刮刮乐效果、生成图片文件、在XML

效果展示:

直接上代码：

package com.example.administrator.mybitmap.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffColorFilter;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

import com.example.administrator.mybitmap.R;

/**
 * Created by Administrator on 2015/9/17.
 */
public class MyBitmap2 extends View {
    private int width;
    private int height;
    private Paint mPaintCircle;
    private Paint mPaintRect;
    private Paint mPaintBackground;
    private Bitmap bitmap;
    private Bitmap bitmapback;
    private Matrix matrix;

    public MyBitmap2(Context context) {
        super(context);
    }

    public MyBitmap2(Context context, AttributeSet attrs) {
        super(context, attrs);
        final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.MyBitmap2);
        BitmapDrawable dra = (BitmapDrawable) a.getDrawable(R.styleable.MyBitmap2_myview_background);
        if (dra != null) {
            bitmapback = dra.getBitmap();
        } else {
            bitmapback = BitmapFactory.decodeResource(getResources(), R.mipmap.lol);
        }
        int paintWidth = a.getDimensionPixelOffset(R.styleable.MyBitmap2_myview_paint, 70);

        mPaintCircle = new Paint();
        mPaintCircle.setColor(Color.BLUE);
        mPaintRect = new Paint();
        mPaintRect.setColor(Color.GREEN);
        mPaintCircle = new Paint();
        mPaintCircle.setColor(Color.YELLOW);
        //设置图形的交互模式
        PorterDuffXfermode mode = new PorterDuffXfermode(PorterDuff.Mode.XOR);
        mPaintRect.setXfermode(mode);
        mPaintRect.setStyle(Paint.Style.STROKE);
        mPaintRect.setStrokeJoin(Paint.Join.ROUND); // 连接点处样式圆角
        mPaintRect.setStrokeCap(Paint.Cap.ROUND); //  覆盖时的样式.圆角
        mPaintRect.setStrokeWidth(paintWidth);
        matrix = new Matrix();
        // 设置画笔宽度
//        mPaintRect.setStrokeWidth(20);
//        bitmapback = BitmapFactory.decodeResource(getResources(), R.mipmap.lol);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        width = getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec);
        height = getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec);
        setMeasuredDimension(width, height);
        bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        mCanvas = new Canvas(bitmap);
        mPath = new Path();
        matrix.reset();
        matrix.postScale((width + 0.0f) / bitmapback.getWidth(), (height + 0.0f) / bitmapback.getHeight());
    }

    private Path mPath;
    private Canvas mCanvas;

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //矩阵的方法来放大图片
        canvas.drawBitmap(bitmapback, matrix, null);
        // 用裁剪的方法放大图片
        //  canvas.drawBitmap(bitmapback
        //             , new Rect(0, 0, bitmapback.getWidth(), bitmapback.getHeight())
        //             , new Rect(0, 0, width, height), null);


        mCanvas.drawRect(0, 0, width, height, mPaintCircle);
        mCanvas.drawPath(mPath, mPaintRect);//xor效果的笔
        canvas.drawBitmap(bitmap, 0, 0, null);
    }

    float x;
    float y;
    float new_x;
    float new_y;

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {

            case MotionEvent.ACTION_DOWN:
                x = event.getX();
                y = event.getY();
                mPath.moveTo(x, y);
                break;
            case MotionEvent.ACTION_MOVE:
                new_x = event.getX();
                new_y = event.getY();

                mPath.lineTo(new_x, new_y);
                x = new_x;
                y = new_y;


//                mPath.addCircle(x, y, 50, Path.Direction.CW);//在点击出画一个圆，

                break;
        }
        invalidate();
        return true;

    }
}

MainActivity

package com.example.administrator.mybitmap;

import android.graphics.Bitmap;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.example.administrator.mybitmap.widget.MyBitmap2;
import com.example.administrator.mybitmap.widget.MySlider;

import org.w3c.dom.Text;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {
    private MySlider mySlider;
    private TextView mTextView;
    private Button mBtnToBePicture;
 private MyBitmap2 myBitmap2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_bitmap2);
        mBtnToBePicture= (Button) findViewById(R.id.btn_tobepicture);
        myBitmap2= (MyBitmap2) findViewById(R.id.myview_bitmap2);
        /**
        *生成图片文件的方法
        */
        mBtnToBePicture.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                myBitmap2.setDrawingCacheEnabled(true);
                Bitmap bitmap=myBitmap2.getDrawingCache(true);
                File file=new File(Environment.getExternalStorageDirectory(),System.currentTimeMillis()+".jpg");
                if(!file.exists()){

                    try {
                        file.createNewFile();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }

                }
                try {
                    bitmap.compress(Bitmap.CompressFormat.JPEG,100,new FileOutputStream(file));
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                }
            }
        });

//        mySlider = (MySlider) findViewById(R.id.view_slider);
//        mTextView = (TextView) findViewById(R.id.textview);
//        mySlider.setonItemSelectLinser(new MySlider.onItemSelect() {
//            @Override
//            public void onItemSelected(int index, String nameString) {
//               if(index!=-1){
//                   mTextView.setText(nameString);
//                   mTextView.setVisibility(View.VISIBLE);
//               }
//            }
//        });
    }


}

布局文件activity_main

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:myview_values="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <Button
        android:id="@+id/btn_tobepicture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="生成图片"/>
    <com.example.administrator.mybitmap.widget.MyBitmap2
        android:id="@+id/myview_bitmap2"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        myview_values:myview_background="@mipmap/an"
        myview_values:myview_paint="40dp"
        />

</LinearLayout>

myview_values中：

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="MyBitmap2">
        <attr name="myview_background" format="reference"></attr>//设置背景
        <attr name="myview_paint" format="dimension|reference"></attr>//dimension表示可以是xx dp sp等，reference指可以获取res下的资源
    </declare-styleable>
</resources>