仿真期间出现冗余警告和应用崩溃（Android Studio）（Java）

Question

I have two issues (that I'm aware of) on this calculation program (taking several inputs, run calculation, several outputs). Thanks for any help!!

1) Variable 'aResult' initializer 'Double.parseDouble(tvaResult.getText().toString()) is redundant similar warning on cResult etResult beta1Result phiResult MnResult & phiMnResult

2) Application is crashing after clicking the button. This leads me to believe that either some of my calculations are running into errors, or the button coding itself is incorrect.

--------- beginning of crash E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.ericallenbellville.rcbeamdesign, PID: 3087 java.lang.NumberFormatException: empty String at java.lang.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1071) at java.lang.Double.parseDouble(Double.java:547) at com.example.ericallenbellville.rcbeamdesign.MainActivity.onClick(MainActivity.java:54) at android.view.View.performClick(View.java:5637) at android.view.View$PerformClick.run(View.java:22429) at android.os.Handler.handleCallback(Handler.java:751) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6119) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

    package com.example.ericallenbellville.rcbeamdesign;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;


public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    public Button btnCalc;
    private TextView tvaResult;
    private TextView tvcResult;
    private TextView tvetResult;
    private TextView tvphiResult;
    private TextView tvMnResult;
    private TextView tvphiMnResult;
    private TextView tvbeta1Result;
    private EditText etB,etD,etAs,etFc,etFy;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }

    private void init() {
        btnCalc = (Button)findViewById(R.id.btnCalc);
        etB = (EditText)findViewById(R.id.etB);
        etD = (EditText)findViewById(R.id.etD);
        etAs = (EditText)findViewById(R.id.etAs);
        etFc = (EditText)findViewById(R.id.etFc);
        etFy = (EditText)findViewById(R.id.etFy);
        tvaResult = (TextView)findViewById(R.id.tvaResult);
        tvcResult = (TextView)findViewById(R.id.tvcResult);
        tvetResult = (TextView)findViewById(R.id.tvetResult);
        tvphiResult = (TextView)findViewById(R.id.tvphiResult);
        tvMnResult = (TextView)findViewById(R.id.tvMnResult);
        tvphiMnResult = (TextView)findViewById(R.id.tvphiMnResult);
        tvbeta1Result = (TextView)findViewById(R.id.tvbeta1Result);

        btnCalc.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
            Double B = Double.parseDouble(etB.getText().toString());
            Double D = Double.parseDouble(etD.getText().toString());
            Double As = Double.parseDouble(etAs.getText().toString());
            Double Fc = Double.parseDouble(etFc.getText().toString());
            Double Fy = Double.parseDouble(etFy.getText().toString());
            Double aResult = Double.parseDouble(tvaResult.getText().toString());
            Double cResult = Double.parseDouble(tvcResult.getText().toString());
            Double etResult = Double.parseDouble(tvetResult.getText().toString());
            Double beta1Result = Double.parseDouble(tvbeta1Result.getText().toString());
            Double phiResult = Double.parseDouble(tvphiResult.getText().toString());
            Double MnResult = Double.parseDouble(tvMnResult.getText().toString());
            Double phiMnResult = Double.parseDouble(tvphiMnResult.getText().toString());
            switch(view.getId()) {
                case R.id.btnCalc:
                    if (Fc <= 4000) {
                        beta1Result = (0.85);
                    } else if (4000 < Fc && Fc <= 8000) {
                        beta1Result = ((0.85)-(0.05 * ((Fc - 4000) / (1000))));
                    } else {
                        beta1Result = 0.65;
                    }
                    aResult = ((Fy * As) / (0.85 * Fc * B));
                    cResult = (aResult / beta1Result);
                    etResult = (((D - cResult) / (cResult)) * 0.003);
                    if (etResult >= 0.005) {
                        phiResult = (0.9);
                    } else if (0.002 <= etResult && etResult < 0.005) {
                        phiResult = (0.65 + (etResult - 0.002) * 0.25 / (0.005 - 0.002));
                    } else {
                        phiResult = (0.00);
                    }
                    MnResult = (((Fy * As) * (D - (aResult / 2.0))));
                    phiMnResult = phiResult * MnResult;
                    tvaResult.setText(String.valueOf(aResult));
                    tvcResult.setText(String.valueOf(cResult));
                    tvetResult.setText(String.valueOf(etResult));
                    tvphiResult.setText(String.valueOf(phiResult));
                    tvMnResult.setText(String.valueOf(MnResult));
                    tvphiMnResult.setText(String.valueOf(phiMnResult));
                    break;

            }}
    }

Answer 1

You are not using the values, aResult , cResult , etc until you calculate them inside the switch statement. So why initialize them using the text from the textviews? The reason you are getting an exception, is because the textviews are empty and you are trying to parse empty string into a Double .

double aResult = 0; //Double.parseDouble(tvaResult.getText().toString());
double cResult = 0; //Double.parseDouble(tvcResult.getText().toString());
double etResult = 0; //Double.parseDouble(tvetResult.getText().toString());
double beta1Result = 0; //Double.parseDouble(tvbeta1Result.getText().toString());
double phiResult = 0; //Double.parseDouble(tvphiResult.getText().toString());
double MnResult = 0; //Double.parseDouble(tvMnResult.getText().toString());
double phiMnResult = 0; //Double.parseDouble(tvphiMnResult.getText().toString());
switch(view.getId()) {
    case R.id.btnCalc:
    if (Fc <= 4000) {
        beta1Result = (0.85);
    } else if (4000 < Fc && Fc <= 8000) {
        beta1Result = ((0.85)-(0.05 * ((Fc - 4000) / (1000))));
    } else {
        beta1Result = 0.65;
    }
    aResult = ((Fy * As) / (0.85 * Fc * B));
    cResult = (aResult / beta1Result);
    etResult = (((D - cResult) / (cResult)) * 0.003);
    if (etResult >= 0.005) {
        phiResult = (0.9);
    } else if (0.002 <= etResult && etResult < 0.005) {
        phiResult = (0.65 + (etResult - 0.002) * 0.25 / (0.005 - 0.002));
    } else {
        phiResult = (0.00);
    }
    MnResult = (((Fy * As) * (D - (aResult / 2.0))));
    phiMnResult = phiResult * MnResult;
    tvaResult.setText(String.valueOf(aResult));
    tvcResult.setText(String.valueOf(cResult));
    tvetResult.setText(String.valueOf(etResult));
    tvphiResult.setText(String.valueOf(phiResult));
    tvMnResult.setText(String.valueOf(MnResult));
    tvphiMnResult.setText(String.valueOf(phiMnResult));
    break;
}