公共类 MainActivity 扩展 AppCompatActivity 实现 GestureDetector.OnGestureListener

Question

public class MainActivity extends AppCompatActivity implements GestureDetector.OnGestureListener {

    private GestureDetectorCompat gestureDetector;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.i(TAG, "onCreate");

        this.gestureDetector = new GestureDetectorCompat(this,this);
    }

this line:

public class MainActivity extends AppCompatActivity implements GestureDetector.OnGestureListener 

is red and reads this error:

Error:(12, 8) error: MainActivity is not abstract and does not override abstract method onLongPress(MotionEvent) in OnGestureListener

Answer 1

First of all import the necessary headers. [press the combination cmd + shift + O if it is windows]

After that you will see a error under MainActivity. Move the cursor on to MainActivity and click on implement methods.

Answer 2

Since you have declared the MainActivity class as implementing the OnGestureListener interface, you have to implement all of the methods that that interface defines.

You haven't done that.

Solution: do that.

Here's an example that may help you:

https://github.com/filajust/man-from-mars/blob/master/ManFromMars/src/edu/msu/filajustmanfrommars/GameView.java

Note that the example uses GestureDetector.SimpleOnGestureListener to implement the listener functionality.