【Android开发】ArrayAdapter

适配器是AdapterView视图与数据之间的桥梁，用来处理数据并将数据绑定到AdapterView上

步骤

1. 准备布局（每一项的显示效果）
2. 准备数据源
3. 实例化适配器
4. 为ListView设置适配器

ArrayAdapter 主题容器

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ArrayActivity">

    <ListView
        android:id="@+id/list_view1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"></ListView>

</androidx.constraintlayout.widget.ConstraintLayout>

每个item的布局设置

<?xml version="1.0" encoding="utf-8"?>
<!--注意是TextView-->
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textSize="28sp"
    android:textColor="#fbb8ac">

</TextView>

准备数据源和适配器

class ArrayActivity : AppCompatActivity() {
    
    
    override fun onCreate(savedInstanceState: Bundle?) {
    
    
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_array)

        val listView1 = findViewById<ListView>(R.id.list_view1)

        //参数1：环境上下文(this)
        //参数2：代表数据项所应用的布局
        //参数3：数据源(数组)
        val data = arrayOf<String?>("AA", "BB", "CC", "DD", "FF", "AA", "BB", "CC", "DD", "FF", "AA", "BB", "CC", "DD", "FF", "AA", "BB", "CC", "DD", "FF", "AA", "BB", "CC", "DD", "FF")
        val adapter: ArrayAdapter<*> = ArrayAdapter<Any?>(this, R.layout.item, data)
        listView1.adapter = adapter
    }
}

//使用android自带的资源
val adapter: ArrayAdapter<*> = ArrayAdapter<Any?>(this, android.R.layout.simple_list_item_1, data)

在每一行的文字旁加上图片

<?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:orientation="horizontal">

    <ImageView
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:background="@mipmap/ic_launcher" />

    <TextView
        android:id="@+id/txt1"
        android:layout_width="match_parent"
        android:layout_height="50dp" />

</LinearLayout>

//这里有4个参数，第三个参数是选定作为数据源的TextView
val adapter: ArrayAdapter<*> = ArrayAdapter<Any?>(this, R.layout.item2, R.id.txt1, data)