Java Reflection in android

Question

This is my TYPEFACE class

public class TYPEFACE {

    public static final Typeface Rupee(Context ctx){
        Typeface typeface = Typeface.createFromAsset(ctx.getAssets(), "Rupee_Foradian.ttf");
        return typeface;
    }
    public static final Typeface ArialRounded(Context ctx){
        Typeface typeface = Typeface.createFromAsset(ctx.getAssets(), "Rupee_Foradian.ttf");
        return typeface;
    }

}

And I try to access the methods from this class using Reflection by the following way

Method method;
TYPEFACE typeface;
try{            
    method = typeface.getClass().getMethod("Rupee",Context.class);
}catch(Exception e){
    System.out.println("method : "+e);
}

But it throws the nullpointerexception.

05-21 17:12:07.026: I/System.out(14917): method : java.lang.NullPointerException

I dont know What is wrong with this way. Sombody can help me please.

Thanks in advance.

If this is your real code, then you try apply `getClass()` to `null`. — PM 77-1, Mar 16 '15 at 00:41

score 4 · Accepted Answer · answered May 21 '13 at 11:30

4

typeface is null, because it's not initialized

Change this to TYPEFACE typeface = new TYPEFACE();

answered May 21 '13 at 11:30

Vincent van der Weele

12,682
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Thank you. This works perfectly. Can you give hint to how to invoke this `method`. – Gunaseelan May 21 '13 at 11:37
@Gunaseelan see for instance http://stackoverflow.com/questions/160970/how-do-i-invoke-a-java-method-when-given-the-method-name-as-a-string – Vincent van der Weele May 21 '13 at 11:41

sanbhat · Answer 2 · 2013-05-21T11:48:48.740

2

The NullPointerException is due to the variable typeface being null.

But you don't need an instance of TYPEFACE class to invoke that method. Simply try

try{            
    method = TYPEFACE.class.getMethod("Rupee",Context.class);
    method.invoke(null, new Context()); // since its a static method, can be invoked directly
}catch(Exception e){
    System.out.println("method : "+e);
}

edited May 21 '13 at 11:48

answered May 21 '13 at 11:40

sanbhat

17,162
6
47
63

score 0 · Answer 3 · answered May 21 '13 at 11:36

you want to initialize the typeface then after use it so

you second code is like....

Method method;
TYPEFACE typeface=new TYPEFACE();
try{            
    method = typeface.getClass().getMethod("Rupee",Context.class);
}catch(Exception e){
    System.out.println("method : "+e);
}

Java Reflection in android

3 Answers3