我的try catch函数无法按预期工作 [英] My try catch function won't work as expected

问题描述

我的程序应该采用给定值并用它找到另一个值.但是，我的try catch语句似乎不起作用.它永远不会执行前2个if语句，而if语句是程序最重要的部分.当您输入两个值时，第三个值确实起作用.预先感谢.

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();
        }

    }

推荐答案

据我了解，

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

或

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

仅在用户未输入任何内容时为true.如果有，则按预期执行第三个如果".但是当用户没有输入任何内容时

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());

无法完成.因为它是空的.我认为情况就是这样.如果不是这样，请告诉我.如果我错了，抱歉.这就是我从这里了解到的.如果您可以调试并针对场景或异常(如果有的话)进行详细说明，那将更有帮助

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

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