刮刮卡效果

刮刮卡类：

package com.reyo.view;import android.content.Context;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.Path;import android.graphics.PorterDuff;import android.graphics.PorterDuffXfermode;import android.util.AttributeSet;import android.view.MotionEvent;import android.widget.TextView;/** * 刮刮卡类 * @author reyo * */public class ScratchTextView extends TextView{private float TOUCH_TOLERANCE;private Bitmap mBitmap;private Canvas mCanvas;private Paint mPaint;private Path  mPath;private float mX,mY;private boolean isDraw = false;public ScratchTextView(Context context) {super(context);}public ScratchTextView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);}public ScratchTextView(Context context, AttributeSet attrs) {super(context, attrs);}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);if (isDraw) {mCanvas.drawPath(mPath, mPaint);//mCanvas.drawPoint(mX, mY, mPaint);canvas.drawBitmap(mBitmap, 0, 0, null);}}/** * 初始化刮刮卡 * @param bgColor 刮刮卡背景色 * @param paintStrokeWidth 擦除线宽 * @param touchTolerance 画线容差 */public void initScratchCard(final int bgColor,final int paintStrokeWidth,float touchTolerance) {TOUCH_TOLERANCE = touchTolerance;mPaint = new Paint();//mPaint.setAlpha(0);//mPaint.setColor(Color.BLACK);//mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));mPaint.setAlpha(0);mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));mPaint.setAntiAlias(true);mPaint.setDither(true);mPaint.setStyle(Paint.Style.STROKE);mPaint.setStrokeJoin(Paint.Join.ROUND);mPaint.setStrokeCap(Paint.Cap.ROUND);mPaint.setStrokeWidth(paintStrokeWidth);mPath =  new Path();mBitmap = Bitmap.createBitmap(getLayoutParams().width, getLayoutParams().height, Config.ARGB_8888);mCanvas = new Canvas(mBitmap);mCanvas.drawColor(bgColor);isDraw = true;}@Overridepublic boolean onTouchEvent(MotionEvent event) {if (!isDraw) {return true;}switch (event.getAction()) {case MotionEvent.ACTION_DOWN:touchDown(event.getX(), event.getY());invalidate();break;case MotionEvent.ACTION_MOVE:touchMove(event.getX(), event.getY());invalidate();break;case MotionEvent.ACTION_UP:touchUp(event.getX(), event.getY());invalidate();break;default:break;}return true;}private void touchDown(float x,float y){mPath.reset();mPath.moveTo(x, y);mX = x;mY = y;}private void touchMove(float x,float y){float dx = Math.abs(x - mX);float dy = Math.abs(y - mY);if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2);mX = x;mY = y;}}private void touchUp(float x,float y){mPath.lineTo(x, y);mCanvas.drawPath(mPath, mPaint);mPath.reset();}}

使用：

package com.reyo.app;import com.reyo.view.ScratchTextView;import android.app.Activity;import android.content.Context;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Path;import android.graphics.PorterDuff;import android.graphics.PorterDuffXfermode;import android.graphics.Rect;import android.graphics.drawable.BitmapDrawable;import android.graphics.drawable.Drawable;import android.os.Bundle;import android.util.DisplayMetrics;import android.view.MotionEvent;import android.view.View;public class RubberActivity extends Activity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// setContentView(new RubberView(this,"title",new Rect(100, 200,300,250),5,1f,18));setContentView(R.layout.main);((ScratchTextView) findViewById(R.id.rubbler)).initScratchCard(0xFFFFFFFF, 5, 1f);}class RubberView extends View {private final int PAINT_STROKE_WIDTH;private final float TOUCH_TOLERANCE;private final int TEXT_SIZE;private Bitmap mBitmap;private Canvas mCanvas;private Paint mPaint;private Path mPath;private float mX, mY;private final int X, Y, W, H;private final Rect touchRect;public RubberView(Context context, String bgText, Rect rect,int paintStrokeWidth, float touchTolerance, int textSize) {super(context);setFocusable(true);touchRect = rect;W = rect.right - rect.left;H = rect.bottom - rect.top;X = rect.left;Y = rect.top;TEXT_SIZE = textSize;PAINT_STROKE_WIDTH = paintStrokeWidth;TOUCH_TOLERANCE = touchTolerance;setBackground(touchRect, bgText);initDrowTools();}private void setBackground(Rect rect, String bgText) {DisplayMetrics dm = new DisplayMetrics();dm = this.getResources().getDisplayMetrics();Bitmap bitmap = Bitmap.createBitmap(dm.widthPixels,dm.heightPixels, Config.ARGB_8888);Canvas canvas = new Canvas(bitmap);Paint paint = new Paint();paint.setColor(0x88000000);// paint.setStyle(Style.STROKE);// paint.setTextAlign(Align.CENTER);paint.setTextSize(TEXT_SIZE);// paint.setTextScaleX(1.5f);canvas.drawColor(Color.WHITE);int x = rect.left + (rect.right - rect.left - bgText.length() * TEXT_SIZE) / 2;int y = rect.top + (rect.bottom - rect.top - TEXT_SIZE) / 2;// int y = 218+25;canvas.drawText(bgText, x, y, paint);Drawable drawable = new BitmapDrawable(bitmap);setBackgroundDrawable(drawable);}private void initDrowTools() {mPaint = new Paint();// mPaint.setAlpha(0);//mPaint.setColor(Color.BLACK); //mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT)); mPaint.setAlpha(0); mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));mPaint.setAntiAlias(true);mPaint.setDither(true);mPaint.setStyle(Paint.Style.STROKE);mPaint.setStrokeJoin(Paint.Join.ROUND); mPaint.setStrokeCap(Paint.Cap.ROUND); mPaint.setStrokeWidth(PAINT_STROKE_WIDTH); mPath = new Path();mBitmap = Bitmap.createBitmap(W, H, Config.ARGB_8888);mCanvas = new Canvas(mBitmap);mCanvas.drawColor(0x88000000);}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);mCanvas.drawPath(mPath, mPaint);// mCanvas.drawPoint(mX, mY, mPaint);canvas.drawBitmap(mBitmap, X, Y, null);}@Overridepublic boolean onTouchEvent(MotionEvent event) {if (!touchRect.contains((int) event.getX(), (int) event.getY())) {return false;}switch (event.getAction()) {case MotionEvent.ACTION_DOWN: touchDown(event.getRawX(), event.getRawY());touchDown(event.getX() - touchRect.left, event.getY()- touchRect.top);invalidate();break;case MotionEvent.ACTION_MOVE: touchMove(event.getX() - touchRect.left, event.getY()- touchRect.top);invalidate();break;case MotionEvent.ACTION_UP: touchUp(event.getX() - touchRect.left, event.getY()- touchRect.top);invalidate();break;default:break;}return true;}private void touchDown(float x, float y) {mPath.reset();mPath.moveTo(x, y);mX = x;mY = y;}private void touchMove(float x, float y) {float dx = Math.abs(x - mX);float dy = Math.abs(y - mY);if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);mX = x;mY = y;}}private void touchUp(float x, float y) {mPath.lineTo(x, y);mCanvas.drawPath(mPath, mPaint);mPath.reset();}}}

布局：

<?xml version="1.0" encoding="utf-8"?><AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="fill_parent"    android:layout_height="fill_parent" ><!-- 必须设置 android:layout_width android:layout_height  的值为常量--><com.reyo.view.ScratchTextViewandroid:id="@+id/rubbler"android:layout_y="100dip"android:layout_x="100dip"    android:layout_width="100dip"     android:layout_height="50dip"     android:text="谢谢您"    android:textSize="18sp"  android:gravity="center"    /></AbsoluteLayout>

仿刮奖效果的控件
https://github.com/winsontan520/Android-WScratchView