android_65_简易画画板

效果:

清单:

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.sg31.draw"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="8"        android:targetSdkVersion="21" />    // 注意权限     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />          <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />                     <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name=".MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application></manifest>

布局:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    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"    tools:context="com.sg31.draw.MainActivity" >            <ImageView        android:id="@+id/iv"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world"         /><LinearLayout     android:layout_width="match_parent"    android:layout_height="wrap_content"    android:orientation="horizontal"    android:layout_alignParentBottom="true"    >    <Button         android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="红色"        android:onClick="redColorBtnClicked"        />    <Button         android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="绿色"        android:onClick="greenColorBtnClicked"        />    <Button         android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="刷子"        android:onClick="brushBtnClicked"        />    <Button         android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="保存"        android:onClick="savePicBtnClicked"        /></LinearLayout>    </RelativeLayout>

代码:

package com.sg31.draw;import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.text.SimpleDateFormat;import java.util.Date;import android.support.v7.app.ActionBarActivity;import android.content.Intent;import android.graphics.Bitmap;import android.graphics.Bitmap.CompressFormat;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.Bundle;import android.os.Environment;import android.view.Menu;import android.view.MenuItem;import android.view.MotionEvent;import android.view.View;import android.view.View.OnTouchListener;import android.widget.ImageView;public class MainActivity extends ActionBarActivity {private ImageView iv;int startX;int startY;private Canvas canvas;private Paint paint;private Bitmap bmCopy;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 加载画画板的背景图Bitmap bmSrc = BitmapFactory.decodeResource(getResources(),R.drawable.bg);bmCopy = Bitmap.createBitmap(bmSrc.getWidth(), bmSrc.getHeight(),bmSrc.getConfig());paint = new Paint();canvas = new Canvas(bmCopy);// 绘制canvas.drawBitmap(bmSrc, new Matrix(), paint);iv = (ImageView) findViewById(R.id.iv);iv.setImageBitmap(bmCopy);// 设置触摸侦听iv.setOnTouchListener(new OnTouchListener() {// 触摸屏幕时，触摸事件产生时，此方法调用@Overridepublic boolean onTouch(View v, MotionEvent event) {int action = event.getAction();switch (action) {// 用户手指摸到屏幕case MotionEvent.ACTION_DOWN:startX = (int) event.getX();startY = (int) event.getY();break;// 用户手指正在滑动case MotionEvent.ACTION_MOVE:int x = (int) event.getX();int y = (int) event.getY();canvas.drawLine(startX, startY, x, y, paint);// 每次绘制完毕之后，本次绘制的结束坐标变成下一次绘制的初始坐标startX = x;startY = y;iv.setImageBitmap(bmCopy);break;// 用户手指离开屏幕case MotionEvent.ACTION_UP:break;}// true：告诉系统，这个触摸事件由我来处理// false：告诉系统，这个触摸事件我不处理，这时系统会把触摸事件传递给imageview的父节点return true;}});}public void redColorBtnClicked(View v) {paint.setColor(Color.RED);}public void greenColorBtnClicked(View v) {paint.setColor(Color.GREEN);}public void brushBtnClicked(View v) {paint.setStrokeWidth(7);}public void savePicBtnClicked(View v) {File file = new File("sdcard/"+tool_currentDateTime()+".png");FileOutputStream fos = null;try {fos = new FileOutputStream(file);} catch (FileNotFoundException e) {e.printStackTrace();}bmCopy.compress(CompressFormat.PNG, 100, fos);// 发送sd卡就绪广播,重新装载和扫描sd卡内的文件Intent intent = new Intent();// ACTION_MEDIA_SCANNER_SCAN_FILE.// ACTION_MEDIA_MOUNTED// MediaScannerConnection intent.setAction(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);intent.setData(Uri.fromFile(Environment.getExternalStorageDirectory()));sendBroadcast(intent);}public String tool_currentDateTime(){SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式System.out.println(df.format(new Date()));// new Date()为获取当前系统时间return df.format(new Date());}}