Question

我试图让SignatureView在填写表单后捕获我的用户签名，但我的代码并没有让它绘制。我在youtube上找到了这个绘图代码并尝试了它们但它没有绘制任何东西，虽然滚动锁正在工作。

代码如下

签名视图的xml

<SignatureView
            android:background="#FFFFFF"
            android:layout_width="match_parent"
            android:layout_height="400dp"
            android:id="@+id/signatureView"/>

用于启用绘图的签名视图的代码

public class SignatureView extends View {

public static int BRUSH_SIZE = 5;
public static final int DEFAULT_COLOR = Color.BLACK;
public static final int DEFAUL_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 = DEFAUL_BG_COLOR;
private int strokewidth;
private Bitmap mBitmap;
private Canvas mCanvas;
private Paint mBitmapPaint = new Paint(Paint.DITHER_FLAG);
public SignatureView(Context context){
    this(context, null);
}

public SignatureView(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);
}

public void init(DisplayMetrics metrics){
    int height = metrics.heightPixels;
    int width = metrics.widthPixels;

    mBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    mCanvas = new Canvas(mBitmap);

    currentColor = DEFAULT_COLOR;
    strokewidth = BRUSH_SIZE;
}

protected void onDraw(Canvas canvas){
    canvas.save();
    mCanvas.drawColor(backgroundColor);
    for (FingerPath fp : paths){
        mPaint.setColor(fp.color);
        mPaint.setStrokeWidth(fp.strokewidth);
    }

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

private void touchStart(float x, float y){
    mPath = new Path();
    FingerPath fp = new FingerPath(currentColor, 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();
    getParent().requestDisallowInterceptTouchEvent(true);

    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;
}

指纹类

public class FingerPath {
public int color;
public int strokewidth;
public Path path;

public FingerPath(int color, int strokewidth, Path path){
    this.color = color;
    this.strokewidth = strokewidth;
    this.path = path;
}
}

页面的java类

public class Application_applicant extends AppCompatActivity {
private SignatureView sv;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_app_applicant);
    sv = (SignatureView)findViewById(R.id.signatureView);
    DisplayMetrics metrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(metrics);
    sv.init(metrics);
}
}

Answer 1

请在此链接的Android演示文稿中查看MyView课程：https://android.googlesource.com/platform/development/+/master/samples/ApiDemos/src/com/example/android/apis/graphics/FingerPaint.java

您可以在此项目中找到一些演示。这非常有用

Answer 2

my drawing worked with this, tried a lot of ways to do this signature thing but this is the best way ive found

使用自定义视图“SignatureView”来捕获用户签名

2 个答案: