Android 仿通讯录侧边栏滑动 SiderBar效果

之前看到某些应用的侧边栏做得不错，想想自己也弄一个出来，现在分享出来，当然里面还有不足的地方，请大家多多包涵。

先上图：

具体实现的代码如下：

package com.freesonfish.listview_index;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class MySideBar extends View {

	private OnTouchingLetterChangedListener touchListener;
	// 26个字母
	public static String[] b = { "#", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T",
			"U", "V", "W", "X", "Y", "Z" };

	private boolean showBkg = false;
	int choose = -1;
	int scrollChoose = -1;
	Paint paint = new Paint();
	Paint rectPaint = new Paint();
	float rectWidth = 0f;

	public MySideBar(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		init();
	}

	public MySideBar(Context context, AttributeSet attrs) {
		super(context, attrs);
		init();
	}

	public MySideBar(Context context) {
		super(context);
		init();
	}

	private void init() {
		rectPaint.setColor(Color.parseColor("#CCCCCC"));
		rectWidth = paint.measureText("#");
	}

	/**
	 * 重写这个方法
	 */
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		if (showBkg) {
			canvas.drawColor(Color.parseColor("#CCCCCC"));
		}
		final int height = getHeight();
		final int width = getWidth();
		final int singleHeight = height / b.length;
		final float xRectPos = ((float) width - paint.measureText("#")) / 2.0f - rectWidth;
		final float xRectPos2 = xRectPos + 3.0f * rectWidth;
		for (int i = 0; i < b.length; i++) {
			paint.setFakeBoldText(true);
			paint.setAntiAlias(true);
			final float xPos = ((float) width - paint.measureText(b[i])) / 2.0f;
			final float yPos = singleHeight * i + singleHeight;
			if (i == choose) {
				paint.setColor(Color.RED);
				canvas.drawRect(xRectPos, yPos - singleHeight / 2.0f, xRectPos2, yPos + rectWidth, rectPaint);
			}
			canvas.drawText(b[i], xPos, yPos, paint);
			paint.reset();
		}

	}

	@Override
	public boolean dispatchTouchEvent(MotionEvent event) {
		final int action = event.getAction();
		final float y = event.getY();
		final int c = (int) (y / getHeight() * b.length);
		switch (action) {
		case MotionEvent.ACTION_DOWN:
			showBkg = true;
			if (choose != c && touchListener != null) {
				doOnActionDown(c);
			}
			break;
		case MotionEvent.ACTION_MOVE:
			if (choose != c && touchListener != null) {
				doOnActionDown(c);
			}
			break;
		case MotionEvent.ACTION_UP:
			showBkg = false;
			invalidate();
			break;
		}
		return true;
	}

	/**
	 * listview滚动时候调用它
	 * 
	 * @param c
	 */
	public void setColorWhenListViewScrolling(int c) {
		if (scrollChoose != c) {
			scrollChoose = c;
			String string = ListContantsUtil.AbcList.get(c);
			for (int i = c; i < b.length; ++i) {
				if (string.equals(b[i])) {
					choose = i;
					invalidate();
					break;
				}
			}
		}
	}

	/**
	 * 当侧边栏被按下的动作
	 * @param c
	 */
	private void doOnActionDown(int c) {
		if (c > 0 && c < b.length) {
			if (ListContantsUtil.indexPositionMap.containsKey(b[c])) {
				touchListener.onTouchingLetterChanged(b[c]);
				choose = c;
				invalidate();
			} else {
				c = c - 1;
				doOnActionDown(c);
			}
		}
	}

	@Override
	public boolean onTouchEvent(MotionEvent event) {
		return super.onTouchEvent(event);
	}

	public void setOnTouchingLetterChangedListener(OnTouchingLetterChangedListener touchListener) {
		this.touchListener = touchListener;
	}

	/**
	 * 用来通知activity显示选中的字母
	 * @author freeson
	 *
	 */
	public interface OnTouchingLetterChangedListener {
		public void onTouchingLetterChanged(String s);
	}

}

然后ListContantsUtil类是存储通讯录名字的拼音等的类，具体也如下：

package com.freesonfish.listview_index;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class ListContantsUtil {

	static final List<Integer> indexPositionList = new ArrayList<Integer>();
	static final List<String> AbcList = new ArrayList<String>();
	static final HashMap<String, Integer> indexPositionMap = new HashMap<String, Integer>();

	static void putNameIndexToMap(List<String> list, HashMap<String, String> nameAndPinyin) {
		int lenght = list.size();
		for (int i = 0; i < lenght; ++i) {
			String name = nameAndPinyin.get(list.get(i)).substring(0, 1);
			// 判断该字符是属于字母还是数字或其他的
			int ascii = name.toCharArray()[0];
			if (ascii >= 65 && ascii <= 90) {
				if (!indexPositionMap.containsKey(name)) {
					indexPositionMap.put(name, i);
					AbcList.add(name);
					indexPositionList.add(i);
				}
			} else {
				if (!indexPositionMap.containsKey("#")) {
					indexPositionMap.put("#", i);
					AbcList.add("#");
					indexPositionList.add(i);
				}
			}

		}

	}
}

注意，上面的程序还是有些小问题的，请大家注意优化解决。