Android - Toggle visible/invisible on multiple imageviews via their ID or TAG

Question

I have four imageviews which are set to invisible at activity start (or rather at row inflation). I would like to press a button and have them ALL become visible (and subsequently be operational as onclicks...). I have the following summary code, but I keep getting errors whenever I try to access any other imageview other than the last one.

public class xx {

    private ImageView up;
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // Log.i(TAG, "excersizeAdapter getView");
            View v = convertView;
            if (v == null) {
                LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                v = vi.inflate(R.layout.row, null);
            }

            Excersize e = items.get(position);
            if (e != null) {
                TextView exTitle      = (TextView) v.findViewById(R.id.ex_type_title);
                TextView exOn         = (TextView) v.findViewById(R.id.ex_on_title);
                TextView exRestAmount = (TextView) v.findViewById(R.id.ex_rest_amount);
                TextView exSequence   = (TextView) v.findViewById(R.id.ex_sequence);

                up                    = (ImageView) v.findViewById(R.id.moveup);
                down                  = (ImageView) v.findViewById(R.id.movedown);

                if (exTitle !=null) {
                    exTitle.setText(e.getTypeTitle());
                }

                if (exOn !=null) {
                    exOn.setText("On: "+e.getTypeOn());
                }

                if (exRestAmount !=null) {
                    exRestAmount.setText(e.getRestAmount().toString());
                }

                if (exSequence !=null) {
                    exSequence.setText(e.getSequence().toString());
                    up.setTag(8881);
                    down.setTag(8882);

                    up.setId(((Integer)e.getSequence()));
                    down.setId(((Integer)e.getSequence()));

                    Log.i(TAG, "up,down values=" +e.getSequence());
                }
            }
            return v;
        }
    }

    public void toggleReorderButtons() {
        up.findViewById(2).setVisibility(View.VISIBLE);
        up.setVisibility(View.VISIBLE);
        up.setOnClickListener(this);
    }
}

OK, this is cut down code, but in the makevisinvis method up.findview... it causes a crash and up.setvis, etc. will turn on only the last one that was added to my activity.

I also tried the following with no success.

ImageView upper = (ImageView) up.findViewById(2);
upper.setVisibility(View.VISIBLE);

A lovely error dump:

04-21 09:10:55.650: W/dalvikvm(22392): threadid=1: thread exiting with uncaught exception (group=0x4001e578)
04-21 09:10:55.675: E/AndroidRuntime(22392): FATAL EXCEPTION: main
04-21 09:10:55.675: E/AndroidRuntime(22392): java.lang.NullPointerException
04-21 09:10:55.675: E/AndroidRuntime(22392):     at com.mediabarltd.digittrainer.ProgramDisplay.toggleReorderButtons(ProgramDisplay.java:437)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at com.mediabarltd.digittrainer.ProgramDisplay.onClick(ProgramDisplay.java:391)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at android.view.View.performClick(View.java:2538)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at android.view.View$PerformClick.run(View.java:9152)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at android.os.Handler.handleCallback(Handler.java:587)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at android.os.Handler.dispatchMessage(Handler.java:92)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at android.os.Looper.loop(Looper.java:130)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at android.app.ActivityThread.main(ActivityThread.java:3691)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at java.lang.reflect.Method.invokeNative(Native Method)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at java.lang.reflect.Method.invoke(Method.java:507)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:665)
04-21 09:10:55.675: E/AndroidRuntime(22392):     at dalvik.system.NativeStart.main(Native Method)

It took some serious looking and a total rework of what I was doing. but...

Basically I followed the tutorial Android ListView and ListActivity and then implemented the neat 'trick' described in Android ListView Adapter OnClickListener issue.

(I'm really having a hard time with this.)

according to the posted log NPE happens not in 'makevisinvis'. Can you please double check? also, can you post code that defines/inits up and down objects/ — Asahi, Apr 21 '12 at 08:25
sorry that was mebeing stupid with my examlpe, I changed the method name when writing it out on SO. i'll update.... — Purplemonkey, Apr 21 '12 at 08:30

score 1 · Answer 1 · edited Sep 08 '12 at 18:06

1

You must give the ImageView an ID, like

android:id="@+id/some_name"

Then find it like this:

up.findViewById(R.id.some_name);

edited Sep 08 '12 at 18:06

Peter Mortensen

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answered Apr 21 '12 at 08:17

Andreas Linden

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I already did this during the initial inflate process "up = (ImageView) v.findViewById(R.id.moveup);" Is that what you mean, or do I need to do this again? After I did this I assigned the ID, and thought I'd be able to use that to reference it? (Also I've added this line above) – Purplemonkey Apr 21 '12 at 08:25
How do I then refer individually to each version of the imageview? I thought that was where the setId came in to it? – Purplemonkey Apr 21 '12 at 08:29
in the "public View getView" which is building my row data, I use a unique field from the database and assign this to the Id of the up imageview. this is setting the ID unique, no? – Purplemonkey Apr 21 '12 at 08:35
1

use setTag method and then use getTag method. – Zaz Gmy Apr 21 '12 at 08:39
@ZazGmy that was my first avenue of exploration, but I cannot find how to 'use' a getTag. i.e. up.getTag(8881).setvisible(View.VISIBLE); Doesn't exist for me? – Purplemonkey Apr 21 '12 at 08:44

score 1 · Accepted Answer · answered Apr 21 '12 at 09:27

1

You define up as a class member and re-init it every time getView gets called - therefore it always points to the last image view created. Also, I am not sure it is correct to call findViewById of up: instead set its OnClickListener inside getView and whenever clicked look for the required views inside a layout it belongs to.

answered Apr 21 '12 at 09:27

Asahi

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I think you're on to something there. I've just done some checking and the ID is always the last one that id is set against. it must be overwriting the others.. – Purplemonkey Apr 21 '12 at 10:15
thanks for the help, I have now sorted out my code and included my solution in my original post. – Purplemonkey Apr 23 '12 at 08:53

score 0 · Answer 3 · edited Sep 08 '12 at 18:06

0

Use this:

int i = (int) up.getTag();
if (i == 8881) {
    //Do something here
}

edited Sep 08 '12 at 18:06

Peter Mortensen

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21
105
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answered Apr 21 '12 at 09:06

Zaz Gmy

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ok I can see how that can act on the existance of my tags, but using this how to I set all 4 of my up imageviews to visible? – Purplemonkey Apr 21 '12 at 09:25
get tag of each imageview and use nested condition. – Zaz Gmy Apr 21 '12 at 09:33

Android - Toggle visible/invisible on multiple imageviews via their ID or TAG

3 Answers3