具体内容如下

package com.xx; import android.content.Context;import android.graphics.Bitmap;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Path;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.MotionEvent;import android.view.View;import android.widget.Button;import android.widget.FrameLayout;import android.widget.ImageView;import com.xx.R; /** * Description: 签名类 * Copyright:  Copyright (c)2018 * Company:    * author:   Corwin * version:   1.0 * date:    2018/9/5 18:32 * Modification History: * Date     Author   Version   Description * ------------------------------------------------------------------ * 2018/9/5  Corwin   1.0     1.0 Version */public class SignatureActivity extends AppCompatActivity {  private ImageView imageSign; private SignatureView mView;  @Override public void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_signature);   imageSign = findViewById(R.id.iv_sign);  FrameLayout frameLayout = findViewById(R.id.fl_view);   mView = new SignatureView(this);  frameLayout.addView(mView);  mView.requestFocus();   Button btnClear = findViewById(R.id.btn_clear);  btnClear.setOnClickListener((v) -> {    mView.clear();  });   Button btnOk = findViewById(R.id.btn_ok);  btnOk.setOnClickListener((v) -> {    Bitmap imageBitmap = mView.getCachebBitmap();    imageSign.setImageBitmap(imageBitmap);  }); }  /**  * 自定义签名控件  */ class SignatureView extends View {   //画笔  private Paint paint;   //画布  private Canvas cacheCanvas;   //位图  private Bitmap cachebBitmap;   //图片保存路径  private Path path;   //位图缓存  public Bitmap getCachebBitmap() {   return cachebBitmap;  }   public SignatureView(Context context) {   super(context);   init();  }   /**   * 初始化   */  private void init() {   //设置画笔   paint = new Paint();   paint.setAntiAlias(true);   paint.setStrokeWidth(3);   paint.setStyle(Paint.Style.STROKE);   paint.setColor(Color.BLACK);   path = new Path();    //创建位图   cachebBitmap = Bitmap.createBitmap(10, 10, Bitmap.Config.ARGB_8888);    //用自定义位图构建画布   cacheCanvas = new Canvas(cachebBitmap);   //设置画布为白色   cacheCanvas.drawColor(Color.WHITE);  }   /**   * 清除画板，重置画笔   */  public void clear() {   if (cacheCanvas != null) {    paint.setColor(Color.WHITE);    cacheCanvas.drawPaint(paint);    paint.setColor(Color.BLACK);    cacheCanvas.drawColor(Color.WHITE);    invalidate();   }  }   @Override protected void onDraw(Canvas canvas) {   canvas.drawBitmap(cachebBitmap, 0, 0, null);   canvas.drawPath(path, paint);  }   @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) {    int curW = cachebBitmap != null ? cachebBitmap.getWidth() : 0;   int curH = cachebBitmap != null ? cachebBitmap.getHeight() : 0;   if (curW >= w && curH >= h) {    return;   }    if (curW < w) curW = w;   if (curH < h) curH = h;   Bitmap newBitmap = Bitmap.createBitmap(curW, curH, Bitmap.Config.ARGB_8888);   Canvas newCanvas = new Canvas();   newCanvas.setBitmap(newBitmap);   if (cachebBitmap != null) {    newCanvas.drawBitmap(cachebBitmap, 0, 0, null);   }   cachebBitmap = newBitmap;   cacheCanvas = newCanvas;  }  private float cur_x, cur_y;  @Override public boolean onTouchEvent(MotionEvent event) {   float x = event.getX();   float y = event.getY();   switch (event.getAction()) {    case MotionEvent.ACTION_DOWN: {     cur_x = x;     cur_y = y;     path.moveTo(cur_x, cur_y);     break;    }    case MotionEvent.ACTION_MOVE: {     path.quadTo(cur_x, cur_y, x, y);     cur_x = x;     cur_y = y;     break;    }    case MotionEvent.ACTION_UP: {     cacheCanvas.drawPath(path, paint);     path.reset();     break;    }   }   invalidate();   return true;  } }}

布局文件：