Android 自定义View手写签名并保存图片功能

/**
* Created by YyyyQ on 2020/3/5.
* 电子签名
*/
public class SignatureView extends View {
private Context context;
//X轴起点
private float x;
//Y轴起点
private float y;
//画笔
private final Paint paint = new Paint();
//路径
private final Path path = new Path();
//画布
private Canvas canvas;
//生成的图片
private Bitmap bitmap;
//画笔的宽度
private int paintWidth = 10;
//签名颜色
private int paintColor = Color.BLACK;
//背景颜色
private int backgroundColor = Color.WHITE;
//是否已经签名
private boolean isTouched = false;
//签名开始与结束
public interface Touch {
void OnTouch(boolean isTouch);
}
private Touch touch;
public SignatureView(Context context) {
super(context);
init(context);
}
public SignatureView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init(context);
}
public SignatureView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}
private void init(Context context) {
this.context = context;
//抗锯齿
paint.setAntiAlias(true);
//样式
paint.setStyle(Paint.Style.STROKE);
//画笔颜色
paint.setColor(paintColor);
//画笔宽度
paint.setStrokeWidth(paintWidth);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
//创建于view大小一致的bitmap
bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
canvas = new Canvas(bitmap);
canvas.drawColor(backgroundColor);
isTouched = false;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (touch != null) touch.OnTouch(true);
switch (event.getAction()) {
//手指按下
case MotionEvent.ACTION_DOWN:
touchDwon(event);
break;
//手指移动
case MotionEvent.ACTION_MOVE:
isTouched = true;
if (touch != null) touch.OnTouch(false);
touchMove(event);
break;
//手指抬起
case MotionEvent.ACTION_UP:
canvas.drawPath(path, paint);
path.reset();
break;
}
// 更新绘制
invalidate();
return true;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//画此次笔画之前的签名
canvas.drawBitmap(bitmap, 0, 0, paint);
// 通过画布绘制多点形成的图形
canvas.drawPath(path, paint);
}
//手指按下的方法
private void touchDwon(MotionEvent event) {
//重置绘制路径
path.reset();
float downX = event.getX();
float downY = event.getY();
x = downX;
y = downY;
//绘制起点
path.moveTo(downX, downY);
}
//手指滑动的方法
private void touchMove(MotionEvent event) {
//当前的x,y坐标点
final float moveX = event.getX();
final float moveY = event.getY();
//之前的x,y坐标点
final float previousX = x;
final float previousY = y;
//获取绝对值
final float dx = Math.abs(moveX - previousX);
final float dy = Math.abs(moveY - previousY);
if (dx  = 3 || dy  = 3) {
float cX = (moveX + previousX) / 2;
float cY = (moveY + previousY) / 2;
path.quadTo(previousX, previousY, cX, cY);
x = moveX;
y = moveY;
}
}
/**
* 设置画笔颜色
*
* @param paintColor
*/
public void setPaintColor(int paintColor) {
this.paintColor = paintColor;
paint.setColor(paintColor);
}
/**
* 设置画笔宽度
*
* @param paintWidth
*/
public void setPaintWidth(int paintWidth) {
this.paintWidth = paintWidth;
paint.setStrokeWidth(paintWidth);
}
/**
* 设置画板颜色
*
* @param canvasColor
*/
public void setCanvasColor(int canvasColor) {
this.backgroundColor = canvasColor;
}
/**
* 清除画板
*/
public void clear() {
if (canvas != null) {
isTouched = false;
//更新画板
paint.setColor(paintColor);
paint.setStrokeWidth(paintWidth);
canvas.drawColor(backgroundColor, PorterDuff.Mode.CLEAR);
invalidate();
}
}
/**
* 获取画板的Bitmap
*
* @return
*/
public Bitmap getBitmap() {
setDrawingCacheEnabled(true);
buildDrawingCache();
Bitmap bitmap = getDrawingCache();
setDrawingCacheEnabled(false);
return bitmap;
}
/**
* 是否有签名
*
* @return
*/
public Boolean getSigstatus() {
return isTouched;
}
/**
* 保存画板
*
* @param path 保存到路径
*/
@SuppressLint("WrongThread")
public Boolean save(String path) throws IOException {
Bitmap bitmap = this.bitmap;
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();
return true;
} else {
return false;
}
}
}

<?xml version="1.0" encoding="utf-8"? 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" 
<!--自定义view的绝对路径-- 
<com.example.customviewdemo.view.SignatureView
android:id="@+id/signature"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="#fff" / 
<LinearLayout
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_margin="20dp"
android:orientation="horizontal" 
<Button
android:id="@+id/clear"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:gravity="center"
android:text="清除" / 
<Button
android:id="@+id/isSignature"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_marginLeft="10dp"
android:layout_weight="1"
android:gravity="center"
android:text="是否签名" / 
<Button
android:id="@+id/save"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_marginLeft="10dp"
android:layout_weight="1"
android:gravity="center"
android:text="保存" / 
</LinearLayout 
</LinearLayout 

/**
* Created by YyyyQ on 2020/3/9.
*/
public class SignatureActivity extends AppCompatActivity {
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_signature);
SignatureView signatureView = findViewById(R.id.signature);
//设置画笔颜色(可以不设置--默认画笔宽度10,画笔颜色黑,背景颜色白)
signatureView.setPaintColor(Color.BLACK);
signatureView.setPaintWidth(20);
signatureView.setCanvasColor(Color.WHITE);
//清除
Button clear = findViewById(R.id.clear);
clear.setOnClickListener(view -  {
signatureView.clear();
//设置画笔颜色(可以不设置--默认画笔宽度10,画笔颜色黑,背景颜色白)
signatureView.setPaintColor(Color.BLACK);
signatureView.setPaintWidth(20);
signatureView.setCanvasColor(Color.WHITE);
});
//是否含有签名
Button isSignature = findViewById(R.id.isSignature);
isSignature.setOnClickListener(view -  {
if (signatureView.getSigstatus()) {
Toast.makeText(SignatureActivity.this, "有签名", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(SignatureActivity.this, "无签名", Toast.LENGTH_SHORT).show();
}
});
//保存
Button save = findViewById(R.id.save);
save.setOnClickListener(view -  {
try {
if (signatureView.save("/sdcard/YyyyQ.png")) {
Toast.makeText(SignatureActivity.this, "保存成功", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(SignatureActivity.this, "保存失败", Toast.LENGTH_SHORT).show();
}
} catch (IOException e) {
e.printStackTrace();
}
});
}
}