android - 如何用手指在ImageView Bitmap上绘制并获取坐标并保存绘制的图像

Question

基本上我有一个像这样的网格(存储为图像):

我需要做的是用手指在这个网格上绘制(多笔划)并显示并保存这个新的位图。

此外，在绘制时我需要获取笔划的坐标，以便从中计算一些数据(整个网格被划分为区域)。

坐标部分很简单，我使用 Rect()、getX() 和 getY() 即完成。

int getZoneLocation(int x, int y)
    {

        Rect rectangle = new Rect();

        amslerView.getGlobalVisibleRect(rectangle);

        String coords = "Left:%d Top:%d Right:%d Bottom:%d ActionBarHeight:%d StatusBarHeight:%d";

        // Zone 1 Rectangle

        Log.i("Rectangle Coordinates",
                String.format(coords, rectangle.left, rectangle.top, rectangle.right, rectangle.bottom, getActionBarHeight(), getStatusBarSize()));

        Rect outerMostRect = new Rect(rectangle);

        int xOffset = rectangle.width() / 10;
        int yOffset = rectangle.height() / 10;

        Log.i("Rectangle Attribs", "Width: " + xOffset + "Height: " + yOffset);

        // Zone 2 Rectangle

        Rect zone2Rectangle = new Rect(outerMostRect.left + xOffset, outerMostRect.top + yOffset, outerMostRect.right - xOffset, outerMostRect.bottom
                - yOffset);

        Log.i("Zone 2 Coordinates", "" + zone2Rectangle.left + " " + zone2Rectangle.top + " " + zone2Rectangle.right + " " + zone2Rectangle.bottom);

        // Zone 3 Rectangle

        Rect zone3Rectangle = new Rect(zone2Rectangle.left + xOffset, zone2Rectangle.top + yOffset, zone2Rectangle.right - xOffset,
                zone2Rectangle.bottom - yOffset);

        // Zone 4 Rectangle

        Rect zone4Rectangle = new Rect(zone3Rectangle.left + xOffset, zone3Rectangle.top + yOffset, zone3Rectangle.right - xOffset,
                zone3Rectangle.bottom - yOffset);

        // Zone 5 Rectangle
        Rect zone5Rectangle = new Rect(zone4Rectangle.left + xOffset, zone4Rectangle.top + yOffset, zone4Rectangle.right - xOffset,
                zone4Rectangle.bottom - yOffset);

        // Check from inside out for point existence
        if (zone5Rectangle.contains(x, y))
        {
            return 5;
        } else if (zone4Rectangle.contains(x, y))
        {
            return 4;
        } else if (zone3Rectangle.contains(x, y))
        {
            return 3;
        } else if (zone2Rectangle.contains(x, y))
        {
            return 2;
        } else if (outerMostRect.contains(x, y))
        {
            return 1;
        }
        return -1;
    }

基本上我所做的是从显示此网格的 ImageView 获取 localVisibleRect，然后简单地调用此方法以获取我需要的数据到 onTouchListener。

现在对我来说真正的困境是如何实现手指绘图，以及究竟用什么来实现它。

到目前为止，我已经看过 SurfaceView、Canvas 甚至 GestureOverlayView(我知道这很愚蠢)。

我还从 api 示例中查看了 FingerPaint 演示，但它绘制到一个空 View 上，老实说，我不知道如何使用 ImageView 实现它。

任何建议都是无价的。

Answer 1

你可以使用这个类:

import android.view.View.OnTouchListener;

public class XCanvas extends ImageView implements OnTouchListener
{               
    private Activity context = null;
    private Paint paint = null;        

    public XCanvas(Activity context)
    {
        super(context); 
        this.context = context;

        this.paint = new Paint();       

        setFocusable(true);
        setFocusableInTouchMode(true);

        this.setOnTouchListener(this);     

        paint.setAntiAlias(true);       
    }   

    @Override
    protected void onDraw(Canvas g) 
    {                               
        super.onDraw(g);    

        //Set background        
        this.paint.setColor(Color.rgb(0xff, 0xff, 0xff));       
        g.drawRect(0, 0, this.getWidth(), this.getHeight(), this.paint);

        //Paint everything here!
    }             

    @Override
    public boolean onTouch(View v, MotionEvent event) 
    {
        int action = event.getAction() & MotionEvent.ACTION_MASK;

        switch (action) 
        {
            case MotionEvent.ACTION_DOWN:
            {
                this.pointerPressed(event);
                break;
            }
            case MotionEvent.ACTION_MOVE:
            {
                this.pointerDragged(event);         
                break;  
            }
            case MotionEvent.ACTION_UP:
            {
                this.pointerReleased();
                break;
            }                   
        }

        return true;
    }        

    protected void pointerPressed(MotionEvent event)
    {
        //you can save touch point here!
    }

    protected void pointerDragged(MotionEvent event)
    {
        //for get x ==>  eveevent.getX()
        //for get y ==>  eveevent.getY()        

        this.repaint();
    }

    protected void pointerReleased()
    {

    }    

    public void repaint() 
    {       
        this.invalidate();
    }           
}

对于使用类，将此代码粘贴到主要 Activity 中:

    private XCanvas xCanvas = null;

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

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

    //getWindow().setBackgroundDrawableResource(R.color.MapBackground);

    this.xCanvas = new XCanvas(this);                               
    this.xCanvas.repaint();

    setContentView(this.xCanvas);
    this.xCanvas.requestFocus();
}