Android自定义控件，实现iphone的picker效果

效果图如下：

1.不带有图标的

2.带有图标的

主要有两个类：

1.Picker

2.CustomListView

Picker控件的外部接口：

Picker控件的使用方法：

public class Main extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        final Picker picker=new Picker(this);
        
    	ArrayList<String> data = new ArrayList<String>();
    	ArrayList<Drawable> icons = new ArrayList<Drawable>();
    	
    	icons.add(getResources().getDrawable(R.drawable.icon1));
    	icons.add(getResources().getDrawable(R.drawable.icon2));
    	icons.add(getResources().getDrawable(R.drawable.icon3));
    	icons.add(getResources().getDrawable(R.drawable.icon1));
    	icons.add(getResources().getDrawable(R.drawable.icon2));
    	icons.add(getResources().getDrawable(R.drawable.icon3));

		for (int i = 2000; i < 2006; i++) {
			data.add("" + i);
		}
		picker.setPickerData(data);
		picker.setPickerSize(100, 200);
		picker.defaultScrollToPos(4);
		picker.setOnPickerItemSelectedListener(new OnPickerItemSelectedListener() {
			@Override
			public void onItemSelected(View view, int pos, String text) {
				
			}
		});
		
        setContentView(picker);
        
    }
}

Picker控件的核心代码如下：

public class Picker extends LinearLayout implements
        CustomScrollView.OnScrollOverListener { 

    private ArrayList<String> data;   //字符串数据List
    private ArrayList<Drawable> iconList;  //与data相对应的图标List 

    private int headAndFootHeight = 150; 

    private int cellHeight = 50; 

    private Context mContext; 

    private LinearLayout contentLinear; 

    private CustomScrollView scrollview; 

    private TextView selector; 

    private int indicaterOffset; // 选择条的偏移量 

    private View ipicker; 

    private int width; 

    private int height; 

    private int defaultPos; 

    private ArrayList<View> viewlist = new ArrayList<View>(); // 每一项中的View（可以是他的子类） 

    private boolean isLayoutOnce; // 只是layout一次的标记
    private int destPos; 

    public Picker(Context context) {
        this(context,null);
    } 

    public Picker(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.mContext = context; 

        defaultPos = headAndFootHeight + cellHeight * 1 - indicaterOffset;
        FrameLayout frameLayout=new FrameLayout(mContext);
        frameLayout.setBackgroundResource(R.drawable.while_bg);
        LayoutParams params=new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
        frameLayout.setLayoutParams(params);
        CustomScrollView myScroll=new CustomScrollView(mContext);
        myScroll.setVerticalFadingEdgeEnabled(false);
        myScroll.setVerticalScrollBarEnabled(false);
        LayoutParams params2=new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
        myScroll.setLayoutParams(params2);
        LinearLayout linear=new LinearLayout(mContext);
        linear.setLayoutParams(params2);
        linear.setOrientation(LinearLayout.VERTICAL);
        myScroll.addView(linear);
        myScroll.setLayoutParams(params2);
        TextView selector1=new TextView(mContext);
        selector1.setBackgroundResource(R.drawable.selector_bg);
        selector1.setLayoutParams(params2);
        frameLayout.addView(myScroll);
        FrameLayout.LayoutParams params3=new FrameLayout.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
        params3.gravity=Gravity.CENTER_VERTICAL;
        frameLayout.addView(selector1, params3); 

        scrollview = myScroll;
        contentLinear = linear;
        selector =selector1;
        ipicker=frameLayout;
        selector.setHeight(cellHeight); // 将所有设置child宽高，位置的代码在onlayout之前调用
        addView(ipicker);
    } 

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        super.onLayout(false, l, t, r, b);
        Log.e("", "onLayout");
        if (isLayoutOnce) {
            return;
        }
        isLayoutOnce = true;
        int top = selector.getTop()-4;   //9 patch 图片的问题，经多次调试偏移四个像素最好
        indicaterOffset = top;
        if (defaultPos == 0) { 

            scrollview.scrollTo(0, headAndFootHeight - indicaterOffset);
        } else {
            scrollview.smoothScrollTo(0, defaultPos);
        } 

        this.handler.sendEmptyMessage(destPos); 

    } 

    private Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            scrollToPos(destPos);
            super.handleMessage(msg);
        } 

    }; 

    private TextView footText;
    /**Ipicker显示的时候，默认滚动到pos位置*/
    public void defaultScrollToPos(int pos) {
        this.destPos = pos;
        // flag = true;
        // defaultPos = headAndFootHeight + cellHeight * pos - indicaterOffset;
    } 

    /**滚动到Pos位置*/
    public void scrollToPos(int pos) {
        scrollview.smoothScrollTo(0, headAndFootHeight + cellHeight * pos
                - indicaterOffset);
    }
    /**为控件添加数据
     * list  StringList
     * */
    public void setPickerData(ArrayList<String> list) {
        this.data = list;
        prepare();
    }
    /**为控件添加数据
     * list  StringList
     * */
    public void setPickerData(ArrayList<String> stringlist,ArrayList<Drawable> iconlist) {
        if(stringlist.size()!=iconlist.size()){
            Log.e("error", "!!error!! the length of stringlist and iconlist is not same!!"); 

            return;
        }
        this.data = stringlist;
        this.iconList=iconlist;
        prepare();
    } 

    /** set the size of the picker */
    public void setPickerSize(int width, int height) {
        this.width = width;
        this.height = height;
    } 

    /**
     *  prepare picker view ,prepare the ipcker's children (will call onlayout again)
     * */
    private void prepare() {
        contentLinear.removeAllViews();
        LayoutParams params = new LayoutParams(LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT);
        if (width == 0 || height == 0) {
            params.width = 200;
            params.height = 200;
        } else {
            params.width = width;
            params.height = height;
        }
        ipicker.setLayoutParams(params); 

        scrollview.setOnScrollOverListener(this);
        TextView headText = new TextView(mContext);
        headText.setHeight(headAndFootHeight);
        contentLinear.addView(headText); 

        insertData(); 

        footText = new TextView(mContext);
        footText.setHeight(headAndFootHeight);
        contentLinear.addView(footText);
    } 

    private void insertData() {
        viewlist.clear();
        if (data == null || data.size() == 0) {
            selector.setVisibility(View.GONE);
            return;
        }
        for (int i = 0; i < data.size(); i++) {
            LinearLayout itemLayout=new LinearLayout(mContext);
            itemLayout.setGravity(Gravity.CENTER_VERTICAL);
            itemLayout.setPadding(20, 0, 0, 0);
            if(iconList!=null){
                ImageView image=new ImageView(mContext);
                image.setBackgroundDrawable(iconList.get(i));
                itemLayout.addView(image);
            }
            TextView text = new TextView(mContext);
            text.setHeight(cellHeight);
            text.setGravity(Gravity.CENTER);
            text.setTextSize(25);
            text.setTypeface(Typeface.DEFAULT_BOLD);
            text.setTextColor(Color.BLACK);
            itemLayout.addView(text);
            LayoutParams params = new LayoutParams(LayoutParams.FILL_PARENT,
                    LayoutParams.WRAP_CONTENT);
            text.setLayoutParams(params);
            text.setText(data.get(i));
            contentLinear.addView(itemLayout);
            viewlist.add(itemLayout);
        }
    } 

    @Override
    public void onScrollOver(final int stopy) { 

        final int num = (stopy - headAndFootHeight + indicaterOffset)
                / cellHeight;
        if (stopy + indicaterOffset // to triger onItemSelected only one time
                - (headAndFootHeight + cellHeight * (num)) == 0) {
            if(listener!=null){
                listener.onItemSelected(viewlist.get(num), num, data.get(num));
            }
        } 

        ((Activity) mContext).runOnUiThread(new Runnable() {
            @Override
            public void run() { 

                if (stopy + indicaterOffset < headAndFootHeight) {
                    scrollview.smoothScrollTo(0, headAndFootHeight
                            - indicaterOffset);
                                } else if (stopy + indicaterOffset >= headAndFootHeight
                        + cellHeight * num
                        && stopy + indicaterOffset <= headAndFootHeight
                                + cellHeight * (data.size() - 1)) {
                    if (stopy + indicaterOffset
                            - (headAndFootHeight + cellHeight * (num)) <= cellHeight / 2) { // less 

                        scrollview.smoothScrollTo(0, headAndFootHeight
                                + cellHeight * num - indicaterOffset);
                    } else {
                        scrollview.smoothScrollTo(0, headAndFootHeight
                                + cellHeight * (num + 1) - indicaterOffset);
                    } 

                } else if (stopy + indicaterOffset > headAndFootHeight
                        + cellHeight * (data.size() - 1)) {
                    scrollview.smoothScrollTo(0, headAndFootHeight + cellHeight
                            * (data.size() - 1) - indicaterOffset);
                } else {
                } 

            }
        });
    } 

    private OnPickerItemSelectedListener listener; 

    public void setOnPickerItemSelectedListener(
            OnPickerItemSelectedListener listener) {
        this.listener = listener;
    } 

    interface OnPickerItemSelectedListener {
        /**
         * @param view: view of the a specific item (linearLayout)
         * @param pos:position
         * @param text:String of the a specific item
         * */
        void onItemSelected(View view, int pos, String text);
    }
}

//欢迎提出宝贵意见