CODEWITHSUNDEEP
androidbuttontextviewtext-size
Ajinkya More
Ajinkya More

Reputation: 425

Unable to change TextView size on button click, why?

Hello guys right now I'm working on an app in which there are many quotes, in a TextView and I want to change the size of TextView on button click, like if Small button is clicked then the TextView should become small, if Large is clicked it should be large, etc. But each time I press the Button app force closes! What's the problem? Here's OnClickListener for the Button:

small = (Button) findViewById(R.id.small);

small.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                TextView tv = (TextView)findViewById(R.id.quotes);
                tv.setTextSize(20);
            }
        });

P.S: The TextView and the Button are in different Activities.

Upvotes: 0

Views: 473

Answers (1)

Konrad Krakowiak
Konrad Krakowiak

Reputation: 12365

There is no way to change the TextView size by Button from one Activity in other Activity. You will get NullPointerException because the findViewById method will not find view and will return null. You should use SharedPreferences. You should save text size value when you click Button and read it in the second Activity.

In your setting Activity:

   small.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(YourActivity.this.getBaseContext());
            sharedPreferences.edit()
            .putFloat("FONT_SIZE", 22)
            .apply();
        }
    });

In your activity where you have TextView

     TextView tv = (TextView)findViewById(R.id.quotes);
     SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(YourActivity.this.getBaseContext());
     tv.setTextSize(sharedPreferences.getFloat("FONT_SIZE", 13/*DEFAULT VALUE*/));

Upvotes: 2

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