Android ViewFlipper que sigue gestos inmediatamente

Question

Estoy usando GestureDetector en ViewFlipper para implementar showPrevious y showNext. Todo está bien. Sin embargo, quiero tener el efecto de que la animación de ViewFlipper sigue el gesto con el dedo de inmediato, en lugar de hacer un gesto. ¿Algún consejo?

Answer 1

Por lo que sé, tienes que hacerlo manualmente. El siguiente código debe indicarle la dirección correcta. Tienes que agregar animaciones dinámicas para que la vista no parpadee durante la flipp. Hay más cosas que debe hacer, dependiendo del contenido del viewflipper, pero debe comenzar.

public boolean onTouch(View v, MotionEvent event) { 
    switch (event.getAction()) 
    { 
     case MotionEvent.ACTION_DOWN: 
     { 
      //Gets the startpoint for you finger 
      pressDownPoint = event.getX(); 

      //Gets how many view there is in the viewflipper 
      flipperViewCount = flipper.getChildCount(); 

      //Checks if there is a view to the left of the current view 
//if there is, it positions it to the left of the current view 
      if (flipper.getDisplayedChild() > 0) 
      { 
       View leftChild = flipper.getChildAt(flipper.getDisplayedChild() - 1); 
       //You must set the left view to invisible or visible 
//or it will not move to the position you tell it 
       leftChild.setVisibility(View.INVISIBLE); 
       leftChild.layout(-screenWidth, 
         leftChild.getTop(), 0, 
         leftChild.getBottom()); 
      } 

      //Same as above but for the view to the right 
      if (flipper.getDisplayedChild() < flipperViewCount - 1) 
      { 
       View rightChild = flipper.getChildAt(flipper.getDisplayedChild() + 1); 
       rightChild.setVisibility(View.INVISIBLE); 
       rightChild.layout(screenWidth, 
         rightChild.getTop(), screenWidth * 2, 
         rightChild.getBottom()); 
      } 
      break; 
     } 
     case MotionEvent.ACTION_UP: 
     { 
      //Gets the absolute position on the screen 
      float releasePoint = event.getRawX(); 

      //Calculates if the fling is to the right or left 
//The screenDensity variable is simply the density of the device 
//Have in mind that this will not flipp the viewflipper if you drag 
//your finger less than about 0.5cm (depeding on the device) 
//In that case you need to make an animation that takes the view back 
//to its original position. Else it will just get stuck where you 
//let go with your finger. 
      if (Math.abs(pressDownPoint - releasePoint)/screenDensity > 30) 
      { 
       if (pressDownPoint > releasePoint) 
       { 
        myAnimLeft(); //Method with your animation 
        flipper.showNext(); 
       } 
       else 
       { 
        myAnimRight(); 
        flipper.showPrevious(); 
       } 
      } 
      break; 
     } 
     case MotionEvent.ACTION_MOVE: 
     { 
      View currentView = flipper.getCurrentView(); 

      //Moves the current view 
//screenWidth is based on the current devices screen width 
      currentView.layout((int)(event.getRawX() - pressDownPoint), 
        currentView.getTop(), (int)(event.getRawX() - pressDownPoint) + screenWidth, 
        currentView.getBottom()); 

      //Moves the view to the left if there is one 
      if (flipper.getDisplayedChild() > 0) 
      { 
       View leftChild = flipper.getChildAt(flipper.getDisplayedChild() - 1); 
       leftChild.layout((int)(event.getRawX() - pressDownPoint - screenWidth), 
         leftChild.getTop(), (int)(event.getRawX() - pressDownPoint), 
         leftChild.getBottom()); 

       //Sets the left view to visible so it shows 
       if (leftChild.getVisibility() == View.INVISIBLE) 
       { 
        leftChild.setVisibility(View.VISIBLE); 
       } 
      } 

      //Same as above but for the view to the right 
      if (flipper.getDisplayedChild() < flipperViewCount - 1) 
      { 
       View rightChild = flipper.getChildAt(flipper.getDisplayedChild() + 1); 
       rightChild.layout((int)(event.getRawX() - pressDownPoint + screenWidth), 
         rightChild.getTop(), (int)(event.getRawX() - pressDownPoint + (screenWidth * 2)), 
         rightChild.getBottom()); 

       if (rightChild.getVisibility() == View.INVISIBLE) 
       { 
        rightChild.setVisibility(View.VISIBLE); 
       } 
      } 
     } 

    } 
    return true; 
}