Android ListView Common Tips Summary _android

ListView's position in our Android program is obvious to all, and I believe almost every app has its shadow.
ListView mainly uses the list form to load the data, needs to realize some special functions in the specific situation: for example refreshes the data, the load data, realizes the animation effect and so on.
What do we need to be aware of as our common control?
* * Set divider line for each item of ListView

The first method: also the simplest way to set the ListView in the layout file
Divider Property
such as: android:divider= "@color/black"
The second method: set the android:divider= "@null" to indicate that you don't want to divide the line, and then add the separator line yourself in the item layout.

 <ListView>
    android:id= "@+id/test_lv"
    android:layout_width= "match_parent"
    android:layout_ height= "Wrap_content"
    android:divider= "#d1d1d1" <!--set separator line color-->
    android:dividerheight= "1px" <!-- Set divider height-->
    >
 </ListView>

* * By default, listview item has click Effect, how to change this effect?
Set the Android:listselector property of the LISTVIEWR, such as setting the transparency to cancel the effect android:listselector= "@android: Color/transparent"
You can also set the effect you want, add the corresponding color resources or drawble resources.
* * When the data is more, ListView will display a default scroll bar when scrolling, to cancel the scroll bar, you can set the Android:scrollbars property
such as: android:scrollbars= "None"
* * ListView Performance optimization, must use Viewholder to give full play to the ListView recycle mechanism
* * ListView Data dynamic changes, add or delete data operations, the effect is obvious.

Implement ListView Data add delete public class Mainactivity extends activity implements View.onclicklistener {private ListView test_l
  V
  Private list<testbean> dataList;
  Private Testadapter adapter;
  Private Button add_btn, del_btn;
  Private ImageView Emptyiv;

  Private LinearLayout Operator_ll;
    @Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);
    Setcontentview (R.layout.activity_main);
    Initdatas ();

  Initviews ();
    private void Initdatas () {dataList = new arraylist<> ();
      for (int i = 0; i < 5; i++) {Testbean bean = new Testbean ();
      Bean.settitle ("title _" + i);
      Bean.setcontent ("This is content _" + i);
      Bean.settype (i% 2 = 0? 1:2);
    Datalist.add (Bean);
    } private void Initviews () {this.test_lv = (ListView) Findviewbyid (R.ID.TEST_LV);
    THIS.ADD_BTN = (Button) Findviewbyid (R.ID.ADD_BTN);
    THIS.DEL_BTN = (Button) Findviewbyid (R.ID.DEL_BTN); Emptyiv = (ImagevieW) Findviewbyid (R.ID.EMPTY_IV);
    Operator_ll= (LinearLayout) Findviewbyid (R.ID.OPERATOR_LL);
    This.add_btn.setOnClickListener (this);
    This.del_btn.setOnClickListener (this);
      if (datalist.size () = = 0) {emptyiv.setvisibility (view.visible);
      Operator_ll.setvisibility (View.gone);
    Test_lv.setemptyview (Emptyiv);
      else {emptyiv.setvisibility (view.gone);
      Operator_ll.setvisibility (view.visible);
      adapter = new Testadapter (this, dataList);
    Test_lv.setadapter (adapter);
  } test_lv.setselection (15);
        @Override public void OnClick (View v) {switch (V.getid ()) {case R.ID.ADD_BTN://default add in first position
        Testbean bean = new Testbean ();
        Bean.settitle ("Add Item");
        Bean.setcontent ("This is added content");
        Bean.settype (1);
        Datalist.add (0, Bean);
      Break
        Case R.ID.DEL_BTN://default Delete First Data datalist.remove (0);
    Break
Adapter.notifydatasetchanged ()//Refresh ListView Data}//listview corresponds to adapter public class Testadapter extends Baseadapter {private context mcontext;

  Private list<testbean> Listdatas;
    Public Testadapter (Context Mcontext, list<testbean> listdatas) {this.mcontext = Mcontext;
  This.listdatas = Listdatas;
  @Override public int GetCount () {return listdatas.size ();
  @Override public Object getitem (int position) {return listdatas.get (position);
  @Override public long getitemid (int position) {return position;
    @Override public View getview (int position, View Convertview, ViewGroup parent) {Viewholder holder = null;
      if (Convertview = = null) {holder = new Viewholder ();
      Convertview = Layoutinflater.from (Mcontext). Inflate (R.layout.test_item, NULL);
      Holder.title = (TextView) Convertview.findviewbyid (r.id.item_title);
      Holder.content = (TextView) Convertview.findviewbyid (r.id.item_content);
    Convertview.settag (holder); else {HoldeR = (viewholder) convertview.gettag ();
    } holder.content.setText (Listdatas.get (position). GetContent ());
    Holder.title.setText (Listdatas.get (position). GetTitle ());
  return convertview;
    Final class Viewholder {TextView title;
  TextView content;

 }
}

* * Similar to the chat interface, ListView has a variety of item style effects

Implement the various item styles in ListView public class Typeactivity extends activity {private ListView type_lv;
  Private list<testbean> dataList;

  Private Typeadapter adapter;
    @Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);
    Setcontentview (R.layout.activity_type);
    Initdatas ();

  Initviews ();
    private void Initdatas () {dataList = new arraylist<> ();
      for (int i = 0; i < 9; i++) {Testbean bean = new Testbean ();
      Bean.settitle ("title _" + i);
      Bean.setcontent ("This is content _" + i);
      Bean.settype (i% 2 = 0? 1:2);
    Datalist.add (Bean);
    } private void Initviews () {this.type_lv = (ListView) Findviewbyid (R.ID.TYPE_LV);
    adapter = new Typeadapter (this, dataList);

  Type_lv.setadapter (adapter);
  }//corresponds to adapter public class Typeadapter extends Baseadapter {private context mcontext;

  Private list<testbean> Listdatas; Public Typeadapter (Context Mcontext, list<Testbean> listdatas) {this.mcontext = Mcontext;
  This.listdatas = Listdatas;
  @Override public int GetCount () {return listdatas.size ();
  @Override public Object getitem (int position) {return listdatas.get (position);
  @Override public long getitemid (int position) {return position;
    @Override public View getview (int position, View Convertview, ViewGroup parent) {Viewholder holder = null;
    Different layouts and data display according to styles the int type = Getitemviewtype (position);
      if (Convertview = = null) {holder = new Viewholder ();
        if (type = = 1) {Convertview = Layoutinflater.from (Mcontext). Inflate (R.layout.test_item, NULL);
        Holder.title = (TextView) Convertview.findviewbyid (r.id.item_title);
      Holder.content = (TextView) Convertview.findviewbyid (r.id.item_content);
        else {Convertview = Layoutinflater.from (Mcontext). Inflate (R.layout.type_item, NULL); Holder.title = (TextView) convertview.finDviewbyid (R.id.type_title);
      Holder.content = (TextView) Convertview.findviewbyid (r.id.type_title);
    } convertview.settag (holder);
    else {holder = (Viewholder) convertview.gettag ();
    } holder.content.setText (Listdatas.get (position). GetContent ());
    Holder.title.setText (Listdatas.get (position). GetTitle ());
  return convertview;
  }//Key method Getviewtypecount: Get how many styles @Override public int getviewtypecount () {return 2; }//Key method Getitemviewtype: Get item type @Override public int getitemviewtype (int position) {return Listdatas.get (Positi
  ON). GetType ();
    Final class Viewholder {TextView title;
  TextView content;

 }
}

Related layouts

Activity_main.xml <?xml version= "1.0" encoding= "Utf-8"?> <linearlayout "xmlns:android=" http:// Schemas.android.com/apk/res/android "xmlns:tools=" Http://schemas.android.com/tools "android:layout_width=" Match_ Parent "android:layout_height=" match_parent "android:orientation=" vertical "> <linearlayout android:id=" @+ Id/operator_ll "android:layout_width=" match_parent "android:layout_height=" Wrap_content "android:orientation=" Horizontal "> <button android:id=" @+id/add_btn "android:layout_width=" 0DP "Android:layout_heig ht= "Wrap_content" android:layout_weight= "1" android:gravity= "center" android:text= "add"/> <bu Tton android:id= "@+id/del_btn" android:layout_width= "0DP" android:layout_height= "Wrap_content" and roid:layout_weight= "1" android:gravity= "center" android:text= "delete"/> </LinearLayout> <listvie W android:id= "@+id/test_lv" Android:layoUt_width= "Match_parent" android:layout_height= "wrap_content" android:divider= "#d1d1d1" <!--separator Line Color-->
    id:dividerheight= "1px" <!--divider height--> android:listselector= "@android: Color/transparent" <!--cancel default Click Effect-->
    Android:scrollbars= "None" ><!--hidden scroll bars--> </ListView> <imageview android:id= "@+id/empty_iv" Android:layout_width= "Wrap_content" android:layout_height= "wrap_content" android:layout_gravity= "center" Andro

 id:layout_margintop= "100DP" android:src= "@mipmap/empty" android:visibility= "Gone"/> </LinearLayout>

Activity_type.xml

<?xml version= "1.0" encoding= "Utf-8"?> <linearlayout xmlns:android=
"http://schemas.android.com/apk/" Res/android "
  xmlns:tools=" Http://schemas.android.com/tools "
  android:layout_width=" Match_parent
  " android:layout_height= "Match_parent"
  android:orientation= "vertical" >


  <listview android:id=
    "@ +id/type_lv "
    android:layout_width=" match_parent "
    android:layout_height=" wrap_content "
    ></" Listview>


</LinearLayout>

Test_item.xml

<?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=" wrap_content "
 android:o" rientation= "vertical"
 android:paddingleft= "15DP"
 android:layout_margintop= "5DP"
 android:layout_ marginbottom= "5DP" >

 <textview
  android:id= "@+id/item_title"
  android:layout_width= "WRAP_" Content "
  android:layout_height=" wrap_content "
  android:text=" Hello world!/>

 <textview
  android:id= "@+id/item_content"
  android:layout_width= "wrap_content"
  android:layout_height= "wrap" _content "
  android:layout_margintop=" 5DP "
  android:text=" Hello world!/>
</LinearLayout>

The above is the collection of Android ListView common tips for all the content, I hope to help you learn.