<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main"android:layout_width="match_parent" android:layout_height="match_parent"android:paddingBottom="@dimen/activity_vertical_margin"android:paddingLeft="@dimen/activity_horizontal_margin"android:paddingRight="@dimen/activity_horizontal_margin"android:paddingTop="@dimen/activity_vertical_margin"android:orientation="vertical"tools:context="com.example.it.MainActivity"><LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <Button android:text="修改颜色" android:onClick="color" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <Button android:text="粗细+1" android:onClick="size" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <Button android:text="保存图片" android:onClick="save" android:layout_width="wrap_content" android:layout_height="wrap_content" /></LinearLayout><ImageView android:id="@+id/iv_bg" android:layout_width="wrap_content" android:layout_height="wrap_content" /></LinearLayout>
package com.example.it;import android.content.Intent;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Matrix;import android.graphics.Paint;import android.net.Uri;import android.os.Environment;import android.os.SystemClock;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;import android.view.MotionEvent;import android.view.View;import android.widget.ImageView;import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;public class MainActivity extends AppCompatActivity {private final String TAG = getClass().getSimpleName();private ImageView iv_show;private Bitmap copyBm;private float x;private float y;private Paint paint;private int paintsize = 1;private FileOutputStream fos;@Overrideprotected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //初始化控件 iv_show = (ImageView) findViewById(R.id.iv_bg); //创建一个空白的bitmap Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.bg); copyBm = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig()); //创建画布 final Canvas canvas = new Canvas(copyBm); //使用画布绘制图片 paint = new Paint(); canvas.drawBitmap(bitmap,new Matrix(), paint); iv_show.setImageBitmap(copyBm); //为画笔在屏幕上移动设置监听事件 iv_show.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { //获取当前事件的类型 int action = event.getAction(); switch (action){ case MotionEvent.ACTION_DOWN: //如果是手指按下时,记录一下手指的位置 x = event.getX(); y = event.getY(); Log.e(TAG,x+"******"+y); break; case MotionEvent.ACTION_MOVE: //如果手指正在移动时 float x1 = event.getX(); float y1 = event.getY(); canvas.drawLine(x,y,x1,y1, paint); x = x1; y = y1; Log.e(TAG,x1+"**********"+y1); break; case MotionEvent.ACTION_UP: break; } iv_show.setImageBitmap(copyBm); return true; } });}//修改颜色public void color(View view) { paint.setColor(Color.RED);}//修改线条粗细public void size(View view) { paintsize+=1; paint.setStrokeWidth(paintsize);}//保存图片public void save(View view) { //设置图片保存的位置 File file = new File(Environment.getExternalStorageDirectory(), SystemClock.currentThreadTimeMillis()+".png"); try { fos = new FileOutputStream(file); } catch (FileNotFoundException e) { e.printStackTrace(); } //设置参数保存的质量 copyBm.compress(Bitmap.CompressFormat.PNG,100,fos); //定义一个意图,通过发出广播告诉系统扫描指定的位置的文件 Intent intent = new Intent(); intent.setAction(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE); intent.setData(Uri.fromFile(file)); sendBroadcast(intent);}} 
