一、多媒體數(shù)據(jù)庫與ContentResovler：
Android提供的多媒體數(shù)據(jù)庫MediaStore保存了音頻、視頻、圖片的全部基本信息，
保存在/data/data/com.android.providers.media/databases下的external.db數(shù)據(jù)庫
事實上以下URI是ContentProvider給我們封裝了用來訪問系統(tǒng)數(shù)據(jù)庫的入口
二、ContentResobler相關(guān)類比
- ContentProvider相當(dāng)于服務(wù)器，將系統(tǒng)的數(shù)據(jù)庫訪問接口URI給我們；
- ContentResolver相當(dāng)于瀏覽器，輸入URI和相應(yīng)的條件，就可以訪問數(shù)據(jù)；
- 每個URI都對應(yīng)著一個相關(guān)數(shù)據(jù)表，使用ContentResolver相關(guān)方法進行表查詢；
- ContentResolver更像是SQLiteDatebase類,有查詢，刪除等相關(guān)方法；
三、一些常用的URI(表)：
- 音樂URI(表)
MediaStore.Audio.Media.EXTERNAL_CONTENT_URI=content://media/external/audio/media - 專輯URI(表)
MediaStore.Audio.Albums.EXTERNAL_CONTENT_URI=//content://media/external/audio/albums - 圖片URI(表)
MediaStore.Images.Media.EXTERNAL_CONTENT_URI=content://media/external/images/media - 視頻URI(表)
MediaStore.Video.Media.EXTERNAL_CONTENT_URI=content://media/external/video/media
除了媒體庫，訪問通訊錄時，使用通訊錄數(shù)據(jù)庫 - 通訊錄URI(表)
ContactsContract.Contacts.CONTENT_URI=content://com.android.contacts/contacts - 電話URI(表) 取得電話號
ContactsContract.CommonDataKinds.Phone.CONTENT_URI=content://com.android.contacts/data/phones
在Activity中獲取ContentResolver對象，并在AndroidManifest.xml加上訪問外部數(shù)據(jù)庫權(quán)限
ContentResolver resolver=getContentResolver()
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
四、對URI操作，取數(shù)據(jù)
以下java代碼都在Activity中書寫，含有View對象參數(shù)的為Button的Click點擊事件
(一)、訪問sd卡的圖片
獲取圖片相關(guān)信息,使用存放圖片的URI(表)存放
public void getImage(View view){
ContentResolver resolver=getContentResolver();
Uri imageUri=MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
String imageName=MediaStore.Images.Media.DISPLAY_NAME;
String path=MediaStore.Images.Media.DATA;
String dirName= MediaStore.Images.Media.BUCKET_DISPLAY_NAME;//存儲文件夾的名字
String id=MediaStore.Images.Media._ID;
Cursor cursor=resolver.query(imageUri,new String[]{imageName,path,dirName,id},null,null,null,null);
while(cursor.moveToNext()){
Log.i("dayang","imageName:"+cursor.getString(cursor.getColumnIndex(imageName)));
Log.i("dayang","path:"+cursor.getString(cursor.getColumnIndex(path)));
Log.i("dayang","dirName:"+cursor.getString(cursor.getColumnIndex(dirName)));
String image_id=cursor.getString(cursor.getColumnIndex(id));
Log.i("dayang","id:"+image_id);
Log.i("dayang","縮略圖存放路徑path:"+getThumbnail(image_id));
}
}
獲取圖片縮略圖相關(guān)信息，使用圖片縮略圖的URI(表)
private String getThumbnail(String id){
ContentResolver resolver=getContentResolver();
Uri imageUri=MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI;
String path=MediaStore.Images.Thumbnails.DATA;
String image_id=MediaStore.Images.Thumbnails.IMAGE_ID;
Cursor cursor=resolver.query(imageUri,new String[]{path},image_id+"=?",new String[]{id},null);
String str;
while(cursor.moveToNext()){
str=cursor.getString(cursor.getColumnIndex(path));
return str;
}
return null;
}
(二)、訪問sd卡的音頻
獲取音樂的相關(guān)信息，使用音樂URI(表)
public void getMusic(View view){
ContentResolver resolver=getContentResolver();
Uri musicUri=MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
String musicName=MediaStore.Audio.Media.TITLE;
String musicFileName=MediaStore.Audio.Media.DISPLAY_NAME;
String artist=MediaStore.Audio.Media.ARTIST;
String album=MediaStore.Audio.Media.ALBUM;
String path=MediaStore.Audio.Media.DATA;
String album_id=MediaStore.Audio.Media.ALBUM_ID;
Cursor cursor=resolver.query(musicUri,new String[]{musicFileName,musicName,artist,album,path,album_id},null,null,null,null);
while(cursor.moveToNext()){
Log.i("dayang","帶文件后綴，musicFileName:"+cursor.getString(cursor.getColumnIndex(musicFileName)));
Log.i("dayang","musicName:"+cursor.getString(cursor.getColumnIndex(musicName)));
Log.i("dayang","artist:"+cursor.getString(cursor.getColumnIndex(album)));
Log.i("dayang","path:"+cursor.getString(cursor.getColumnIndex(path)));
Log.i("dayang","album:"+cursor.getString(cursor.getColumnIndex(album)));
String id=cursor.getString(cursor.getColumnIndex(album_id));
Log.i("dayang","album_id"+id);
Log.i("dayang","album_thumbnial"+getAlbumThumbnail(id));//獲取縮略圖
}
}
獲取專輯縮略圖，使用專輯URI(表)
/**
* 得到專輯縮略圖
* @return
*/
public String getAlbumThumbnail(String album_id){
ContentResolver resolver=getContentResolver();
Uri albumUri=MediaStore.Audio.Albums.EXTERNAL_CONTENT_URI;
String thumbnail=MediaStore.Audio.Albums.ALBUM_ART;
String id=MediaStore.Audio.Albums._ID;
String str=null;
Cursor cursor=resolver.query(albumUri,new String[]{thumbnail},id+"=?",new String[]{album_id},null);
while(cursor.moveToNext()){
str=cursor.getString(cursor.getColumnIndex(thumbnail));
}
return str;
}
(三)、訪問sd卡的視頻，使用視頻URI(表)
public void getVideo(View view){
ContentResolver resolver=getContentResolver();
Uri videoUri=MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
String videoName=MediaStore.Video.Media.DISPLAY_NAME;
String videoArtist=MediaStore.Video.Media.ARTIST;
String path=MediaStore.Video.Media.DATA;
String parentFile=MediaStore.Video.Media.BUCKET_DISPLAY_NAME;
Cursor cursor=resolver.query(videoUri,new String[]{videoName,videoArtist,path,parentFile},null,null,null);
while(cursor.moveToNext()){
Log.i("dayang","videoName"+cursor.getString(cursor.getColumnIndex(videoName)));
Log.i("dayang","path"+cursor.getString(cursor.getColumnIndex(videoArtist)));
Log.i("dayang","parentFile"+cursor.getString(cursor.getColumnIndex(parentFile)));
Log.i("dayang","videoArtist"+cursor.getString(cursor.getColumnIndex(videoArtist)));
}
}
(四)、獲取通訊錄，使用通訊錄URI(表)
訪問通訊錄數(shù)據(jù)庫，在AndroidManifest.xml加上訪問通訊錄權(quán)限
<uses-permission android:name="android.permission.READ_CONTACTS" />
<uses-permission android:name="android.permission.WRITE_CONTACTS"/>
獲取通訊錄中聯(lián)系人名字，相應(yīng)id
public void getContact(View view){
ContentResolver resolver=getContentResolver();
Uri contactUri= ContactsContract.Contacts.CONTENT_URI;
String name=ContactsContract.Contacts.DISPLAY_NAME;
String id=ContactsContract.Contacts._ID;
Cursor cursor=resolver.query(contactUri,new String[]{name,id},null,null,null,null);
while(cursor.moveToNext()){
Log.i("dayang","name:"+cursor.getString(cursor.getColumnIndex(name)));
String contact_id=cursor.getString(cursor.getColumnIndex(id));
Log.i("dayang","id:"+contact_id);
Log.i("dayang","number:"+getNumber(contact_id));//調(diào)用getNumber方法
}
}
獲取通訊錄中聯(lián)系人電話號
public String getNumber(String id){
ContentResolver resolver=getContentResolver();
Uri numberUri=ContactsContract.CommonDataKinds.Phone.CONTENT_URI;
Log.i("dayang",numberUri+"");
String number=ContactsContract.CommonDataKinds.Phone.NUMBER;
String nickname=ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME;
String contact_id=ContactsContract.CommonDataKinds.Phone.CONTACT_ID;
Cursor cursor=resolver.query(numberUri,new String[]{number,nickname},contact_id+"=?",new String[]{id},null);
String str=null;
while(cursor.moveToNext()){
str=cursor.getString(cursor.getColumnIndex(number));
Log.i("dayang","nickname"+cursor.getString(cursor.getColumnIndex(nickname)));
return str;
}
return str;
}
