删除最后一个颜色表单位图撤消

Question

我需要关于撤销方法的帮助，我试图像下面的代码一样实现它，但它不会删除最后一个颜色，请帮助我解决它。

等待您的回应。

在此先感谢。

---

MainActivity

public class MainActivity extends AppCompatActivity implements 
View.OnTouchListener { 
Button red, blue, yellow, undo; 
Paint paint; 
private RelativeLayout drawingLayout; 
private MyView myView; 
private ArrayList<Path> paths = new ArrayList<Path>(); 
private ArrayList<Path> undonePaths = new ArrayList<Path>(); 

/** 
* Called when the activity is first created. 
*/ 
    /* 
    * 
    * private ImageView imageView; private Canvas cv; private Bitmap mask, 
    * original, colored; private int r,g,b; private int sG, sR, sB; 
    */ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 

    myView = new MyView(this); 
    drawingLayout = (RelativeLayout) findViewById(R.id.relative_layout); 
    drawingLayout.addView(myView); 

    red = (Button) findViewById(R.id.btn_red); 
    blue = (Button) findViewById(R.id.btn_blue); 
    yellow = (Button) findViewById(R.id.btn_yellow); 
    undo = (Button) findViewById(R.id.undo); 

    red.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      paint.setColor(Color.RED); 
     } 
    }); 

    yellow.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      paint.setColor(Color.YELLOW); 
     } 
    }); 
    blue.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      paint.setColor(Color.BLUE); 
     } 
    }); 
    undo.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      myView.onClickUndo(); 
     } 
    }); 
} 

@Override 
public boolean onTouch(View v, MotionEvent event) { 
    // TODO Auto-generated method stub 
    return false; 
} 


// flood fill 
public class MyView extends View { 

    final Point p1 = new Point(); 
    Bitmap mBitmap; 
    ProgressDialog pd; 
    Canvas canvas; 
    private Path path; 

    // Bitmap mutableBitmap ; 
    public MyView(Context context) { 
     super(context); 

     paint = new Paint(); 
     paint.setAntiAlias(true); 
     pd = new ProgressDialog(context); 
     paint.setStyle(Paint.Style.STROKE); 
     paint.setStrokeJoin(Paint.Join.ROUND); 
     paint.setStrokeWidth(5f); 
     mBitmap = BitmapFactory.decodeResource(getResources(), 
       R.drawable.gp1_1).copy(Bitmap.Config.ARGB_8888, true); 

     this.path = new Path(); 


    } 

    public void onClickUndo() { 
     if (paths.size() > 0) { 
      undonePaths.add(paths.remove(paths.size() - 1)); 
      invalidate(); 
     } else { 
      Toast.makeText(getContext(), getString(R.string.nomore), Toast.LENGTH_SHORT).show(); 
     } 
    } 

    @Override 
    protected void onDraw(Canvas canvas) { 
     this.canvas = canvas; 
     paint.setColor(Color.GREEN); 
     // int width = drawingLayout.getWidth(); 
    // int height = drawingLayout.getHeight(); 
    // float centerX = (width - mBitmap.getWidth()) * 0.5f; 
    //float centerY = (height - mBitmap.getHeight()) * 0.5f; 
     canvas.drawBitmap(mBitmap, 0, 0, paint); 
     /////////////////////////////// 
     for (Path p : paths) { 
      canvas.drawPath(p, paint); 
      ////////////////////////// 
     } 

    } 

    @Override 
    public boolean onTouchEvent(MotionEvent event) { 
     float x = event.getX(); 
     float y = event.getY(); 
     switch (event.getAction()) { 
      case MotionEvent.ACTION_DOWN: 

       p1.x = (int) x; 
       p1.y = (int) y; 
       final int sourceColor = mBitmap.getPixel((int) x, (int) y); 
       final int targetColor = paint.getColor(); 
       new TheTask(mBitmap, p1, sourceColor, targetColor).execute(); 
       paths.add(path); 

       invalidate(); 
     } 
     return true; 
    } 

    public void clear() { 
     path.reset(); 
     invalidate(); 
    } 

    public int getCurrentPaintColor() { 
     return paint.getColor(); 
    } 

    class TheTask extends AsyncTask<Void, Integer, Void> { 

     Bitmap bmp; 
     Point pt; 
     int replacementColor, targetColor; 

     public TheTask(Bitmap bm, Point p, int sc, int tc) { 
      this.bmp = bm; 
      this.pt = p; 
      this.replacementColor = tc; 
      this.targetColor = sc; 
      pd.setMessage(getString(R.string.wait)); 
      pd.show(); 
     } 

     @Override 
     protected void onPreExecute() { 
      pd.show(); 

     } 

     @Override 
     protected void onProgressUpdate(Integer... values) { 

     } 

     @Override 
     protected Void doInBackground(Void... params) { 
      FloodFill f = new FloodFill(); 
      f.floodFill(bmp, pt, targetColor, replacementColor); 
      return null; 
     } 

     @Override 
     protected void onPostExecute(Void result) { 
      pd.dismiss(); 
      invalidate(); 
     } 
    } 
} 

public class FloodFill { 
    public void floodFill(Bitmap image, Point node, int targetColor, 
          int replacementColor) { 
     int width = image.getWidth(); 
     int height = image.getHeight(); 
     int target = targetColor; 
     int replacement = replacementColor; 
     if (target != replacement) { 
      Queue<Point> queue = new LinkedList<Point>(); 
      do { 

       int x = node.x; 
       int y = node.y; 
       while (x > 0 && image.getPixel(x - 1, y) == target) { 
        x--; 

       } 
       boolean spanUp = false; 
       boolean spanDown = false; 
       while (x < width && image.getPixel(x, y) == target) { 
        image.setPixel(x, y, replacement); 
        if (!spanUp && y > 0 
          && image.getPixel(x, y - 1) == target) { 
         queue.add(new Point(x, y - 1)); 
         spanUp = true; 
        } else if (spanUp && y > 0 
          && image.getPixel(x, y - 1) != target) { 
         spanUp = false; 
        } 
        if (!spanDown && y < height - 1 
          && image.getPixel(x, y + 1) == target) { 
         queue.add(new Point(x, y + 1)); 
         spanDown = true; 
        } else if (spanDown && y < height - 1 
          && image.getPixel(x, y + 1) != target) { 
         spanDown = false; 
        } 
        x++; 
       } 
      } while ((node = queue.poll()) != null); 
     } 
    } 
} 
    } 

Answer 1

似乎不可能返回以前的颜色，它需要一个数组为每个点在每个点存储使用的颜色。

Answer 2

我想你指的是撤消方法不起作用。可能的原因是以前的画布在画布上未被删除。在绘制onDraw()方法之前，尝试清除画布。

@Override protected void onDraw(Canvas canvas) { 
this.canvas = canvas; 
canvas. drawColor(0,PorterDuff.Mode.CLEAR); //This clears the canvas. 
paint.setColor(Color.GREEN); 
//rest of the code 
}