28自定义View 模仿联系人字母侧栏

时间:2024-06-24 15:38:08

28自定义View 模仿联系人字母侧栏

28自定义View 模仿联系人字母侧栏

自定义View

LetterView.java

package com.qf.sxy.customview02;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.TextView; /**
* Created by sxy on 2016/9/29.
*/
public class LetterView extends View { // 索引的字母
public static final String[] LETTES ={"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 Paint mTextPaint;
//指定一个位置 不在索引范围内
private int pressedPosition = -1; //获取展示的View
private TextView mSelectView;
public void setSelectTextView(TextView tv){
this.mSelectView = tv;
} public LetterView(Context context, AttributeSet attrs) {
super(context, attrs);
//初始化画笔
initPaint();
} private void initPaint() {
mTextPaint = new Paint();
mTextPaint.setAntiAlias(true);
mTextPaint.setColor(Color.RED);
mTextPaint.setTextSize(30);
} public LetterView(Context context) {
this(context,null);
} /**
* 进行绘制
* @param canvas
*/
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas); //获取 宽和高
int height = getHeight();
int width = getWidth();
//字符串序列的长度
int lettersLength = LETTES.length;
//获取每个字符的高度
int singleHeight = height/lettersLength; //开始绘制
for(int i=0;i<lettersLength;i++){
//获取x的位置
int xPos = (int)(width/2-mTextPaint.measureText(LETTES[i])/2);
//获取Y的位置
int yPos = singleHeight+i*singleHeight;
//设置文字颜色
if(pressedPosition == i){
mTextPaint.setColor(Color.BLUE); }else{
mTextPaint.setColor(Color.BLACK);
}
//绘制文本
canvas.drawText(LETTES[i],xPos,yPos,mTextPaint);
}
} /**
* 触摸事件
*
* true 消费事件 false 不处理
* @param event
* @return
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()){
case MotionEvent.ACTION_DOWN://按下
case MotionEvent.ACTION_MOVE://移动
//获取手指的Y位置
float eventY = event.getY();
//每个字母单独的高度
int singleHeight = getMeasuredHeight()/LETTES.length;
//获取你当前索引位置
pressedPosition = (int)(eventY/singleHeight);
//显示提示的VIew 设置内容
if(mSelectView!=null){
if(pressedPosition>=0&&pressedPosition<LETTES.length){
mSelectView.setVisibility(View.VISIBLE);
mSelectView.setText(LETTES[pressedPosition]);
}
} invalidate();//刷新 break;
case MotionEvent.ACTION_UP://抬起
//还原当前位置
pressedPosition = -1;
//隐藏提示的View
if (mSelectView!=null){
mSelectView.setVisibility(View.GONE);
} invalidate();//刷新 break;
} return true;
}
}

MainActivity.java

package com.qf.sxy.customview02;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView; public class MainActivity extends AppCompatActivity { private TextView tv;
private LetterView letterView; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); tv = ((TextView) findViewById(R.id.select_tv));
letterView = ((LetterView) findViewById(R.id.letterView)); //传递展示的View
letterView.setSelectTextView(tv);
}
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<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"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.qf.sxy.customview02.MainActivity"> <com.qf.sxy.customview02.LetterView
android:id="@+id/letterView"
android:layout_width="40dp"
android:layout_height="match_parent"
android:layout_alignParentRight="true"
/> <TextView
android:id="@+id/select_tv"
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_centerInParent="true"
android:gravity="center"
android:background="#00ff00"
android:textSize="30sp"
android:visibility="gone"
android:text="A"
/>
</RelativeLayout>