Start Activity only if a condition is true after a button click in Android

Question

I have three Activities and two AsynTasks.

Activity 1 - Goes to AsyncTask1
Activity 2 - Goes to AsyncTask2
Activity 3 - No AsyncTask required

I have a user selection wizard that lasts for a number of times defined dynamically. I am successfully able to keep track of that count. Below the flow.

For the sake of explanation, let's keep the count as 3.

Activity 1 - Activity loads for the first time with Count set to 1. The user makes a selection and clicks on a button. This takes the user to Activity 2.

The way I am going to Activity 2 is as below.

I load AsyncTask that is pulling the data from db. In the external AsyncTask file, I load the next activity on onPostExecute.

Activity 2 - User makes a selection and clicks on a button. The button checks if the Count is 1, it sets it to 2. Since the count is still less than 3, it goes back to Activity 1 using the AsyncTask.

The process continues and once the Count reaches 3, I want to go to Activity 3. Now the Activity 3 needs to be loaded without any AsyncTask. How to do that? Below is the code.

ImageButton imgButton = (ImageButton) findViewById(R.id.imageButton);
imgButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            //code that I process and define value_i_am_taking_forward_successfully. It is working fine.

            proceedNext();
        }
});

private void proceedNext() {
    if (my_counter > max_count) {
        //This is not working. I want to start Activity3 here.
        Intent intent = new Intent(ctx, Activity3.class);

        ctx.startActivity(intent);
    }
    else {
        //This works fine. 
        String requested_method = value_i_am_taking_forward_successfully;

        LoadAsyncTask2 loadAsyncTask2 = new LoadAsyncTask2(this);
        loadAsyncTask2.execute(requested_method);
    }
}

Below is the code in AsyncTask that loads the Activity. result is coming through doInBackground

@Override
protected void onPostExecute(String result) {
    Intent intent = new Intent(ctx, Activity1.class);

    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

    intent.putExtra("value_to_take_forward",result);

    ctx.startActivity(intent);
}

Can anyone help please?

Below is the error I am getting:

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference

use your className instead of `ctx` – John Joe Mar 11 '17 at 06:31 — John Joe, Mar 11 '17 at 06:31
Worked! Please post it as an answer so I can accept it. – Mohammed Akhtar Zuberi Mar 11 '17 at 06:36 — Mohammed Akhtar Zuberi, Mar 11 '17 at 06:36

score 2 · Accepted Answer · edited May 23 '17 at 12:31

2

Use your current ClassName instead of ctx

Source : android.content.Context.getPackageName()' on a null object reference

edited May 23 '17 at 12:31

Community

1
1

answered Mar 11 '17 at 06:33

John Joe

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score 1 · Answer 2 · edited Mar 11 '17 at 06:40

1

If this code runs in the UI thread and in from the Activity itself, then you should use this,

Intent intent = new Intent(this, Activity3.class);
startActivity(intent);

You should be using the Activity context to load the next Activity.

edited Mar 11 '17 at 06:40

John Joe

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70
135

answered Mar 11 '17 at 06:35

Aritra Roy

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score 0 · Answer 3 · answered Mar 11 '17 at 06:24

0

What is value of max_count?

Try my_counter >= max_count.

answered Mar 11 '17 at 06:24

babedev

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5

The problem is not with the counter. It is working perfectly fine. It is just that the Activity 3 doesn't load. – Mohammed Akhtar Zuberi Mar 11 '17 at 06:25
For the reference, I have mentioned the max_count as 3. – Mohammed Akhtar Zuberi Mar 11 '17 at 06:25
I am able to go into the correct condition of 'if' by checking the counter. The problem is that once my_count and max_count are equal, the activity doesn't load. I have added the error it throws in my question. – Mohammed Akhtar Zuberi Mar 11 '17 at 06:29

Start Activity only if a condition is true after a button click in Android

3 Answers3