how to draw-Linie auf Bildansicht zusammen mit dem finger in android

Sollten Sie überschreiben die onDraw Methode Ihrer Ansicht.

screen_drawing_room.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/rlid"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<LinearLayout   <!--set background for the bottom layout set image here. -->
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:gravity="bottom"
    android:orientation="vertical"
    android:weightSum="1.0" >

    <LinearLayout
        android:id="@+id/view_drawing_pad" <!--your drawing pad on foreground -->
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >
    </LinearLayout>
</LinearLayout>
</RelativeLayout

In Ihren Aktivitäten onCreate()

DrawingView mDrawingView=new DrawingView(this);
setContentView(R.layout.screen_drawing_room);    
LinearLayout mDrawingPad=(LinearLayout)findViewById(R.id.view_drawing_pad);
mDrawingPad.addView(mDrawingView);

DrawingView.java

Definieren Sie Ihre DrawingView. Die unten kann verwendet werden, für Freihand-Zeichnung. Ändern Sie die gleichen Linien zeichnen, Texte und Farbe( geschlossene Fläche). Für die fülle sehen, die akzeptierten Antworten in dem link android mit flood-fill-Algorithmus immer out of memory-Ausnahme.

class DrawingView extends View {
    Paint       mPaint;
    //MaskFilter  mEmboss;
    //MaskFilter  mBlur;
    Bitmap  mBitmap;
    Canvas  mCanvas;
    Path    mPath;
    Paint   mBitmapPaint;

    public DrawingView(Context context) {
        super(context);
        //TODO Auto-generated constructor stub
        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setDither(true);
        mPaint.setColor(0xFFFF0000);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeJoin(Paint.Join.ROUND);
        mPaint.setStrokeCap(Paint.Cap.ROUND);
        mPaint.setStrokeWidth(20);

        mPath = new Path();
        mBitmapPaint = new Paint();
        mBitmapPaint.setColor(Color.RED);
    }
    @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
    public void draw(Canvas canvas) {
        //TODO Auto-generated method stub
        super.draw(canvas);
        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);
        //mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SCREEN));
        //kill this so we don't double draw
        mPath.reset();
       //mPath= new Path();
    }

    @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;
    }   
}

Ihre Zeichnung Ansicht eingestellt ist. Studie der fingerpaint.java aus der Stichprobe auf die sdk unter den graphics Ordner.

Resultierenden sanpshot. Was Sie sehen, im hintergrund ist ein Bild. Auf der Vorder-ich zeichne hi. Ich habe zeichnen von Linien um die Ecke. Wenn Sie heraus, es ist rot.

Zeichnen von Linien, die Aussehen wie border. Festlegen der Strichstärke für die Farbe, was Sie wollen. Ebenso können Sie Linien zeichnen, wo Sie wollen, indem Sie ändern die x1,y1 und x2,y2-Koordinaten.

Display display = ( (Activity) mcontext).getWindowManager().getDefaultDisplay();  
float w = display.getWidth(); 
float h = display.getHeight();
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
canvas.drawLine(0, 0, w, 0,mBitmapPaint);
canvas.drawLine(0, 0, 0, h,mBitmapPaint);
canvas.drawLine(w,h,w,0,mBitmapPaint);
canvas.drawLine(w, h, 0,h , mBitmapPaint);

Edit:

Bild aus der Galerie

File fp;
Drawable d;   

public void  setImagefrmGallery() {
    //To open up a gallery browser
    Intent intent = new Intent();
    intent.setType("image/*");
    intent.setAction(Intent.ACTION_GET_CONTENT);
    startActivityForResult(Intent.createChooser(intent, "Select Picture"),1);
    //To handle when an image is selected from the browser, add the following to your Activity 
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode == RESULT_OK) {
        if (requestCode == 1) {
            //currImageURI is the global variable I�m using to hold the content://URI of the image
            Uri currImageURI = data.getData();
            System.out.println("Hello======="+getRealPathFromURI(currImageURI));
            String s= getRealPathFromURI(currImageURI);
            File file = new File(s);

            if (file.exists()) {
                fp=file.getAbsolutePath();
                d = Drawable.createFromPath(file.getAbsolutePath());
                mDrawingPad.setBackgroundDrawable(d);
            } else {
                System.out.println("File Not Found");
            }
        }
    }
}

//And to convert the image URI to the direct file system path of the image file
public String getRealPathFromURI(Uri contentUri) {
    //can post image
    String [] proj={MediaStore.Images.Media.DATA};
    Cursor cursor = managedQuery( contentUri,
            proj, //Which columns to return
            null, //WHERE clause; which rows to return (all rows)
            null, //WHERE clause selection arguments (none)
            null); //Order-by clause (ascending by name)
    int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
    cursor.moveToFirst();
    return cursor.getString(column_index); 
}

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