上次备份发生时提示用户的日期和时间

Question

我开发了一个Android应用程序，其中添加了备份选项。现在，我想添加在用户带有日期和时间的最后一次备份时提示用户的功能。如果他们没有做备份然后允许他们做备份。

请有人帮我解释如何执行此操作吗？

Answer 1

假设您有备份功能：

public void backup(){
    //get time of last backup
    SharedPreferences sharedPref = context.getSharedPreferences(
    "PrefsFile", Context.MODE_PRIVATE);
    long time = System.currentTimeMillis();
    long lastBackup = sharedPref.getLong("BackupTime", 0);
    //if there was no previous backup, lastBackup will be 0
    if (lastBackup != 0){
        long timeDiff = time - lastBackup; //difference will be in milliseconds
        //do what you need with the time difference 
    }
    //code for backup
    SharedPreferences.Editor editor = sharedPref.edit();
    editor.putLong(getString("BackupTime), time); //update last backup time
    editor.commit();
}