根据（https://github.com/Geek8ug/SignatureView ） 整理
1.画笔工具类 SignatureView：
public class SignatureView extends View {
private Context mContext;
private int targetWidth = 100, targetHeight = 100;
private ISignatureCallBack signatureCallBack;
public void setSignatureCallBack(ISignatureCallBack signatureCallBack) {
this.signatureCallBack = signatureCallBack;
}
/**
* 笔画X坐标起点
*/
private float mX;
/**
* 笔画Y坐标起点
*/
private float mY;
/**
* 手写画笔
*/
private final Paint mGesturePaint = new Paint();
/**
* 路径
*/
private final Path mPath = new Path();
/**
* 签名画笔
*/
private Canvas cacheCanvas;
/**
* 签名画布
*/
private Bitmap cachebBitmap;
/**
* 画笔宽度 px；
*/
private int mPaintWidth = 10;
/**
* 前景色
*/
private int mPenColor = Color.BLACK;
/**
* 背景色（指最终签名结果文件的背景颜色，默认为透明色）
*/
private int mBackColor = Color.WHITE;
/**
* 是否签字
*/
private boolean isDown = false;
public SignatureView(Context context) {
super(context);
this.mContext = context;
init(context);
}
public SignatureView(Context context, AttributeSet attrs) {
super(context, attrs);
this.mContext = context;
init(context);
}
public SignatureView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.mContext = context;
init(context);
}
public void init(Context context) {
this.mContext = context;
mGesturePaint.setAntiAlias(true);//抗锯齿
mGesturePaint.setStyle(Paint.Style.STROKE);
mGesturePaint.setStrokeWidth(mPaintWidth);
mGesturePaint.setColor(mPenColor);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
touchDown(event);
break;
case MotionEvent.ACTION_MOVE:
touchMove(event);
break;
case MotionEvent.ACTION_UP:
Log.e("TAG", "onTouchEventup");
isDown = true;
break;
}
// 更新绘制
invalidate();
return true;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawPath(mPath, mGesturePaint);
}
private long startTime;
private void touchDown(MotionEvent event) {
startTime = SystemClock.elapsedRealtime();
float x = event.getX();
float y = event.getY();
mX = x;
mY = y;
// mPath绘制的绘制起点
mPath.moveTo(x, y);
}
// 手指在屏幕上滑动时调用
private void touchMove(MotionEvent event) {
final float x = event.getX();
final float y = event.getY();
final float previousX = mX;
final float previousY = mY;
final float dx = Math.abs(x - previousX);
final float dy = Math.abs(y - previousY);
// 两点之间的距离大于等于3时，生成贝塞尔绘制曲线
if (dx >= 3 || dy >= 3) {
// 设置贝塞尔曲线的操作点为起点和终点的一半
float cX = (x + previousX) / 2;
float cY = (y + previousY) / 2;
// 二次贝塞尔，实现平滑曲线；previousX, previousY为操作点，cX, cY为终点
mPath.quadTo(previousX, previousY, cX, cY);
// 第二次执行时，第一次结束调用的坐标值将作为第二次调用的初始坐标值
mX = x;
mY = y;
}
}
/**
* 清除画板
*/
public void clear() {
if (cacheCanvas != null) {
//更新画板信息
mGesturePaint.setColor(mPenColor);
cacheCanvas.drawColor(mBackColor, PorterDuff.Mode.CLEAR);
mGesturePaint.setColor(mPenColor);
invalidate();
}
}
/**
* 保存画板
*
* @param path 保存到路径
*/
public void save(String path) throws IOException {
save(path, false, 0);
}
public void setMakeImage() {
if (isDown) {
cachebBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
cacheCanvas = new Canvas(cachebBitmap);
cacheCanvas.drawColor(mBackColor);
cacheCanvas.drawPath(mPath, mGesturePaint);
if (signatureCallBack != null) {
Log.e("TAG", "finish");
Bitmap b = clearBlank(cachebBitmap, 0);
Log.e("TAG", "finish b-->" + b);
if (b == null) {
clear();
}
signatureCallBack.onSignCompeleted(SignatureView.this, clearBlank(cachebBitmap, 0));
}
mPath.reset();
invalidate();
}
}
/**
* 保存画板
*
* @param path 保存到路径
* @param clearBlank 是否清除边缘空白区域
* @param blank 要保留的边缘空白距离
*/
public void save(String path, boolean clearBlank, int blank) throws IOException {
Bitmap bitmap = cachebBitmap;
//BitmapUtil.createScaledBitmapByHeight(srcBitmap, 300);// 压缩图片
if (clearBlank) {
bitmap = clearBlank(bitmap, blank);
}
ByteArrayOutputStream bos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, bos);
byte[] buffer = bos.toByteArray();
if (buffer != null) {
File file = new File(path);
if (file.exists()) {
file.delete();
}
OutputStream outputStream = new FileOutputStream(file);
outputStream.write(buffer);
outputStream.close();
}
}
/**
* 获取画板的bitmap
*
* @return
*/
public Bitmap getBitMap() {
setDrawingCacheEnabled(true);
buildDrawingCache();
Bitmap bitmap = getDrawingCache();
setDrawingCacheEnabled(false);
return bitmap;
}
/**
* 逐行扫描 清楚边界空白。
*
* @param bp
* @param blank 边距留多少个像素
* @return
*/
private Bitmap clearBlank(Bitmap bp, int blank) {
try {
int HEIGHT = bp.getHeight();
int WIDTH = bp.getWidth();
int top = 0, left = 0, right = 0, bottom = 0;
int[] pixs = new int[WIDTH];
boolean isStop;
for (int y = 0; y < HEIGHT; y++) {
bp.getPixels(pixs, 0, WIDTH, 0, y, WIDTH, 1);
isStop = false;
for (int pix : pixs) {
if (pix != mBackColor) {
top = y;
isStop = true;
break;
}
}
if (isStop) {
break;
}
}
for (int y = HEIGHT - 1; y >= 0; y--) {
bp.getPixels(pixs, 0, WIDTH, 0, y, WIDTH, 1);
isStop = false;
for (int pix : pixs) {
if (pix != mBackColor) {
bottom = y;
isStop = true;
break;
}
}
if (isStop) {
break;
}
}
pixs = new int[HEIGHT];
for (int x = 0; x < WIDTH; x++) {
bp.getPixels(pixs, 0, 1, x, 0, 1, HEIGHT);
isStop = false;
for (int pix : pixs) {
if (pix != mBackColor) {
left = x;
isStop = true;
break;
}
}
if (isStop) {
break;
}
}
for (int x = WIDTH - 1; x > 0; x--) {
bp.getPixels(pixs, 0, 1, x, 0, 1, HEIGHT);
isStop = false;
for (int pix : pixs) {
if (pix != mBackColor) {
right = x;
isStop = true;
break;
}
}
if (isStop) {
break;
}
}
if (blank < 0) {
blank = 0;
}
left = left - blank > 0 ? left - blank : 0;
top = top - blank > 0 ? top - blank : 0;
right = right + blank > WIDTH - 1 ? WIDTH - 1 : right + blank;
bottom = bottom + blank > HEIGHT - 1 ? HEIGHT - 1 : bottom + blank;
Bitmap b = Bitmap.createBitmap(bp, left, top, (right - left), (bottom - top));
int resultW = b.getWidth() * targetHeight / b.getHeight();
return Bitmap.createScaledBitmap(b, resultW, targetHeight, false);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
public interface ISignatureCallBack {
void onSignCompeleted(View view, Bitmap bitmap);
}
}
2.xml文件中使用：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<!--引入画板-->
<com.example.administrator.xingtest.SignatureView
android:id="@+id/view_signature"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="60dp"
app:penColor="#000"
app:penWidth="10"
app:backColor="#fff" />
<View
android:layout_alignBottom="@id/view_signature"
android:layout_width="match_parent"
android:layout_height="0.5dp"
android:background="#000"/>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="50dp"
android:orientation="horizontal"
android:layout_alignParentBottom="true">
<Button
android:id="@+id/btn_clear"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="清除"
android:layout_marginLeft="30dp"
/>
<Button
android:id="@+id/btn_save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:text="保存"
android:layout_marginRight="30dp"
/>
</RelativeLayout>
</RelativeLayout>
3.Activity中使用：
public class MainActivity extends AppCompatActivity {
private Button btnClear;
private Button btnSave;
private SignatureView viewSignature;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initVIew();
}
private void initVIew(){
btnClear = (Button) findViewById(R.id.btn_clear);
btnSave = (Button) findViewById(R.id.btn_save);
viewSignature = (SignatureView) findViewById(R.id.view_signature);
btnClear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//清空画笔
viewSignature.clear();
}
});
btnSave.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (viewSignature.getTouched()) {
try {
viewSignature.save("/sdcard/sign.png", true, 10);
Toast.makeText(MainActivity.this, "图片保存在："+viewSignature.getSavePath(), Toast.LENGTH_SHORT).show();
} catch (IOException e) {
e.printStackTrace();
}
} else {
Toast.makeText(MainActivity.this, "请先签名", Toast.LENGTH_SHORT).show();
}
}
});
}
}
4.attrs.xml 文件
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="SignatureView">
<attr format="color" name="penColor"/>
<attr format="color" name="backColor"/>
<attr format="integer" name="penWidth"/>
</declare-styleable>
</resources>
5.AndroidManifest.xml 添加写权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />