Android Canvas在3D视图中查看形状（手指绘制）

Question

我使用Canvas使用手指绘制形状或路径，并在绘图路径上执行各种操作或清除，撤消，重做，填充，厚度等图像。

我成功地完成了所有这些但是在绘制路径或形状之后我需要的东西可以在3D视图中查看它。我的意思是当用户点击3D按钮时，视图变为3D，用户在滚动后可以看到。我不了解使用Canvas的3D图像视图。

如果有任何解决方案可以做到这一点，那将很高兴听到它们。

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN);

    setContentView(R.layout.drawactivity);
    drawView = new DrawView(DrawActivity.this);
    FrameLayout frm_layout = (FrameLayout) findViewById(R.id.main_frame);
    frm_layout.addView(drawView);
}

public void colorChanged(int color) {
    mPaint.setColor(color);
}

public void onButtonClick(View view) {

    int view_id = view.getId();

    switch (view_id) {

    case R.id.undo:
        isToBeEdited = true;
        drawView.onClickUndo();
        break;
    case R.id.redo:
        isToBeEdited = true;
        drawView.onClickRedo();
        break;
    case R.id.ClearPaint:
        isToBeEdited = true;
        undonePaths.clear();
        paths.clear();
        mPath.reset();
        drawView.invalidate();
        break;
    case R.id.Upload:
        isToBeEdited = true;
        Intent i = new Intent(
            Intent.ACTION_PICK,
            android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI
        );
        startActivityForResult(i, RESULT_LOAD_IMAGE);
        break;
    case R.id.Fill:
        isToBeEdited = false;
        if (Fill) {
            mPaint.setStyle(Paint.Style.FILL);
            Fill = false;

        } else {
            mPaint.setStyle(Paint.Style.STROKE);
            Fill = true;
        }
        break;
    case R.id.Thikness:
        if (thick) {
            mPaint.setStrokeWidth(15);
            thick = false;
            //drawView.setDrawingCacheEnabled(false);
        } else {
            mPaint.setStrokeWidth(8);
            thick = true;
        }
        break;
    case R.id.ThreeD:
        isToBeEdited = false;
        if (shad) {
            mPaint.setShadowLayer(5, 4, 12, Color.BLACK);
            mPaint.setColor(getResources().getColor(R.color.lightgreen));
            shad = false;
        } else {
            mPaint.clearShadowLayer();
            mPaint.setColor(Color.YELLOW);
            shad = true;
        }
        break;
    case R.id.Rotate:
        Log.d("mvc", "m in Rotate");
        mCanvas.rotate(180, mCanvas.getWidth() / 2, mCanvas.getHeight() / 2);
        break;
    default:
        break;
    }
}

public class DrawView extends View implements OnTouchListener {

    public DrawView(Context context) {
        super(context);
        setFocusable(true);
        setFocusableInTouchMode(true);
        this.setOnTouchListener((OnTouchListener) this);

        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setDither(true);
        mPaint.setColor(Color.YELLOW);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeJoin(Paint.Join.ROUND);
        mPaint.setStrokeCap(Paint.Cap.ROUND);
        mPaint.setStrokeWidth(7);

        mCanvas = new Canvas();
        // mCanvas.rotate(320, 166, 678);
        // mCanvas.save(Canvas.MATRIX_SAVE_FLAG);
        // mCanvas.restore();
        mPath = new Path();
        paths.add(mPath);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        for (Path p : paths) {
            Log.d("mvc", "m in onDraw");
            canvas.drawPath(p, mPaint);
        }
    }

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

    private void touch_start(float x, float y) {
        Log.d("mvc", "m in touchStart");
        mPath.reset();
        mPath.moveTo(x, y);
        mX = x;
        mY = y;
    }

    private void touch_move(float x, float y) {
        Log.d("mvc", "m in touch_move");
        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() {
        Log.d("mvc", "m in touch_up");
        mPath.lineTo(mX, mY);
        mCanvas.drawPath(mPath, mPaint);
        mCanvas.drawPath(mPath, mPaint);
        // kill this so we don't double draw
        mPath = new Path();
        paths.add(mPath);
    }

    public void onClickUndo() {
        if (paths.size() > 0) {
            undonePaths.add(paths.remove(paths.size() - 1));
            invalidate();
        } else {
            Log.i("undo", "Undo elsecondition");
        }
    }

    public void onClickRedo() {
        if (undonePaths.size() > 0) {
            paths.add(undonePaths.remove(undonePaths.size() - 1));
            invalidate();
        } else {
            Log.i("undo", "Redo elsecondition");
        }
    }

    public boolean onTouch(View arg0, 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;
    }
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK
            && null != data) {
        Uri selectedImage = data.getData();
        String[] filePathColumn = { MediaStore.Images.Media.DATA };

        Cursor cursor = getContentResolver().query(selectedImage,
                filePathColumn, null, null, null);
        cursor.moveToFirst();

        int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
        String picturePath = cursor.getString(columnIndex);
        cursor.close();

        ImageView imageView = (ImageView) findViewById(R.id.imageView1);
        imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));
    }
}