实例讲解Android应用中自定义组合控件的方法

自定义view大概可以分成：

• 继承view
• 组合view
• 自己画的view（用paint和canvas）
• 自定义viewgroup（widget）

最近又跟同学聊起来了，于是就准备自己实现一个imagebutton来练练手。（最简单的了）以及后面一个把imageview与textview结合使用的案例。

imagebutton
要实现imagebutton最容易想到的不就是把button和imageview合在一起么。嗯，人容易就想到这是一个组合自定义view。可是如何把一个image放到button上呢，自然就是用一个framelayout把button和imageview包裹起来，然后将这个layout当作一个weidgt。把一个layout当成一个控件我开始不太理解。后来了解到一些东西。

补充知识点（安卓的顶层视图）
在android里面，你的app界面的活动的视图并非是最*的视图。大家应该都知道viewtree。在安卓里面，最*的视图是一个叫decorview的东西。它包括你的状态栏，标题栏，以及你的活动界面。而且这个活动界面，安卓会自动帮你提前弄进去一个framelayout。可以这么理解吧，在安卓这个上帝的面前，你的activity就是放在他的framelayout的一个个view。上一张图～

decorview->linearlayout(状态栏和activity)->framelayout(activity)->你自己的acitivty视图。

实例讲解
好啦，回归正题。我上代码了。
myimagebutton_layout.xml

<framelayout  
 xmlns:android="http://schemas.android.com/apk/res/android"    
 android:layout_width="match_parent"       
 android:layout_height="match_parent">  
 <button    
  android:layout_width="match_parent"    
  android:layout_height="match_parent"    
  android:id="@+id/button_imagebutton"    />  
 <imageview 
  android:layout_width="match_parent"    
  android:layout_height="match_parent"    
  android:id="@+id/imageview_button"    />
</framelayout>

用一个framelayout把两个控件装起来，然后组合。组合了之后我们就去自定义我们这个控件的属性。button不用变对吧，用原生的就好了，就是需要有一个图片的src这个属性就好了。
在values目录下的attrs.xml文件_

<?xml version="1.0" encoding="utf-8"?>
<resources>在
  <declare-styleable name="myimagebutton">
    <attr name="imagesrc" format="reference"/>
  </declare-styleable>
</resources>

一般来说，declare-styleable标签的名字都是你的自定义控件的名字。attr就是你的自定义控件属性。format是这个属性的值的数据类型。这里的reference表示引用。dimension表示的是dp或者sp的大小。还有一些可以自己去看看。定义好属性，我们就开始写控件了。
myimagebutton.java

public class myimagebutton2 extends framelayout{

  imageview mimageview;
  button mbutton;
  int resid;

  public myimagebutton2(context context) {
    super(context);
  }

  public myimagebutton2(context context, attributeset attrs) {
    super(context, attrs);
    //导入布局
    layoutinflater.from(context).inflate(r.layout.myimagebutton_layout, this);

   mimageview＝(imageview)findviewbyid(r.id.imageview_button);

   mbutton = (button) findviewbyid(r.id.button_imagebutton);
    //获得这个控件对应的属性。
   typedarray a = getcontext().obtainstyledattributes(attrs, r.styleable.myimagebutton);

    try{
     //获得属性值
      resid = a.getresourceid(r.styleable.myimagebutton_imagesrc, 0);
    }finally {
     //回收这个对象
      a.recycle();
    }

    if(resid != 0){
      mimageview.setimageresource(resid);
    }
  }

  public void setimage(int resid){
    mimageview.setimageresource(resid);
  }

}

一般来说，继承view（就这么说吧，反正都是都是继承view的），实现两三个构造函数就可以了。在第二个里面有一个attr，这就是传进来的属性。如果resid不为默认值，就表示用户在xml里面传入了这个属性值，你也必须要写一个set方法，让用户可以在java代码中去改变属性值。
test.myimagebutton.layout.xml_

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="match_parent"
  android:layout_height="match_parent">

  <com.example.think.testview.customview.myimagebutton2
    xmlns:pt = "http://schemas.android.com/apk/res/com.example.think.testview"
    android:layout_height="100dp"
    android:layout_width="match_parent"
    pt:imagesrc = "@drawable/ic_launcher"
    />

</linearlayout>

效果图

另一个实例

这里我们来看一个view组合控件的例子：

<string-array name="bao_type"> 
   <item>测试1</item> 
   <item>测试2</item> 
   <item>测试3</item> 
   <item>测试4</item> 
 </string-array> 

<?xml version="1.0" encoding="utf-8"?> 
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:background="@color/gray_common_background" 
  android:orientation="vertical"> 
 
 
 
  <linearlayout 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:orientation="horizontal"> 
 
    <textview 
      android:id="@+id/txt_viewpage_bar1" 
      style="@style/style_common_pagebar" 
      android:textcolor="@color/theme_red" /> 
 
    <textview 
      android:id="@+id/txt_viewpage_bar2" 
      style="@style/style_common_pagebar" /> 
 
    <textview 
      android:id="@+id/txt_viewpage_bar3" 
      style="@style/style_common_pagebar" /> 
 
    <textview 
      android:id="@+id/txt_viewpage_bar4" 
      style="@style/style_common_pagebar" /> 
  </linearlayout> 
 
  <linearlayout 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:orientation="horizontal"> 
 
    <view 
      android:id="@+id/view_viewpage_bar1" 
      style="@style/style_common_pagebar_view" /> 
 
    <view 
      android:id="@+id/view_viewpage_bar2" 
      style="@style/style_common_pagebar_view" /> 
 
    <view 
      android:id="@+id/view_viewpage_bar3" 
      style="@style/style_common_pagebar_view" /> 
 
    <view 
      android:id="@+id/view_viewpage_bar4" 
      style="@style/style_common_pagebar_view" /> 
  </linearlayout> 
 
 
 
  <android.support.v4.view.viewpager 
    android:id="@+id/common_viewpage_buttom" 
    android:layout_width="match_parent" 
    android:layout_height="0dp" 
    android:layout_weight="1" /> 
</linearlayout> 

public interface slbpageviewonpagechangelistener { 
   void onpageselected(int position); 
 
   void onpagescrollstatechanged(int state); 
 } 

public class slbpageviewbar extends linearlayout { 

  private textview[] mtotaltxtviews; 
  private view[] mtotalviews; 
  private list<textview> mtxtviews; 
  private list<view> mviews; 
 
  private viewpager mviewpager; 
  private slbpageviewonpagechangelistener mslbpageviewonpagechangelistener; 
 
 
  public slbpageviewbar(context context, attributeset attrs) { 
    super(context, attrs); 
    mtotaltxtviews = new textview[4]; 
    mtotalviews = new view[4]; 
    mtxtviews = new arraylist<>(); 
    mviews = new arraylist<>(); 
    initview(); 
  } 
 
  private void initview() { 
    view.inflate(getcontext(), r.layout.layout_common_top_pageview_bar, this); 
    mviewpager = (viewpager) findviewbyid(r.id.common_viewpage_buttom); 
    mtotaltxtviews[0] = (textview) findviewbyid(r.id.txt_viewpage_bar1); 
    mtotaltxtviews[1] = (textview) findviewbyid(r.id.txt_viewpage_bar2); 
    mtotaltxtviews[2] = (textview) findviewbyid(r.id.txt_viewpage_bar3); 
    mtotaltxtviews[3] = (textview) findviewbyid(r.id.txt_viewpage_bar4); 
    mtotalviews[0] = findviewbyid(r.id.view_viewpage_bar1); 
    mtotalviews[1] = findviewbyid(r.id.view_viewpage_bar2); 
    mtotalviews[2] = findviewbyid(r.id.view_viewpage_bar3); 
    mtotalviews[3] = findviewbyid(r.id.view_viewpage_bar4); 
 
  } 
 
  /** 
   * @param title 标题名称数组 
   */ 
 
  public void settitleview(string[] title) { 
    int legth = title.length > 4 ? 4 : title.length; 
    for (int i = 0; i < legth; i++) { 
      mtotaltxtviews[i].settext(title[i]); 
      mtotaltxtviews[i].setvisibility(view.visible); 
      mtotalviews[i].setvisibility(view.invisible); 
      mtotaltxtviews[i].setonclicklistener(new slbtextviewonlister(i)); 
      mtxtviews.add(mtotaltxtviews[i]); 
      mviews.add(mtotalviews[i]); 
    } 
    mtotalviews[0].setvisibility(view.visible); 
    mviewpager.setonpagechangelistener(monbuttompagechangelistener); 
  } 
 
  public viewpager getviewpager(){ 
    return mviewpager; 
  } 
 
  public void setslbpageviewonpagechangelistener(slbpageviewonpagechangelistener slbpageviewonpagechangelistener) { 
    this.mslbpageviewonpagechangelistener = slbpageviewonpagechangelistener; 
  } 
 
  private void changeviewbg(int textviewid, int viewid) { 
    for (view view : mviews) { 
      if (viewid == view.getid()) { 
        view.setvisibility(view.visible); 
      } else { 
        view.setvisibility(view.invisible); 
      } 
    } 
    for (textview view : mtxtviews) { 
      if (textviewid == view.getid()) { 
        view.settextcolor(getresources().getcolor(r.color.theme_red)); 
      } else { 
        view.settextcolor(getresources().getcolor(r.color.black_normal_text_33333)); 
      } 
    } 
  } 
 
 
  class slbtextviewonlister implements onclicklistener { 
 
    private int mitem; 
 
 
    public slbtextviewonlister(int item) { 
      this.mitem = item; 
 
    } 
 
    @override 
    public void onclick(view v) { 
      mviewpager.setcurrentitem(mitem); 
    } 
  } 
 
  private viewpager.onpagechangelistener monbuttompagechangelistener = new viewpager.onpagechangelistener() { 
    @override 
    public void onpagescrolled(int position, float positionoffset, int positionoffsetpixels) { 
 
    } 
 
    @override 
    public void onpageselected(int position) { 
      switch (position) { 
        case 0: 
          changeviewbg(r.id.txt_viewpage_bar1, r.id.view_viewpage_bar1); 
          break; 
        case 1: 
          changeviewbg(r.id.txt_viewpage_bar2, r.id.view_viewpage_bar2); 
 
          break; 
        case 2: 
          changeviewbg(r.id.txt_viewpage_bar3, r.id.view_viewpage_bar3); 
          break; 
        case 3: 
          changeviewbg(r.id.txt_viewpage_bar4, r.id.view_viewpage_bar4); 
          break; 
      } 
      if (mslbpageviewonpagechangelistener != null) 
        mslbpageviewonpagechangelistener.onpageselected(position); 
    } 
 
    @override 
    public void onpagescrollstatechanged(int state) { 
      if (mslbpageviewonpagechangelistener != null) 
        mslbpageviewonpagechangelistener.onpagescrollstatechanged(state); 
    } 
  }; 
 
 
} 

public class commonviewpageadapter extends fragmentpageradapter { 
  private list<fragment> mfragments; 
  private string [] mtitles; 
 
  public commonviewpageadapter(fragmentmanager fm, list<fragment> fragments, string [] titles) { 
    super(fm); 
    mfragments = fragments; 
    mtitles = titles; 
  } 
 
  @override 
  public fragment getitem(int position) { 
    return mfragments.get(position); 
  } 
 
  @override 
  public int getcount() { 
    return mfragments.size(); 
  } 
 
  @override 
  public charsequence getpagetitle(int position) { 
    return mtitles[position]; 
  } 
 
  @override 
  public void destroyitem(viewgroup container, int position, object object) { 
    super.destroyitem(container, position, object); 
  } 
} 

<com.slfinance.app.slb.common.ui.view.slbpageviewbar 
    android:id="@+id/slbpv_buy_huoqibao_slbpageviewbarshow" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:orientation="vertical"/> 

private void initbuttompagefragment(slbpageviewbar slbpageviewbar) { 
  list<fragment> fragmentlist = new arraylist<>(); 
  test1fragment test1fragment = new test1fragment(); 
  test2fragment test2fragment = new test2fragment(); 
  test3fragment test3fragment = new test3fragment(); 
  test4fragment test4fragment = new test4fragment(); 
  fragmentlist.add(test1fragment); 
  fragmentlist.add(test2fragment); 
  fragmentlist.add(test3fragment); 
  fragmentlist.add(test4fragment); 
  string[] titles = getresources().getstringarray(r.array.buy_huoqi_bao_zanquan_detail); 
  slbpageviewbar.settitleview(titles); 
  commonviewpageadapter viewpageradapter = new commonviewpageadapter( 
      getsupportfragmentmanager(), fragmentlist, titles); 
  mbuttompageview.setadapter(viewpageradapter); 
  mbuttompageview.setoffscreenpagelimit(3); 
  mbuttompageview.setcurrentitem(0); 
}