高仿launcher和墨迹左右拖动效果

2012/03/20 18:51
阅读数 2.6K

           半个月前就有这样的想法,做出一个模仿launcher的效果。自己也曾从网上搜过很多资料,也思考过怎么实现,最终还是参考了别人的资料实现了此效果,也解决了我这半个多月的冥思苦想,再次感谢,今天把代码贴出来供大家学习,因为这方面做得比较好的资料缺失比较少(因为本人搜了很多资料都不能达到效果),如果大家觉得还不错,请顶起。

       

            首先自定义一个 ViewGroup:

 

public class MyScrollLayout extends ViewGroup{

    private VelocityTracker mVelocityTracker;  			// 用于判断甩动手势    
    private static final int SNAP_VELOCITY = 600;        
    private Scroller  mScroller;						// 滑动控制器	
    private int mCurScreen;    						    
	private int mDefaultScreen = 0;    						 
    private float mLastMotionX;       
 //   private int mTouchSlop;							
    
   private OnViewChangeListener mOnViewChangeListener;	
 
	public MyScrollLayout(Context context) {
		super(context);
		// TODO Auto-generated constructor stub
		init(context);
	}	
	public MyScrollLayout(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
		init(context);
	}
	
	public MyScrollLayout(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		// TODO Auto-generated constructor stub		
		init(context);
	}
	
	private void init(Context context)
	{
		mCurScreen = mDefaultScreen;    	  
	 //   mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();    	        
	    mScroller = new Scroller(context); 
	    
	}

	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {
		// TODO Auto-generated method stub		
		 if (changed) {    
	            int childLeft = 0;    
	            final int childCount = getChildCount();    	                
	            for (int i=0; i<childCount; i++) {    
	                final View childView = getChildAt(i);    
	                if (childView.getVisibility() != View.GONE) {    
	                    final int childWidth = childView.getMeasuredWidth();    
	                    childView.layout(childLeft, 0,     
	                            childLeft+childWidth, childView.getMeasuredHeight());    
	                    childLeft += childWidth;    
	                }    
	            }    
	        }    
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		// TODO Auto-generated method stub
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);		
		final int width = MeasureSpec.getSize(widthMeasureSpec);       
	    final int widthMode = MeasureSpec.getMode(widthMeasureSpec);      
	    		
		final int count = getChildCount();       
        for (int i = 0; i < count; i++) {       
            getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);       
        }                
        scrollTo(mCurScreen * width, 0);		
	}

	 public void snapToDestination() {    
	        final int screenWidth = getWidth();    
	        final int destScreen = (getScrollX()+ screenWidth/2)/screenWidth;    
	        snapToScreen(destScreen);    
	 }  
	
	 public void snapToScreen(int whichScreen) {    	
	        // get the valid layout page    
	        whichScreen = Math.max(0, Math.min(whichScreen, getChildCount()-1));    
	        if (getScrollX() != (whichScreen*getWidth())) {    	                
	            final int delta = whichScreen*getWidth()-getScrollX();    
	      	            mScroller.startScroll(getScrollX(), 0,     
	                    delta, 0, Math.abs(delta)*2);
	            
	            mCurScreen = whichScreen;    
	            invalidate();       // Redraw the layout    	            
	            if (mOnViewChangeListener != null)
	            {
	            	mOnViewChangeListener.OnViewChange(mCurScreen);
	            }
	        }    
	    }    

	@Override
	public void computeScroll() {
		// TODO Auto-generated method stub
		if (mScroller.computeScrollOffset()) {    
            scrollTo(mScroller.getCurrX(), mScroller.getCurrY());  
            postInvalidate();    
        }   
	}

	@Override
	public boolean onTouchEvent(MotionEvent event) {
		// TODO Auto-generated method stub           	            
	        final int action = event.getAction();    
	        final float x = event.getX();    
	        final float y = event.getY();    
	            
	        switch (action) {    
	        case MotionEvent.ACTION_DOWN: 	        	
	        	  Log.i("", "onTouchEvent  ACTION_DOWN");	        	  
	        	if (mVelocityTracker == null) {    
			            mVelocityTracker = VelocityTracker.obtain();    
			            mVelocityTracker.addMovement(event); 
			    }        	 
	            if (!mScroller.isFinished()){    
	                mScroller.abortAnimation();    
	            }                
	            mLastMotionX = x;	           
	            break;    
	                
	        case MotionEvent.ACTION_MOVE:  
	           int deltaX = (int)(mLastMotionX - x);	           
        	   if (IsCanMove(deltaX))
        	   {
        		 if (mVelocityTracker != null)
  		         {
  		            	mVelocityTracker.addMovement(event); 
  		         }   
  	            mLastMotionX = x;     
  	            scrollBy(deltaX, 0);	
        	   }
         
	           break;    	                
	        case MotionEvent.ACTION_UP:       	        	
	        	int velocityX = 0;
	            if (mVelocityTracker != null)
	            {
	            	mVelocityTracker.addMovement(event); 
	            	mVelocityTracker.computeCurrentVelocity(1000);  
	            	velocityX = (int) mVelocityTracker.getXVelocity();
	            }	               	                
	            if (velocityX > SNAP_VELOCITY && mCurScreen > 0) {       
	                // Fling enough to move left          
	                snapToScreen(mCurScreen - 1);       
	            } else if (velocityX < -SNAP_VELOCITY       
	                    && mCurScreen < getChildCount() - 1) {       
	                // Fling enough to move right          
	                snapToScreen(mCurScreen + 1);       
	            } else {       
	                snapToDestination();       
	            }      
	            	            
	            if (mVelocityTracker != null) {       
	                mVelocityTracker.recycle();       
	                mVelocityTracker = null;       
	            }       
	      //      mTouchState = TOUCH_STATE_REST;
	            break;      
	        }    	            
	        return true;    
	}

	private boolean IsCanMove(int deltaX)
	{
		if (getScrollX() <= 0 && deltaX < 0 ){
			return false;
		}	
		if  (getScrollX() >=  (getChildCount() - 1) * getWidth() && deltaX > 0){
			return false;
		}		
		return true;
	}
	
	public void SetOnViewChangeListener(OnViewChangeListener listener)
	{
		mOnViewChangeListener = listener;
	}
}


public class SwitchViewDemoActivity extends Activity implements OnViewChangeListener, OnClickListener{
    /** Called when the activity is first created. */

	private MyScrollLayout mScrollLayout;	
	private ImageView[] mImageViews;	
	private int mViewCount;	
	private int mCurSel;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);        
        init();
        
    }
    
    private void init()
    {
    	mScrollLayout = (MyScrollLayout) findViewById(R.id.ScrollLayout); 	
    	LinearLayout linearLayout = (LinearLayout) findViewById(R.id.llayout);
    	//动态添加一个layout控件
    	LinearLayout layout=new LinearLayout(this);
    	layout.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT));
    	layout.setBackgroundResource(R.drawable.guide01);
    	mScrollLayout.addView(layout);
    	//动态添加一个imageView控件        
    	ImageView imageView=new ImageView(this);
    	imageView.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
    	imageView.setPadding(15, 15, 15, 15);
    	imageView.setImageResource(R.drawable.guide_round);
    	linearLayout.addView(imageView);
    	
    	mViewCount = mScrollLayout.getChildCount();
    	mImageViews = new ImageView[mViewCount];   	
    	for(int i = 0; i < mViewCount; i++)    	{
    		mImageViews[i] = (ImageView) linearLayout.getChildAt(i);
    		mImageViews[i].setEnabled(true);
    		mImageViews[i].setOnClickListener(this);
    		mImageViews[i].setTag(i);
    	}    	
    	mCurSel = 0;
    	mImageViews[mCurSel].setEnabled(false);    	
    	mScrollLayout.SetOnViewChangeListener(this);
    	
    }

    private void setCurPoint(int index)
    {
    	if (index < 0 || index > mViewCount - 1 || mCurSel == index)    	{
    		return ;
    	}    	
    	mImageViews[mCurSel].setEnabled(true);
    	mImageViews[index].setEnabled(false);    	
    	mCurSel = index;
    }

    @Override
	public void OnViewChange(int view) {
		// TODO Auto-generated method stub
		setCurPoint(view);
	}

	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
		int pos = (Integer)(v.getTag());
		setCurPoint(pos);
		mScrollLayout.snapToScreen(pos);
	}
}

最后是布局文件 :

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <cn.com.karl.scroll.MyScrollLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/ScrollLayout"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:background="@drawable/guide01" >
        </LinearLayout>

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:background="@drawable/guide02" >
        </LinearLayout>

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:background="@drawable/guide03" >
        </LinearLayout>

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:background="@drawable/guide04" >
        </LinearLayout>

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:background="@drawable/guide05" >
        </LinearLayout>
    </cn.com.karl.scroll.MyScrollLayout>

    <LinearLayout
        android:id="@+id/llayout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="24.0dip"
        android:orientation="horizontal" >

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:clickable="true"
            android:padding="15.0dip"
            android:src="@drawable/guide_round" />

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:clickable="true"
            android:padding="15.0dip"
            android:src="@drawable/guide_round" />

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:clickable="true"
            android:padding="15.0dip"
            android:src="@drawable/guide_round" />

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:clickable="true"
            android:padding="15.0dip"
            android:src="@drawable/guide_round" />

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:clickable="true"
            android:padding="15.0dip"
            android:src="@drawable/guide_round" />
    </LinearLayout>

</RelativeLayout>

看看运行后的效果到底怎么样吧!



原文链接: http://blog.csdn.net/wangkuifeng0118/article/details/7374460
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