什麼是Android ListView？

ListView是一個顯示可滾動的專案列表檢視組。 該列表中的專案使用的是自動插入到列表Adapter ，拉從源內容，如陣列或資料庫查詢，把每個專案導如成被放置到列表的檢視。

在android開發中ListView是比較常用的元件，它以列表的形式展示具體內容，並且能夠根據資料的長度自適應顯示。

說到ListView就不得不說Adapter介面卡，因為只有通過Adapter才可以把列表中的資料對映到ListView中。

在android的開發中最Adapter 一共可以分為

• ArrayAdapter
• BaseAdapter
• CursorAdapter
• HeaderViewListAdapter
• ResourceCursorAdapter
• SimpleAdapter
• SimpleCursorAdapter
• WrapperListAdapter

軟體開發中最常用的有ArrayAdapter, BaseAdapter, SimpleAdapter。

ListView的例項

簡單的ListView

在List列表中如果不存在過於複雜的東西 我們可以直接去new ArrayAdapter() 來繪製列表，無須繼承ArrayAdapter，重寫它的方法。但是如果列表中過於複雜的話就需要使用自定義佈局來實現List列表。

public
 
 class SimpleList extends ListActivity {
 private String[] mListStr = {"姓名：哈哈","性別：男","年齡：25","居住地：北京","郵箱：[email protected]"};
 ListView mListView = null;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 mListView = getListView();
 setListAdapter(new ArrayAdapter<String>(this
 
,
 android.R.layout.simple_list_item_1, mListStr));
 mListView.setOnItemClickListener(new OnItemClickListener() {
 @Override
 public void onItemClick(AdapterView<?> adapterView, View view, int position,
 long id) {
 Toast.makeText(SimpleList.this,"您選擇了" + mListStr[position], Toast.LENGTH_LONG).show();
 }
 });

 super.onCreate(savedInstanceState);
 }
}

帶標題的ListView列表

使用 simpleAdapter 需要注意的是須要用Map<String,Object> item 來儲存列表中每一項的顯示的title與text , new SimpleAdapter的時候將map中的資料寫入 ，程式就會幫我們繪製列表了。

public class TitleList extends ListActivity {
 private String[] mListTitle = { "姓名", "性別", "年齡", "居住地","郵箱"};
 private String[] mListStr = { "哈哈", "男", "25", "北京",
 "[email protected]" };
 ListView mListView = null;
 ArrayList<Map<String,Object>> mData= new ArrayList<Map<String,Object>>();;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 mListView = getListView();

 int lengh = mListTitle.length;
 for(int i =0; i < lengh; i++) {
 Map<String,Object> item = new HashMap<String,Object>();
 item.put("title", mListTitle[i]);
 item.put("text", mListStr[i]);
 mData.add(item);
 }
 SimpleAdapter adapter = new SimpleAdapter(this,mData,android.R.layout.simple_list_item_2,
 new String[]{"title","text"},new int[]{android.R.id.text1,android.R.id.text2});
 setListAdapter(adapter);
 mListView.setOnItemClickListener(new OnItemClickListener() {
 @Override
 public void onItemClick(AdapterView<?> adapterView, View view, int position,
 long id) {
 Toast.makeText(TitleList.this,"您選擇了標題：" + mListTitle[position] + "內容："+mListStr[position], Toast.LENGTH_LONG).show();
 }
 });
 super.onCreate(savedInstanceState);
 }
}

帶圖片的ListView列表

使用 simpleAdapter 來操作 但是構造simpleAdapter的時候須要使用我們自己寫的佈局來完成 ，因為系統的佈局已經不能滿足需求了，同樣Map<String,Object> item 來儲存列表中每一項須要的顯示內容 如 圖片 標題 內容等。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent" android:layout_height="?android:attr/listPreferredItemHeight">
 <ImageView android:id="@+id/image"
 android:layout_width="wrap_content" android:layout_height="fill_parent"
 android:layout_alignParentTop="true" android:layout_alignParentBottom="true"
 android:adjustViewBounds="true"
 android:padding="2dip" />
 <TextView android:id="@+id/title"
 android:layout_width="wrap_content" android:layout_height="wrap_content"
 android:layout_toRightOf="@+id/image"
 android:layout_alignParentRight="true" android:layout_alignParentTop="true"
 android:layout_above="@+id/text"
 android:layout_alignWithParentIfMissing="true" android:gravity="center_vertical"
 android:textSize="15dip" />
 <TextView android:id="@+id/text"
 android:layout_width="fill_parent" android:layout_height="wrap_content"
 android:layout_toRightOf="@+id/image"
 android:layout_alignParentBottom="true"
 android:layout_alignParentRight="true" android:singleLine="true"
 android:ellipsize="marquee"
 android:textSize="20dip" />
</RelativeLayout>

MainActivity.java

public class MainActivity extends ListActivity {
 private String[] mListTitle = { "姓名", "性別", "年齡", "居住地","郵箱"};
 private String[] mListStr = { "哈哈", "男", "25", "北京",
 "[email protected]" };
 ListView mListView = null;
 ArrayList<Map<String,Object>> mData= new ArrayList<Map<String,Object>>();;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 mListView = getListView();

 int lengh = mListTitle.length;
 for(int i =0; i < lengh; i++) {
 Map<String,Object> item = new HashMap<String,Object>();
 item.put("image", R.drawable.jay);
 item.put("title", mListTitle[i]);
 item.put("text", mListStr[i]);
 mData.add(item);
 }
 SimpleAdapter adapter = new SimpleAdapter(this,mData,R.layout.iconlist,
 new String[]{"image","title","text"},new int[]{R.id.image,R.id.title,R.id.text});
 setListAdapter(adapter);
 mListView.setOnItemClickListener(new OnItemClickListener() {
 @Override
 public void onItemClick(AdapterView<?> adapterView, View view, int position,
 long id) {
 Toast.makeText(IconList.this,"您選擇了標題：" + mListTitle[position] + "內容："+mListStr[position], Toast.LENGTH_LONG).show();
 }
 });
 super.onCreate(savedInstanceState);
 }
}

自定義佈局BaseAdapter修改列表顏色

因為通過直接 構造系統的佈局來繪製列表方法肯定是有限的，所以我們需要重寫繪製方法 ，寫一個類去繼承BaseAdapter 並實現這個類中的方法，listView在一開始繪製的時候首先會呼叫getCout()方法得到繪製次數 ，然後會例項化自己定義的BaseAdapter通過getView()方法一層一層繪製ListView,所以我們可以在這裡面根據position(當前繪製的ID)來任意的修改繪製的內容，做出好看漂亮的ListView,下面這個例子我通過重寫getView修改每個列表的顏色 並且實現使用者選中後成高亮狀態。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent" android:layout_height="wrap_content">
 <ImageView android:id="@+id/color_image"
 android:layout_width="wrap_content" android:layout_height="fill_parent"
 android:layout_alignParentTop="true" android:layout_alignParentBottom="true"
 android:adjustViewBounds="true"
 android:padding="2dip" />
 <TextView android:id="@+id/color_title"
 android:layout_width="fill_parent" android:layout_height="wrap_content"
 android:layout_toRightOf="@+id/color_image"
 android:layout_alignParentBottom="true"
 android:layout_alignParentRight="true" android:singleLine="true"
 android:ellipsize="marquee"
 android:textSize="15dip" />
 <TextView android:id="@+id/color_text"
 android:layout_width="fill_parent" android:layout_height="wrap_content"
 android:layout_toRightOf="@+id/color_image"
 android:layout_below="@+id/color_title"
 android:layout_alignParentBottom="true"
 android:layout_alignParentRight="true"
 android:singleLine="true"
 android:ellipsize="marquee"
 android:textSize="20dip" />
</RelativeLayout>

MianActivity.java

public class MianActivity extends ListActivity {
 private String[] mListTitle = { "姓名", "性別", "年齡", "居住地","郵箱"};
 private String[] mListStr = { "哈哈", "男", "25", "北京",
 "[email protected]" };
 ListView mListView = null;
 MyListAdapter myAdapter = null;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 mListView = getListView();
 myAdapter = new MyListAdapter(this);
 setListAdapter(myAdapter);
 mListView.setOnItemClickListener(new OnItemClickListener() {
 @Override
 public void onItemClick(AdapterView<?> adapterView, View view, int position,
 long id) {
 View v=adapterView.getChildAt(position);
 v.setBackgroundColor(Color.RED);
 Toast.makeText(ColorList.this,"您選擇了" + mListStr[position], Toast.LENGTH_LONG).show();
 }
 });

 super.onCreate(savedInstanceState);
 }

 class MyListAdapter extends BaseAdapter {
 private int[] colors = new int[] { 0xff626569, 0xff4f5257 };
 public MyListAdapter(Context context) {
 mContext = context;
 }

 public int getCount() {
 return mListStr.length;
 }

 @Override
 public boolean areAllItemsEnabled() {
 return false;
 }

 public Object getItem(int position) {
 return position;
 }

 public long getItemId(int position) {
 return position;
 }

 public View getView(int position, View convertView, ViewGroup parent) {
 ImageView iamge = null;
 TextView title = null;
 TextView text = null;
 if (convertView == null) {
 convertView = LayoutInflater.from(mContext).inflate(R.layout.colorlist, null);
 iamge = (ImageView) convertView.findViewById(R.id.color_image);
 title =(TextView) convertView.findViewById(R.id.color_title);
 text= (TextView) convertView.findViewById(R.id.color_text);
 }
 int colorPos = position % colors.length;
 convertView.setBackgroundColor(colors[colorPos]);
 title.setText(mListTitle[position]);
 text.setText(mListStr[position]);
 iamge.setImageResource(R.drawable.jay);
 return convertView;
 }

 private Context mContext;
 }
}

自定義佈局ArrayAdapter

ArrayAdapter是BaseAdapter的子類，ArrayAdapter不僅具有BaseAdapter的所有方法還自定義了一些新的方法來處理列表項，所以單純的從功能能上來講ArrayAdapter遠遠強與BaseAdapter，如果是繪製一些數量比較少的列表建議使用BaseAdapter 如果繪製一些比較複雜的列表項 並且列表項很多的 建議使用ArrayAdapter。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent" android:layout_height="wrap_content">
 <Button
 android:id="@+id/array_button"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:text="使用者"
 />
 <ImageView android:id="@+id/array_image"
 android:layout_toRightOf="@+id/array_button"
 android:layout_width="wrap_content" android:layout_height="fill_parent"
 android:layout_alignParentTop="true" android:layout_alignParentBottom="true"
 android:adjustViewBounds="true"
 android:padding="2dip" />
 <TextView android:id="@+id/array_title"
 android:layout_width="fill_parent" android:layout_height="wrap_content"
 android:layout_toRightOf="@+id/array_image"
 android:layout_alignParentBottom="true"
 android:layout_alignParentRight="true" android:singleLine="true"
 android:ellipsize="marquee"
 android:textSize="15dip" />
 <TextView android:id="@+id/array_text"
 android:layout_width="fill_parent" android:layout_height="wrap_content"
 android:layout_toRightOf="@+id/array_image"
 android:layout_below="@+id/array_title"
 android:layout_alignParentBottom="true"
 android:layout_alignParentRight="true"
 android:singleLine="true"
 android:ellipsize="marquee"
 android:textSize="20dip" />

</RelativeLayout>

MianActivity.java

public class ArrayList extends ListActivity {
 private String[] mListTitle = { "姓名", "性別", "年齡", "居住地","郵箱"};
 private String[] mListStr = { "哈哈", "男", "25", "北京",
 "[email protected]" };
 ListView mListView = null;
 MyListAdapter myAdapter = null;
 ArrayList arrayList = null;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 arrayList = this;
 mListView = getListView();
 myAdapter = new MyListAdapter(this,R.layout.arraylist);
 setListAdapter(myAdapter);
 super.onCreate(savedInstanceState);
 }

 public class MyListAdapter extends ArrayAdapter<Object> {
 int mTextViewResourceID = 0;
 private Context mContext;
 public MyListAdapter(Context context, int textViewResourceId) {
 super(context, textViewResourceId);
 mTextViewResourceID = textViewResourceId;
 mContext = context;
 }

 private int[] colors = new int[] { 0xff626569, 0xff4f5257 };

 public int getCount() {
 return mListStr.length;
 }

 @Override
 public boolean areAllItemsEnabled() {
 return false;
 }

 public Object getItem(int position) {
 return position;
 }

 public long getItemId(int position) {
 return position;
 }

 public View getView(final int position, View convertView, ViewGroup parent) {
 ImageView iamge = null;
 TextView title = null;
 TextView text = null;
 Button button = null;
 if (convertView == null) {
 convertView = LayoutInflater.from(mContext).inflate(
 mTextViewResourceID, null);
 iamge = (ImageView) convertView.findViewById(R.id.array_image);
 title = (TextView) convertView.findViewById(R.id.array_title);
 text = (TextView) convertView.findViewById(R.id.array_text);
 button = (Button)convertView.findViewById(R.id.array_button);
 button.setOnClickListener(new OnClickListener() {

 @Override
 public void onClick(View arg0) {
 Toast.makeText(arrayList,"您點選的第"+position +"個按鈕", Toast.LENGTH_LONG).show();

 }
 });
 }
 int colorPos = position % colors.length;
 convertView.setBackgroundColor(colors[colorPos]);
 title.setText(mListTitle[position]);
 text.setText(mListStr[position]);
 if(colorPos == 0)
 iamge.setImageResource(R.drawable.jay);
 else
 iamge.setImageResource(R.drawable.image);
 return convertView;
 }
 }
}