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: android:layout_width='1200px' android:layout_height='1500px' android:layout_alignParentLeft='true' android:layout_alignParentRight='true' android:layout_alignParentStart='true' /> <LinearLayout android: 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: 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: 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(); } }}

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