Code problem

There are no errors in the android studio, the application crashes. What I do wrong. . It happened when I inserted a part of the color change code. Here's the code:

public void buttonClickedIzracunaj(View v) {

    EditText visina = (EditText) findViewById(R.id.txtVisina);
    EditText tezina = (EditText) findViewById(R.id.txtTezina);
    TextView rezultat = (TextView) findViewById(R.id.txtRez);

    if (visina.getText().length() == 0 && tezina.getText().length() == 0) return;

    double vi = Double.parseDouble(visina.getText().toString());
    double te = Double.parseDouble(tezina.getText().toString());

    double ITM = te / ((vi / 100) * (vi / 100));

    rezultat.setText(String.format("%.2f", ITM));

    String value = rezultat.getText().toString();
    int i = Integer.parseInt(value);

    if(i<20){
        rezultat.setTextColor(Color.parseColor("blue"));
    }else if(i<=20 && i<25){
        rezultat.setTextColor(Color.parseColor("green"));
    }else if(i>25){
        rezultat.setTextColor(Color.parseColor("red"));
    }

Greeting.
Android studio has no errors. The application works on the emulator (API 22). The Samsung J3 2016 is launched but when I press the button calculate the application crashes. The message that writes to J3 "has been a mistake".

I think this is it:
01-19 13:40:45.682 4700-4700/com.example.marin.bmi_indextjelesnemase E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.marin.bmi_indextjelesnemase, PID: 4700
java.lang.NumberFormatException: Invalid double: "21,46"
at java.lang.StringToReal.invalidReal(StringToReal.java:63)
at java.lang.StringToReal.initialParse(StringToReal.java:164)
at java.lang.StringToReal.parseDouble(StringToReal.java:282)
at java.lang.Double.parseDouble(Double.java:301)
at com.example.marin.bmi_indextjelesnemase.MainActivity$1.onClick(MainActivity.java:46)
at android.view.View.performClick(View.java:5246)
at android.widget.TextView.performClick(TextView.java:10620)
at android.view.View$PerformClick.run(View.java:21256)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:7007)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)

Not.
This is the calculated data.
The problem appeared when I wrote a piece of code that changed color in TextView.