How to Iterate Through the Id Properties of R.Java Class

How do I iterate through the id properties of R.java class?

Something like that?

import java.lang.reflect.Field;
/* ... */

for (int i = 1; i < 16; i++) {
    int id = R.id.class.getField("s" + i).getInt(0);
    tv[i] = (TextView)findViewById(id);
    tv[i].setTypeface(face);
    tv[i].setClickable(true);
    tv[i].setOnClickListener(clickListener);
}

Enable iterate through R file in android

getFields() return all the public fields inside the R.id class, which is a static inner class inside the R class, which is a Java auto generated class for Resources. That method, getFields(), doesn't take any argument

You are looking for getField(), not getFields()

public void initializeChipsViewholdersArray (){
   for (int i = 1; i<10; i ++){
        String viewholderName = "chip_00"+i;
       int id_2 = R.id.class.getField(viewholderName).getInt(0);
   ImageView chipViewholder= (ImageView)findViewById(id);
           chipViewholder.setVisibility(View.INVISIBLE);
}

How to reference R.id s with indices?

You can achieve this by using getIdentifier()

for(int i=0; i<8; i++) {
   for(int j=0; j<8; j++) {
    String editTextID = "btn" + i + "-" + j;
    int resID = getResources().getIdentifier(editTextID
    ,"id", "com.example.yourpackagename");
    buttons[i][j] = ((EditTextID) findViewById(resID));
   }
}

Android: What's the class of R.id.class.getFields()?

R.java is a class. Auto generated class from the Resources. R.id is accessing to a inner class. The public static final class id. R.id.class will give you a Class object of R.id and getFields method will return all the public fields inside the class R.id . Take a look to the reflection mechanism.

EDIT: reflection.

Iteration Through R class

You can do this using java reflection:

Class raw = R.raw.class;
Field[] fields = raw.getFields();
for (Field field : fields) {
    try {
        Log.i("REFLECTION",
            String.format("%s is %d", field.getName(), field.getInt(null)));
    } catch(IllegalAccessException e) {
        Log.e("REFLECTION", String.format("%s threw IllegalAccessException.",
            field.getName()));
    }
}

iterate through images

At OP's request, answering with a copypasta from a comment:

Have a look at How do I iterate through the id properties of R.java class? and Android: Programatically iterate through Resource ids.

...though this question should really just be closed as a dup.

Looping through json and picking random objects by id - Android/JAVA

value is not a JSONObject, but a JSONArray, this should give you two random jokes

String finalJson = buffer.toString();

JSONObject parentObject = new JSONObject((finalJson));

//JSONObject finalObj = parentObject.getJSONObject("value");
JSONArray jokeArray = parentObject.getJSONArray("value");

Random r = new Random();
String joke1 = jokeArray.getJSONObject(r.nextInt(jokeArray.length())).getString("joke");
String joke2 = jokeArray.getJSONObject(r.nextInt(jokeArray.length())).getString("joke");

This also depends on the fact the ids will always start at 1 and increment 1 at a time

EDIT

To display the ID too, break it down further...

String finalJson = buffer.toString();

JSONObject parentObject = new JSONObject((finalJson));

//JSONObject finalObj = parentObject.getJSONObject("value");
JSONArray jokeArray = parentObject.getJSONArray("value");

Random r = new Random();
int id1 = r.nextInt(jokeArray.length())
String joke1 = jokeArray.getJSONObject(id1).getString("joke");

int id2 = r.nextInt(jokeArray.length())
String joke2 = jokeArray.getJSONObject(id1).getString("joke");

String joke1WithID = id1 + "  " + joke1
String joke2WithID = id2 + "  " + joke2

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