簡單的手指繪圖并儲存所繪圖檔【源碼】

public class SimpleFingerDraw extends Activity implements OnTouchListener,
        OnClickListener
{
    ImageView imageView;
    Button choosePicture, savePicture;
    Bitmap bitmap;
    Bitmap alteredBitmap;
    Canvas canvas;
    Paint paint;
    Matrix matrix;
    float downx = 0;
    float downy = 0;
    float upx = 0;
    float upy = 0;
    float top = 0, bottom = 0;
    String TAG = "FingerDraw";
 
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageView = (ImageView) findViewById(R.id.ChosenImageView);
        choosePicture = (Button) findViewById(R.id.ChoosePictureButton);
        savePicture = (Button) findViewById(R.id.SavePictureButton);
        choosePicture.setOnClickListener(this);
        savePicture.setOnClickListener(this);
        savePicture.setVisibility(View.GONE);
    }
 
    @Override
    public boolean onTouch(View v, MotionEvent event)
    {
        // TODO Auto-generated method stub
        int action = event.getAction();
        switch (action)
        {
            case MotionEvent.ACTION_DOWN:
                downx = event.getX();// 擷取的是以ImageView左上角為原點的坐标
                downy = event.getY();
                Log.e(TAG, "downx:" + downx + " downy:" + downy);
                break;
            case MotionEvent.ACTION_MOVE:
                upx = event.getX();
                upy = event.getY();
                canvas.drawLine(downx, downy, upx, upy, paint);
                imageView.invalidate();
                downx = upx;
                downy = upy;
                break;
            case MotionEvent.ACTION_UP:
                upx = event.getX();
                upy = event.getY();
                canvas.drawLine(downx, downy, upx, upy, paint);// 注意：這裡是以圖像的左上角為原點進行繪制直線
                imageView.invalidate();
                break;
            default:
                break;
        }
        return true;
    }
 
    @Override
    public void onClick(View v)
    {
        // TODO Auto-generated method stub
        if (v == choosePicture)
        {
            Intent choosePictureIntent = new Intent(Intent.ACTION_PICK,
                    Media.EXTERNAL_CONTENT_URI);
            startActivityForResult(choosePictureIntent, 0);
 
        } else
        {
            if (alteredBitmap != null)
            {
                try
                {
                    Uri ImageFileUri = getContentResolver().insert(
                            Media.EXTERNAL_CONTENT_URI, new ContentValues());
                    OutputStream imageFileOS = getContentResolver()
                            .openOutputStream(ImageFileUri);
                    alteredBitmap.compress(CompressFormat.JPEG, 100,
                            imageFileOS);
                    Toast.makeText(this, "Saved! ", Toast.LENGTH_LONG).show();
                } catch (FileNotFoundException e)
                {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
 
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data)
    {
        // TODO Auto-generated method stub
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK)
        {
            savePicture.setVisibility(View.VISIBLE);
            Uri imageFileUri = data.getData();
            Display currentDisplay = getWindowManager().getDefaultDisplay();
            @SuppressWarnings("deprecation")
            float dw = currentDisplay.getWidth();
            @SuppressWarnings("deprecation")
            float dh = currentDisplay.getHeight();
 
            BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
            bmpFactoryOptions.inJustDecodeBounds = true;
            try
            {
                bitmap = BitmapFactory
                        .decodeStream(
                                getContentResolver().openInputStream(
                                        imageFileUri), null, bmpFactoryOptions);
            } catch (FileNotFoundException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            int heightRatio = (int) Math.ceil(bmpFactoryOptions.outHeight / dh);
            int widthRatio = (int) Math.ceil(bmpFactoryOptions.outWidth / dw);
            if (heightRatio >= 1 && widthRatio >= 1)
            {
                if (heightRatio > widthRatio)
                {
                    bmpFactoryOptions.inSampleSize = heightRatio;
                    // Log.e(TAG,"heightRatio");
                } else
                {
                    bmpFactoryOptions.inSampleSize = widthRatio;
                    // Log.e(TAG,"widthRatio");
                }
            }
            // Log.e(TAG,"heightRatio:"+heightRatio+" widthRatio:"+widthRatio);
 
            bmpFactoryOptions.inJustDecodeBounds = false;
            try
            {
                bitmap = BitmapFactory
                        .decodeStream(
                                getContentResolver().openInputStream(
                                        imageFileUri), null, bmpFactoryOptions);
            } catch (FileNotFoundException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            alteredBitmap = Bitmap.createBitmap(bitmap.getWidth(),
                    bitmap.getHeight(), bitmap.getConfig());
            Log.e(TAG, "bitmap.Height:" + bitmap.getHeight());
            canvas = new Canvas(alteredBitmap);
            paint = new Paint();
            paint.setColor(Color.GREEN);
            paint.setStrokeWidth(5);
            matrix = new Matrix();
            canvas.drawBitmap(bitmap, matrix, paint);
 
            imageView.setImageBitmap(alteredBitmap);
            // top=imageView.getTop(); //144.0
            // bottom=imageView.getBottom();//144.0
            // height=imageView.getHeight(); //0.0
            // Log.e(TAG, "bottom:"+bottom);
            imageView.setOnTouchListener(this);
        }
    }
 
}