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;

	@Override
	protected 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
			@Override
			public 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());
	}
}