Android TouchListener实现拖拽删实例代码

import android.util.Log; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup;  /**  * Created by zhangjg on 14-10-10.  */ public class DragTouchListener implements View.OnTouchListener {    /**    * drag directions    */   public static final int DIRECTION_UP = 0;   public static final int DIRECTION_DOWN = 1;   public static final int DIRECTION_LEFT = 2;   public static final int DIRECTION_RIGHT = 3;     private int mDragDirection = -1;   private int mDragDistance = -1;   private ViewGroup.MarginLayoutParams mParams;   private ViewGroup.MarginLayoutParams mOriginParams;     private int viewOriginMargin = -1000;    private float mStartY = 0;   private float mStartX = 0;   private boolean isTouched = false;    public DragTouchListener(int dragDirection, int dragDistance){     mDragDirection = dragDirection;     mDragDistance = dragDistance;   }    protected void onClick(View view){    }    protected void onDragComplete(View view){    }    protected void onDragRebound(View view){    }    @Override   public boolean onTouch(View view, MotionEvent motionEvent) {       if (viewOriginMargin == -1000){       mParams = (ViewGroup.MarginLayoutParams)view.getLayoutParams();       if (mDragDirection == DIRECTION_UP) {         viewOriginMargin = mParams.bottomMargin;       }else if (mDragDirection == DIRECTION_DOWN){         viewOriginMargin = mParams.topMargin;       }else if (mDragDirection == DIRECTION_LEFT){         viewOriginMargin = mParams.rightMargin;       }else if (mDragDirection == DIRECTION_RIGHT){         viewOriginMargin = mParams.leftMargin;       }     }       int action = motionEvent.getAction();     switch (action){       case MotionEvent.ACTION_DOWN:         isTouched = true;         mStartY = motionEvent.getY();         mStartX = motionEvent.getX();         return true;       case MotionEvent.ACTION_MOVE:         float y = motionEvent.getY();         float x = motionEvent.getX();          if (mDragDirection == DIRECTION_UP){           if(y < mStartY){             mParams.bottomMargin = viewOriginMargin +(int) (mStartY - y);           }         }else if (mDragDirection == DIRECTION_DOWN){           if (y > mStartY){             mParams.topMargin = viewOriginMargin + (int) (y - mStartY);           }         }else if (mDragDirection == DIRECTION_LEFT){           if (x < mStartX){             mParams.rightMargin = viewOriginMargin + (int) (mStartX - x);           }         }else if (mDragDirection == DIRECTION_RIGHT){           if (x > mStartX){             mParams.leftMargin = viewOriginMargin + (int) (x - mStartX);           }         }          view.setLayoutParams(mParams);         break;       case MotionEvent.ACTION_UP:         float nowY = motionEvent.getY();         float nowX = motionEvent.getX();          int deltaX = (int)nowX - (int)mStartX;         int deltaY = (int)nowY - (int)mStartY;          if (isTouched && Math.abs(deltaX) < 5 && Math.abs(deltaY) < 5){           onClick(view);           break;         }          if (mDragDirection == DIRECTION_UP){           if (isTouched && mStartY - nowY > mDragDistance){  //            Log.i("test-drag", "direction up , startY = " + mStartY + ", nowY = " + nowY + //                ", startY - nowY = " + (mStartY - nowY) + ", dragDistance : " + mDragDistance);             onDragComplete(view);            }else if (mStartY - nowY > 0 && mStartY - nowY < mDragDistance ){             mParams.bottomMargin = viewOriginMargin;             view.setLayoutParams(mParams);             onDragRebound(view);           }         }else if (mDragDirection == DIRECTION_DOWN){            if (isTouched && nowY - mStartY > mDragDistance){             onDragComplete(view);           }else if ( nowY - mStartY > 0 && nowY - mStartY < mDragDistance ){             mParams.topMargin = viewOriginMargin;             view.setLayoutParams(mParams);             onDragRebound(view);           }         }else if (mDragDirection == DIRECTION_LEFT){           if (isTouched && mStartX - nowX > mDragDistance){             onDragComplete(view);           }else if ( mStartX - nowX > 0 && mStartX - nowX < mDragDistance ){             mParams.rightMargin = viewOriginMargin;             view.setLayoutParams(mParams);             onDragRebound(view);           }         }else if (mDragDirection == DIRECTION_RIGHT){           if (isTouched && nowX - mStartX > mDragDistance){             onDragComplete(view);           }else if ( nowX - mStartX > 0 && nowX - mStartX < mDragDistance ){             mParams.leftMargin = viewOriginMargin;             view.setLayoutParams(mParams);             onDragRebound(view);           }         }          isTouched = false;          break;     }     return false;   } }