Android 图片裁剪功能实现详解

 最近有看到有朋友在讨论QQ头像的裁剪上传是怎么实现的，吼吼，小马也没做过，好奇之下学习下，发现以前项目中有类型的功能，结合官方文档里面的解释，就更好玩了，周末，急急忙忙写的，记录在博客里，希望能与大家交流学习，也恳请高手能解答小马在代码注释中提出的疑问，不管有没有人回答，小马先谢谢了，一样的，先看下效果图（效果图小马不解释了，直接流水写下去，小马是直接在模拟器里写的，能在真机上使用，因为很简单），再看代码是怎么实现的：

一：主布局界面

二：点击控件触发事件后效果图

三：拍照完之后效果图

四：裁剪界面效果图

五：点击相册后返回的图片效果图

六：裁剪完从相册PICK的保存后的效果图 

下面直接来看下主控制类代码，如下：

package com.xiaoma.piccut.demo;

import java.io.File;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ImageView;
/**
 * @Title: PicCutDemoActivity.java
 * @Package com.xiaoma.piccut.demo
 * @Description: 图片裁剪功能测试
 * @author XiaoMa
 */
public class PicCutDemoActivity extends Activity implements OnClickListener {

    private ImageButton ib = null;
    private ImageView iv = null;
    private Button btn = null;
    private String tp = null;


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //初始化
        init();
    }

    /**
     * 初始化方法实现
     */
    private void init() {
        ib = (ImageButton) findViewById(R.id.imageButton1);
        iv = (ImageView) findViewById(R.id.imageView1);
        btn = (Button) findViewById(R.id.button1);
        ib.setOnClickListener(this);
        iv.setOnClickListener(this);
        btn.setOnClickListener(this);
    }


    /**
     * 控件点击事件实现
     *
     * 因为有朋友问不同控件的背景图裁剪怎么实现，
     * 我就在这个地方用了三个控件，只为了自己记录学习
     * 大家觉得没用的可以跳过啦
     */
    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.imageButton1:
            ShowPickDialog();
            break;
        case R.id.imageView1:
            ShowPickDialog();
            break;
        case R.id.button1:
            ShowPickDialog();
            break;

        default:
            break;
        }
    }

    /**
     * 选择提示对话框
     */
    private void ShowPickDialog() {
        new AlertDialog.Builder(this)
                .setTitle("设置头像...")
                .setNegativeButton("相册", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                        /**
                         * 刚开始，我自己也不知道ACTION_PICK是干嘛的，后来直接看Intent源码，
                         * 可以发现里面很多东西，Intent是个很强大的东西，大家一定仔细阅读下
                         */
                        Intent intent = new Intent(Intent.ACTION_PICK, null);

                        /**
                         * 下面这句话，与其它方式写是一样的效果，如果：
                         * intent.setData(MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                         * intent.setType(""image/*");设置数据类型
                         * 如果朋友们要限制上传到服务器的图片类型时可以直接写如："image/jpeg 、 image/png等的类型"
                         * 这个地方小马有个疑问，希望高手解答下：就是这个数据URI与类型为什么要分两种形式来写呀？有什么区别？
                         */
                        intent.setDataAndType(
                                MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                                "image/*");
                        startActivityForResult(intent, 1);

                    }
                })
                .setPositiveButton("拍照", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {
                        dialog.dismiss();
                        /**
                         * 下面这句还是老样子，调用快速拍照功能，至于为什么叫快速拍照，大家可以参考如下官方
                         * 文档，you_sdk_path/docs/guide/topics/media/camera.html
                         * 我刚看的时候因为太长就认真看，其实是错的，这个里面有用的太多了，所以大家不要认为
                         * 官方文档太长了就不看了，其实是错的，这个地方小马也错了，必须改正
                         */
                        Intent intent = new Intent(
                                MediaStore.ACTION_IMAGE_CAPTURE);
                        //下面这句指定调用相机拍照后的照片存储的路径
                        intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri
                                .fromFile(new File(Environment
                                        .getExternalStorageDirectory(),
                                        "xiaoma.jpg")));
                        startActivityForResult(intent, 2);
                    }
                }).show();
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
        // 如果是直接从相册获取
        case 1:
            startPhotoZoom(data.getData());
            break;
        // 如果是调用相机拍照时
        case 2:
            File temp = new File(Environment.getExternalStorageDirectory()
                    + "/xiaoma.jpg");
            startPhotoZoom(Uri.fromFile(temp));
            break;
        // 取得裁剪后的图片
        case 3:
            /**
             * 非空判断大家一定要验证，如果不验证的话，
             * 在剪裁之后如果发现不满意，要重新裁剪，丢弃
             * 当前功能时，会报NullException，小马只
             * 在这个地方加下，大家可以根据不同情况在合适的
             * 地方做判断处理类似情况
             *
             */
            if(data != null){
                setPicToView(data);
            }
            break;
        default:
            break;

        }
        super.onActivityResult(requestCode, resultCode, data);
    }

    /**
     * 裁剪图片方法实现
     * @param uri
     */
    public void startPhotoZoom(Uri uri) {
        /*
         * 至于下面这个Intent的ACTION是怎么知道的，大家可以看下自己路径下的如下网页
         * yourself_sdk_path/docs/reference/android/content/Intent.html
         * 直接在里面Ctrl+F搜：CROP ，之前小马没仔细看过，其实安卓系统早已经有自带图片裁剪功能,
         * 是直接调本地库的，小马不懂C C++  这个不做详细了解去了，有轮子就用轮子，不再研究轮子是怎么
         * 制做的了...吼吼
         */
        Intent intent = new Intent("com.android.camera.action.CROP");
        intent.setDataAndType(uri, "image/*");
        //下面这个crop=true是设置在开启的Intent中设置显示的VIEW可裁剪
        intent.putExtra("crop", "true");
        // aspectX aspectY 是宽高的比例
        intent.putExtra("aspectX", 1);
        intent.putExtra("aspectY", 1);
        // outputX outputY 是裁剪图片宽高
        intent.putExtra("outputX", 150);
        intent.putExtra("outputY", 150);
        intent.putExtra("return-data", true);
        startActivityForResult(intent, 3);
    }

    /**
     * 保存裁剪之后的图片数据
     * @param picdata
     */
    private void setPicToView(Intent picdata) {
        Bundle extras = picdata.getExtras();
        if (extras != null) {
            Bitmap photo = extras.getParcelable("data");
            Drawable drawable = new BitmapDrawable(photo);

            /**
             * 下面注释的方法是将裁剪之后的图片以Base64Coder的字符方式上
             * 传到服务器，QQ头像上传采用的方法跟这个类似
             */

            /*ByteArrayOutputStream stream = new ByteArrayOutputStream();
            photo.compress(Bitmap.CompressFormat.JPEG, 60, stream);
            byte[] b = stream.toByteArray();
            // 将图片流以字符串形式存储下来

            tp = new String(Base64Coder.encodeLines(b));
            这个地方大家可以写下给服务器上传图片的实现，直接把tp直接上传就可以了，
            服务器处理的方法是服务器那边的事了，吼吼

            如果下载到的服务器的数据还是以Base64Coder的形式的话，可以用以下方式转换
            为我们可以用的图片类型就OK啦...吼吼
            Bitmap dBitmap = BitmapFactory.decodeFile(tp);
            Drawable drawable = new BitmapDrawable(dBitmap);
            */
            ib.setBackgroundDrawable(drawable);
            iv.setBackgroundDrawable(drawable);
        }
    }

}

下面来看下裁剪中用到的类，大家详细看下头注释：

package com.xiaoma.piccut.demo;




/**
 * 下面这些注释是下载这个类的时候本来就有的，本来要删除的，但看了下竟然是license，吼吼，
 * 好东西，留在注释里，以备不时之用，大家有需要加license的可以到下面的网址找哦
 */

//EPL, Eclipse Public License, V1.0 or later, http://www./legal
//LGPL, GNU Lesser General Public License, V2.1 or later, http://www./licenses/lgpl.html
//GPL, GNU General Public License, V2 or later, http://www./licenses/gpl.html
//AL, Apache License, V2.0 or later, http://www./licenses
//BSD, BSD License, http://www./licenses/bsd-license.php
/**
* A Base64 encoder/decoder.
*
* <p>
* This class is used to encode and decode data in Base64 format as described in RFC 1521.
*
* <p>
* Project home page: <a href="http://www./base64coder/java/">www./base64coder/java</a><br>
* Author: Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland<br>
* Multi-licensed: EPL / LGPL / GPL / AL / BSD.
*/

/**
 * 这个类在上面注释的网址中有，大家可以自行下载下，也可以直接用这个，
 * 公开的Base64Coder类（不用深究它是怎么实现的，
 * 还是那句话，有轮子直接用轮子），好用的要死人了...
 * 小马也很无耻的引用了这个网址下的东东，吼吼...
* @Title: Base64Coder.java
* @Package com.xiaoma.piccut.demo
* @Description: TODO
* @author XiaoMa
 */

public class Base64Coder {

//The line separator string of the operating system.
private static final String systemLineSeparator = System.getProperty("line.separator");

//Mapping table from 6-bit nibbles to Base64 characters.
private static char[]    map1 = new char[64];
static {
   int i=0;
   for (char c='A'; c<='Z'; c++) map1[i++] = c;
   for (char c='a'; c<='z'; c++) map1[i++] = c;
   for (char c='0'; c<='9'; c++) map1[i++] = c;
   map1[i++] = '+'; map1[i++] = '/'; }

//Mapping table from Base64 characters to 6-bit nibbles.
private static byte[]    map2 = new byte[128];
static {
   for (int i=0; i<map2.length; i++) map2[i] = -1;
   for (int i=0; i<64; i++) map2[map1[i]] = (byte)i; }

/**
* Encodes a string into Base64 format.
* No blanks or line breaks are inserted.
* @param s  A String to be encoded.
* @return   A String containing the Base64 encoded data.
*/
public static String encodeString (String s) {
return new String(encode(s.getBytes())); }

/**
* Encodes a byte array into Base 64 format and breaks the output into lines of 76 characters.
* This method is compatible with <code>sun.misc.BASE64Encoder.encodeBuffer(byte[])</code>.
* @param in  An array containing the data bytes to be encoded.
* @return    A String containing the Base64 encoded data, broken into lines.
*/
public static String encodeLines (byte[] in) {
return encodeLines(in, 0, in.length, 76, systemLineSeparator); }

/**
* Encodes a byte array into Base 64 format and breaks the output into lines.
* @param in            An array containing the data bytes to be encoded.
* @param iOff          Offset of the first byte in <code>in</code> to be processed.
* @param iLen          Number of bytes to be processed in <code>in</code>, starting at <code>iOff</code>.
* @param lineLen       Line length for the output data. Should be a multiple of 4.
* @param lineSeparator The line separator to be used to separate the output lines.
* @return              A String containing the Base64 encoded data, broken into lines.
*/
public static String encodeLines (byte[] in, int iOff, int iLen, int lineLen, String lineSeparator) {
int blockLen = (lineLen*3) / 4;
if (blockLen <= 0) throw new IllegalArgumentException();
int lines = (iLen+blockLen-1) / blockLen;
int bufLen = ((iLen+2)/3)*4 + lines*lineSeparator.length();
StringBuilder buf = new StringBuilder(bufLen);
int ip = 0;
while (ip < iLen) {
   int l = Math.min(iLen-ip, blockLen);
   buf.append (encode(in, iOff+ip, l));
   buf.append (lineSeparator);
   ip += l; }
return buf.toString(); }

/**
* Encodes a byte array into Base64 format.
* No blanks or line breaks are inserted in the output.
* @param in  An array containing the data bytes to be encoded.
* @return    A character array containing the Base64 encoded data.
*/
public static char[] encode (byte[] in) {
return encode(in, 0, in.length); }

/**
* Encodes a byte array into Base64 format.
* No blanks or line breaks are inserted in the output.
* @param in    An array containing the data bytes to be encoded.
* @param iLen  Number of bytes to process in <code>in</code>.
* @return      A character array containing the Base64 encoded data.
*/
public static char[] encode (byte[] in, int iLen) {
return encode(in, 0, iLen); }

/**
* Encodes a byte array into Base64 format.
* No blanks or line breaks are inserted in the output.
* @param in    An array containing the data bytes to be encoded.
* @param iOff  Offset of the first byte in <code>in</code> to be processed.
* @param iLen  Number of bytes to process in <code>in</code>, starting at <code>iOff</code>.
* @return      A character array containing the Base64 encoded data.
*/
public static char[] encode (byte[] in, int iOff, int iLen) {
int oDataLen = (iLen*4+2)/3;       // output length without padding
int oLen = ((iLen+2)/3)*4;         // output length including padding
char[] out = new char[oLen];
int ip = iOff;
int iEnd = iOff + iLen;
int op = 0;
while (ip < iEnd) {
   int i0 = in[ip++] & 0xff;
   int i1 = ip < iEnd ? in[ip++] & 0xff : 0;
   int i2 = ip < iEnd ? in[ip++] & 0xff : 0;
   int o0 = i0 >>> 2;
   int o1 = ((i0 &   3) << 4) | (i1 >>> 4);
   int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
   int o3 = i2 & 0x3F;
   out[op++] = map1[o0];
   out[op++] = map1[o1];
   out[op] = op < oDataLen ? map1[o2] : '='; op++;
   out[op] = op < oDataLen ? map1[o3] : '='; op++; }
return out; }

/**
* Decodes a string from Base64 format.
* No blanks or line breaks are allowed within the Base64 encoded input data.
* @param s  A Base64 String to be decoded.
* @return   A String containing the decoded data.
* @throws   IllegalArgumentException If the input is not valid Base64 encoded data.
*/
public static String decodeString (String s) {
return new String(decode(s)); }

/**
* Decodes a byte array from Base64 format and ignores line separators, tabs and blanks.
* CR, LF, Tab and Space characters are ignored in the input data.
* This method is compatible with <code>sun.misc.BASE64Decoder.decodeBuffer(String)</code>.
* @param s  A Base64 String to be decoded.
* @return   An array containing the decoded data bytes.
* @throws   IllegalArgumentException If the input is not valid Base64 encoded data.
*/
public static byte[] decodeLines (String s) {
char[] buf = new char[s.length()+3];
int p = 0;
for (int ip = 0; ip < s.length(); ip++) {
   char c = s.charAt(ip);
   if (c != ' ' && c != '\r' && c != '\n' && c != '\t')
      buf[p++] = c; }
   while ((p % 4) != 0)
       buf[p++] = '0';

return decode(buf, 0, p); }

/**
* Decodes a byte array from Base64 format.
* No blanks or line breaks are allowed within the Base64 encoded input data.
* @param s  A Base64 String to be decoded.
* @return   An array containing the decoded data bytes.
* @throws   IllegalArgumentException If the input is not valid Base64 encoded data.
*/
public static byte[] decode (String s) {
return decode(s.toCharArray()); }

/**
* Decodes a byte array from Base64 format.
* No blanks or line breaks are allowed within the Base64 encoded input data.
* @param in  A character array containing the Base64 encoded data.
* @return    An array containing the decoded data bytes.
* @throws    IllegalArgumentException If the input is not valid Base64 encoded data.
*/
public static byte[] decode (char[] in) {
return decode(in, 0, in.length); }

/**
* Decodes a byte array from Base64 format.
* No blanks or line breaks are allowed within the Base64 encoded input data.
* @param in    A character array containing the Base64 encoded data.
* @param iOff  Offset of the first character in <code>in</code> to be processed.
* @param iLen  Number of characters to process in <code>in</code>, starting at <code>iOff</code>.
* @return      An array containing the decoded data bytes.
* @throws      IllegalArgumentException If the input is not valid Base64 encoded data.
*/
public static byte[] decode (char[] in, int iOff, int iLen) {
if (iLen%4 != 0) throw new IllegalArgumentException ("Length of Base64 encoded input string is not a multiple of 4.");
while (iLen > 0 && in[iOff+iLen-1] == '=') iLen--;
int oLen = (iLen*3) / 4;
byte[] out = new byte[oLen];
int ip = iOff;
int iEnd = iOff + iLen;
int op = 0;
while (ip < iEnd) {
   int i0 = in[ip++];
   int i1 = in[ip++];
   int i2 = ip < iEnd ? in[ip++] : 'A';
   int i3 = ip < iEnd ? in[ip++] : 'A';
   if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127)
      throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
   int b0 = map2[i0];
   int b1 = map2[i1];
   int b2 = map2[i2];
   int b3 = map2[i3];
   if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)
      throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
   int o0 = ( b0       <<2) | (b1>>>4);
   int o1 = ((b1 & 0xf)<<4) | (b2>>>2);
   int o2 = ((b2 &   3)<<6) |  b3;
   out[op++] = (byte)o0;
   if (op<oLen) out[op++] = (byte)o1;
   if (op<oLen) out[op++] = (byte)o2; }
return out; }

//Dummy constructor.
private Base64Coder() {}

} // end class Base64Coder

           最后，小马还把小DEMO源码放在附件里面，有需要的朋友可以下载下来，共同交流学习，也恳请高人回答下小马在文章注释中提出的问题，谢谢，文章是小马急急忙忙在家写的，在网吧发的，晕...不是我有多用功，这边下雨，讨厌下雨，下雨我就郁闷，来网吧玩的，顺带发下文章，吼吼，该玩的时候死命的玩，该工作的时候死命的工作，年轻时疯狂，老了不后悔，吼吼，加油加油！大家工作，也注意身体健康，嘿嘿，你懂的，不解释...哈哈