Android 实现银联刷卡机消费后手动签名的功能(示例代码)

package com.view;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;
/**
 * Created by jiang on 2017/12/25.
 */
public class MDrawLineView extends View {
 public MDrawLineView(Context context){
  super(context);
 }
 public MDrawLineView(Context context,AttributeSet attrs){
  super(context, attrs);
  paint=new Paint(Paint.DITHER_FLAG);//创建一个画笔
  if(bitmap==null){
   bitmap = Bitmap.createBitmap(900, 1200, Bitmap.Config.ARGB_8888); //设置位图的宽高
  }
  canvas=new Canvas();
  canvas.setBitmap(bitmap);
  paint.setStyle(Paint.Style.STROKE);//设置非填充
  paint.setStrokeWidth(5);//笔宽5像素
  paint.setColor(Color.RED);//设置为红笔
  paint.setAntiAlias(true);//锯齿不显示
 }
 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  if(bitmap==null){
   bitmap = Bitmap.createBitmap(900, 1200, Bitmap.Config.ARGB_8888); //设置位图的宽高
  }
  canvas.drawBitmap(bitmap,0,0,null);
 }
 public void clear(){
  canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
 }
 @Override
 public boolean onTouchEvent(MotionEvent event) {
  switch (event.getAction()){
   case MotionEvent.ACTION_MOVE: //用户手指在屏幕上移动画线
    canvas.drawLine(mov_x,mov_y,event.getX(),event.getY(),paint);
    invalidate();
    break;
   case MotionEvent.ACTION_DOWN://用户手指按下时画起点
    mov_x=(int) event.getX();
    mov_y=(int) event.getY();
    canvas.drawPoint(mov_x,mov_y,paint);
    invalidate();
    break;
   case MotionEvent.ACTION_UP:
    break;
  }
  mov_x=(int) event.getX();
  mov_y=(int) event.getY();
  return true;
  //return super.onTouchEvent(event);
 }
 private int mov_x;//声明起点x坐标
 private int mov_y;//声明起点y坐标
 private Paint paint;//声明画笔
 private Canvas canvas;//画布
 private Bitmap bitmap;//位图
 private int blcolor;
}

<?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:gravity="center_horizontal"
 android:padding="10dp"
 android:orientation="vertical">
 <com.view.MDrawLineView
  android:id="@+id/mDrawLine"
  android:layout_width="300dp"
  android:layout_height="400dp"
  android:background="@drawable/bg_drawline" />
 <Button
  android:id="@+id/clearBut"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="清空" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
 <!-- 描边-->
 <stroke android:width="2dp" android:color="#45c01a"></stroke>
 <!-- 填充颜色 -->
 <solid android:color="#fff"></solid>
 <!-- 圆角 -->
 <corners android:radius="10dp"></corners>
</shape>

package com.cktest;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import com.view.MDrawLineView;
/**
 * Created by jiang on 2017/12/25.
 */
public class DrawLineAct extends AppCompatActivity implements View.OnClickListener{
 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.act_drawline);
  mDrawLine = (MDrawLineView) findViewById(R.id.mDrawLine);
  clearBut = (Button) findViewById(R.id.clearBut);
  clearBut.setOnClickListener(this);
 }
 @Override
 public void onClick(View v) {
  switch (v.getId()){
   case R.id.clearBut:
    mDrawLine.clear();
    break;
  }
 }
 private MDrawLineView mDrawLine;
 private Button clearBut;
}