聯繫人 豎嚮導航欄

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.graphics.drawable.ColorDrawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.TextView;


/**
 * @author Lee
 * @date 2018/11/16 11:11
 * @Description
 */
public class SideBar extends View {

    // 觸摸事件
    private OnTouchingLetterChangedListener onTouchingLetterChangedListener;
    // 26個字母
    public static String[] A_Z = {"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;// 選中
    //選中時的字體顏色
    private final String selectedColor = "#ffffff";
    //選擇過程 bar 的背景
    private final int touchBack = R.drawable.sidebar_background;//(改成自己的樣式)
    private Paint paint = new Paint();

    private TextView mTextDialog;

    /**
     * 爲SideBar設置顯示字母的TextView
     *
     * @param 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);
    }

    /**
     * 重寫這個方法
     */
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // 獲取焦點改變背景顏色.
        int height = getHeight();// 獲取對應高度
        int width = getWidth(); // 獲取對應寬度
        int singleHeight = height / A_Z.length - 2;// 獲取每一個字母的高度  (這裏-2僅僅是爲了好看而已)

        for (int i = 0; i < A_Z.length; i++) {
            paint.setColor(Color.rgb(33, 65, 98));  //設置字體顏色
            paint.setTypeface(Typeface.DEFAULT_BOLD);  //設置字體
            paint.setAntiAlias(true);  //設置抗鋸齒
            paint.setTextSize(30);  //設置字母字體大小
            // 選中的狀態
            if (i == choose) {
                paint.setColor(Color.parseColor(selectedColor));  //選中的字母改變顏色
                paint.setFakeBoldText(true);  //設置字體爲粗體
            }
            // x座標等於中間-字符串寬度的一半.
            float xPos = width / 2 - paint.measureText(A_Z[i]) / 2;
            float yPos = singleHeight * i + singleHeight;
            canvas.drawText(A_Z[i], xPos, yPos, paint);  //繪製所有的字母
            paint.reset();// 重置畫筆
        }
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        final int action = event.getAction();
        final float y = event.getY();// 點擊y座標
        final int oldChoose = choose;
        final OnTouchingLetterChangedListener listener = onTouchingLetterChangedListener;
        final int c = (int) (y / getHeight() * A_Z.length);// 點擊y座標所佔總高度的比例*b數組的長度就等於點擊b中的個數.

        switch (action) {
            case MotionEvent.ACTION_UP:
                setBackgroundDrawable(new ColorDrawable(0x00000000));
                choose = -1;//
                invalidate();
                if (mTextDialog != null) {
                    mTextDialog.setVisibility(View.INVISIBLE);
                }
                break;
            default:
                setBackgroundResource(touchBack);
                if (oldChoose != c) {  //判斷選中字母是否發生改變
                    if (c >= 0 && c < A_Z.length) {
                        if (listener != null) {
                            listener.onTouchingLetterChanged(A_Z[c]);
                        }
                        if (mTextDialog != null) {
                            mTextDialog.setText(A_Z[c]);
                            mTextDialog.setVisibility(View.VISIBLE);
                        }
                        choose = c;
                        invalidate();
                    }
                }
                break;
        }
        return true;
    }

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

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

sidebar_background.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="#55307BF4" />
    <corners android:radius="10dp" />
</shape>

轉載自 https://www.cnblogs.com/scetopcsa/p/4724308.html