ImageView、Adapter

ImageView

ImageView是用于在界面上展示图片的一个控件。

它里面主要用到src 、 background 、 scaleType其中src的图片不会拉伸，background的图片会拉伸，scaleType表示一些图片放置的位置。

相关程序

XML
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    >
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">
   <ImageView
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:src="@mipmap/uqiwei"
       android:background="@mipmap/uqiwei"/>
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/uqiwei"
        android:tint="#5f0f01"
        android:scaleType="center"/>
    <ImageView
        android:id="@+id/image"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/uqiwei"
        android:scaleType="centerCrop"/>
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/uqiwei"
        android:scaleType="centerInside"/>
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/uqiwei"
        android:scaleType="fitCenter"/>
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/uqiwei"
        android:scaleType="fitEnd"/>
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/uqiwei"
        android:scaleType="fitStart"/>
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/uqiwei"
        android:scaleType="fitXY"/>
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/uqiwei"
        android:scaleType="fitCenter"/>
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/uqiwei"
        android:scaleType="fitCenter"/>
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/uqiwei"
        android:scaleType="fitCenter"/>
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/uqiwei"
        android:scaleType="fitCenter"/>
</LinearLayout>
</ScrollView>
******************manifest代码**********************
public class MyImageViewActivity extends AppCompatActivity {
private ImageView mImageView;
private Button mBtnAdd;
   private Button mBtnSub;
    private  int mAlphaCount;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.imageview_layout);
        mImageView= (ImageView) findViewById(R.id.image);
        mImageView.setImageResource(R.mipmap.yangmi);
        mBtnAdd= (Button) findViewById(R.id.alpha_add);
        mBtnSub= (Button) findViewById(R.id.alpha_sub);
         mBtnSub.setOnClickListener(this);
        mBtnAdd.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
  switch (v.getId()){
      case R.id.alpha_add:
          mAlphaCount+=5;
int Code=android.os.Build.VERSION.SDK_INT;
          Log.d("versoncode","当前手机版本号："+Code);
          if(Code<16){
              mImageView.setAlpha(mAlphaCount);
          }
          else {
              mImageView.setImageAlpha(mAlphaCount);
          }
          break;
      case R.id.alpha_sub:
          mAlphaCount-=5;
          mImageView.setAlpha(mAlphaCount);
          break;
      default:
          break;

  }
    }

结果图

AdapterView

1、AdapterView即Adapter(适配器)控件,其内容通常是一个包含多项相同的格式资源的列表，每次只显示其中的一项。
2、需要先把多项内容放入一个列表，然后将这个列表加载到Adapter控件中。
3、这个存放Adapter控件内容的列表，在Android中被称为Adapter(适配器)。

Adapter分为四种

1、ArrayAdapter：最简单的Adapter，表项中只含有文本信息的情况。
2、SimpleAdapter：比ArrayAdapter复杂，每一个列表项中含有不同的子控件。
3、SimpleCursorAdapter：把从数据库查出的数据适配给AdapterView。
4、自定义Adapter：完全自行定义数据的适配方式，灵活性最强，也最常用。

ArrayAdapter程序

ListView程序

public class MyListViewActivity extends AppCompatActivity {
private ListView mListView;
    private List<Student> mData;
     @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_my_list_view);
 mListView= (ListView) findViewById(R.id.listview);
       initData();
        LayoutInflater inflater=getLayoutInflater();
        Studentadapter adapter=new Studentadapter(inflater,mData);
mListView.setAdapter(adapter);
}

    private void initData() {
        mData=new ArrayList<>();
        Student zhangsan=new Student("张三","20","男","吃",R.mipmap.uqiwei);
        Student lisi=new Student("李四","22","女","睡觉",R.mipmap.yangmi);
        Student wangwu=new Student("王五","25","男","打游戏",R.mipmap.ic_launcher);
        Student zhaoliu=new Student("赵六","23","女","逛街",R.mipmap.uqiwei);
        mData.add(zhangsan);
        mData.add(lisi);
        mData.add(wangwu);
        mData.add(zhaoliu);
    }
   " ***************** Studentadapter************"
    public class Studentadapter extends BaseAdapter{
private List<Student> mData;
    private LayoutInflater mInflater;
   public Studentadapter(LayoutInflater inflater,List<Student> data ){
       mInflater=inflater;
       mData=data;
   }
    @Override
    public int getCount() {
        //得到ListView要显示数据的条数
        return mData.size();
    }

    @Override
    public Object getItem(int position) {
        //返回索引
        return position;
    }

    @Override
    public long getItemId(int position) {
        //返回索引
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
       //LayoutInflater
        View view=mInflater.inflate(R.layout.simple_adapter, null);
        Student student=mData.get(position);
        ImageView imageView= (ImageView) view.findViewById(R.id.imageview_photo);
        TextView textView_name= (TextView) view.findViewById(R.id.textview_name);
        TextView textView_age= (TextView) view.findViewById(R.id.textview_age);
        TextView textView_sex= (TextView) view.findViewById(R.id.textview_sex);
        TextView textView_hobby= (TextView) view.findViewById(R.id.textview_hobby);
        textView_name.setText(student.getName());
        textView_age.setText(student.getAge());
        textView_sex.setText(student.getHobby());
        imageView.setImageResource(student.getImg());
        return view;
    }
}
"***************Student********************"
public class Student {
    private String name;
    private String hobby;
    private String  age;
    private String  sex;
    private int img;
    public Student(String name,String age,String sex,String hobby,int img){
        this.name=name;
        this.age=age;
        this.sex=sex;
        this.hobby=hobby;
        this.img=img;
    }

    public int getImg() {
      return img;
    }

    public void setImg(int img) {
        this.img = img;
    }



    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setHobby(String hobby) {
        this.hobby = hobby;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }


    public String getSex() {
        return sex;
    }

    public String getHobby() {
        return hobby;
    }

    public String getAge() {
        return age;
    }
}

SimpleAdapter程序

"*************XML文件*******"
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="match_parent">

    <ImageView
        android:id="@+id/imageview_photo"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:src="@mipmap/yangmi"
        />
<LinearLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="horizontal"

    android:layout_margin="20dp">
    <TextView
        android:id="@+id/textview_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="姓名"/>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
       >
        <TextView
            android:id="@+id/textview_age"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="年龄"/>
        <TextView
            android:id="@+id/textview_sex"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="性别"/>
    </LinearLayout>
    <TextView
        android:id="@+id/textview_hobby"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="爱好"/>

</LinearLayout>
</LinearLayout>
"****************************************************"
   private ListView mListView;
   private String []array={"张三","李四","赵六","mary","Dave"};
    private List<HashMap<String,String>> mData;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_my_list_view);
        mListView= (ListView) findViewById(R.id.listview);
        initData();
        SimpleAdapter adapter=new SimpleAdapter(this,mData,R.layout.simple_adapter,
                new String[] {"name","age","sex","hobby"},new int[]{R.id.textview_name,R.id.textview_age,R.id.textview_sex,R.id.textview_hobby});
   mListView.setAdapter(adapter);
   private void initData() {
        mData=new ArrayList<>();
        Student zhangsan=new Student("张三","20","男","吃",R.mipmap.uqiwei);
        Student lisi=new Student("李四","22","女","睡觉",R.mipmap.yangmi);
        Student wangwu=new Student("王五","25","男","打游戏",R.mipmap.ic_launcher);
        Student zhaoliu=new Student("赵六","23","女","逛街",R.mipmap.uqiwei);
        mData.add(zhangsan);
        mData.add(lisi);
        mData.add(wangwu);
        mData.add(zhaoliu);
    }


    private void initData(){
    mData=new ArrayList<>();
    HashMap<String,String> zhangsan=createHashMap("张三","20","男","吃");
    mData.add(zhangsan);
    HashMap<String,String> lisi=createHashMap("李四","21","男","睡");
    mData.add(lisi);
    HashMap<String,String> zhaoliu=createHashMap("赵六","18","女","减肥");
    mData.add(zhaoliu);
    HashMap<String,String> mary=createHashMap("mary","15","女","漂亮的衣服");
    mData.add(mary);
    HashMap<String,String> Dave=createHashMap("Dave","25","男","爬山");
    mData.add(Dave);

}
    private HashMap<String,String>createHashMap(String name,String age,String sex,String hobby){
        HashMap<String,String> zhangsan=new HashMap<>();
        zhangsan.put("name",name);
        zhangsan.put("age",age);
        zhangsan.put("sex",sex);
        zhangsan.put("hobby",hobby);
        return zhangsan;
    }

CheckBox结果图