Android实现手绘功能

本文实例为大家分享了android实现手绘功能的具体代码，供大家参考，具体内容如下

布局文件如下

<?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="com.example.administrator.main.drawactivity">
 
 <imageview
  android:id="@+id/iv"
  android:layout_width="1200px"
  android:layout_height="1500px"
  android:layout_alignparentleft="true"
  android:layout_alignparentright="true"
  android:layout_alignparentstart="true" />
 
 <linearlayout
  android:id="@+id/linearlayout4"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignparentbottom="true"
  android:layout_gravity="center_horizontal"
  android:orientation="horizontal">
 
 </linearlayout>
 
 <button
  android:id="@+id/btn_resume"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignparentbottom="true"
  android:layout_alignparentend="true"
  android:layout_marginend="79dp"
  android:text="重绘" />
 
 <button
  android:id="@+id/btn_save"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignbottom="@+id/linearlayout4"
  android:layout_marginstart="91dp"
  android:layout_toendof="@+id/linearlayout4"
  android:text="保存" />
</relativelayout>

activity代码如下，其中线的颜色，宽度等属性都可以修改。

package com.example.administrator.main;
 
import android.content.intent;
import android.graphics.bitmap;
import android.graphics.canvas;
import android.graphics.color;
import android.graphics.paint;
import android.net.uri;
import android.os.environment;
import android.support.v7.app.appcompatactivity;
import android.os.bundle;
import android.view.motionevent;
import android.view.view;
import android.widget.button;
import android.widget.imageview;
import android.widget.toast;
 
import java.io.file;
import java.io.fileoutputstream;
 
public class drawactivity extends appcompatactivity {
 private imageview iv;
 private bitmap basebitmap;
 private button btn_resume;
 private button btn_save;
 private canvas canvas;
 private paint paint;
 
 float radio;
 
 @override
 protected void oncreate(bundle savedinstancestate) {
  super.oncreate(savedinstancestate);
  setcontentview(r.layout.activity_draw);
  radio = 10;
  iv = (imageview) findviewbyid(r.id.iv);
  // 初始化一个画笔，笔触宽度为5，颜色为红色
  paint = new paint();
  paint.setstrokewidth(radio);
  paint.setcolor(color.black);
  iv = (imageview) findviewbyid(r.id.iv);
  btn_resume = (button) findviewbyid(r.id.btn_resume);
  btn_save = (button) findviewbyid(r.id.btn_save);
 
  btn_resume.setonclicklistener(click);
  btn_save.setonclicklistener(click);
  iv.setontouchlistener(touch);
 }
 
 private view.ontouchlistener touch = new view.ontouchlistener() {
  // 定义手指开始触摸的坐标
  float startx;
  float starty;
 
  @override
  public boolean ontouch(view v, motionevent event) {
   switch (event.getaction()) {
    // 用户按下动作
    case motionevent.action_down:
     // 第一次绘图初始化内存图片，指定背景为白色
     if (basebitmap == null) {
      basebitmap = bitmap.createbitmap(iv.getwidth(),
        iv.getheight(), bitmap.config.argb_8888);
      canvas = new canvas(basebitmap);
      canvas.drawcolor(color.white);
     }
     // 记录开始触摸的点的坐标
     startx = event.getx();
     starty = event.gety();
     break;
    // 用户手指在屏幕上移动的动作
    case motionevent.action_move:
     // 记录移动位置的点的坐标
     float stopx = event.getx();
     float stopy = event.gety();
 
     thread t = new thread(new runnable() {
      @override
      public void run() {
       radio += 0.1;
 
       try {
        thread.sleep(1000);
       } catch (interruptedexception e) {
        e.printstacktrace();
       }
      }
     });
     t.start();
 
     paint.setstrokewidth(radio);
     //根据两点坐标，绘制连线
     canvas.drawline(startx, starty, stopx, stopy, paint);
 
     // 更新开始点的位置
     startx = event.getx();
     starty = event.gety();
     // 把图片展示到imageview中
     iv.setimagebitmap(basebitmap);
     break;
    case motionevent.action_up:
     radio = 5;
     break;
    default:
     break;
   }
   return true;
  }
 };
 private view.onclicklistener click = new view.onclicklistener() {
 
  @override
  public void onclick(view v) {
   switch (v.getid()) {
    case r.id.btn_save:
     savebitmap();
     break;
    case r.id.btn_resume:
     resumecanvas();
     break;
    default:
     break;
   }
  }
 };
 
 /**
  * 保存图片到sd卡上
  */
 protected void savebitmap() {
  try {
   // 保存图片到sd卡上
   string filename = "/sdcard/"+system.currenttimemillis() + ".png";
   file file = new file(filename);
   fileoutputstream stream = new fileoutputstream(file);
   basebitmap.compress(bitmap.compressformat.png, 100, stream);
   toast.maketext(drawactivity.this, "保存图片成功", toast.length_short).show();
    // android设备gallery应用只会在启动的时候扫描系统文件夹
    // 这里模拟一个媒体装载的广播，用于使保存的图片可以在gallery中查看
   intent intent = new intent();
   intent.setaction(intent.action_media_mounted);
   intent.setdata(uri.fromfile(environment
     .getexternalstoragedirectory()));
   sendbroadcast(intent);
  } catch (exception e) {
   toast.maketext(drawactivity.this, "保存图片失败", toast.length_short).show();
   e.printstacktrace();
  }
 }
 
 // 手动清除画板的绘图，重新创建一个画板
 protected void resumecanvas() {
  if (basebitmap != null) {
   basebitmap = bitmap.createbitmap(iv.getwidth(),
     iv.getheight(), bitmap.config.argb_8888);
   canvas = new canvas(basebitmap);
   canvas.drawcolor(color.white);
   iv.setimagebitmap(basebitmap);
   toast.maketext(drawactivity.this, "清除画板成功，可以重新开始绘图", toast.length_short).show();
  }
 }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。