Question

我正在尝试实施一个简单的“刮刮卡”。 java代码是由关于绘画（WHERE to find Android "Fingerpaint" demo? (Android Studio era)）的Android演示程序拍摄的，我想要的只是在surfaceview下面显示图像。

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">

 <ImageView
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:src="@drawable/android"
    android:scaleType="fitXY"
    />

<com.example.jammtup.ErasableView
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    /></RelativeLayout>

java代码：

public class ErasableView extends SurfaceView {

private Bitmap mBitmap;
private Canvas mCanvas;
private Paint mPaint;
private Path mPath;
private Paint mBitmapPaint;


public ErasableView(Context context) {
    super(context);
    mPaint = new Paint();
    mPath = new Path();
    mBitmapPaint = new Paint(Paint.DITHER_FLAG);
}


public void init() {

    setFocusableInTouchMode(true);


    mPaint.setAntiAlias(true);
    mPaint.setDither(true);
    mPaint.setColor(Color.TRANSPARENT);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeWidth(64);
    mPaint.setColor(0xFFFF0000);
    mPaint.setStrokeCap(Paint.Cap.ROUND);
    mPaint.setStrokeJoin(Paint.Join.ROUND);
    mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));

}


@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
    mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
    mCanvas = new Canvas(mBitmap);

}


@Override
protected void onDraw(Canvas canvas) {

    canvas.drawColor(Color.TRANSPARENT);
    canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
    canvas.drawPath(mPath, mPaint);
}



private float mX, mY;
private static final float TOUCH_TOLERANCE = 4;

private void touch_start(float x, float y) {
    mPath.reset();
    mPath.moveTo(x, y);
    mX = x;
    mY = y;
}

private void touch_move(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 touch_up() {
    mPath.lineTo(mX, mY);
    // commit the path to our offscreen
    mCanvas.drawPath(mPath, mPaint);
    // kill this so we don't double draw
    mPath.reset();
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    float x = event.getX();
    float y = event.getY();

    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            touch_start(x, y);
            invalidate();
            break;
        case MotionEvent.ACTION_MOVE:
            touch_move(x, y);
            invalidate();
            break;
        case MotionEvent.ACTION_UP:
            touch_up();
            invalidate();
            break;
    }
    return true;
} }

我得到的是一个不可擦除的黑色视图。这不允许显示下面的图像。

我需要你的帮助!!

Answer 1

尝试使用此代替您的视图如果您想要整个项目，请查看我的Github存储库https://github.com/amarvadla/ScratchCoupon

ExecuteScalar()

公共类ScratchTextView扩展了TextView {

    import android.content.Context;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.graphics.Canvas;
    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.os.AsyncTask;
    import android.support.v4.content.ContextCompat;
    import android.text.TextPaint;
    import android.util.AttributeSet;
    import android.view.Gravity;
    import android.view.MotionEvent;
    import android.widget.TextView;

创建刮刮卡android

1 个答案: