如何使用共享的首选项和切换方法进行自动保存？

Question

Lets say, we have variable var, that store information abaut name of activity. It gets it from shared preferences. I want to make some kind o autosave. Last activity that was initiated send its name do shared preferences. The thing that i dont now, is how to put the name of activity from variable var to intent in switch method in buttonlastactivity. The first buttonnew goes to first activity that is actbegin.

Example:

public void onClick(View view) {
Intent intent;

switch (view.getId()) {
case R.id.buttonnew:
intent = new Intent(actmenu.this, actbegin.class);
startActivity(intent);
break;
case R.id.buttonlastactivity:
intent = new Intent(actmenu.this, ??????.class);
startActivity(intent);
break;

The question is, what to put instead of question marks, to take name of activity that is stored in variable var.

Any suggestions?

Answer 1

You could save the fully qualified class name in your shared preferences and use that .
eg. : If you save "com.test.MyLastActivity" in your SharedPreferences, then you could do this :

try {
        Class<?> lastActivity = Class.forName("com.test.MyLastActivity");
        Intent intent = new Intent(this, lastActivity);
        startActivity(intent);
    } catch (ClassNotFoundException e) {
        Log.e("TAG", "Couldn't find class", e);
    }

Answer 2

I did it like this:

public void onClick(View view) {
      Intent intent;
      switch (view.getId()) {
 case R.id.buttonnew:
      intent = new Intent(actmenu.this,actbegin.class);
      startActivity(intent);
      break;
case R.id.buttonlastactivity:
       try
       {
       Class<?> lastActivity = Class.forName(var);
       intent = new Intent(actmenu.this, lastActivity);
       startActivity(intent);
       break;
       }
       catch (ClassNotFoundException e)
       {
       Log.e("TAG", "Couldn't find class", e);
}

}
}

and it doesnt give errors, but after app start and after pressing the buttonlastactivity (when variable var has full name of last activity) the app is going back to activity that starts app, not to the activity that name is written in variable var. I want to use vvariable, because it is changing depending on what activity the user was, before he quited the app. And the variable gets it from shared preferences. Shared preferences get the name of activity in moment of starting of the activity. Or is there any other way to do some kind of autosave, that will allow user to go to the last visited activity.