学习篇---刮刮卡

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效果图：

GuaGuaKa.java

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.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.View;/*** Created by Administrator on 2016/5/24.*/
public class GuaGuaKa extends View {private Paint sweepPaint;//擦除的画笔private Canvas mCanvas;//起缓存作用的画布private Path sweepPath;//擦除的路径private Bitmap mBitmap;//与刮刮卡大小相同的图片private Bitmap bgBitmap;//刮刮卡的表面图片private Paint textPaint;//文本画笔private Paint bgPanit;//表面图片画笔private Rect textBound;//用于储存文字的长和宽private int textSize;//文本的大小private int textColor;//文本颜色private String text;//文本内容private volatile boolean isComplete;//是否擦除完毕private OnCompleteListener  onCompleteListener;//擦除完毕调用的回调接口public GuaGuaKa(Context context) {this(context, null);}public GuaGuaKa(Context context, AttributeSet attrs) {this(context, attrs, 0);}public GuaGuaKa(Context context, AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);bgBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.fg_guaguaka);//获取自定义属性TypedArray typedArray=context.getTheme().obtainStyledAttributes(attrs,R.styleable.GuaGuaKa,defStyleAttr,0);textColor=typedArray.getColor(R.styleable.GuaGuaKa_textColor,Color.RED);textSize= (int) typedArray.getDimension(R.styleable.GuaGuaKa_textSize, TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,25,getResources().getDisplayMetrics()));//默认的字体大小是25sp，转化为pxtext=typedArray.getString(R.styleable.GuaGuaKa_text);typedArray.recycle();if(text==null){text="谢谢惠顾";}init();}
//初始化画笔private void init() {bgPanit=new Paint();bgPanit.setAntiAlias(true);bgPanit.setColor(Color.parseColor("#c0c0c0"));bgPanit.setStyle(Paint.Style.FILL);sweepPath = new Path();sweepPaint = new Paint();sweepPaint.setAntiAlias(true);sweepPaint.setDither(true);sweepPaint.setStrokeCap(Paint.Cap.ROUND);sweepPaint.setStrokeJoin(Paint.Join.ROUND);sweepPaint.setStrokeWidth(20);sweepPaint.setStyle(Paint.Style.STROKE);textPaint=new Paint();textPaint.setTextSize(textSize);textPaint.setColor(textColor);textPaint.setStyle(Paint.Style.STROKE);textBound=new Rect();textPaint.getTextBounds(text,0, text.length(),textBound);//获取文本的长宽}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);int width = getMeasuredWidth();int height = getMeasuredHeight();mBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);mCanvas = new Canvas(mBitmap);//创建画布mCanvas.drawRoundRect(new RectF(0,0,getMeasuredWidth(),getMeasuredHeight()),30,30,bgPanit);//画圆角矩形mCanvas.drawBitmap(bgBitmap,null,new RectF(0,0,getMeasuredWidth(),getMeasuredHeight()),bgPanit);//画刮刮卡表面图片}@Overridepublic boolean onTouchEvent(MotionEvent event) {int action = event.getAction();float x = event.getX();float y = event.getY();switch (action) {case MotionEvent.ACTION_DOWN:sweepPath.moveTo(x, y);break;case MotionEvent.ACTION_MOVE:sweepPath.lineTo(x, y);break;case MotionEvent.ACTION_UP:runnable.run();break;}invalidate();return true;}//线程用于计算已经被擦除的像素量private Runnable runnable=new Runnable() {@Overridepublic void run() {int widthPx=getWidth();int heightPx=getHeight();int sweepArea=0;int totalArea=widthPx*heightPx;int totalPx[]=new int[totalArea];int percentPx;mBitmap.getPixels(totalPx,0,mBitmap.getWidth(),0,0,mBitmap.getWidth(),mBitmap.getHeight());for(int i=0;i<widthPx;i++){for(int j=0;j<heightPx;j++){int dex=i+j*widthPx;if(totalPx[dex]==0){sweepArea++;}}}percentPx=sweepArea*100/totalArea;
//            Log.e("percentPx",percentPx+"" );if(percentPx>50){isComplete=true;postInvalidate();}}};public interface OnCompleteListener{public void onComlete();}public void setOnCompleteListener(OnCompleteListener onCompleteListener) {this.onCompleteListener = onCompleteListener;}@Overrideprotected void onDraw(Canvas canvas) {//画文本canvas.drawText(text,getWidth()/2-textBound.width()/2,getHeight()/2+textBound.height()/2,textPaint);if(!isComplete) {sweepPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));//设置画笔xformodemCanvas.drawPath(sweepPath, sweepPaint);canvas.drawBitmap(mBitmap, 0, 0, null);}if(isComplete){if (onCompleteListener!=null){onCompleteListener.onComlete();onCompleteListener=null;//防止再次被调用}}}//设置文本内容public void setText(String text){textPaint.getTextBounds(text,0, text.length(),textBound);this.text=text;invalidate();}public String getText(){return text;}
}

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources><declare-styleable name="GuaGuaKa"><attr name="text" format="string"/><attr name="textSize" format="dimension"/><attr name="textColor" format="color"/></declare-styleable>
</resources>

MainActivity.java

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;public class MainActivity extends AppCompatActivity {
private GuaGuaKa guaGuaKa;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);guaGuaKa= (GuaGuaKa) findViewById(R.id.guaguaKa);guaGuaKa.setText("妹纸一位");guaGuaKa.setOnCompleteListener(new GuaGuaKa.OnCompleteListener() {@Overridepublic void onComlete() {Toast.makeText(MainActivity.this,"恭喜你获得了："+guaGuaKa.getText(),Toast.LENGTH_SHORT).show();}});}
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:songdongwan="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context="com.songdongwan.guguka.MainActivity">
<com.songdongwan.guguka.GuaGuaKaandroid:id="@+id/guaguaKa"songdongwan:textSize="35sp"songdongwan:textColor="#f00"android:layout_centerInParent="true"android:layout_width="300dp"android:layout_height="100dp" /></RelativeLayout>

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