Android gesture operation example of and and left and right judgment

This paper describes the Android gesture operation method with examples. Share it for your reference, as follows:

Android provides an interface for judging gestures, so we can realize various gesture functions according to the provided API to improve the user experience of mobile phone applications.

The following is a small Demo I wrote:

GestureActivity.Java

public class GestureActivity extends Activity {
  private GestureDetector gestureDetector;
  private Screen screen;
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    gestureDetector = new GestureDetector(this,onGestureListener);
    // Get the size of the screen 
    screen = GestureUtils.getScreenPix(this);
  }
  @Override
  public boolean onTouchEvent(MotionEvent event) {
    return gestureDetector.onTouchEvent(event);
  }
  GestureDetector.OnGestureListener onGestureListener = new GestureDetector.SimpleOnGestureListener(){
    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
        float velocityY) {
      float x = e2.getX() - e1.getX();
      float y = e2.getY() - e1.getY();
      // Limit the number that must be crossed the screen 1/3 To be counted as crossing 
      float x_limit = screen.widthPixels / 3;
      float y_limit = screen.heightPixels / 3;
      float x_abs = Math.abs(x);
      float y_abs = Math.abs(y);
      if(x_abs >= y_abs){
        //gesture left or right
        if(x > x_limit || x < -x_limit){
          if(x>0){
            //right
            show("right");
          }else if(x
            //left
            show("left");
          }
        }
      }else{
        //gesture down or up
        if(y > y_limit || y < -y_limit){
          if(y>0){
            //down
            show("down");
          }else if(y
            //up
            show("up");
          }
        }
      }
      return true;
    }
  };
  private void show(String value){
    Toast.makeText(this, value, Toast.LENGTH_SHORT).show();
  }
}

GestureUtils.java

public class GestureUtils {
  // Gets the size of the screen 
  public static Screen getScreenPix(Context context) {
    DisplayMetrics dm = new DisplayMetrics();
    WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
    windowManager.getDefaultDisplay().getMetrics(dm);
    return new Screen(dm.widthPixels,dm.heightPixels);
  }
  public static class Screen{
    public int widthPixels;
    public int heightPixels;
    public Screen(){
    }
    public Screen(int widthPixels,int heightPixels){
      this.widthPixels=widthPixels;
      this.heightPixels=heightPixels;
    }
    @Override
    public String toString() {
      return "("+widthPixels+","+heightPixels+")";
    }
  }
}

For more readers interested in Android related contents, please check the topics on this site: "Summary of Android File Operation Skills", "Summary of SD Card Operation Methods for Android Programming Development", "Introduction and Advanced Tutorial for Android Development", "Summary of Android Resource Operation Skills", "Summary of Android View View Skills" and "Summary of Android Control Usage"

I hope this article is helpful to everyone's Android programming.