Android 如何将Canvas上绘制的内容保存成本地图片

<!-- 在SDCard中创建与删除文件权限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
<!-- 往SDCard写入数据权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.demo.picturetest"
android:versionCode="1"
android:versionName="1.0" >

<!-- 在SDCard中创建与删除文件权限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
<!-- 往SDCard写入数据权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />

<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>

package com.demo.picturetest;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.widget.ImageView;

public class MainActivity extends Activity {
private Bitmap mBitmap;
// 画布
private Canvas mCanvas;
// 画笔－－画图片
private Paint mPicturePaint = new Paint();
// 画笔－－写字
private Paint mTextPaint = new Paint();
// 画笔－－写运动数据
private Paint mDataPaint = new Paint();

private ImageView mImageView;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
drawBitmap();
init();
// 展示
mImageView.setImageBitmap(mBitmap);

}

private void init() {
mImageView = (ImageView) findViewById(R.id.mImageView);
}

/**
* 根据图片和文字生成图片
* */
private void drawBitmap() {

Bitmap bm_bg = BitmapFactory.decodeResource(getResources(),
R.drawable.dashboard_bg);
// 得到图片的宽、高
int width_bg = bm_bg.getWidth();
int height_bg = bm_bg.getHeight();

// 创建一个你需要尺寸的Bitmap
mBitmap = Bitmap.createBitmap(width_bg, height_bg, Config.ARGB_8888);
// 用这个Bitmap生成一个Canvas,然后canvas就会把内容绘制到上面这个bitmap中
mCanvas = new Canvas(mBitmap);

// 绘制背景图片
mCanvas.drawBitmap(bm_bg, 0.0f, 0.0f, mPicturePaint);
// 绘制图片
Bitmap bm_head = BitmapFactory.decodeResource(getResources(),
R.drawable.share_head_img);

// 得到图片的宽、高
int width_head = bm_head.getWidth();
int height_head = bm_head.getHeight();
// 绘制图片－－保证其在水平方向居中
mCanvas.drawBitmap(bm_head, (width_bg - width_head) / 2, 0.0f,
mPicturePaint);

// 绘制文字
mTextPaint.setColor(Color.WHITE);// 白色画笔
mTextPaint.setTextSize(80.0f);// 设置字体大小

// 绘制文字
mDataPaint.setColor(Color.RED);// 红色画笔
mDataPaint.setTextSize(120.0f);// 设置字体大小

String distanceTextString = "运动距离：";
String distanceDataString = String.valueOf(888);
String distanceScalString = "米";

float distanceTextString_width = mTextPaint.measureText(
distanceTextString, 0, distanceTextString.length());

float distanceDataString_width = mDataPaint.measureText(
distanceDataString, 0, distanceDataString.length());
float distanceScalString_width = mTextPaint.measureText(
distanceScalString, 0, distanceScalString.length());
float x = (width_bg - distanceTextString_width
- distanceDataString_width - distanceScalString_width) / 2;

mCanvas.drawText(distanceTextString, x, height_head, mTextPaint);// 绘制文字
mCanvas.drawText(distanceDataString, x + distanceTextString_width,
height_head, mDataPaint);// 绘制文字

mCanvas.drawText(distanceScalString, x + distanceTextString_width
+ distanceDataString_width, height_head, mTextPaint);// 绘制文字

// 保存绘图为本地图片
mCanvas.save(Canvas.ALL_SAVE_FLAG);
mCanvas.restore();

File file = new File(Environment.getExternalStorageDirectory()
.getPath() + "/share_pic.png");// 保存到sdcard根目录下，文件名为share_pic.png
Log.i("CXC", Environment.getExternalStorageDirectory().getPath());
FileOutputStream fos = null;
try {
fos = new FileOutputStream(file);
mBitmap.compress(Bitmap.CompressFormat.PNG, 50, fos);

} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
fos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}
}