我正在开发Android应用程序。在我的项目中，我有一个关于签名捕获的任务，即用户应将他/她的签名保留在移动设备的屏幕上，并且一次保存按钮单击签名必须存储在数据库中。我搜索并找到了一些链接，但我仍然没有找到确切的解决方案。 我也试过TouchPaint.java，但在那里我找不到布局的xml文件。 你能用一些示例代码向我们建议吗？我会感激你的....
答案 0 :(得分：37)
以下是Has AlTaiar的C＃签名视图的Java版本， 花了一些时间让它正常工作
public class CaptureSignatureView extends View {
private Bitmap _Bitmap;
private Canvas _Canvas;
private Path _Path;
private Paint _BitmapPaint;
private Paint _paint;
private float _mX;
private float _mY;
private float TouchTolerance = 4;
private float LineThickness = 4;
public CaptureSignatureView(Context context, AttributeSet attr) {
super(context, attr);
_Path = new Path();
_BitmapPaint = new Paint(Paint.DITHER_FLAG);
_paint = new Paint();
_paint.setAntiAlias(true);
_paint.setDither(true);
_paint.setColor(Color.argb(255, 0, 0, 0));
_paint.setStyle(Paint.Style.STROKE);
_paint.setStrokeJoin(Paint.Join.ROUND);
_paint.setStrokeCap(Paint.Cap.ROUND);
_paint.setStrokeWidth(LineThickness);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
_Bitmap = Bitmap.createBitmap(w, (h > 0 ? h : ((View) this.getParent()).getHeight()), Bitmap.Config.ARGB_8888);
_Canvas = new Canvas(_Bitmap);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawColor(Color.WHITE);
canvas.drawBitmap(_Bitmap, 0, 0, _BitmapPaint);
canvas.drawPath(_Path, _paint);
}
private void TouchStart(float x, float y) {
_Path.reset();
_Path.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 >= TouchTolerance || dy >= TouchTolerance) {
_Path.quadTo(_mX, _mY, (x + _mX) / 2, (y + _mY) / 2);
_mX = x;
_mY = y;
}
}
private void TouchUp() {
if (!_Path.isEmpty()) {
_Path.lineTo(_mX, _mY);
_Canvas.drawPath(_Path, _paint);
} else {
_Canvas.drawPoint(_mX, _mY, _paint);
}
_Path.reset();
}
@Override
public boolean onTouchEvent(MotionEvent e) {
super.onTouchEvent(e);
float x = e.getX();
float y = e.getY();
switch (e.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;
}
public void ClearCanvas() {
_Canvas.drawColor(Color.WHITE);
invalidate();
}
public byte[] getBytes() {
Bitmap b = getBitmap();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
b.compress(Bitmap.CompressFormat.PNG, 100, baos);
return baos.toByteArray();
}
public Bitmap getBitmap() {
View v = (View) this.getParent();
Bitmap b = Bitmap.createBitmap(v.getWidth(), v.getHeight(), Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);
v.layout(v.getLeft(), v.getTop(), v.getRight(), v.getBottom());
v.draw(c);
return b;
}
}
我尝试过Rob Croll的建议，这个建议效果很好，但它很直率，使得签名不像人类。如果你知道我的意思：P
以下是在空线性布局上附加视图的方法
LinearLayout mContent = (LinearLayout) findViewById(R.id.linearLayout);
CaptureSignatureView mSig = new CaptureSignatureView(this, null);
mContent.addView(mSig, LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
以下是如何获取签名的字节或位图
byte[] signature = mSig.getBytes();
Bitmap signature = mSig.getBitmap();
答案 1 :(得分：26)
对于寻找解决方案的任何人，您都可以在http://www.mysamplecode.com/2011/11/android-capture-signature-using-canvas.html
找到解决方案它实际上将签名写入文件，但它很容易改变并写入数据库。
答案 2 :(得分：4)
您可能需要手势构建器。
我认为这个链接。
http://android-developers.blogspot.com/2009/10/gestures-on-android-16.html
对您有用。如果你需要再次检查签名。
<强>更新
你在谈论这个吗？然后此示例不使用xml 。它具有内部类（MyView）
的视图答案 3 :(得分：4)
我知道这是一个老问题，但我需要实现自己的视图来捕获签名，因为我使用的是MonoForAndroid（C＃而不是Java）。所以我在这里添加我的View代码以防有人需要它。
using System;
using Android.Content;
using Android.Graphics;
using Android.Views;
namespace MyApp.Views
{
public class CaptureSignatureView : View
{
public CaptureSignatureView(Context c, SignatureData signatureData) : base(c)
{
SignatureData = signatureData;
_Path = new Path();
_BitmapPaint = new Paint(PaintFlags.Dither);
_paint = new Paint
{
AntiAlias = true,
Dither = true,
Color = Color.Argb(255, 0, 0, 0)
};
_paint.SetStyle(Paint.Style.Stroke);
_paint.StrokeJoin = Paint.Join.Round;
_paint.StrokeCap = Paint.Cap.Round;
_paint.StrokeWidth = 8;
}
protected override void OnSizeChanged(int w, int h, int oldw, int oldh)
{
base.OnSizeChanged(w, h, oldw, oldh);
_Bitmap = Bitmap.CreateBitmap(w, (h > 0 ? h : ((View)this.Parent).Height), Bitmap.Config.Argb8888);
_Canvas = new Canvas(_Bitmap);
}
protected override void OnDraw(Canvas canvas)
{
canvas.DrawColor(Color.White);
canvas.DrawBitmap(_Bitmap, 0, 0, _BitmapPaint);
canvas.DrawPath(_Path, _paint);
}
private float _mX, _mY;
private const float TouchTolerance = 4;
private void TouchStart(float x, float y)
{
_Path.Reset();
_Path.MoveTo(x, y);
_mX = x;
_mY = y;
SignatureData.AddPoint(SignatureState.Start, (int)x, (int)y);
}
private void TouchMove(float x, float y)
{
float dx = Math.Abs(x - _mX);
float dy = Math.Abs(y - _mY);
if (dx >= TouchTolerance || dy >= TouchTolerance)
{
_Path.QuadTo(_mX, _mY, (x + _mX) / 2, (y + _mY) / 2);
SignatureData.AddPoint(SignatureState.Move, (int)x, (int)y);
_mX = x;
_mY = y;
}
}
private void TouchUp()
{
if (!_Path.IsEmpty)
{
_Path.LineTo(_mX, _mY);
_Canvas.DrawPath(_Path, _paint);
}
else
{
_Canvas.DrawPoint(_mX, _mY, _paint);
}
SignatureData.AddPoint(SignatureState.End, (int)_mX, (int)_mY);
_Path.Reset();
}
public override bool OnTouchEvent(MotionEvent e)
{
var x = e.GetX();
var y = e.GetY();
switch (e.Action)
{
case MotionEventActions.Down:
TouchStart(x, y);
Invalidate();
break;
case MotionEventActions.Move:
TouchMove(x, y);
Invalidate();
break;
case MotionEventActions.Up:
TouchUp();
Invalidate();
break;
}
return true;
}
public void ClearCanvas()
{
_Canvas.DrawColor(Color.White);
Invalidate();
}
public Bitmap CanvasBitmap()
{
return _Bitmap;
}
public void Clear()
{
ClearCanvas();
SignatureData = new SignatureData();
}
#region Implementation
private Bitmap _Bitmap;
private Canvas _Canvas;
private readonly Path _Path;
private readonly Paint _BitmapPaint;
private readonly Paint _paint;
public SignatureData SignatureData;
#endregion
}
}
另外，我有一个blog post here，详细介绍了如何捕获签名。基本上你可以用两种不同的方式做到这一点。您可以使用签名捕获视图作为图像，然后保存该位图（并将其发送到服务器）。或者你可以捕获一个二维点阵列，并以你想要的任何方式重建签名。