android攻城狮之自定义控件(二) 滑动开关
android自定义控件是作为一名优秀的android攻城狮必不可少的技能，为了进一步认识自定义控件，层次递进的学习，今天给大家以案例（滑动开关案例）的形式说明自定义控件的使用（案例UI图片取自网上图库，在此致谢图片分享者）。
首先晒上案例效果图
1.回顾一下自定义控件是什么？
1.自定义控件实现很简单，我们可以将他分为两大类：
（1）通过组合原生的控件，加上一些特殊动画的组合来达到自定义的需求
（2）定义一个类继承View，或者还可以继承ViewGroup
2.View和ViewGroup的区别：
ViewGroup里面可以添加自己的孩子（LinearLayout、FrameLayout、TableLayout、RelativeLayout、AbsoluteLayout这几大布局都继承ViewGroup）
2.滑动开关案例下面将以代码+注释的形式详解，直接看代码感觉更爽一些
1.定义一个类ToggleView，继承View
package com.example.toggleview;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
public class ToggleView extends View {
private Bitmap switch_background;
private Bitmap slide_button_background;
private boolean toggleCurrentState = false; //当前开关的状态
private boolean isSliding = false; //默认不滑动
private int downX;
private OnToggleStateChangeListener mToggleStateChangeListener;
//直接new 初始化的时候调用
public ToggleView(Context context) {
super(context);
}
public ToggleView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
//在布局里面使用的时候调用
public ToggleView(Context context, AttributeSet attrs) {
super(context, attrs);
String namespace = "http://schemas.android.com/apk/res/com.example.toggleview";
int switchBackground = attrs.getAttributeResourceValue(namespace, "switchBackground", -1);
int slidingBackground = attrs.getAttributeResourceValue(namespace, "slidingBackground", -1);
//设置开关的状态
toggleCurrentState = attrs.getAttributeBooleanValue(namespace, "toggleState", false);
//设置 开关的背景
setToggleBackground(switchBackground);
//设置滑动块的背景
setToggleSlidBackGround(slidingBackground);
}
//设置开关背景
public void setToggleBackground(int switchBackground) {
switch_background = BitmapFactory.decodeResource(getResources(), switchBackground);
}
//设置开关的滑动块
public void setToggleSlidBackGround(int slideButtonBackground) {
slide_button_background = BitmapFactory.decodeResource(getResources(),slideButtonBackground);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
//测量当前viwe的宽和高
setMeasuredDimension(switch_background.getWidth(), switch_background.getHeight());
}
//绘制内容 被绘制到了当前控件上
@Override
protected void onDraw(Canvas canvas) {
//[1]画开关的背景
canvas.drawBitmap(switch_background, 0, 0, null);
if (isSliding) {
//[2]根据当前dwonX 画滑动块
int left = downX - slide_button_background.getWidth()/2;
//[2.1]对边界进行处理
int rightAlgin = switch_background.getWidth() - slide_button_background.getWidth();
if (left<0) {
left = 0;
}else if (left > rightAlgin) {
left = rightAlgin;
}
canvas.drawBitmap(slide_button_background, left, 0, null);
}else {
//不是滑动状态 根据 当前开关的状态 画
//[2]画滑动块背景
if (toggleCurrentState) {
//开关打开状态
int left = switch_background.getWidth() - slide_button_background.getWidth();
canvas.drawBitmap(slide_button_background, left, 0,null);
}else {
//开关关闭
canvas.drawBitmap(slide_button_background, 0, 0,null);
}
}
super.onDraw(canvas);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN: //按下
//[1]获取手指触摸的位置
isSliding = true;
downX = (int) event.getX();
break;
case MotionEvent.ACTION_MOVE: //移动
downX = (int) event.getX();
break;
case MotionEvent.ACTION_UP: //抬起
downX = (int) event.getX();
//[0]手指抬起 处于不是滑动状态
isSliding = false;
//[1]获取开关背景一半
int center = switch_background.getWidth()/2;
boolean state = downX > center;
//[1.1]开关的状态没有发生改变的时候 不触发我们写回调事件
if (toggleCurrentState!=state) {
toggleCurrentState = state;
//[2]触发我们定义的回调方法
if (mToggleStateChangeListener!=null) {
mToggleStateChangeListener.onToggleState(toggleCurrentState);
}
}
break;
}
//当前view 会进行重绘 会调用onDraw
invalidate();
//让当前控件处理事件
return true;
}
//设置开关的状态
public void setToggleState(boolean b) {
toggleCurrentState = b;
}
//设置开关改变的监听
public void setOnToggleStateLinstener(OnToggleStateChangeListener listen){
mToggleStateChangeListener = listen;
}
//开关滑动接口
public interface OnToggleStateChangeListener{
public void onToggleState(boolean state);
}
}
2.在布局文件中将其定义出来
res/layout/activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:example="http://schemas.android.com/apk/res/com.example.toggleview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center" >
<com.example.toggleview.ToggleView
android:id="@+id/toggleView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
example:slidingBackground="@drawable/slide_button_background"
example:switchBackground="@drawable/switch_background"
example:toggleState="true" />
</RelativeLayout>
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="toggleview">
<attr name="switchBackground" format="reference" />
<attr name="slidingBackground" format="reference" />
<attr name="toggleState" format="boolean" />
</declare-styleable>
</resources>
3.在MainActivity中找到我们自己定义的开关控件设置相关属性和监听事件
package com.example.toggleview;
import com.example.toggleview.ToggleView.OnToggleStateChangeListener;
import android.os.Bundle;
import android.app.Activity;
import android.widget.Toast;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//[1]找到我们自己定义的开关控件
ToggleView toggleView = (ToggleView) findViewById(R.id.toggleView1);
//[2]设置开关的背景
// toggleView.setToggleBackground(R.drawable.switch_background);
//[3]设置开关的滑动块
// toggleView.setToggleSlidBackGround(R.drawable.slide_button_background);
//[4]设置开关的状态
// toggleView.setToggleState(false);
//[5]设置一个开关状态的监听
toggleView.setOnToggleStateLinstener(new OnToggleStateChangeListener() {
@Override
public void onToggleState(boolean state) {
if (state) {
Toast.makeText(getApplicationContext(), "开", 0).show();
//TODO
}else{
Toast.makeText(getApplicationContext(), "关", 0).show();
}
}
});
}
}
案例到这里就基本上大功告成了
3.代码托管
托管地址：http://download.csdn.net/detail/smartbetter/9453078 点击下载