BMI-Rechner

[Beka1801]

Hallo,

ich habe versucht einen BMI-Rechner zu erstellen. Allerdings beim Click auf den Button wird die App beendet. Hier mal meinen Code.
Im "Home_Fragment"

private EditText groesse;
private EditText gewicht;
private TextView ergebnis;

private HomeViewModel homeViewModel;

public View onCreateView(@NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
homeViewModel =
ViewModelProviders.of(this).get(HomeViewModel.class);
View root = inflater.inflate(R.layout.fragment_home, container, false);

//final TextView textView = root.findViewById(R.id.text_home);
//homeViewModel.getText().observe(getViewLifecycleOwner(), new Observer<String>() {
// @override
// public void onChanged(@Nullable String s) {
// textView.setText(s);
return root;

}
// });
//return root;


public void calculateBMI(View v) {
String heightStr = groesse.getText().toString();
String weightStr = gewicht.getText().toString();


if (heightStr != null && !"".equals(heightStr)
&& weightStr != null && !"".equals(weightStr)) {
float heightValue = Float.parseFloat(heightStr) / 100;
float weightValue = Float.parseFloat(weightStr);

float bmi = weightValue / (heightValue * heightValue);

displayBMI(bmi);
}
}

private void displayBMI(float bmi) {
String bmiLabel = "";

if (Float.compare(bmi, 15f) <= 0) bmiLabel = getString(R.string.very_severely_underweight);
else if (Float.compare(bmi, 15f) > 0 && Float.compare(bmi, 16f) <= 0) {
bmiLabel = getString(R.string.severely_underweight);
} else if (Float.compare(bmi, 16f) > 0 && Float.compare(bmi, 18.5f) <= 0) {
bmiLabel = getString(R.string.underweight);
} else if (Float.compare(bmi, 18.5f) > 0 && Float.compare(bmi, 25f) <= 0) {
bmiLabel = getString(R.string.normal);
} else if (Float.compare(bmi, 25f) > 0 && Float.compare(bmi, 30f) <= 0) {
bmiLabel = getString(R.string.overweight);
} else if (Float.compare(bmi, 30f) > 0 && Float.compare(bmi, 35f) <= 0) {
bmiLabel = getString(R.string.obese_class_i);
} else if (Float.compare(bmi, 35f) > 0 && Float.compare(bmi, 40f) <= 0) {
bmiLabel = getString(R.string.obese_class_ii);
} else {
bmiLabel = getString(R.string.obese_class_iii);
}

bmiLabel = bmi + "\n\n" + bmiLabel;
ergebnis.setText(bmiLabel);

XML
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ui.home.HomeFragment">

<EditText
android:id="@+id/etGewicht"
android:layout_width="127dp"
android:layout_height="42dp"
android:ems="10"
android:hint="Gewicht in kg"
android:inputType="textPersonName"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.134"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.208" />

<EditText
android:id="@+id/etGroesse"
android:layout_width="109dp"
android:layout_height="43dp"
android:ems="10"
android:hint="Größe in cm"
android:inputType="textPersonName"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.125"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.095" />

<Button
android:id="@+id/btBerechnen"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
androidnClick="calculateBMI"
android:text="Berechnen"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.117"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.329" />

<TextView
android:id="@+id/tvAnzeigen"
android:layout_width="408dp"
android:layout_height="71dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.665" />
</androidx.constraintlayout.widget.ConstraintLayout>

 

[jogimuc]

Hallo das onklickt tack im XML layout kannst du bei Fragmenten nicht benutzen.
Du musst in der onCreateview mit der view einen listner erstellen.