How to get values from general settings for a class by another class
I want to get a string from my general preference file and use it for more classes, but I don't know why not work. My reader class:
import android.app.Activity;
import android.content.SharedPreferences;
public class A {
public static String url2;
public void execute() {
String URLPref = "URL";
SharedPreferences prefs = getSharedPreferences("com.exam.search_preferences",Activity.MODE_PRIVATE);
url2 = prefs.getString(URLPref , "");
}
private SharedPreferences getSharedPreferences(String string,
int modePrivate) {
return null;
}
}
And the second class that uses the line
public class SearchHome extends Activity {
static String url2;
A cls2= new A();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.search_activity);
cls2.execute();
url2 = A.url2;
Toast.makeText(getApplicationContext(),"URL:" + url2 ,
Toast.LENGTH_LONG).show();
...
Sorry for my bad english, I never learned. But I'm trying!
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You need to pass Context
to a class A
because you can get SharedPreferences
from an object Context
. NOTE. Activity
is Context
to some extent
public class A {
public static String url2;
/** @param context used to get the SharedPreferences */
public void execute(Context context) {
String URLPref = "URL";
SharedPreferences prefs = context.getSharedPreferences("com.exam.search_preferences",Activity.MODE_PRIVATE);
url2 = prefs.getString(URLPref , "");
}
}
And then pass the context to your execution method
public class SearchHome extends Activity {
static String url2;
A cls2= new A();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.search_activity);
// pass context 'this' to the execute function
// This works, because SearchHome extends Activity
cls2.execute(this);
url2 = A.url2;
...
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If your data is not sensitive, it would be much easier if you can create a class specifically for general preferences and access other activities. you will save a lot of time and the code will be much easier to track
public class HelperShared {
public static final String score = "Score";
public static final String tag_User_Machine = "tag_User_Machine",
tag_Machine_Machine = "tag_Machine_Machine",
tag_Draw_Machine = "tag_Draw_Machine",
tag_Total_Machine = "tag_Total_Machine";
public static SharedPreferences preferences;
public static Editor editor;
public HelperShared(Context context) {
this.preferences = context.getSharedPreferences(score,
Activity.MODE_PRIVATE);
this.editor = preferences.edit();
}
/*
* Getter and Setter methods for Machine
*/
public void setUserMachine(int UserMachine) {
editor.putInt(tag_User_Machine, UserMachine);
editor.commit();
}
public void setMachineMachine(int MachineMachine) {
editor.putInt(tag_Machine_Machine, MachineMachine);
editor.commit();
}
public void setDrawMachine(int DrawMachine) {
editor.putInt(tag_Draw_Machine, DrawMachine);
editor.commit();
}
public void setTotalMachine(int TotalMachine) {
editor.putInt(tag_Total_Machine, TotalMachine);
editor.commit();
}
public int getUserMachine() {
return preferences.getInt(tag_User_Machine, 0);
}
public int getMachineMachine() {
return preferences.getInt(tag_Machine_Machine, 0);
}
public int getDrawMachine() {
return preferences.getInt(tag_Draw_Machine, 0);
}
public int getTotalMachine() {
return preferences.getInt(tag_Total_Machine, 0);
}
}
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Call this if you want to put a pref:
putPref("myKey", "mystring", getApplicationContext());
Call it if you want to get the prefix:
getPref("myKey", getApplicationContext());
You can use SharedPreferences to store any primitive data: booleans, floats, ints, longs and strings. This data will persist in user sessions (even if your application is killed).
Different Modes:
1 MODE_APPEND
This will append the new preferences with the already exisiting preferences
2 MODE_ENABLE_WRITE_AHEAD_LOGGING
Database open flag. When it is set , it would enable write ahead logging by default
3 MODE_MULTI_PROCESS
This method will check for modification of preferences even if the sharedpreference instance has already been loaded
4 MODE_PRIVATE
By setting this mode , the file can only be accessed using calling application
5 MODE_WORLD_READABLE
This mode allow other application to read the preferences
6 MODE_WORLD_WRITEABLE
This mode allow other application to write the preferences
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