### opdracht 1 ###
public class MainActivity extends AppCompatActivity {
...
double num1, num2, div;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
...
btnAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
...
div = num1 / num2;
...
} catch (Exception e) {
...
}
}
});
}
}
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### opdracht 2 ###
public void onClick(View v) {
try {
...
if (num2 == 0) {
addResult.setText("Delen door 0 niet toegestaan!");
} else {
addResult.setText(Double.toString(div));
}
...
} catch (Exception e) {
...
}
}
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### oefneing 3 ### https://www.w3schools.com/java/java_try_catch.asp
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### oefneing 4 ###
public void onClick(View v) {
try {
num1 = Double.parseDouble(firstNumber.getText().toString());
num2 = Double.parseDouble(secondNumber.getText().toString());
div = num1 / num2;
if (num2 == 0) {
throw new ArithmeticException();
} else {
addResult.setText(Double.toString(div));
}
} catch (Exception e) {
if (e instanceof NumberFormatException) {
addResult.setText("Geen tekst a.u.b.");
} else if (e instanceof ArithmeticException){
addResult.setText("Delen door 0 niet toegestaan!");
} else {
addResult.setText(e.getMessage());
}
}
}
Download hier het bestand.