Tạo 1 ứng dụng Paint trong android

public class FingerPath { public int color; public boolean emboss; public boolean blur; public int strokeWidth; public Path path; public FingerPath(int color, boolean emboss, boolean blur, int strokeWidth, Path path) { this.color = color; this.emboss = emboss; this.blur = blur; this.strokeWidth = strokeWidth; this.path = path; } }

public PaintView(Context context) { this(context, null); } public PaintView(Context context, AttributeSet attrs) { super(context, attrs); mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setDither(true); mPaint.setColor(DEFAULT_COLOR); mPaint.setStyle(Paint.Style.STROKE); mPaint.setStrokeJoin(Paint.Join.ROUND); mPaint.setStrokeCap(Paint.Cap.ROUND); mPaint.setXfermode(null); mPaint.setAlpha(0xff); mEmboss = new EmbossMaskFilter(new float[] {1, 1, 1}, 0.4f, 6, 3.5f); mBlur = new BlurMaskFilter(5, BlurMaskFilter.Blur.NORMAL); } }

public class PaintView extends View { public static int BRUSH_SIZE = 20; public static final int DEFAULT_COLOR = Color.RED; public static final int DEFAULT_BG_COLOR = Color.WHITE; private static final float TOUCH_TOLERANCE = 4; private float mX, mY; private Path mPath; private Paint mPaint; private ArrayList<FingerPath> paths = new ArrayList<>(); private int currentColor; private int backgroundColor = DEFAULT_BG_COLOR; private int strokeWidth; private boolean emboss; private boolean blur; private MaskFilter mEmboss; private MaskFilter mBlur; private Bitmap mBitmap; private Canvas mCanvas; private Paint mBitmapPaint = new Paint(Paint.DITHER_FLAG); public PaintView(Context context) { this(context, null); } public PaintView(Context context, AttributeSet attrs) { super(context, attrs); mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setDither(true); mPaint.setColor(DEFAULT_COLOR); mPaint.setStyle(Paint.Style.STROKE); mPaint.setStrokeJoin(Paint.Join.ROUND); mPaint.setStrokeCap(Paint.Cap.ROUND); mPaint.setXfermode(null); mPaint.setAlpha(0xff); mEmboss = new EmbossMaskFilter(new float[] {1, 1, 1}, 0.4f, 6, 3.5f); mBlur = new BlurMaskFilter(5, BlurMaskFilter.Blur.NORMAL); } public void init(DisplayMetrics metrics) { int height = metrics.heightPixels; int awidth = metrics.awidthPixels; mBitmap = Bitmap.createBitmap(awidth, height, Bitmap.Config.ARGB_8888); mCanvas = new Canvas(mBitmap); currentColor = DEFAULT_COLOR; strokeWidth = BRUSH_SIZE; } public void normal() { emboss = false; blur = false; } public void emboss() { emboss = true; blur = false; } public void blur() { emboss = false; blur = true; } public void clear() { backgroundColor = DEFAULT_BG_COLOR; paths.clear(); normal(); invalidate(); } @Override protected void onDraw(Canvas canvas) { canvas.save(); mCanvas.drawColor(backgroundColor); for (FingerPath fp : paths) { mPaint.setColor(fp.color); mPaint.setStrokeWidth(fp.strokeWidth); mPaint.setMaskFilter(null); if (fp.emboss) mPaint.setMaskFilter(mEmboss); else if (fp.blur) mPaint.setMaskFilter(mBlur); mCanvas.drawPath(fp.path, mPaint); } canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint); canvas.restore(); } }

private void touchStart(float x, float y) { mPath = new Path(); FingerPath fp = new FingerPath(currentColor, emboss, blur, strokeWidth, mPath); paths.add(fp); mPath.reset(); mPath.moveTo(x, y); mX = x; mY = y; } private void touchMove(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 touchUp() { mPath.lineTo(mX, mY); } @Override public boolean onTouchEvent(MotionEvent event) { float x = event.getX(); float y = event.getY(); switch(event.getAction()) { case MotionEvent.ACTION_DOWN : touchStart(x, y); invalidate(); break; case MotionEvent.ACTION_MOVE : touchMove(x, y); invalidate(); break; case MotionEvent.ACTION_UP : touchUp(); invalidate(); break; } return true; } }