我的應用程序商店SD卡上的數據庫的Android刪除數據庫Programitically-:android.system.ErrnoException命令:chmod失敗:EPERM(不允許的操作)
數據庫處理器類
private static final String DATABASE_NAME = "MyDb";
private static final String KEY_ROOT_FOLDER= Environment.getExternalStorageDirectory().getAbsolutePath() + "/.MYAPP/" + DATABASE_NAME;
public DatabaseHandler(Context context) {
Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator+ FOLDER_NAME+File.separator, null, DATABASE_VERSION);
super(context, KEY_ROOT_FOLDER, null, DATABASE_VERSION);
}
所以我的DB不在用戶卸載應用程序時刪除(因爲其存儲位於ExternalStorageDirectory下)。我想在用戶再次安裝應用程序時創建數據庫的新副本。
因此,即時檢查第一次運行應用程序,並通過使用此代碼刪除以前的數據庫。
public void checkReinstallApp(){
SharedPreferences settings = getSharedPreferences("FIRSTRUN", 0); // Get preferences file (0 = no option flags set)
boolean firstRun = settings.getBoolean("firstRun", true); // Is it first run? If not specified, use "true"
if (firstRun) {
Log.w("activity", "first time");
isFirstTime=true;
if(permissionHelper.isPermissionGranted(Manifest.permission.READ_EXTERNAL_STORAGE)){ //for getting permission Android 6
SharedPreferences.Editor editor = settings.edit(); // Open the editor for our settings
editor.putBoolean("firstRun", false); // It is no longer the first run
editor.commit(); // Save all changed settings
try{
WebViewActivity.this.deleteDatabase(SET_START_DIRECTORY+"MyDb");
}catch (Exception e){
// Error
}
File f = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/.MYAPP/");
deleteFile(f);
}else{
permissionHelper.setForceAccepting(true).request(PERMISSION);
}
} else {
Log.w("activity", "second time");
}
}
林調用checkReinstallApp()方法對我
的onCreate
但是,當我卸載應用程序,並重新安裝它,它沒有表現出error.But數據庫沒有得到刪除。請爲此提出解決方案。
PS-I嘗試使用此代碼刪除包含DB文件和其他文件的文件夾。
File f = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/.MYAPP/");
deleteFile(f);
public boolean deleteFile(File file) {
if(permissionHelper.isPermissionGranted(Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
if (file != null) {
if (file.isDirectory()) {
String[] children = file.list();
for (int i = 0; i < children.length; i++) {
boolean success = deleteFile(new File(file, children[i]));
if (!success) {
return false;
}
}
}
return file.delete();
}
}else {
permissionHelper.setForceAccepting(true).request(PERMISSION);
deleteFile(file);
}
return false;
}
那麼它顯示此警告消息
:android.system.ErrnoException命令:chmod失敗:EPERM(不允許的操作)
是多數民衆贊成我對code..please檢查WebViewActivity.this.deleteDatabase(SET_START_DIRECTORY + 「MYDB」)完成的; – san88
好吧,File dbFile = getDatabasePath(SET_START_DIRECTORY +「MyDb」); boolean is_deleted = dbFile.delete(); –
我檢查過.its返回false.But dbFile.exists()返回true – san88