Question

I am sure this is really a simple solution that I am just not seeing. However, I changed some features (which seems unrelated), but now I am getting a null pointer exception error and it just isn’t making itself obvious to where I can find it. If anyone could look at my code and help me out. I have been able to narrow it down to a key section of my code.
This code triggers an alert dialog:

    tableRowShots = (TableRow)findViewById(R.id.shots_row);
    tableRowShots.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            shotTextDialog().show();
            calculate();
      }

    });

here is the code for the shotTextDialog():

private Dialog shotTextDialog() {
    final View layout = View.inflate(this, R.layout.amount_edittext, null);

    final EditText savedText = (EditText) layout.findViewById(R.id.amountEditText);
    textViewShotsAmount = (TextView)findViewById(R.id.shots_amount);

    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle("Choose how many shots:");
    builder.setPositiveButton("Save", new Dialog.OnClickListener() {
        public void onClick(DialogInterface dialog, int which) {
            myTextString = savedText.getText().toString().trim();
            TextView sizeText = (TextView)findViewById(R.id.shots_amount);
            sizeText.setText(myTextString);
            Toast.makeText(getApplicationContext(), "You have chosen " + myTextString + " shots for your drink", Toast.LENGTH_SHORT).show();
        }
    });
    builder.setView(layout);
    return builder.create();
 }

here is the code for calculate():

public void calculate() {
    double leftoverLiquid = 0;

    TextView shots = (TextView) this.findViewById(R.id.shots_amount);
    double shotsDouble = 0;
    if(shots != null) {
        shotsDouble = Double.valueOf(shots.getEditableText().toString());           
    }

    TextView powder = (TextView) this.findViewById(R.id.powder_amount);
    double powderDouble = 0;
    if(powder != null) {
        powderDouble = Double.valueOf(powder.getText().toString());
    }

    TextView add1 = (TextView) this.findViewById(R.id.additive_amount_1);
    double add1Double = 0;
    if(add1 != null) {
        add1Double = Double.valueOf(add1.getEditableText().toString());
    }

    TextView add2 = (TextView) this.findViewById(R.id.additive_amount_2);
    double add2Double = 0;
    if(add2 != null) {
        add2Double = Double.valueOf(add2.getEditableText().toString());
    }

    leftoverLiquid = size() - (powderDouble + shotsDouble + add1Double + add2Double);

    TextView liquid = (TextView) findViewById(R.id.liquid_amount);
    textViewLiquidAmount = liquid;
    liquid.setText(Double.toString(leftoverLiquid));

}

The NullPointerException error seems to fall somewhere near the line of code:

shotsDouble = Double.valueOf(shots.getEditableText().toString());

Can anyone see anything that I am missing?

Answer 1

Just check the your TextView shots.getEditableText().toString() value, Either is not empty or it contains digits not other alphabets.

And it something like,

 shotsDouble = Double.valueOf(shots.getText().toString().trim());  

One more thing,

public Editable getEditableText ()

Return the text the TextView is displaying as an Editable object. If the text is not editable, null is returned.