Android自定义字母选择侧边栏 Android自定义字母选择侧边栏

本文实例为大家分享了Android自定义字母选择侧边栏的具体代码，供大家参考，具体内容如下
LetterSideBar.java

package com.zb.customview.widgets; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Rect; import android.text.TextUtils; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import androidx.annotation.Nullable; import com.zb.customview.R; public class LetterSideBar extends View { private Paint mPaint; private int color, selectedColor; private float textSize, spacing; private String mChoosing = "Z"; private OnLetterSelectedListener listener; private int width, height; private 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"}; public interface OnLetterSelectedListener {//空表示取消选中void onSelected(String letter); } public void setOnLetterSelectedListener(OnLetterSelectedListener listener) {this.listener = listener; } public LetterSideBar(Context context) {this(context, null); } public LetterSideBar(Context context, @Nullable AttributeSet attrs) {super(context, attrs); if(null != attrs) {TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.LetterSideBar); color = ta.getColor(R.styleable.LetterSideBar_LetterSideBar_textColor, Color.BLACK); selectedColor = ta.getColor(R.styleable.LetterSideBar_LetterSideBar_textSelectedColor, Color.RED); textSize = ta.getDimensionPixelSize(R.styleable.LetterSideBar_LetterSideBar_textSize, sp2px(12)); spacing = ta.getDimensionPixelSize(R.styleable.LetterSideBar_LetterSideBar_spacing, dp2px(5)); ta.recycle(); }init(); } private void init() {mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setColor(color); mPaint.setTextSize(textSize); } @Overrideprotected void onDraw(Canvas canvas) {drawText(canvas); drawSelectedText(canvas, mChoosing); } private void drawText(Canvas canvas) {mPaint.setColor(color); for (int i=0; i= LETTERS.length)return; drawLetterAt(canvas, position, selected); } @Overridepublic boolean onTouchEvent(MotionEvent event) {int action = event.getAction(); switch (action) {case MotionEvent.ACTION_DOWN:case MotionEvent.ACTION_MOVE:float x = event.getX(); float y = event.getY(); if(isTouchInsideView(x, y)) {//触摸在控件内int position = caculatePosition(y); if(position >= 0 && position < LETTERS.length) {//合规位置String letter = LETTERS[position]; if(!letter.equals(mChoosing)) { //与选中的不符去刷新控件mChoosing = letter; performListener(mChoosing); invalidate(); }} else {//不合规位置if(null != mChoosing) {mChoosing = null; performListener(mChoosing); invalidate(); }}} else if(null != mChoosing) { //点击事件不在view内部mChoosing = null; performListener(mChoosing); invalidate(); //触摸在view之外取消选中}return true; default:if(mChoosing != null) {mChoosing = null; performListener(mChoosing); invalidate(); }break; }return super.onTouchEvent(event); } private void performListener(String letter) {if(null != listener)listener.onSelected(letter); } private boolean isTouchInsideView(float x, float y) {//左右可以适当判断在控件内if(x >= 0 && x <= width && y >= getPaddingTop() && y < height)return true; return false; } /*** 计算触摸的位置* @param y* @return*/private int caculatePosition(float y) {float heightWithOutPadding = height - getPaddingTop() - getPaddingBottom(); float eachElementHeight = heightWithOutPadding / LETTERS.length; y -= getPaddingTop(); int position = (int) (y / eachElementHeight); return position; } private void drawLetterAt(Canvas canvas, int position, String letter) { float heightForEach = ((height * 1f - getPaddingTop() - getPaddingBottom())- (LETTERS.length - 1) * spacing) / LETTERS.length; float spacingInUp = spacing * (position - 1); if(spacingInUp < 0)spacingInUp = 0; float currentTop = getPaddingTop() + (heightForEach * position) + spacingInUp; float currentBottom = currentTop + heightForEach; Paint.FontMetrics fmi = mPaint.getFontMetrics(); float x = (width - getPaddingLeft() - getPaddingRight() - mPaint.measureText(letter)) / 2f + getPaddingLeft(); float baseLine = (fmi.descent + Math.abs(fmi.ascent)) / 2f - fmi.descent; float y = (currentBottom + currentTop) / 2f + baseLine; canvas.drawText(letter, 0, 1, x, y, mPaint); } @Overrideprotected void onLayout(boolean changed, int left, int top, int right, int bottom) {super.onLayout(changed, left, top, right, bottom); if(changed) {width = getWidth(); height = getHeight(); }} @Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec); int textWidth = (int) (getPaddingLeft() + getPaddingRight() + mPaint.measureText("A")); Rect textBounds = new Rect(); mPaint.getTextBounds("A", 0, 1, textBounds); int singleTextHeight = textBounds.height(); int totalHeight = (int) (27f * singleTextHeight + 26f * spacing) + getPaddingBottom() + getPaddingTop(); //26个字母+1个# int widthMode = MeasureSpec.getMode(widthMeasureSpec); int heightMode = MeasureSpec.getMode(widthMeasureSpec); int specWidth = MeasureSpec.getSize(widthMeasureSpec); int specHeight = MeasureSpec.getSize(widthMeasureSpec); int realWidth, realHeight; if(widthMode == MeasureSpec.EXACTLY) {realWidth = specWidth; } else {realWidth = textWidth; }if(heightMode == MeasureSpec.EXACTLY) {realHeight = specHeight; } else {realHeight = totalHeight; }setMeasuredDimension(realWidth, realHeight); } protected int dp2px(int dp) {return (int) (getContext().getResources().getDisplayMetrics().density * dp + 0.5); }protected int sp2px(int sp) {return (int) (getContext().getResources().getDisplayMetrics().scaledDensity * sp + 0.5); }}

attrs.xml

layout.xml

代码中使用

sideBar.setOnLetterSelectedListener(new LetterSideBar.OnLetterSelectedListener() {@Overridepublic void onSelected(String letter) {if(TextUtils.isEmpty(letter)) {P.p("取消选中"); letterTxt.setVisibility(View.GONE); } else {P.p("选中" + letter); letterTxt.setText(letter); letterTxt.setVisibility(View.VISIBLE); }}});

【Android自定义字母选择侧边栏】以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。