已经给出了你的问题的答案都指向了正确的方向：你需要在单独的图层中分离背景颜色块和前景图，然后合并它们，然后将它们全部保存在.png文件中。 这就是Adobe Photoshop工作流程的设计……如果我们考虑它，它确实有意义：例如像MsPaint这样的软件：因为它不使用图层，它必须依赖于类似填充算法的东西完成(虽然以不完整的方式)远程类似于背景变化的东西……

实现这种方法的一种方法是实例化由2个不同位图支持的2个Canvas对象。 第一个Canvas-Bitmap对将用于前景中的绘制，第二个Canvas-Bitmap对将用于合并图层绘制(即前景绘图+背景颜色块)。 然后第二个位图将在您需要保存时保存到.png文件中。 这样，我们的第一个Canvas-Bitmap对存储了您的前景信息，如果需要进行背景颜色更改，则不会销毁该信息。 每次进行操作时，图层都可以合并到第二个Canvas-Bitmap对中，这样总有一个Bitmap具有正确的内容，可以随心所欲地保存。

这是我制作的自定义视图，以便清除此方法。 它实现了一个简单的视图，用于使用手指在触摸屏上绘制蓝线，背景颜色根据所述手指的XY位置而变化，以便演示背景颜色变化，而没有完整实现固有的不必要的代码复杂性带色轮/菜单/ 除其他外 ：

package com.epichorns.basicpaint; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Point; import android.graphics.Paint.Style; import android.view.View; public class PaintView extends View{ Bitmap mMergedLayersBitmap=null; //Note: this bitmap here contains the whole of the drawing (background+foreground) to be saved. Canvas mMergedLayersCanvas=null; Bitmap mBitmap = null; //bitmap onto which we draw our stuff Canvas mCanvas = null; //Main canvas. Will be linked to a .bmp file int mBackgroundColor = 0xFF000000; //default background color Paint mDefaultPaint = new Paint(); Paint mDrawPaint = new Paint(); //used for painting example foreground stuff... We draw line segments. Point mDrawCoor = new Point(); //used to store last location on our PaintView that was finger-touched //Constructor: we instantiate 2 Canvas-Bitmap pairs public PaintView(Context context, int width, int height) { super(context); mMergedLayersBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888); mMergedLayersCanvas = new Canvas(mMergedLayersBitmap); mBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888); mCanvas = new Canvas(mBitmap); } //Change background color public void changeColor(int newColor){ mBackgroundColor = newColor; invalidate(); //refresh view: this will indirectly invoke onDraw soon afterwards } //Called by user of PaintView in order to start a painting "stroke" (finger touching touch-screen): stores the //location of the finger when it first touched the screen public void startDraw(int x, int y, int radius, int color){ mDrawPaint.setColor(color); mDrawPaint.setStyle(Style.STROKE); mDrawPaint.setStrokeWidth(radius); mDrawCoor.x = x; mDrawCoor.y = y; } //Called by user of PaintView when finger touching touch-screen is moving (must be called after a startDraw, //as the latter initializes a couple of necessary things) public void continueDraw(int x, int y){ mCanvas.drawLine(mDrawCoor.x, mDrawCoor.y, x, y, mDrawPaint); mDrawCoor.x = x; mDrawCoor.y = y; invalidate(); //refresh view: this will indirectly invoke onDraw soon afterwards } //Merge the foreground Canvas-Bitmap with a solid background color, then stores this in the 2nd Canvas-Bitmap pair. private void mergeLayers(){ mMergedLayersCanvas.drawColor(mBackgroundColor); mMergedLayersCanvas.drawBitmap(mBitmap, 0, 0, mDefaultPaint); } @Override public void onDraw(Canvas canvas){ mergeLayers(); canvas.drawBitmap(mMergedLayersBitmap, 0, 0, mDefaultPaint); } }

为了测试这个视图，这里是一个使用PaintView类的测试Activity。 这两个文件在Android项目中都是自给自足的，因此您可以在真实设备上进行测试而不会有麻烦：

package com.epichorns.basicpaint; import android.app.Activity; import android.graphics.Color; import android.os.Bundle; import android.util.Log; import android.view.Display; import android.view.MotionEvent; import android.view.View; import android.widget.LinearLayout; import com.epichorns.basicpaint.PaintView; public class BasicPaintActivity extends Activity { PaintView mPaintView=null; LinearLayout mL = null; boolean mIsDrawing=false; int mBackgroundColor = 0xFF000000; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Display display = getWindowManager().getDefaultDisplay(); final float dispWidth = (float)display.getWidth(); final float dispHeight = (float)display.getHeight(); mPaintView = new PaintView(this, display.getWidth(), display.getHeight()); mPaintView.changeColor(mBackgroundColor); mPaintView.setOnTouchListener(new View.OnTouchListener(){ public boolean onTouch(View v, MotionEvent event) { if(event.getAction()==MotionEvent.ACTION_DOWN){ mPaintView.startDraw((int)event.getX(), (int)event.getY(), 6, 0x806060FF); mIsDrawing=true; return true; } else if(event.getAction()==MotionEvent.ACTION_UP){ mIsDrawing=false; return true; } else if(event.getAction()==MotionEvent.ACTION_MOVE){ if(mIsDrawing){ //To demonstrate background change, change background color depending on XY position int r = (int)(255f*event.getX()/dispWidth); int g = (int)(255f*event.getY()/dispHeight); mBackgroundColor = Color.argb(0xFF, r,g, 0x00); Log.d("DEBUG1", "Color channels: (r, g) = ("+String.valueOf(r)+", "+String.valueOf(g)+")"); mPaintView.changeColor(mBackgroundColor); //now, draw stuff where finger was dragging... mPaintView.continueDraw((int)event.getX(), (int)event.getY()); return true; } else{ return false; } } return false; } }); setContentView(mPaintView); } }