I am working on android paint signature application where it has the flexibility to clear the paint and save the canvas as bitmap image. I am facing an issue in this app, whenever i want to save the canvas as bitmap i need to check whether the signature is lengthy enough or not. If the signature is too short them i have to ask the user to put a signature again. The following is my code: There are two classes in this.

FeperPaint 活性

public class FeperPaint 活性 extends Activity implements OnClickListener{

private Button clearBtn, saveBtn;

private View myView;

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

    setContentView(R.layout.main);

    myView = findViewById(R.id.myView);

    clearBtn = (Button) findViewById(R.id.clearBtn);
    clearBtn.setOnClickListener(this);

    saveBtn = (Button) findViewById(R.id.submitBtn);
    saveBtn.setOnClickListener(this);

时 时

@Override
public void onClick(View v) {

    if (v == clearBtn) {

        MyView.clearCanvas();
        myView.invalidate();
        myView.refreshDrawableState();

    时 时 else {

        myView.setDrawingCacheEnabled(true);

        myView.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
        myView.layout(0, 0, myView.getWidth(), myView.getHeight());
        myView.buildDrawingCache(true);
        Bitmap bm = Bitmap.createBitmap(myView.getDrawingCache());
        myView.setDrawingCacheEnabled(false);
        if (bm != null) {
            try {
                String path = Environment.getExternalStorageDirectory().toString();
                OutputStream fOut = null;
                File file = new File(path, "screentest.jpg");
                fOut = new FileOutputStream(file);
                bm.compress(Bitmap.CompressFormat.JPEG, 85, fOut);
                fOut.flush();
                fOut.close();
                Log.e("ImagePath", "Image Path : " + MediaStore.Images.Media.insertImage( getContentResolver(), file.getAbsolutePath(), file.getName(), file.getName()));

                sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse("file://"+ Environment.getExternalStorageDirectory())));
            时 时
            catch (Exception e) {
                e.printStackTrace();
            时 时
        时 时
    时 时
时 时
时 时

This is the second class: MyView

public class MyView extends View {

// private static final float MINP = 0.25f;
// private static final float MAXP = 0.75f;

private Bitmap mBitmap;
private static Canvas mCanvas;
private Path mPath;
private Paint mBitmapPaint;
private Paint mPaint;

public MyView(Context c) {
    super(c);

时 时

public MyView(Context context, AttributeSet attrs) {
    super(context, attrs);

    mPaint = new Paint();
    mPaint.setAntiAlias(true);
    mPaint.setDither(true);
    mPaint.setColor(Color.BLACK);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeJoin(Paint.Join.ROUND);
    mPaint.setStrokeCap(Paint.Cap.ROUND);
    mPaint.setStrokeWidth(6);
    mBitmap = Bitmap.createBitmap(320, 480, Bitmap.Config.ARGB_8888);
    mCanvas = new Canvas(mBitmap);
    mPath = new Path();
    mBitmapPaint = new Paint(Paint.DITHER_FLAG);
时 时

public MyView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
时 时

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
时 时

@Override
protected void onDraw(Canvas canvas) {

    canvas.drawColor(0xFFAAAAAA);

    canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);

    canvas.drawPath(mPath, mPaint);
时 时

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;
时 时

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;
    时 时
时 时

private void touch_up() {
    mPath.lineTo(mX, mY);
    // commit the path to our offscreen
    mCanvas.drawPath(mPath, mPaint);
    // kill this so we don t double draw
    mPath.reset();
时 时

@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;
    时 时
    return true;
时 时

public static void clearCanvas() {
    Paint paint = new Paint();
    paint.setXfermode(new PorterDuffXfermode(Mode.CLEAR));
    mCanvas.drawPaint(paint);
    paint.setXfermode(new PorterDuffXfermode(Mode.SRC));

时 时

时 时

The only problem i am facing is while saving the signature i have to check the size of bitmap or canvas or paint before saving it. i don t know which one to check for If anyone has idea please help me out.