笔记20 | 学习整理开源APP(BaseAnimation)程序源码“中的通讯录效果(一)

<TextView
            android:id="@+id/dialog"
            android:layout_width="80.0dip"
            android:layout_height="80.0dip"
            android:layout_gravity="center"
            android:background="@drawable/sorlistview_show_head_toast_bg"
            android:gravity="center"
            android:textColor="#ffffffff"
            android:textSize="30.0dip"
            android:visibility="invisible" />

        <com.example.book_mediarecorder.SideBar
            android:id="@+id/sidrbar"
            android:layout_width="30.0dip"
            android:layout_height="fill_parent"
            android:layout_gravity="right|center" />

public class SideBar extends View {

    // 触摸事件
    private OnTouchingLetterChangedListener onTouchingLetterChangedListener;
    // 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 int choose = -1;// 选中
    private Paint paint = new Paint();

    private TextView mTextDialog;

    public void setTextView(TextView mTextDialog) {
        this.mTextDialog = mTextDialog;
    }


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

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

    public SideBar(Context context) {
        super(context);
    }

    /**
     * 重写这个方法
     */
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // 获取焦点改变背景颜色.
        int height = getHeight();// 获取对应高度
        int width = getWidth(); // 获取对应宽度
        int singleHeight = height / b.length;// 获取每一个字母的高度

        for (int i = 0; i < b.length; i++) {
            paint.setColor(Color.rgb(33, 65, 98));
            // paint.setColor(Color.WHITE);
            paint.setTypeface(Typeface.DEFAULT_BOLD);
            paint.setAntiAlias(true);
            paint.setTextSize(20);
            // 选中的状态
            if (i == choose) {
                paint.setColor(Color.parseColor("#3399ff"));
                paint.setFakeBoldText(true);
//                paint.setTextSize(30);
            }
            // x坐标等于中间-字符串宽度的一半.
            float xPos = width / 2 - paint.measureText(b[i]) / 2;
            float yPos = singleHeight * i + singleHeight;
            canvas.drawText(b[i], xPos, yPos, paint);
            paint.reset();// 重置画笔
        }
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        final int action = event.getAction();
        final float y = event.getY();// 点击y坐标
        final int oldChoose = choose;
        final OnTouchingLetterChangedListener listener = onTouchingLetterChangedListener;
        final int c = (int) (y / getHeight() * b.length);// 点击y坐标所占总高度的比例*b数组的长度就等于点击b中的个数.

        switch (action) {
        case MotionEvent.ACTION_UP: 
            setBackgroundDrawable(new ColorDrawable(0x00000000));
            choose = -1;//
            invalidate();
            if (mTextDialog != null) {
                mTextDialog.setVisibility(View.INVISIBLE);
            }
            break;

        default:
            //设置右侧字母列表[A,B,C,D,E....]的背景颜色
            setBackgroundResource(R.drawable.sortlistview_sidebar_background);
            if (oldChoose != c) {
                if (c >= 0 && c < b.length) {
                    if (listener != null) {
                        listener.onTouchingLetterChanged(b[c]);
                    }
                    if (mTextDialog != null) {
                        mTextDialog.setText(b[c]);
                        mTextDialog.setVisibility(View.VISIBLE);
                    }
                    choose = c;
                    invalidate();
                }
            }
            break;
        }
        return true;
    }

    /**
     * 向外公开的方法
     * 
     * @param onTouchingLetterChangedListener
     */
    public void setOnTouchingLetterChangedListener(
            OnTouchingLetterChangedListener onTouchingLetterChangedListener) {
        this.onTouchingLetterChangedListener = onTouchingLetterChangedListener;
    }

    /**
     * 接口
     * 
     * @author coder
     * 
     */
    public interface OnTouchingLetterChangedListener {
        public void onTouchingLetterChanged(String s);
    }

}

dialog = (TextView) findViewById(R.id.dialog); //中间显示的大字母
sideBar.setTextView(dialog);
      //设置右侧触摸监听
                sideBar = (SideBar) findViewById(R.id.sidrbar);

        sideBar.setOnTouchingLetterChangedListener(new OnTouchingLetterChangedListener() {

            @Override
            public void onTouchingLetterChanged(String s) {
                //该字母首次出现的位置
                int position = adapter.getPositionForSection(s.charAt(0));
                Log.i("md", "position: "+position);
                if(position != -1){
                    //根据索引更新联系人列表位置
                    sortListView.setSelection(position);
                }
            }
        });

/**
     * 根据分类的首字母的Char ascii值获取其第一次出现该首字母的位置
     */
    public int getPositionForSection(int section) {
        for (int i = 0; i < getCount(); i++) {
            String sortStr = list.get(i).getSortLetters();
            char firstChar = sortStr.toUpperCase().charAt(0);
            if (firstChar == section) {
                return i;
            }
        }
        return -1;
    }