Android右侧字母排序

最新推荐文章于 2021-05-26 06:58:30 发布

原创最新推荐文章于 2021-05-26 06:58:30 发布 · 478 阅读

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CC 4.0 BY-SA版权

介绍了一个自定义Android视图，用于展示并响应触摸操作的字母集合。

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.Typeface;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

public class RightLetterView extends View {

String[] letters = { "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" };

Paint paint = new Paint();

OnTouchingLetterChangedListener onTouchingLetterChangedListener;

boolean showBkg = false;

int choose = -1;

int lettersLength;

public RightLetterView(Context context) {

super(context);

}

public RightLetterView(Context arg0, AttributeSet arg1, int arg2) {

super(arg0, arg1, arg2);

}

public RightLetterView(Context context, AttributeSet attrs) {

super(context, attrs);

}

@Override

protected void onAttachedToWindow() {

// TODO Auto-generated method stub

super.onAttachedToWindow();

lettersLength = letters.length;

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

if (showBkg) {

canvas.drawColor(Color.parseColor("#10000000")); // 画透明黑色背景

}

int height = getHeight();

int width = getWidth();

int singleHeight = height / lettersLength;

for (int i = 0; i < lettersLength; i++) {

paint.setColor(Color.BLACK);

paint.setTypeface(Typeface.DEFAULT_BOLD);

paint.setAntiAlias(true); // 平滑

paint.setTextSize(50.0f);

if (i == choose) {

paint.setColor(Color.parseColor("#3399ff"));

paint.setFakeBoldText(true);

}

float xPos = width / 2 - paint.measureText(letters[i]) / 2;

float yPos = singleHeight * (i + 1);

canvas.drawText(letters[i], xPos, yPos, paint);

paint.reset();

}

@Override

public boolean dispatchTouchEvent(MotionEvent event) {

final int action = event.getAction();

final float y = event.getY();

final int oldChoose = choose;

final OnTouchingLetterChangedListener listener = onTouchingLetterChangedListener;

final int c = (int) (y / getHeight() * lettersLength);

switch (action) {

case MotionEvent.ACTION_DOWN:

showBkg = true;

if (oldChoose != c && listener != null) {

if (c > 0 && c <= lettersLength) {

listener.onTouchingLetterChanged(letters[c]);

choose = c;

invalidate();

}

break;

case MotionEvent.ACTION_MOVE:

if (oldChoose != c && listener != null) {

if (c > 0 && c <= lettersLength) {

listener.onTouchingLetterChanged(letters[c]);

choose = c;

invalidate();

}

break;

case MotionEvent.ACTION_UP:

showBkg = false;

choose = -1;

invalidate();

break;

default:

break;

}

return true;

}

@Override

public boolean onTouchEvent(MotionEvent arg0) {

return super.onTouchEvent(arg0);

}

public void setOnTouchingLetterChangedListener(

OnTouchingLetterChangedListener onTouchingLetterChangedListener) {

this.onTouchingLetterChangedListener = onTouchingLetterChangedListener;

}

public interface OnTouchingLetterChangedListener {

public void onTouchingLetterChanged(String s);

}

public void setLetters(String[] letters) {

this.letters = letters;

}