android 文件更新操作

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1. 发送 Intent.ACTION_MEDIA_SCANNER_SCAN_FILE 广播

sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(new File("/sdcard/xxx/xxx.jpg")));)

2.使用 MediacannerConnection 进行扫描, 也是指定路径对其进行扫描

MediaScannerConnection msc = new MediaScannerConnection(context, new MediaScannerConnectionClient() {

MediaProvider 中的MediaScannerReceiver.java 对接收广播后，中的路径信息有判断（其实是有问题的。外置sd卡扫描不到的哦文件）

public void onReceive(Context context, Intent intent) {     String action = intent.getAction();     Uri uri = intent.getData();    if (action.equals(Intent.ACTION_BOOT_COMPLETED)) {    // scan internal storage    scan(context, MediaProvider.INTERNAL_VOLUME);    } else {   if (uri.getScheme().equals("file")) {      // handle intents related to external storage      String path = uri.getPath();      String externalStoragePath = Environment.getExternalStorageDirectory().getPath();      Log.d(TAG, "action: " + action + " path: " + path);     if (action.equals(Intent.ACTION_MEDIA_MOUNTED)) {           // scan whenever any volume is mounted            scan(context, MediaProvider.EXTERNAL_VOLUME);     } else if (action.equals(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE) &&           path != null && path.startsWith(externalStoragePath + "/")) {           scanFile(context, path);    }        }    }}

稍微算正确点的，要修改 MediaProvider

public void onReceive(Context context, Intent intent) {      String action = intent.getAction();      Uri uri = intent.getData();      // String externalStoragePath =      // Environment.getExternalStorageDirectory().getPath();      String externalSDStoragePath = Environment              .getExternalSDStorageDirectory().getPath();      String externalUDiskStoragePath = Environment              .getExternalUDiskStorageDirectory().getPath();      String externalExtSDStoragePath = Environment              .getExternalExtSDStorageDirectory().getPath();      if (action.equals(Intent.ACTION_BOOT_COMPLETED)) {          // scan internal storage          scan(context, MediaProvider.INTERNAL_VOLUME);      } else {          if (uri.getScheme().equals("file")) {              // handle intents related to external storage              String path = uri.getPath();              if (action.equals(Intent.ACTION_MEDIA_MOUNTED)) {                  if (externalSDStoragePath.equals(path))                      scan(context, MediaProvider.EXTERNAL_VOLUME_SD);                  else if (externalUDiskStoragePath.equals(path))                      scan(context, MediaProvider.EXTERNAL_VOLUME_UDISK);                  else if (externalExtSDStoragePath.equals(path))                      scan(context, MediaProvider.EXTERNAL_VOLUME_EXTSD);                  else                      Slog.w(TAG, "unknown volume path " + path);              } else if (action.equals(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE)                      && path != null                      && (path.startsWith(externalSDStoragePath + "/")                              || path.startsWith(externalExtSDStoragePath                                      + "/") || path                                  .startsWith(externalUDiskStoragePath + "/"))) {               // 在上面的条件多些判断， 不然的话。外置SD卡 可是不扫描的                scanFile(context, path);              }          }      }  }

这里需要说一些。看了源码（MediaProvider），在开机时，他会进行全盘的扫描，所以文件就全出来咯。。

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