android开发仿iphone开关按钮动态效果

package com.netease.nim.uikit.common.ui.widget;

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;

import com.netease.nim.uikit.R;

/**
* 仿iphone 开关按钮
*
* @author dafeige
*
*/
public class SwitchButton extends View implements OnTouchListener {

private boolean isChoose = false;// 记录当前按钮是否打开,true为打开,flase为关闭

private boolean isChecked;

private boolean onSlip = false;// 记录用户是否在滑动的变量

private float down_x, now_x;// 按下时的x,当前的x

private Rect btn_off, btn_on;// 打开和关闭状态下,游标的Rect .

private boolean isChangeOn = false;

private boolean isInterceptOn = false;

private OnChangedListener onChangedListener;

private Bitmap bg_on, bg_off, slip_btn;

public SwitchButton(Context context) {
super(context);
init();
}

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

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

private void init() {// 初始化
bg_on = BitmapFactory.decodeResource(getResources(), R.drawable.nim_slide_toggle_on);
bg_off = BitmapFactory.decodeResource(getResources(), R.drawable.nim_slide_toggle_off);
slip_btn = BitmapFactory.decodeResource(getResources(), R.drawable.nim_slide_toggle);
btn_off = new Rect(0, 0, slip_btn.getWidth(), slip_btn.getHeight());
btn_on = new Rect(bg_off.getWidth() - slip_btn.getWidth(), 0, bg_off.getWidth(), slip_btn.getHeight());
setOnTouchListener(this);// 设置监听器,也可以直接复写OnTouchEvent
}

@SuppressLint("DrawAllocation")
@Override
protected void onDraw(Canvas canvas) {// 绘图函数

super.onDraw(canvas);

Matrix matrix = new Matrix();
Paint paint = new Paint();
float x;
// 滑动到前半段与后半段的背景不同,在此做判断
if (now_x < (bg_on.getWidth() / 2)) {
x = now_x - slip_btn.getWidth() / 2;
canvas.drawBitmap(bg_off, matrix, paint);// 画出关闭时的背景
} else {
x = bg_on.getWidth() - slip_btn.getWidth() / 2;
canvas.drawBitmap(bg_on, matrix, paint);// 画出打开时的背景
}
// 是否是在滑动状态
if (onSlip) {
if (now_x >= bg_on.getWidth()) {// 是否划出指定范围,不能让游标跑到外头,必须做这个判断
x = bg_on.getWidth() - slip_btn.getWidth() / 2;// 减去游标1/2的长度...
} else if (now_x < 0) {
x = 0;
} else {
x = now_x - slip_btn.getWidth() / 2;
}
} else {// 非滑动状态
if (isChoose) {// 根据现在的开关状态设置画游标的位置
x = btn_on.left;
canvas.drawBitmap(bg_on, matrix, paint);// 初始状态为true时应该画出打开状态图片
} else {
x = btn_off.left;
}
}
if (isChecked) {
canvas.drawBitmap(bg_on, matrix, paint);
x = btn_on.left;
isChecked = !isChecked;
}

// 对游标位置进行异常判断...
if (x < 0) {
x = 0;
} else if (x > bg_on.getWidth() - slip_btn.getWidth()) {
x = bg_on.getWidth() - slip_btn.getWidth();
}
canvas.drawBitmap(slip_btn, x, 0, paint);// 画出游标.
}

public boolean onTouch(View v, MotionEvent event) {
boolean old = isChoose;
switch (event.getAction()) {
case MotionEvent.ACTION_MOVE:// 滑动
now_x = event.getX();
break;
case MotionEvent.ACTION_DOWN:// 按下
if (event.getX() > bg_on.getWidth() || event.getY() > bg_on.getHeight()) {
return false;
}
onSlip = true;
down_x = event.getX();
now_x = down_x;
break;
case MotionEvent.ACTION_CANCEL: // 移到控件外部
onSlip = false;
boolean choose = isChoose;
if (now_x >= (bg_on.getWidth() / 2)) {
now_x = bg_on.getWidth() - slip_btn.getWidth() / 2;
isChoose = true;
} else {
now_x = now_x - slip_btn.getWidth() / 2;
isChoose = false;
}
if (isChangeOn && (choose != isChoose)) { // 如果设置了监听器,就调用其方法..
onChangedListener.OnChanged(this, isChoose);
}
break;
case MotionEvent.ACTION_UP:// 松开
onSlip = false;
boolean lastChoose = isChoose;
if (event.getX() >= (bg_on.getWidth() / 2)) {
now_x = bg_on.getWidth() - slip_btn.getWidth() / 2;
isChoose = true;
} else {
now_x = now_x - slip_btn.getWidth() / 2;
isChoose = false;
}
if (lastChoose == isChoose) {// 相等表示点击状态未切换，之后切换状态
if (event.getX() >= (bg_on.getWidth() / 2)) {
now_x = 0;
isChoose = false;
} else {
now_x = bg_on.getWidth() - slip_btn.getWidth() / 2;
isChoose = true;
}
}
// 如果设置了监听器,就调用其方法..
if (isChangeOn) {
onChangedListener.OnChanged(this, isChoose);
}
break;
default:
}
if (!old && isInterceptOn) {
isChoose = false;
} else {
invalidate();// 重画控件
}
return true;
}

public void setOnChangedListener(OnChangedListener listener) {// 设置监听器,当状态修改的时候
isChangeOn = true;
onChangedListener = listener;
}

public interface OnChangedListener {

abstract void OnChanged(View v, boolean checkState);
}

public void setCheck(boolean isChecked) {
this.isChecked = isChecked;
isChoose = isChecked;
if (isChecked == false) {
now_x = 0;
}
invalidate();
}

public boolean isChoose(){
return this.isChoose;
}

public boolean getCheck(){
return this.isChecked;
}

public void setInterceptState(boolean isIntercept) {// 设置监听器,是否在重画钱拦截事件,状态由false变true时 拦截事件
isInterceptOn = isIntercept;
// onInterceptListener = listener;
}
}