Android學習記錄之ListView和ScrollView區別

ScrollView中不管有多少個數據項都會全部加載

MainActivity.java

package com.example.android.listviewandscrollview;


public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.scrolllist);
        LayoutInflater mflater = LayoutInflater.from(this);
        LinearLayout scroll = (LinearLayout)findViewById(R.id.scrollLayout);
        for(int i =0 ;i<120;i++){
            View infoView  = mflater.inflate(R.layout.listitem, null);
            scroll.addView(infoView);
        }
    }
}

scrolllist.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ScrollView
        android:id="@+id/scrollList"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:orientation="vertical"
            android:id="@+id/scrollLayout"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        </LinearLayout>

    </ScrollView>

</LinearLayout>

listitem.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@mipmap/ic_launcher"/>

    <TextView
        android:id="@+id/textView"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:text="Tom"/>

</LinearLayout>

1.用Android Studio中的Memory監視器可以看出不管怎麼滑動都不會變化

ListView

MainActivity.java

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.listview);
        ListView listView = (ListView)findViewById(R.id.listView);
        ListAdapter listAdapter = new SimpleAdapter(this, getData(), R.layout.listitem
        , new String[]{"image", "text"}, new int[]{R.id.imageView, R.id.textView});
        listView.setAdapter(listAdapter);
    }

    private List<Map<String, Object>> getData(){
        List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
        for(int i=0; i<120; i++) {
            Map<String, Object> map = new HashMap<String, Object>();
            map.put("image", R.mipmap.ic_launcher);
            map.put("text", "Tom");
            list.add(map);
        }

        return list;
    }

}

listview.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

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

</LinearLayout>

listitem.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

    <TextView
        android:id="@+id/textView"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"/>

</LinearLayout>

1.同樣用監視器看會有細微的變化