Android studio实现刮刮乐的方法

public class MainActivity extends AppCompatActivity {  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);  }}

public class GuaTwo extends View {  /*第一种方法*/  private Path mPath;//手刮动的path，过程  private Paint mOutterPaint;//绘制mPath的画笔  private Canvas mCanvas;//临时画布  private Bitmap mBitmap;//临时图片  //记录用户path每次的开始坐标值  private int mLastX;  private int mLastY;  private Bitmap mOutterBitmap;//图片遮罩，就是手刮动，要擦掉的那张图  public GuaTwo(Context context) {    this(context, null);  }  public GuaTwo(Context context, AttributeSet attrs) {    this(context, attrs, 0);  }  public GuaTwo(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);    init();  }  @Override  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {    super.onMeasure(widthMeasureSpec, heightMeasureSpec);    //获得控件的宽高    int width = getMeasuredWidth();    int height = getMeasuredHeight();    //初始化bitmap    mBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);    mCanvas = new Canvas(mBitmap);    //设置画笔属性    setupOutPaint();    mCanvas.drawColor(Color.parseColor("#c0c0c0"));  }  @Override  protected void onDraw(Canvas canvas) {    mOutterPaint.setStyle(Paint.Style.STROKE);    mOutterPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));//Mode.DST_OUT改模式就类似橡皮檫，这个属性设置是关键    canvas.drawBitmap(mOutterBitmap, 0, 0, null);    canvas.drawBitmap(mBitmap, 0, 0, null);    mCanvas.drawPath(mPath, mOutterPaint);  }  @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://按下        //记录按下的时候的X和Y值，以便于之后移动的时候绘制        mLastX = x;        mLastY = y;        mPath.moveTo(mLastX, mLastY);        break;      case MotionEvent.ACTION_MOVE://移动        //拿到用户移动的X绝对值，Y轴绝对值        int dx = Math.abs(x - mLastX);        int dy = Math.abs(y - mLastY);        //用户滑动超过3像素才会改变，这个可以不做，做只是为了避免很频繁的响应而已。        if (dx > 3 || dy > 3) {          mPath.lineTo(x, y);        }        mLastX = x;        mLastY = y;        break;    }    invalidate();//刷新UI    return true;  }  /**   * 绘制path（也就是手刮动的path来绘制） 的画笔属性   * 类似橡皮擦   */  private void setupOutPaint() {    mOutterPaint.setColor(Color.RED);    mOutterPaint.setAntiAlias(true);    mOutterPaint.setDither(true);    mOutterPaint.setStrokeJoin(Paint.Join.ROUND);//设置圆角    mOutterPaint.setStrokeCap(Paint.Cap.ROUND);    mOutterPaint.setStyle(Paint.Style.FILL);    mOutterPaint.setStrokeWidth(60);//设置画笔宽度  }  /**   * 初始化信息   */  private void init() {    mOutterPaint = new Paint();    mPath = new Path();    mOutterBitmap = BitmapFactory.decodeResource(getResources(),        R.drawable.mein);  }

private Path mPath;//手刮动的path，过程  private Paint mOutterPaint;//绘制mPath的画笔  private Canvas mCanvas;  private Bitmap mBitmap;  //记录用户path每次的开始坐标值  private int mLastX;  private int mLastY;  private Bitmap mOutterBitmap;//图片遮罩，就是手刮动，要擦掉的那张图  private String mText;//刮奖文本信息  private Rect mTextBound;  private Paint mBackPaint;//刮奖信息的画笔  public GuaTwo(Context context) {    this(context, null);  }  public GuaTwo(Context context, AttributeSet attrs) {    this(context, attrs, 0);  }  public GuaTwo(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);    init();  }  @Override  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {    super.onMeasure(widthMeasureSpec, heightMeasureSpec);    //获得控件的宽高    int width = getMeasuredWidth();    int height = getMeasuredHeight();    //初始化bitmap    mBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);    mCanvas = new Canvas(mBitmap);//用指定的位图构造一个画布来绘制。    //设置画笔属性    setupOutPaint();    setUpBackPaint();//    mCanvas.drawColor(Color.parseColor("#c0c0c0"));    mCanvas.drawRoundRect(new RectF(0, 0, width, height), 30, 30,        mOutterPaint);//用mOutterPaint画圆角矩形    mCanvas.drawBitmap(mOutterBitmap, null, new Rect(0, 0, width, height),        null);//在刚刚画的圆角矩形上面再画一个bitmap图片，让图片大小和圆角矩形大小相关联  }  @Override  protected void onDraw(Canvas canvas) {    mOutterPaint.setStyle(Paint.Style.STROKE);    mOutterPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));//Mode.DST_OUT改模式就类似橡皮檫，这个属性设置是关键    canvas.drawText(mText, (getWidth() - mTextBound.width()) / 2, getHeight() / 2 - mTextBound.height() / 2, mBackPaint);//把获奖信息放在正中间    mCanvas.drawPath(mPath, mOutterPaint);    canvas.drawBitmap(mBitmap, 0, 0, null);  }  @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://按下        //记录按下的时候的X和Y值，以便于之后移动的时候绘制        mLastX = x;        mLastY = y;        mPath.moveTo(mLastX, mLastY);        break;      case MotionEvent.ACTION_MOVE://移动        //拿到用户移动的X绝对值，Y轴绝对值        int dx = Math.abs(x - mLastX);        int dy = Math.abs(y - mLastY);        //用户滑动超过3像素才会改变，这个可以不做，做只是为了避免很频繁的相应而已。        if (dx > 3 || dy > 3) {          mPath.lineTo(x, y);        }        mLastX = x;        mLastY = y;        break;    }    invalidate();//刷新UI    return true;  }  private void setUpBackPaint() {    mBackPaint.setColor(Color.RED);    mBackPaint.setStyle(Paint.Style.FILL);    mBackPaint.setTextSize(60);    //获得当前画笔绘制文本的宽和高    mBackPaint.getTextBounds(mText, 0, mText.length(), mTextBound);  }  *//**   * 绘制path（也就是手刮动的path来绘制） 的画笔属性   * 类似橡皮擦   *//*  private void setupOutPaint() {    mOutterPaint.setColor(Color.RED);    mOutterPaint.setAntiAlias(true);    mOutterPaint.setDither(true);    mOutterPaint.setStrokeJoin(Paint.Join.ROUND);//设置圆角    mOutterPaint.setStrokeCap(Paint.Cap.ROUND);    mOutterPaint.setStyle(Paint.Style.FILL);    mOutterPaint.setStrokeWidth(60);//设置画笔宽度  }  *//**   * 初始化信息   *//*  private void init() {    mOutterPaint = new Paint();    mPath = new Path();    mOutterBitmap = BitmapFactory.decodeResource(getResources(),        R.drawable.huahua);    mText = "您中奖了！";    mTextBound = new Rect();    mBackPaint = new Paint();  }

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:id="@+id/activity_main"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:paddingBottom="@dimen/activity_vertical_margin"  android:paddingLeft="@dimen/activity_horizontal_margin"  android:paddingRight="@dimen/activity_horizontal_margin"  android:paddingTop="@dimen/activity_vertical_margin"  tools:context="com.bwie.test.guaguale.MainActivity">  <com.bwie.test.guaguale.GuaTwo    android:layout_width="wrap_content"    android:layout_height="wrap_content" /></RelativeLayout>