单击按钮后如何显示文本

Question

I'm trying to make a simple app where when you click on button text appears. But I'm having a problem where when I click the button nothing happens.

public class MainActivity extends AppCompatActivity {
    private TextView textView;
    private Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = (TextView) findViewById(R.id.textView);
        textView.setMovementMethod(new ScrollingMovementMethod());

        button = (Button) findViewById(R.id.button);

        View.OnClickListener ourOnClickListener = new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                textView.setText("It real sent your at. Amounted all shy set why followed declared. Repeated of endeavor mr position kindness offering ignorant so up. Simplicity are melancholy preference considered saw companions. Disposal on outweigh do speedily in on. Him ham although thoughts entirely drawings. Acceptance unreserved.");

            }
        };


    }
}

XML

  <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="84dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="374dp"
        android:layout_height="331dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="16dp"
        android:textSize="8sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

Answer 1

You're initiating an onClickListener , but you're not attaching it to any object. Try to attach the onClickListener to your button like this:

button.setOnClickListener(ourOnClickListener);

Answer 2

Nothing is happening on click, because you have not set the onClickListener on the button yet, you've only defined the functionality for onClick . Add this line in your onCreate : button.setOnClickListener(ourOnClickListener) .

Answer 3

Solution:

Instead of this:

View.OnClickListener ourOnClickListener = new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        textView.setText("It real sent your at. Amounted all shy set why followed declared. Repeated of endeavor mr position kindness offering ignorant so up. Simplicity are melancholy preference considered saw companions. Disposal on outweigh do speedily in on. Him ham although thoughts entirely drawings. Acceptance unreserved.");
    }
};

Write like this:

button.setOnClickListener(new View.OnClickListener) {
    @Override
    public void onClick(View v) {
        textView.setText("It real sent your at. Amounted all shy set why followed declared. Repeated of endeavor mr position kindness offering ignorant so up. Simplicity are melancholy preference considered saw companions. Disposal on outweigh do speedily in on. Him ham although thoughts entirely drawings. Acceptance unreserved.");

    }
};

Hope it helps.

Answer 4

You should put it this way instead,

button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            textView.setText("It real sent your at. Amounted all shy set why followed declared. Repeated of endeavor mr position kindness offering ignorant so up. Simplicity are melancholy preference considered saw companions. Disposal on outweigh do speedily in on. Him ham although thoughts entirely drawings. Acceptance unreserved.");

        }
    });