Android选择图片的两种方式

原文地址 http://www.jb51.net/article/78201.htm

Android选择图片的两种方式：

第一种：单张选取

通过隐式启动activity，跳转到相册选择一张返回结果

关键代码如下：

发送请求：

1 2 3 4 5 6 7 8 9 10 11 private static final int PICTURE = 10086 ; //requestcode Intent intent = new Intent(); if (Build.VERSION.SDK_INT < 19 ) { //因为Android SDK在4.4版本后图片action变化了所以在这里先判断一下 intent.setAction(Intent.ACTION_GET_CONTENT); } else { intent.setAction(Intent.ACTION_OPEN_DOCUMENT); } intent.setType( "image/*" ); intent.addCategory(Intent.CATEGORY_OPENABLE); startActivityForResult(intent, PICTURE);

接收结果：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 @Override protected void onActivityResult( int requestCode, int resultCode, Intent data) { if (data == null ) { this .finish(); return ; } Uri uri = data.getData(); switch (requestCode) { case PICTURE: image = FileUtils.getUriPath( this , uri); //（因为4.4以后图片uri发生了变化）通过文件工具类对uri进行解析得到图片路径 break ; default : break ; } this .finish(); }

文件工具类：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 public class FileUtils { private static final String TAG = "FileUtils" ; private static final boolean DEBUG = false ; /** * 获取可读的文件大小 */ public static String getReadableFileSize( int size) { final int BYTES_IN_KILOBYTES = 1024 ; final DecimalFormat dec = new DecimalFormat( "###.#" ); final String KILOBYTES = " KB" ; final String MEGABYTES = " MB" ; final String GIGABYTES = " GB" ; float fileSize = 0 ; String suffix = KILOBYTES; if (size > BYTES_IN_KILOBYTES) { fileSize = size / BYTES_IN_KILOBYTES; if (fileSize > BYTES_IN_KILOBYTES) { fileSize = fileSize / BYTES_IN_KILOBYTES; if (fileSize > BYTES_IN_KILOBYTES) { fileSize = fileSize / BYTES_IN_KILOBYTES; suffix = GIGABYTES; } else { suffix = MEGABYTES; } } } return String.valueOf(dec.format(fileSize) + suffix); } /** * 获取文件的文件名(不包括扩展名) */ public static String getFileNameWithoutExtension(String path) { if (path == null ) { return null ; } int separatorIndex = path.lastIndexOf(File.separator); if (separatorIndex < 0 ) { separatorIndex = 0 ; } int dotIndex = path.lastIndexOf( "." ); if (dotIndex < 0 ) { dotIndex = path.length(); } else if (dotIndex < separatorIndex) { dotIndex = path.length(); } return path.substring(separatorIndex + 1 , dotIndex); } /** * 获取文件名 */ public static String getFileName(String path) { if (path == null ) { return null ; } int separatorIndex = path.lastIndexOf(File.separator); return (separatorIndex < 0 ) ? path : path.substring(separatorIndex + 1 , path.length()); } /** * 获取扩展名 */ public static String getExtension(String path) { if (path == null ) { return null ; } int dot = path.lastIndexOf( "." ); if (dot >= 0 ) { return path.substring(dot); } else { return "" ; } } public static File getUriFile(Context context, Uri uri) { String path = getUriPath(context, uri); if (path == null ) { return null ; } return new File(path); } public static String getUriPath(Context context, Uri uri) { if (uri == null ) { return null ; } if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT && DocumentsContract.isDocumentUri(context, uri)) { if ( "com.android.externalstorage.documents" .equals(uri.getAuthority())) { final String docId = DocumentsContract.getDocumentId(uri); final String[] split = docId.split( ":" ); final String type = split[ 0 ]; if ( "primary" .equalsIgnoreCase(type)) { return Environment.getExternalStorageDirectory() + "/" + split[ 1 ]; } } else if ( "com.android.providers.downloads.documents" .equals(uri.getAuthority())) { final String id = DocumentsContract.getDocumentId(uri); final Uri contentUri = ContentUris.withAppendedId(Uri.parse( "content://downloads/public_downloads" ), Long.valueOf(id)); return getDataColumn(context, contentUri, null , null ); } else if ( "com.android.providers.media.documents" .equals(uri.getAuthority())) { final String docId = DocumentsContract.getDocumentId(uri); final String[] split = docId.split( ":" ); final String type = split[ 0 ]; Uri contentUri = null ; if ( "image" .equals(type)) { contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI; } else if ( "video" .equals(type)) { contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI; } else if ( "audio" .equals(type)) { contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI; } final String selection = "_id=?" ; final String[] selectionArgs = new String[] {split[ 1 ]}; return getDataColumn(context, contentUri, selection, selectionArgs); } } else if ( "content" .equalsIgnoreCase(uri.getScheme())) { if ( "com.google.android.apps.photos.content" .equals(uri.getAuthority())) { return uri.getLastPathSegment(); } return getDataColumn(context, uri, null , null ); } else if ( "file" .equalsIgnoreCase(uri.getScheme())) { return uri.getPath(); } return null ; } public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) { Cursor cursor = null ; final String column = "_data" ; final String[] projection = {column}; try { cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null ); if (cursor != null && cursor.moveToFirst()) { final int column_index = cursor.getColumnIndexOrThrow(column); return cursor.getString(column_index); } } finally { if (cursor != null ) cursor.close(); } return null ; } }

第二种方式批量选择图片

如果我们需要类似于微信那样的一次选取多张图片，很明显第一种方式是不能满足需求，那么怎么才能批量选取呢？andorid并提供像单张选取似的批量选取的直接方法，所以我们只能自己从数据库中获得。

首先我们要认识一个类mediastore android中所有的多媒体文件都存储在这个数据库中，例如图片视频音频等等，他通过contentprovider 向其他进程提供数据的接口

想要从mediastore中获得数据，我们可以使用与ContentProvider 对应的ContentResolver

关键代码：

1 2 3 4 5 6 7 8 9 10 11 final String[] projectionPhotos = { MediaStore.Images.Media._ID, //每一列的ID 图片的ID MediaStore.Images.Media.BUCKET_ID, //图片所在文件夹ID MediaStore.Images.Media.BUCKET_DISPLAY_NAME, //图片所在文件夹名称 MediaStore.Images.Media.DATA, //图片路径 MediaStore.Images.Media.DATE_TAKEN, //图片创建时间 }; cursor = MediaStore.Images.Media.query(context.getContentResolver(), MediaStore.Images.Media.EXTERNAL_CONTENT_URI , projectionPhotos, "" , null , MediaStore.Images.Media.DATE_TAKEN + " DESC" );

所有图片都在cursor里了再从cursor中取出即可

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