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顶级的视图。大家应该都知道viewtree。在安卓里面，最顶级的视图是一个叫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); }