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学习笔记ListView初识
1.ListView的基本使用
作用：android系统中显示列表的控件
2.两种适配器(ArrayAdapter、simpleAdapter)
数据适配器 是连接数据源和视图界面的桥梁
作用：把复杂的数据(数组、链表、数据库、集合等)填充到指定视图界面上
ArrayAdapter:用于绑定格式单一数据
数据源：集合或者数组
SimpleAdapter:用于绑定格式复杂的数据
数据源：只能是特定泛型的集合
实现过程：新建适配器->添加数据源到适配器->视图加载适配器
使用ArrayAdapter：
package com.drumbass.listviewtest;import android.app.Activity;import android.os.Bundle;import android.widget.ArrayAdapter;import android.widget.ListView;public class MainActivity1 extends Activity { private ListView listView; private ArrayAdapter<String> mArrayAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); listView = (ListView) findViewById(R.id.listView1); String mdata[] = { "DrumBass1", "DrumBass2", "DrumBass3", "DrumBass4", "DrumBass5" }; mArrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mdata); listView.setAdapter(mArrayAdapter); }}
使用simpleAdapter：
1 package com.drumbass.listviewtest; 2 3 import java.util.ArrayList; 4 import java.util.HashMap; 5 import java.util.List; 6 import java.util.Map; 7 8 import android.app.Activity; 9 import android.os.Bundle;10 import android.widget.ListView;11 import android.widget.SimpleAdapter;12 13 public class MainActivity2 extends Activity {14 private ListView listView;15 private SimpleAdapter mSimpleAdapter;16 private List<Map<String, Object>> mDataList;17 18 @Override19 protected void onCreate(Bundle savedInstanceState) {20 super.onCreate(savedInstanceState);21 setContentView(R.layout.activity_main);22 listView = (ListView) findViewById(R.id.listView1);23 mDataList = new ArrayList<Map<String, Object>>();24 mSimpleAdapter = new SimpleAdapter(this, getData(), R.layout.item,25 new String[] { "pic", "text" },26 new int[] { R.id.pic, R.id.text });27 listView.setAdapter(mSimpleAdapter);28 }29 private List<Map<String, Object>> getData(){30 for (int i = 0; i < 20; i++) {31 Map<String,Object> map = new HashMap<String,Object>();32 map.put("pic", R.drawable.ic_launcher);33 map.put("text", "DrumBass"+i);34 mDataList.add(map);35 }36 return mDataList;37 }38 39 }
自定义xml文件：item.xml
1 <?xml version="1.0" encoding="utf-8"?> 2 <LinearLayout 3 xmlns:android="http://schemas.android.com/apk/res/android" 4 android:layout_width="match_parent" 5 android:layout_height="match_parent" 6 android:orientation="horizontal" > 7 <ImageView 8 android:layout_height="wrap_content" 9 android:layout_width="wrap_content"10 android:src="@drawable/ic_launcher"11 android:id="@+id/pic"12 />13 <TextView 14 android:id="@+id/text"15 android:layout_width="wrap_content"16 android:layout_height="wrap_content"17 android:text="DrumBass"18 android:gravity="center"19 />20 21 </LinearLayout>
运行结果：
3.两种监听器(OnScrollingListener、OnItemClickListener)
4.适配器数据刷新(notifyDataChanged)
1 package com.drumbass.listviewtest; 2 3 import java.util.ArrayList; 4 import java.util.HashMap; 5 import java.util.List; 6 import java.util.Map; 7 8 import android.app.Activity; 9 import android.os.Bundle;10 import android.util.Log;11 import android.view.View;12 import android.widget.AbsListView;13 import android.widget.AbsListView.OnScrollListener;14 import android.widget.AdapterView;15 import android.widget.AdapterView.OnItemClickListener;16 import android.widget.ListView;17 import android.widget.SimpleAdapter;18 import android.widget.Toast;19 20 public class MainActivity2 extends Activity implements OnItemClickListener,21 OnScrollListener {22 private ListView listView;23 private SimpleAdapter mSimpleAdapter;24 private List<Map<String, Object>> mDataList;25 26 @Override27 protected void onCreate(Bundle savedInstanceState) {28 super.onCreate(savedInstanceState);29 setContentView(R.layout.activity_main);30 listView = (ListView) findViewById(R.id.listView1);31 mDataList = new ArrayList<Map<String, Object>>();32 mSimpleAdapter = new SimpleAdapter(this, getData(), R.layout.item,33 new String[] { "pic", "text" },34 new int[] { R.id.pic, R.id.text });35 listView.setAdapter(mSimpleAdapter);36 listView.setOnItemClickListener(this);37 listView.setOnScrollListener(this);38 }39 40 private List<Map<String, Object>> getData() {41 for (int i = 0; i < 20; i++) {42 Map<String, Object> map = new HashMap<String, Object>();43 map.put("pic", R.drawable.ic_launcher);44 map.put("text", "DrumBass" + i);45 mDataList.add(map);46 }47 return mDataList;48 }49 50 @Override51 public void onScrollStateChanged(AbsListView view, int scrollState) {52 switch (scrollState) {53 case SCROLL_STATE_FLING:54 Log.i("Main", "用户在手指离开之前，用力滑动，视图还在滚动");55 Map<String, Object> map = new HashMap<String, Object>();56 map.put("pic", R.drawable.ic_launcher);57 map.put("text", "TR");58 mDataList.add(map);59 mSimpleAdapter.notifyDataSetChanged();60 break;61 case SCROLL_STATE_IDLE:62 Log.i("Main", "视图停止滑动");63 break;64 case SCROLL_STATE_TOUCH_SCROLL:65 Log.i("Main", "视图在滚动");66 break;67 }68 }69 70 @Override71 public void onScroll(AbsListView view, int firstVisibleItem,72 int visibleItemCount, int totalItemCount) {73 74 }75 76 @Override77 public void onItemClick(AdapterView<?> parent, View view, int position,78 long id) {79 String text = listView.getItemAtPosition(position) + "";80 Toast.makeText(this, "position" + position + "text" + text,81 Toast.LENGTH_SHORT).show();82 }83 84 }
终于写完了，虽然都只是笔记，但是花了很多时间。也许是我的学习方法错了？ 是不是应该学完后练练再来写？ 那样也许效率会高很多，下次试试。
学习笔记ListView初识
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