CODEWITHSUNDEEP
javaandroid
marjanbaz
marjanbaz

Reputation: 1042

My button for previous ImageView image does not work

I have two button and an ImageView. When I click Next button it goes to next image from drawable folder. But the Previous button does not work. I don't know why, I think my logic is correct. Here's my code:

public class Photo_gallery extends Activity implements OnClickListener{

    Button next,previous;
    ImageView slika;

    int a = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.photo_gallery);

        InicijalizujVarijable();
    }

    private void InicijalizujVarijable() {
        next = (Button) findViewById(R.id.bNext);
        previous = (Button) findViewById(R.id.bPrevious);
        slika = (ImageView) findViewById(R.id.imageView1);


        next.setOnClickListener(this);
        previous.setOnClickListener(this);

    }

    public void onClick(View v) {
        switch (v.getId()){

        case R.id.bNext:
            if (a == 0)
            {
            slika.setImageResource(R.drawable.p2);
            a = 1;
            }
            else if (a == 1)
            {
            slika.setImageResource(R.drawable.p3);
            a = 2;
            }
            else if (a == 2)
            {
            slika.setImageResource(R.drawable.p4);
            a = 3;
.
.
.
.
            }
            else if (a == 56)
            {
                startActivity(new Intent("com.example.apps.MENU"));
                finish();
            }
            break;
        case R.id.bPrevious:
            a--;
            next.performClick();
            break;

        }

    }

Upvotes: 0

Views: 91

Answers (3)

yahya
yahya

Reputation: 4860

Use 

onClick(next);

instead of 

next.performClick();

And also try to save your image's ids in an array then get from it up to "a" value, not write 56 if statement.

Upvotes: 0

MDMalik
MDMalik

Reputation: 4001

Why don't you do it by making it a function

public void onClick(View v) {
    switch (v.getId()){

    case R.id.bNext:
///function calling  
       a++;
       setImage(a);            
        break;

    case R.id.bPrevious:
        if(a>0)
        {
            a--;
            setImage(a);  
            break;
        }

    }

}
private void setImage(int a)
    {   
        if (a == 0)
        {
        slika.setImageResource(R.drawable.p2);
        }
        else if (a == 1)
        {
        slika.setImageResource(R.drawable.p3);
        }
        else if (a == 2)
        {
        slika.setImageResource(R.drawable.p4);
   .
   .
   .
   .
        }
        else if (a == 56)
        {
            startActivity(new Intent("com.example.apps.MENU"));
            finish();
        }
 }

Edit Increment and decrements are done by the onClick method with a++ and a-- remember start your int a =-1. But the default picture will be null until you click on NextPicture
Its always better to you a variable dynamically ie. increasing with ++ or -- rather than initializing it with a value. like a=21. Not preferred.

Upvotes: 2

Naveen R
Naveen R

Reputation: 55

Try this : 

public class MainActivity extends Activity  implements OnClickListener{

    private int[] IMAGE_IDS = { R.drawable.image1, R.drawable.image2,
        R.drawable.image3};

    int imglength=IMAGE_IDS.length;

    int img_position;

    ImageView slidingimage;


 @Override
public void onClick(View v) {
    // TODO Auto-generated method stub  


  switch (v.getId()) {

         case R.id.iv_left_arrow:

              img_position--;  

              break;                    

         case R.id.iv_right_arrow:

             img_position++;

             break;

           }

        if(img_position < 0) img_position = imglength-1;    

        if(img_position >= imglength) img_position = imglength -1;

        slidingimage.setImageResource(IMAGE_IDS[img_position]);


   }

           }

Upvotes: 0

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