java - 在远程图像上绘制（用手指）并保存。（安卓）

Question

我目前正在从目录加载远程图像列表。我希望用户能够选择一个，然后用手指在图像上绘制，然后保存。（最终，将目录中的现有图像替换为修改后的图像）

我喜欢这个指向正确方向的一些指示。

谢谢！

Answer 1

首先研究 graphics 文件夹下示例中的 fingerpaint.java。

您应该覆盖视图的 onDraw 方法。

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

在您的活动 onCreate()

    Drawing View mDrawingView=new DrawingView(this);

    setContentView(R.layout.screen_drawing_room);    

    LinearLayout mDrawingPad=(LinearLayout)findViewById(R.id.view_drawing_pad);

    mDrawingPad.addView(mDrawingView);

绘图视图.java

定义您的绘图视图。以下可用于手绘。修改相同以绘制线条、文本和填充颜色（封闭区域）。

您应该添加一个颜色选择器并将颜色设置为绘画对象，以允许用户选择绘画颜色。

对于洪水填充，请参阅链接android using flood fill algorithm getting out of memory exception中接受的答案。

   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;
    }


}

}

您的绘图视图已设置。在图形文件夹下的 sdk 上的示例中研究 fingerpaint.java。

结果快照。您在背景中看到的是图像。在前景我画了嗨。我在拐角处画线。如果你能认出它是红色的。

画出看起来像边框的线条。将油漆的描边宽度设置为您喜欢的任何值。同样，您可以通过更改 x1,y1 和 x2,y2 坐标来绘制所需的线条。

                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);

保存

 AlertDialog.Builder editalert = new AlertDialog.Builder(DrawingRoomScreen.this);
 editalert.setTitle("Please Enter the name with which you want to Save");
 final EditText input = new EditText(DrawingRoomScreen.this);       LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
                        LinearLayout.LayoutParams.FILL_PARENT,
                        LinearLayout.LayoutParams.FILL_PARENT);
                input.setLayoutParams(lp);
                editalert.setView(input);
                editalert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {
                        content.setDrawingCacheEnabled(true);
                        String name= input.getText().toString();
                        Bitmap bitmap = mDrawingPad.getDrawingCache();//root view

                     String path = Environment.getExternalStorageDirectory().getAbsolutePath(); 
                        File file = new File("/sdcard/"+name+".png");           
                        try 
                        {
                            if(!file.exists())
                        {
                            file.createNewFile();
                        }
                            FileOutputStream ostream = new FileOutputStream(file);
                            bitmap.compress(CompressFormat.PNG, 10, ostream);
                            System.out.println("saving......................................................"+path);
                            ostream.close();
                            //content.invalidate();                         
                        } 
                        catch (Exception e) 
                        {
                            e.printStackTrace();
                        }finally
                        {


                        }
                    }
                });

                editalert.show();       

从图库中获取图像

  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); 
   }