java - 如何将 TextView 的值放入 if 语句中

Question

我正在编写一个 Android 应用程序来计算某人的高度和体重之间的关系。一切都很好，我成功地完成了算术。

但是，当我想将 TextView 的结果放入 if 语句中时，无论结果大于、小于或等于，我都会收到第一个 if 语句的输出。快速地，我希望我的程序根据计算给出三种不同的结果。这是我的代码:

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class Main extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    // My Programming Begins Here
    final EditText editTextHeight = (EditText) findViewById(R.id.editTextHeight);
    final EditText editTextWeight = (EditText) findViewById(R.id.editTextWeight);
    Button calculateButton = (Button) findViewById(R.id.calculateButton);
    final TextView result = (TextView) findViewById(R.id.result);
    final TextView suggestionResult = (TextView) findViewById(R.id.suggestionResult);
    // Coding for the Button
    calculateButton.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            int heightValue = Integer.parseInt(editTextHeight.getText()
                    .toString());

            int weightValue = Integer.parseInt(editTextWeight.getText()
                    .toString());

            // Finding out the square of weightValue and then dividing the
            // heightValue by the sqaure of weightValue
            result.setText(String.valueOf(heightValue
                    / (Math.sqrt(weightValue))));
            if (result.getText().toString().length() >= 1
                    && result.getText().toString().length() < 18.5) {
                suggestionResult.setText("You have to gain weight");
            }
            if (result.getText().toString().length() >= 18.5
                    && result.getText().toString().length() < 24.9) {
                suggestionResult.setText("You are normal");
            } else {
                suggestionResult.setText("You have to lose      weight");
            }
        }
    });

}
}

Answer 1

试试这个

double d=Double.parseDouble(result.getText().toString());

 if ( d<=18.5) {
                suggestionResult.setText("You have to gain weight");
            }
            if (d >= 18.5 && d < 24.9) {
                suggestionResult.setText("You are normal");
            } else {
                suggestionResult.setText("You have to lose  weight");
            }