性,可以仿照上一篇文章重写View的onMearsure方法并增加自定义属性。
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