// /storage/emulated/0/Android/data/app_package_name/files/Pictures
Content.getExternalFilesDir(Environment.DIRECTORY_PICTURES); 
// /storage/emulated/0/Android/data/app_package_name/cache
Content.getExternalCacheDir(); 

Content. getCacheDir(); // /data/data/app_package_name/cache
Content. getFilesDir(); // /data/data/app_package_name/files

/**
 * 獲取應(yīng)用專屬緩存目錄
 * android 4.4及以上系統(tǒng)不需要申請SD卡讀寫權(quán)限
 * 因此也不用考慮6.0系統(tǒng)動(dòng)態(tài)申請SD卡讀寫權(quán)限問題，切隨應(yīng)用被卸載后自動(dòng)清空 不會(huì)污染用戶存儲(chǔ)空間
 * @param context 上下文
 * @param type 文件夾類型 可以為空，為空則返回API得到的一級目錄
 * @return 緩存文件夾 如果沒有SD卡或SD卡有問題則返回內(nèi)存緩存目錄，否則優(yōu)先返回SD卡緩存目錄
 */
public static File getCacheDirectory(Context context,String type) {
  File appCacheDir = getExternalCacheDirectory(context,type);
  if (appCacheDir == null){
    appCacheDir = getInternalCacheDirectory(context,type);
  }

  if (appCacheDir == null){
    Log.e("getCacheDirectory","getCacheDirectory fail ,the reason is mobile phone unknown exception !");
  }else {
    if (!appCacheDir.exists()&&!appCacheDir.mkdirs()){
      Log.e("getCacheDirectory","getCacheDirectory fail ,the reason is make directory fail !");
    }
  }
  return appCacheDir;
}

/**
 * 獲取SD卡緩存目錄
 * @param context 上下文
 * @param type 文件夾類型 如果為空則返回 /storage/emulated/0/Android/data/app_package_name/cache
 *       否則返回對應(yīng)類型的文件夾如Environment.DIRECTORY_PICTURES 對應(yīng)的文件夾為 .../data/app_package_name/files/Pictures
 * {@link android.os.Environment#DIRECTORY_MUSIC},
 * {@link android.os.Environment#DIRECTORY_PODCASTS},
 * {@link android.os.Environment#DIRECTORY_RINGTONES},
 * {@link android.os.Environment#DIRECTORY_ALARMS},
 * {@link android.os.Environment#DIRECTORY_NOTIFICATIONS},
 * {@link android.os.Environment#DIRECTORY_PICTURES}, or
 * {@link android.os.Environment#DIRECTORY_MOVIES}.or 自定義文件夾名稱
 * @return 緩存目錄文件夾 或 null（無SD卡或SD卡掛載失敗）
 */
public static File getExternalCacheDirectory(Context context,String type) {
  File appCacheDir = null;
  if( Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
    if (TextUtils.isEmpty(type)){
      appCacheDir = context.getExternalCacheDir();
    }else {
      appCacheDir = context.getExternalFilesDir(type);
    }

    if (appCacheDir == null){// 有些手機(jī)需要通過自定義目錄
      appCacheDir = new File(Environment.getExternalStorageDirectory(),"Android/data/"+context.getPackageName()+"/cache/"+type);
    }

    if (appCacheDir == null){
      Log.e("getExternalDirectory","getExternalDirectory fail ,the reason is sdCard unknown exception !");
    }else {
      if (!appCacheDir.exists()&&!appCacheDir.mkdirs()){
        Log.e("getExternalDirectory","getExternalDirectory fail ,the reason is make directory fail !");
      }
    }
  }else {
    Log.e("getExternalDirectory","getExternalDirectory fail ,the reason is sdCard nonexistence or sdCard mount fail !");
  }
  return appCacheDir;
}

/**
 * 獲取內(nèi)存緩存目錄
 * @param type 子目錄，可以為空，為空直接返回一級目錄
 * @return 緩存目錄文件夾 或 null（創(chuàng)建目錄文件失敗）
 * 注：該方法獲取的目錄是能供當(dāng)前應(yīng)用自己使用，外部應(yīng)用沒有讀寫權(quán)限，如 系統(tǒng)相機(jī)應(yīng)用
 */
public static File getInternalCacheDirectory(Context context,String type) {
  File appCacheDir = null;
  if (TextUtils.isEmpty(type)){
    appCacheDir = context.getCacheDir();// /data/data/app_package_name/cache
  }else {
    appCacheDir = new File(context.getFilesDir(),type);// /data/data/app_package_name/files/type
  }

  if (!appCacheDir.exists()&&!appCacheDir.mkdirs()){
    Log.e("getInternalDirectory","getInternalDirectory fail ,the reason is make directory fail !");
  }
  return appCacheDir;
}