access the variable in activity in another class

Question

In my application I need a variable from one activity to another activity without using any intent. So I have declared that variable as static and used as FirstActivit

Answer 1

[Edited]

Since you're saying that there is a value returned from this line getIntent().getExtras().getString("StockName"), then try this code:

public class Detail extends Activity{

public static String stringValue; //make it public and static

 protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.stockdetail);

        stringValue = getIntent().getExtras().getString("StockName");
}

Now access the static object in Table class:

   public class Table {
        Context c1;
        Cursor c;

      public String selectdate="Select " + column1 + " as _id, " + column2 + " From " + tablename + " Where " + column3 + " = " + Detail.stringValue;

}

This should work properly. Make sure you're accessing the stringValue variable after the Detail activity is created.

[Original Answer]

Try this:

public class Detail extends Activity{

public static ApplicationClass ac; //make it public and static

 protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.stockdetail);
        ac=new ApplicationClass();

        ac.setStockName(getIntent().getExtras().getString("StockName"));
}

Now access the static object in Table class:

public class Table {

    Context c1;

    Cursor c;

public String selectdate="Select " + column1 + " as _id, " + column2 + " From " + tablename + " Where " + column3 + " = " 
                                + Detail.ac.getStockName();
}

P.S. To access the static object/variable, follow this syntax:

Class_Name.Object_Name.Method_Name();

Answer 2

You should define your subclassed application class in your manifest. And you should never call "new ApplicationClass()". You can get a reference to ApplicationClass instance using activity's getApplication() method.

Detail.java:

public class Detail extends Activity{

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.stockdetail);
    ApplicationClass app = (ApplicationClass)getApplication();
    app.setStockName("blah");
}
}

Table.java

public class Table {
public String selectDate;
public Table(Activity a)
{
    ApplicationClass ac=(ApplicationClass)a.getApplication();
    selectdate="Select " + column1 + " as _id, " + column2 + " From " + tablename + " Where " + column3 + " = " 
                            + ac.getStockName();
}

Instantiate Table.java

public NewActivity extends Activity{

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Table t = new Table(this);

}
}

Answer 3

Try to initialize firstly your class. But what I see you want to have some application context that is accessible via application. For that porpouse you can simply use that method but data try to keep in SharedPreferences. So simply when you get sth from ApplicationClass you simply get it firstly from shared preferences and return. :) And each time when you need your ApplicationClass you initialize it and there methods run shared preferences to get data.

public class Detail extends Activity{

ApplicationClass ac = new ApplicationClass();

 protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.stockdetail);
        ac=new ApplicationClass();

        ac.setStockName(getIntent().getExtras().getString("StockName"));
}

Shared preferences context class.

public ApplicationClassWithSharedPreferences{
   private Context context;
   public ApplicationClassWithSharedPreferences(Context c){
       context = c;
   }

   public String getSomeValueFromContext(){
      SharedPreferences sharedPref = context.getPreferences(Context.MODE_PRIVATE);
      String highScore = sharedPref.getString("KEY", "DEFAULT");
      return highScore;

   }

}

Answer 4

Try this.

Step 1: Create a static Bundle object in Application class.( ApplicationClass.java)

E.g :

     public static Bundle mMyAppsBundle = new Bundle():

Step 2:

Set key values pair in that bundle from anywhere. like this:

   ApplicationClass.mMyAppsBundle.putString("key","value");

Step 3:

Now you can get these values from anywhere like this way:

   String str = ApplicationClass.mMyAppsBundle.getString("key");

Please apply null check before using bundle objects for safety points of view.