Android仿iphone自定义滚动选择器

package com.pickerscrollview.views; 
 
import java.util.ArrayList; 
import java.util.List; 
import java.util.Timer; 
import java.util.TimerTask; 
 
import android.annotation.SuppressLint; 
import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.Paint; 
import android.graphics.Paint.Align; 
import android.graphics.Paint.FontMetricsInt; 
import android.graphics.Paint.Style; 
import android.os.Handler; 
import android.os.Message; 
import android.util.AttributeSet; 
import android.view.MotionEvent; 
import android.view.View; 
 
import com.pickerscrollview.bean.Pickers; 
 
/** 
 * 自定义滚动选择器 
 * 
 * @author zengtao 2015年5月20日 下午7:36:03 
 * 
 */ 
@SuppressLint({ "HandlerLeak", "ClickableViewAccessibility" }) 
public class PickerScrollView extends View { 
 
  public static final String TAG = "PickerView"; 
  /** 
   * text之间间距和minTextSize之比 
   */ 
  public static final float MARGIN_ALPHA = 2.8f; 
  /** 
   * 自动回滚到中间的速度 
   */ 
  public static final float SPEED = 2; 
 
  private List mDataList; 
  /** 
   * 选中的位置，这个位置是mDataList的中心位置，一直不变 
   */ 
  private int mCurrentSelected; 
  private Paint mPaint; 
 
  private float mMaxTextSize = 20; 
  private float mMinTextSize = 10; 
 
  private float mMaxTextAlpha = 255; 
  private float mMinTextAlpha = 120; 
 
  private int mColorText = 0x333333; 
 
  private int mViewHeight; 
  private int mViewWidth; 
 
  private float mLastDownY; 
  /** 
   * 滑动的距离 
   */ 
  private float mMoveLen = 0; 
  private boolean isInit = false; 
  private onSelectListener mSelectListener; 
  private Timer timer; 
  private MyTimerTask mTask; 
 
  Handler updateHandler = new Handler() { 
 
    @Override 
    public void handleMessage(Message msg) { 
      if (Math.abs(mMoveLen)  datas) { 
    mDataList = datas; 
    mCurrentSelected = datas.size() / 2; 
    invalidate(); 
  } 
 
  /** 
   * 选择选中的item的index 
   * 
   * @param selected 
   */ 
  public void setSelected(int selected) { 
    mCurrentSelected = selected; 
    int distance = mDataList.size() / 2 - mCurrentSelected; 
    if (distance  0) 
      for (int i = 0; i (); 
    mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); 
    mPaint.setStyle(Style.FILL); 
    mPaint.setTextAlign(Align.CENTER); 
    mPaint.setColor(mColorText); 
  } 
 
  @Override 
  protected void onDraw(Canvas canvas) { 
    super.onDraw(canvas); 
    // 根据index绘制view 
    if (isInit) 
      drawData(canvas); 
  } 
 
  private void drawData(Canvas canvas) { 
    // 先绘制选中的text再往上往下绘制其余的text 
    float scale = parabola(mViewHeight / 4.0f, mMoveLen); 
    float size = (mMaxTextSize - mMinTextSize) * scale + mMinTextSize; 
    mPaint.setTextSize(size); 
    mPaint.setAlpha((int) ((mMaxTextAlpha - mMinTextAlpha) * scale + mMinTextAlpha)); 
    // text居中绘制，注意baseline的计算才能达到居中，y值是text中心坐标 
    float x = (float) (mViewWidth / 2.0); 
    float y = (float) (mViewHeight / 2.0 + mMoveLen); 
    FontMetricsInt fmi = mPaint.getFontMetricsInt(); 
    float baseline = (float) (y - (fmi.bottom / 2.0 + fmi.top / 2.0)); 
 
    int indexs = mCurrentSelected; 
    String textData = mDataList.get(indexs).getShowConetnt(); 
    canvas.drawText(textData, x, baseline, mPaint); 
 
    // 绘制上方data 
    for (int i = 1; (mCurrentSelected - i) >= 0; i++) { 
      drawOtherText(canvas, i, -1); 
    } 
    // 绘制下方data 
    for (int i = 1; (mCurrentSelected + i)  MARGIN_ALPHA * mMinTextSize / 2) { 
      // 往下滑超过离开距离 
      moveTailToHead(); 
      mMoveLen = mMoveLen - MARGIN_ALPHA * mMinTextSize; 
    } else if (mMoveLen 

package com.pickerscrollview.bean; 
 
import java.io.Serializable; 
 
/** 
 * 
 * @author zengtao 2015年5月20日下午7:18:14 
 * 
 */ 
public class Pickers implements Serializable { 
 
  private static final long serialVersionUID = 1L; 
 
  private String showConetnt; 
  private String showId; 
 
  public String getShowConetnt() { 
    return showConetnt; 
  } 
 
  public String getShowId() { 
    return showId; 
  } 
 
  public Pickers(String showConetnt, String showId) { 
    super(); 
    this.showConetnt = showConetnt; 
    this.showId = showId; 
  } 
 
  public Pickers() { 
    super(); 
  } 
 
} 

package com.pickerscrollview.ui; 
 
import java.util.ArrayList; 
import java.util.List; 
 
import android.app.Activity; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.RelativeLayout; 
 
import com.pickerscrollview.bean.Pickers; 
import com.pickerscrollview.views.PickerScrollView; 
import com.pickerscrollview.views.PickerScrollView.onSelectListener; 
 
/** 
 * 主界面 
 * 
 * @author zengtao 2015年5月20日 下午7:36:03 
 * 
 */ 
public class MainActivity extends Activity { 
 
  private Button bt_scrollchoose; // 滚动选择器按钮 
  private PickerScrollView pickerscrlllview; // 滚动选择器 
  private List list; // 滚动选择器数据 
  private String[] id; 
  private String[] name; 
 
  private Button bt_yes; // 确定按钮 
  private RelativeLayout picker_rel; // 选择器布局 
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
 
    initView(); 
    initLinstener(); 
    initData(); 
  } 
 
  /** 
   * 初始化 
   */ 
  private void initView() { 
    bt_scrollchoose = (Button) findViewById(R.id.bt_scrollchoose); 
    picker_rel = (RelativeLayout) findViewById(R.id.picker_rel); 
    pickerscrlllview = (PickerScrollView) findViewById(R.id.pickerscrlllview); 
    bt_yes = (Button) findViewById(R.id.picker_yes); 
  } 
 
  /** 
   * 设置监听事件 
   */ 
  private void initLinstener() { 
    bt_scrollchoose.setOnClickListener(onClickListener); 
    pickerscrlllview.setOnSelectListener(pickerListener); 
    bt_yes.setOnClickListener(onClickListener); 
  } 
 
  /** 
   * 初始化数据 
   */ 
  private void initData() { 
    list = new ArrayList(); 
    id = new String[] { "1", "2", "3", "4", "5", "6" }; 
    name = new String[] { "中国银行", "农业银行", "招商银行", "工商银行", "建设银行", "民生银行" }; 
    for (int i = 0; i