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Android适配器Adapter学习
来源:互联网   发布日期:2015-10-02 16:21:01   浏览:785次  

导读:在开发中我们需要绑定一些数据展现到桌面上,这是就需要AdapterView。AdapterView是ViewGroup的子类,它决定了怎么展现视图通过Adapter来绑定特殊的数据...

在开发中我们需要绑定一些数据展现到桌面上,这是就需要AdapterView。AdapterView是ViewGroup的子类,它决定了怎么展现视图通过Adapter来绑定特殊的数据类型。AdapterView是非常有帮助的当你展现数据在你的布局中。Gallery,ListView和Spinner是AdapterView的子类。

下面看一下AdapterView的结构图:

然后再看一下Adapter的结构图:

上面已经充分展现了他们的子类和父类的基础关系。

下面我们看一个ListViewDemo的例子:

先来看一个简单的adapter的例子:

public class SimpleList extends ListActivity {

private String[] mListString={"姓名:王魁锋","性别:男","年龄:23",

"居住地:上海市普陀区","邮箱:wangkuifeng0118@126.com"};

private ListView mListView=null;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

mListView=this.getListView();

setListAdapter(new ArrayAdapter<String>(this,

android.R.layout.simple_list_item_1,mListString));

mListView.setOnItemClickListener(new OnItemClickListener() {

@Override

public void onItemClick(AdapterView<?> parent, View view,

int position, long id) {

// TODO Auto-generated method stub

Toast.makeText(SimpleList.this, "你选择了:"+mListString[position], 1).show();

}

});

}

这里用到了系统定义好的适配模式,当然这只能用来简单的数据适配,下面看一下效果:

接下来看一个稍微复杂点的,SimpleAdapter怎么适配:

public class IconList extends ListActivity {

private String[] mListTitle = { "姓名", "性别", "年龄", "居住地","邮箱"};

private String[] mListStr = { "王魁锋", "男", "23", "上海市普陀区",

"wangkuifeng0118@126.com"};

ListView mListView = null;

ArrayList<Map<String,Object>> mData= new ArrayList<Map<String,Object>>();;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

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.portrait);

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<?> parent, View view,

int position, long id) {

// TODO Auto-generated method stub

Toast.makeText(IconList.this,"您选择了标题:" + mListTitle[position] + "内容:"+mListStr[position], Toast.LENGTH_LONG).show();

}

});

super.onCreate(savedInstanceState);

}

}

上面的数据可以是同数据库读取的也可以是从网络获取的,这里不做过多介绍,看下效果:

哈哈 看起来美观了些,如果要做更复杂的布局,哪就要用BaseAdapter了。先看一下布局文件:

<?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_alignParentTop="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>

下面是核心代码:

public class ColorList extends ListActivity {

private String[] mListTitle = { "姓名", "性别", "年龄", "居住地","邮箱"};

private String[] mListText={"王魁锋","男","23","上海市普陀区","wangkuifeng0118@126.com"};

private ListView mListView=null;

private MyListAdapter myAdapter=null;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

mListView=this.getListView();

myAdapter=new MyListAdapter(this);

this.setListAdapter(myAdapter);

mListView.setOnItemClickListener(new OnItemClickListener() {

@Override

public void onItemClick(AdapterView<?> parent, View view,

int position, long id) {

// TODO Auto-generated method stub

View v=parent.getChildAt(position);

v.setBackgroundColor(Color.RED);

Toast.makeText(ColorList.this, "你选择了"+mListText[position], 1).show();

}

});

super.onCreate(savedInstanceState);

}

private class MyListAdapter extends BaseAdapter{

private Context mContext;

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

public MyListAdapter(Context context){

mContext=context;

}

@Override

public int getCount() {

// TODO Auto-generated method stub

return mListText.length;

}

@Override

public Object getItem(int position) {

// TODO Auto-generated method stub

return position;

}

@Override

public long getItemId(int position) {

// TODO Auto-generated method stub

return position;

}

@Override

public View getView(int position, View convertView, ViewGroup parent) {

ImageView image=null;

TextView title=null;

TextViewcontent=null;

if(convertView==null){

convertView=LayoutInflater.from(mContext).inflate(R.layout.colorlist, null);

image=(ImageView) convertView.findViewById(R.id.color_image);

title=(TextView) convertView.findViewById(R.id.color_title);

content=(TextView) convertView.findViewById(R.id.color_text);

}

int colorPos=position%colors.length;

convertView.setBackgroundColor(colors[colorPos]);

title.setText(mListTitle[position]);

content.setText(mListText[position]);

image.setImageResource(R.drawable.portrait);

return convertView;

}

}

}

BaseAdapter可以让我们做比较复杂的布局,只要在xml文件中设置好布局格式,在getView中分别取出放入相应的值就可以了。下面看一些效果:

还有一些SpinnerAdapter和SimpleCursorAdapter等系统自带的适配器,都是比较简单的,可以看下API自行练习一下,这里特别说明一下,从数据库里取出的数据最好直接放入SimpleCursorAdapter很方便的

摘自 wangkuifeng0118的专栏

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