Android系列之图片选择的两种方式

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：

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：

@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：

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：

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

大家可以参考的库：https://github.com/pengjianbo/GalleryFinal