1.獲取數據
a.文件夾列表
相冊的數據當然是媒體數據,包括圖片和視頻。相冊的文件夾列表除了實際的圖片文件夾分類,相冊還添加了相機圖片、相機視頻、所有圖片、所有視頻幾個分類。
這些分類數據也以圖片文件夾的形式列出來。文件夾列表的數據是怎麼獲取的呢,當然,可以自己到sdcard中去找,當然這就2了。系統將這個工作已經做了,系統會維護一個Media數據庫來存儲這些媒體數據信息。以前自己也使用過Media數據庫來查找媒體數據信息,看了相冊使用Media數據庫,瞬間感覺自己的方式弱爆了。
相冊的列表頁面是GalleryPicker,當加載列表數據的時候會執行下面這個方法:
- private void workerRun() {
- ArrayList<Item> allItems = new ArrayList<Item>();
- checkScanning();//檢查系統Media庫掃描後臺是否還在執行
- .....
- checkImageList(allItems);//獲取系統媒體數據列表,這裏就包括所有的圖片文件夾列表、相機圖片、相機視頻、所有圖片、所有視頻
- .....
- checkBucketIds(allItems);//下面是獲取sdcard文件夾列表數據 ps:個人覺得這個方法和上面的checkImageList方法的名字很有歧義啊。根據方法名很容易理解爲checkImageList是先獲取整個列表,checkBucketIds方法是獲取列表需要的數據。被名字忽悠了。應該叫做checkInternalList 和 checkExternalList嘛。
- checkThumbBitmap(allItems);
- checkLowStorage();
- }
下面是獲取系統媒體列表數據,列表有5類,包括相機圖片、相機視頻、相機媒體(相機圖片+相機視頻)、所有圖片、所有視頻
- private void checkImageList(ArrayList<Item> allItems) {
- int length = IMAGE_LIST_DATA.length;//5類列表的數據全部定義在IMAGE_LIST_DATA裏面
- IImageList[] lists = new IImageList[length];
- for (int i = 0; i < length; i++) {
- ImageListData data = IMAGE_LIST_DATA[i];
- lists[i] = createImageList(data.mInclude, data.mBucketId,
- getContentResolver());
- .....
- Item item = new Item(data.mType, data.mBucketId, getResources()
- .getString(data.mStringId), lists[i]);
- allItems.add(item);
- final Item finalItem = item;
- mHandler.post(new Runnable() {
- public void run() {
- updateItem(finalItem);
- }
- });
- }
- }
裏面抽象定義的數據比較多,這裏介紹不可能太清楚。可以取看看代碼,仔細研究一下。總體說來,這裏得到相機圖片、相機視頻、相機媒體(相機圖片+相機視頻)、所有圖片、所有視頻這幾種數據的列表。列表的結構是ImageList、VideoList等,它們都是BaseImageList的子類,代碼在com.android.camera.gallery包下面。
下面是獲取sdcard文件夾列表數據
- private void checkBucketIds(ArrayList<Item> allItems) {
- final IImageList allImages;
- //獲取所有數據列表
- if (!mScanning && !mUnmounted) {
- allImages = ImageManager.makeImageList(getContentResolver(),
- ImageManager.DataLocation.ALL, ImageManager.INCLUDE_IMAGES
- | ImageManager.INCLUDE_VIDEOS,
- ImageManager.SORT_DESCENDING, null);
- } else {
- allImages = ImageManager.makeEmptyImageList();
- }
- .....
- //這個地方這句話,是比較屌的,直接就查到了sdcard中的文件夾列表。以前,自己寫這一塊。就很2地取Media數據庫,把所有的圖片文件路徑讀出來,在來截取生成列表。相冊是不是這樣寫的,具體,下面會介紹
- HashMap<String, String> hashMap = allImages.getBucketIds();
- allImages.close();
- for (Map.Entry<String, String> entry : hashMap.entrySet()) {
- String key = entry.getKey();
- if (!key.equals(CAMERA_BUCKET)) {
- IImageList list = createImageList(ImageManager.INCLUDE_IMAGES
- | ImageManager.INCLUDE_VIDEOS, key,
- getContentResolver());
- .....
- Item item = new Item(Item.TYPE_NORMAL_FOLDERS, key,
- entry.getValue(), list);
- allItems.add(item);
- final Item finalItem = item;
- mHandler.post(new Runnable() {
- public void run() {
- updateItem(finalItem);
- }
- });
- }
- }
- mHandler.post(new Runnable() {
- public void run() {
- checkBucketIdsFinished();
- }
- });
- }
上面的全部都是招式,下面纔是內功,也就是獲取列表的核心部分,由於相冊把這一塊做了很多抽象,因此,我把核心的代碼整理出來
- package com.example.demo;
- import java.util.HashMap;
- import android.content.ContentResolver;
- import android.database.Cursor;
- import android.net.Uri;
- import android.os.Environment;
- import android.provider.MediaStore.Images;
- import android.provider.MediaStore.Images.Media;
- /**
- * 獲取系統Midia數據庫數據,Midia數據庫要這麼用
- *
- * @author johnnyxyz
- * @mail [email protected]
- */
- public class MediaListGetter {
- public static final Uri EXTERNAL_STORAGE_URI = Images.Media.EXTERNAL_CONTENT_URI;
- public static final Uri INTERNAL_STORAGE_URI = Images.Media.INTERNAL_CONTENT_URI;
- public static final Uri VIDEO_STORAGE_URI = Uri.parse("content://media/external/video/media");
- private static final String[] ACCEPTABLE_IMAGE_TYPES = new String[] { "image/jpeg",
- "image/png", "image/gif" };
- private static final String WHERE_CLAUSE = "(" + Media.MIME_TYPE + " in (?, ?, ?))";
- private static final String WHERE_CLAUSE_WITH_BUCKET_ID = WHERE_CLAUSE + " AND "
- + Media.BUCKET_ID + " = ?";
- protected String whereClause(String bucketId) {
- return bucketId == null ? WHERE_CLAUSE : WHERE_CLAUSE_WITH_BUCKET_ID;
- }
- private String[] whereClauseArgs(String bucketId) {
- if (bucketId != null) {
- int count = ACCEPTABLE_IMAGE_TYPES.length;
- String[] result = new String[count + 1];
- System.arraycopy(ACCEPTABLE_IMAGE_TYPES, 0, result, 0, count);
- result[count] = bucketId;
- return result;
- }
- return ACCEPTABLE_IMAGE_TYPES;
- }
- public static final String CAMERA_IMAGE_BUCKET_NAME = Environment.getExternalStorageDirectory()
- .toString() + "/DCIM/Camera";
- public static final String CAMERA_IMAGE_BUCKET_ID = String.valueOf(CAMERA_IMAGE_BUCKET_NAME
- .toLowerCase().hashCode());
- public MediaListGetter(ContentResolver mContentResolver) {
- super();
- this.mContentResolver = mContentResolver;
- }
- private final ContentResolver mContentResolver;
- /**
- * 獲取所有Camera圖片文件夾列表
- * @return
- */
- public HashMap<String, String> getCameraImages() {
- // 內置存儲的圖片
- Uri baseUri = INTERNAL_STORAGE_URI;
- Uri uri = baseUri.buildUpon().appendQueryParameter("distinct", "true").build();
- Cursor internal = Media.query(mContentResolver, uri, new String[] {
- Media.BUCKET_DISPLAY_NAME, Media.BUCKET_ID }, whereClause(CAMERA_IMAGE_BUCKET_ID),
- whereClauseArgs(CAMERA_IMAGE_BUCKET_ID), null);
- // 外置存儲的圖片
- baseUri = EXTERNAL_STORAGE_URI;
- uri = baseUri.buildUpon().appendQueryParameter("distinct", "true").build();
- Cursor external = Media.query(mContentResolver, uri, new String[] {
- Media.BUCKET_DISPLAY_NAME, Media.BUCKET_ID }, whereClause(CAMERA_IMAGE_BUCKET_ID),
- whereClauseArgs(CAMERA_IMAGE_BUCKET_ID), null);
- try {
- HashMap<String, String> hash = new HashMap<String, String>();
- while (internal.moveToNext()) {
- hash.put(internal.getString(1), internal.getString(0));
- }
- while (external.moveToNext()) {
- hash.put(external.getString(1), external.getString(0));
- }
- return hash;
- } finally {
- internal.close();
- external.close();
- }
- }
- /**
- * 獲取所有Camera視頻文件夾列表
- * @return
- */
- public HashMap<String, String> getCameraVidios() {
- Uri baseUri = VIDEO_STORAGE_URI;
- Uri uri = baseUri.buildUpon().appendQueryParameter("distinct", "true").build();
- Cursor cursor = Media.query(mContentResolver, uri, new String[] {
- Media.BUCKET_DISPLAY_NAME, Media.BUCKET_ID },
- (CAMERA_IMAGE_BUCKET_ID != null ? Images.Media.BUCKET_ID + " = '"
- + CAMERA_IMAGE_BUCKET_ID + "'" : null), null, null);
- try {
- HashMap<String, String> hash = new HashMap<String, String>();
- while (cursor.moveToNext()) {
- hash.put(cursor.getString(1), cursor.getString(0));
- }
- return hash;
- } finally {
- cursor.close();
- }
- };
- /**
- * 獲取所有Camera媒體文件夾列表
- * @return
- */
- public void getCameraMedias() {
- // getCameraVidios + getCameraImages
- };
- /**
- * 獲取所有圖片的文件夾列表
- * @return
- */
- public HashMap<String, String> getAllImages() {
- Uri baseUri = EXTERNAL_STORAGE_URI;
- Uri uri = baseUri.buildUpon().appendQueryParameter("distinct", "true").build();
- // 外置存儲camera圖片
- Cursor camera = Media.query(mContentResolver, uri, new String[] {
- Media.BUCKET_DISPLAY_NAME, Media.BUCKET_ID }, whereClause(CAMERA_IMAGE_BUCKET_ID),
- whereClauseArgs(CAMERA_IMAGE_BUCKET_ID), null);
- // 外置存儲非camera圖片
- Cursor external = Media.query(mContentResolver, uri, new String[] {
- Media.BUCKET_DISPLAY_NAME, Media.BUCKET_ID }, whereClause(null),
- whereClauseArgs(null), null);
- // 內置圖片
- baseUri = INTERNAL_STORAGE_URI;
- uri = baseUri.buildUpon().appendQueryParameter("distinct", "true").build();
- Cursor internal = Media.query(mContentResolver, uri, new String[] {
- Media.BUCKET_DISPLAY_NAME, Media.BUCKET_ID }, whereClause(null),
- whereClauseArgs(null), null);
- try {
- HashMap<String, String> hash = new HashMap<String, String>();
- while (camera.moveToNext()) {
- hash.put(camera.getString(1), camera.getString(0));
- }
- while (external.moveToNext()) {
- hash.put(external.getString(1), external.getString(0));
- }
- while (internal.moveToNext()) {
- hash.put(internal.getString(1), internal.getString(0));
- }
- return hash;
- } finally {
- camera.close();
- external.close();
- internal.close();
- }
- };
- /**
- * 獲取所有視頻的文件夾列表
- * @return
- */
- public HashMap<String, String> getAllVidios() {
- Uri baseUri = VIDEO_STORAGE_URI;
- Uri uri = baseUri.buildUpon().appendQueryParameter("distinct", "true").build();
- Cursor cursor = Media.query(mContentResolver, uri, new String[] {
- Media.BUCKET_DISPLAY_NAME, Media.BUCKET_ID }, null, null, null);
- try {
- HashMap<String, String> hash = new HashMap<String, String>();
- while (cursor.moveToNext()) {
- hash.put(cursor.getString(1), cursor.getString(0));
- }
- return hash;
- } finally {
- cursor.close();
- }
- };
- /**
- * 獲取外置存儲的所有文件夾
- * @return
- */
- public HashMap<String, String> getExternalFolders() {
- Uri baseUri = EXTERNAL_STORAGE_URI;
- Uri uri = baseUri.buildUpon().appendQueryParameter("distinct", "true").build();
- Cursor cursor = Media.query(mContentResolver, uri, new String[] {
- Media.BUCKET_DISPLAY_NAME, Media.BUCKET_ID }, null, null, null);
- try {
- HashMap<String, String> hash = new HashMap<String, String>();
- while (cursor.moveToNext()) {
- if (CAMERA_IMAGE_BUCKET_ID.equals(cursor.getString(1)))
- continue;
- hash.put(cursor.getString(1), cursor.getString(0));
- }
- return hash;
- } finally {
- cursor.close();
- }
- }
- }