My try catch function won't work as expected

问题

My program is supposed to take the given value and find the other value with it. However, my try catch statement doesn't seem to be working. It never does the first 2 if statements which are the most essential parts of the program. The 3rd one does work when you input both values. Thanks in Advance.

        public void calculate(View view) {
    EditText length_find = findViewById(R.id.feet);
    EditText pounds_find = findViewById(R.id.pounds);

    try {
        //int length_int = Integer.parseInt(length_find.getText().toString());
        //int pounds_int = Integer.parseInt(pounds_find.getText().toString());

        double d = .29;
        //double length = length_int;
        //double pounds = pounds_int;
        double w = 24.5 / 12;
        double h = .002 / 12;

        //This Calculates if Pounds are given
        if ((length_find).getText().toString().trim().length() == 0){
            Toast.makeText(MainActivity.this, "Given Pounds", LENGTH_LONG).show();
            int pounds_int = Integer.parseInt(pounds_find.getText().toString());
            double pounds = pounds_int;
            double v = pounds / d;
            double length = v / w / h;
            final TextView mTextView = (TextView) findViewById(R.id.length_show);
            mTextView.setText((int) length);
        }


        //This Calculates if Length is given
        if ((pounds_find).getText().toString().trim().length() == 0){
          Toast.makeText(MainActivity.this, "Given Length", LENGTH_LONG).show();
          int lenght_int = Integer.parseInt(length_find.getText().toString());
          double length = lenght_int;
          double v = length * w * h;
          double answer_pounds = v * d;
          final TextView mTextView = (TextView) findViewById(R.id.pound_show);
          mTextView.setText((int) answer_pounds);
        }
        if((pounds_find).getText().toString().trim().length() > 0 && (length_find).getText().toString().trim().length() > 0){
            Toast.makeText(MainActivity.this, "Whata hell you need me for mate!", LENGTH_LONG).show();
        }

    }
    catch(Exception ex) {
            Toast.makeText(this, "Error", Toast.LENGTH_SHORT).show();
        }

    }

回答1:

As i understood,

(pounds_find).getText().toString().trim().length() <= 0

(length_find).getText().toString().trim().length() <= 0

is true only when user hasn't input anything. if he has, then 3rd "if" execute as expected. But when user hasn't input anything then

int length_int = Integer.parseInt(length_find.getText().toString());
int pounds_int = Integer.parseInt(pounds_find.getText().toString());

cannot be done. because it is empty. I think that's the case here. If that isn't please let me know. If i'm wrong sorry. That's what i understood from here. If you could debug and be specific about scenario or exception if it throw any, that would be more helpful

来源：https://stackoverflow.com/questions/53967597/my-try-catch-function-wont-work-as-expected

标签

java

android

if-statement

try-catch