8.快速索引、listview

实现这样的效果

布局：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <ListView
        android:id="@+id/lv_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </ListView>

    <com.itheima.quickindex.ui.QuickIndexBar
        android:id="@+id/bar"
        android:layout_width="30dp"
        android:layout_height="match_parent"
        android:layout_alignParentRight="true"
        android:background="#ff0000" />

    <TextView
        android:id="@+id/tv_center"
        android:layout_width="160dp"
        android:layout_height="100dp"
        android:background="@drawable/bg_index"
        android:gravity="center"
        android:textSize="32sp"
        android:visibility="gone"
        android:textColor="#ffffff"
        android:layout_centerInParent="true"
        android:text="A" />

</RelativeLayout>

字的shape：

<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle" >

    <solid android:color="#66000000"/>
    
    <corners android:radius="20dp"/>
</shape>

QuickIndexBar

/**
 * 快速索引
 * 
 * 用于根据字母快速定位联系人
 * @author poplar
 *
 */
public class QuickIndexBar extends View {
	
	private static final String[] LETTERS = new String[]{
		"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 static final String TAG = "TAG";
	
	private Paint mPaint;

	private int cellWidth;

	private float cellHeight;
	
	/**
	 * 暴露一个字母的监听，交给main执行
	 */
	public interface OnLetterUpdateListener{
		void onLetterUpdate(String letter);
	}
	private OnLetterUpdateListener listener;
	
	public OnLetterUpdateListener getListener() {
		return listener;
	}
	/**
	 * 设置字母更新监听
	 * @param listener
	 */
	public void setListener(OnLetterUpdateListener listener) {
		this.listener = listener;
	}

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

	public QuickIndexBar(Context context, AttributeSet attrs) {
		this(context, attrs, 0);//这样写，只需要在三个参数的构造函数初始化就可以了
	}

	public QuickIndexBar(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		
		mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
		mPaint.setColor(Color.WHITE);
		mPaint.setTypeface(Typeface.DEFAULT_BOLD);//当点中的时候变粗
	}
	
	@Override
	protected void onDraw(Canvas canvas) {
		
		for (int i = 0; i < LETTERS.length; i++) {
			String text = LETTERS[i];
			// 计算坐标
			int x = (int) (cellWidth / 2.0f - mPaint.measureText(text) / 2.0f);//先转成float再转成int，因为有可能丢失精度
			// 获取文本的高度
			Rect bounds = new Rect();// 矩形
			mPaint.getTextBounds(text, 0, text.length(), bounds);//字是矩形，通过矩形获得高
			int textHeight = bounds.height();
			int y = (int) (cellHeight / 2.0f + textHeight / 2.0f + i * cellHeight);
			
			// 根据按下的字母, 设置画笔颜色
			mPaint.setColor(touchIndex == i ? Color.GRAY : Color.WHITE);
			
			// 绘制文本A-Z
			canvas.drawText(text, x, y, mPaint);
		}
	}
	
	int touchIndex = -1;
	@Override
	public boolean onTouchEvent(MotionEvent event) {
		int index = -1;
		switch (MotionEventCompat.getActionMasked(event)) {
			case MotionEvent.ACTION_DOWN:
				// 获取当前触摸到的字母索引
				index = (int) (event.getY() / cellHeight);
				if(index >= 0 && index < LETTERS.length){
					// 判断是否跟上一次触摸到的一样
					if(index != touchIndex) {
						if(listener != null){
							listener.onLetterUpdate(LETTERS[index]);
						}
						Log.d(TAG, "onTouchEvent: " + LETTERS[index]);
						
						touchIndex = index;
					}
				}
				
				break;
			case MotionEvent.ACTION_MOVE:
				index = (int) (event.getY() / cellHeight);
				if(index >= 0 && index < LETTERS.length){
					// 判断是否跟上一次触摸到的一样
					if(index != touchIndex){
						
						if(listener != null){
							listener.onLetterUpdate(LETTERS[index]);
						}
						Log.d(TAG, "onTouchEvent: " + LETTERS[index]);
						
						touchIndex = index;
					}
				}
				break;
			case MotionEvent.ACTION_UP:
				touchIndex = -1;
				break;
	
			default:
				break;
		}
		invalidate();
		
		return true;
	}
	
	@Override
	protected void onSizeChanged(int w, int h, int oldw, int oldh) {
		super.onSizeChanged(w, h, oldw, oldh);
		// 获取单元格的宽和高
		
		cellWidth = getMeasuredWidth();
		
		int mHeight = getMeasuredHeight();
		cellHeight = mHeight * 1.0f / LETTERS.length;
		
	}
	
	
}

PinyinUtils

public class PinyinUtils {

	/**
	 * 根据传入的字符串(包含汉字),得到拼音
	 * 黑马 -> HEIMA
	 * 黑  马*& -> HEIMA
	 * 黑马f5 -> HEIMA
	 * @param str 字符串
	 * @return
	 */
	public static String getPinyin(String str) {
		
		HanyuPinyinOutputFormat format = new HanyuPinyinOutputFormat();
		format.setCaseType(HanyuPinyinCaseType.UPPERCASE);
		format.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
		
		StringBuilder sb = new StringBuilder();
		
		char[] charArray = str.toCharArray();
		for (int i = 0; i < charArray.length; i++) {
			char c = charArray[i];
			// 如果是空格, 跳过
			if(Character.isWhitespace(c)){
				continue;
			}
			if(c >= -127 && c < 128){
				// 肯定不是汉字
				sb.append(c);
			}else {
				String s = "";
				try {
					// 通过char得到拼音集合. 单 -> dan, shan 
					s = PinyinHelper.toHanyuPinyinStringArray(c, format)[0];
					sb.append(s);
				} catch (BadHanyuPinyinOutputFormatCombination e) {
					e.printStackTrace();
					sb.append(s);
				}
			}
		}
		
		return sb.toString();
	}

}

Person

public class Person implements Comparable<Person>{//实现比较功能

	private String name;
	private String pinyin;

	public Person(String name) {
		super();
		this.name = name;
		this.pinyin = PinyinUtils.getPinyin(name);
	}
	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPinyin() {
		return pinyin;
	}
	public void setPinyin(String pinyin) {
		this.pinyin = pinyin;
	}

	@Override
	public int compareTo(Person another) {
		return this.pinyin.compareTo(another.getPinyin());
	}
	
	
	
}

adapter布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/tv_index"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:background="#888888"
        android:gravity="center_vertical"
        android:paddingLeft="20dp"
        android:text="A"
        android:textColor="#ffffff"
        android:textSize="20sp" />

    <TextView
        android:id="@+id/tv_name"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:gravity="center_vertical"
        android:paddingLeft="20dp"
        android:text="宋江"
        android:textSize="24sp" />

</LinearLayout>

HaoHanAdapter

public class HaoHanAdapter extends BaseAdapter {

	private Context mContext;
	private ArrayList<Person> persons;

	public HaoHanAdapter(Context mContext, ArrayList<Person> persons) {
		this.mContext = mContext;
		this.persons = persons;
	}

	@Override
	public int getCount() {
		// TODO Auto-generated method stub
		return persons.size();
	}

	@Override
	public Object getItem(int position) {
		return persons.get(position);
	}

	@Override
	public long getItemId(int position) {
		return position;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		
		View view = convertView;
		if(convertView == null){
			view = view.inflate(mContext, R.layout.item_list, null);
		}
		ViewHolder mViewHolder = ViewHolder.getHolder(view);
		
		Person p = persons.get(position);
		
		String str = null;
		String currentLetter = p.getPinyin().charAt(0) + "";
		// 根据上一个首字母,决定当前是否显示字母
		if(position == 0){
			str = currentLetter;
		}else {
			// 上一个人的拼音的首字母
			String preLetter = persons.get(position - 1).getPinyin().charAt(0) + "";
			if(!TextUtils.equals(preLetter, currentLetter)){
				str = currentLetter;
			}
		}
		
		// 根据str是否为空,决定是否显示索引栏
		mViewHolder.mIndex.setVisibility(str == null ? View.GONE : View.VISIBLE);
		mViewHolder.mIndex.setText(currentLetter);
		mViewHolder.mName.setText(p.getName());
		
		return view;
	}
	
	static class ViewHolder {
		TextView mIndex;
		TextView mName;

		public static ViewHolder getHolder(View view) {//了解这种写法
			Object tag = view.getTag();
			if(tag != null){
				return (ViewHolder)tag;
			}else {
				ViewHolder viewHolder = new ViewHolder();
				viewHolder.mIndex = (TextView) view.findViewById(R.id.tv_index);
				viewHolder.mName = (TextView) view.findViewById(R.id.tv_name);
				view.setTag(viewHolder);
				return viewHolder;
			}
		}
		
	}

}

MainActivity

public class MainActivity extends Activity {

	private ListView mMainList;
	private ArrayList<Person> persons;
	private TextView tv_center;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		QuickIndexBar bar = (QuickIndexBar) findViewById(R.id.bar);
		// 设置监听，和回调一个意思
		bar.setListener(new OnLetterUpdateListener() {
			@Override
			public void onLetterUpdate(String letter) {
//				Utils.showToast(getApplicationContext(), letter);
				
				showLetter(letter);
				// 根据字母定位ListView, 找到集合中第一个以letter为拼音首字母的对象,得到索引
				for (int i = 0; i < persons.size(); i++) {
					Person person = persons.get(i);
					String l = person.getPinyin().charAt(0) + "";
					if(TextUtils.equals(letter, l)){
						// 匹配成功
						mMainList.setSelection(i);
						break;
					}
				}
			}
		});
		
		mMainList = (ListView) findViewById(R.id.lv_main);
		
		persons = new ArrayList<Person>();
		
		// 填充数据 , 排序
		fillAndSortData(persons);
		
		mMainList.setAdapter(new HaoHanAdapter(MainActivity.this , persons));
		
		tv_center = (TextView) findViewById(R.id.tv_center);
		
		
	}

	private Handler mHandler = new Handler();
	
	/**
	 * 显示字母
	 * @param letter
	 */
	protected void showLetter(String letter) {
		tv_center.setVisibility(View.VISIBLE);
		tv_center.setText(letter);
		
		mHandler.removeCallbacksAndMessages(null);
		mHandler.postDelayed(new Runnable() {
			@Override
			public void run() {
				tv_center.setVisibility(View.GONE);				
			}
		}, 2000);
		
	}

	private void fillAndSortData(ArrayList<Person> persons) {
		// 填充数据
		for (int i = 0; i < Cheeses.NAMES.length; i++) {
			String name = Cheeses.NAMES[i];
			persons.add(new Person(name));
		}
		
		// 进行排序
		Collections.sort(persons);
	}
}

来自为知笔记(Wiz)

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