Android学习记录之ListView和ScrollView区别

ScrollView中不管有多少个数据项都会全部加载

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监视器可以看出不管怎么滑动都不会变化

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.同样用监视器看会有细微的变化