从网络上加载XML资源，其中包括图片，我们要做的解析XML里面的数据，并且把图片缓存到本地一个cache目录里面，并且用一个自定义的Adapter去填充到LIstView：
对象类
|
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
public
class
Contact {
int
id;
String image;
String name;
public
Contact() {
super
();
}
public
Contact(
int
id, String image, String name) {
this
.id = id;
this
.image = image;
this
.name = name;
}
public
int
getId() {
return
id;
}
public
void
setId(
int
id) {
this
.id = id;
}
public
String getImage() {
return
image;
}
public
void
setImage(String image) {
this
.image = image;
}
public
String getName() {
return
name;
}
public
void
setName(String name) {
this
.name = name;
}
}
|
service类
|
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
|
public
class
ContactService {
/*
* 从服务器上获取数据
*/
public List<Contact> getContactAll() throws Exception {
List<Contact> contacts = null;
String Parth = "http://10.0.2.2:8080/AsyncTaskTest/list.xml";
URL url = new URL(Parth);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setRequestMethod("GET");
if (conn.getResponseCode() == HttpURLConnection.HTTP_OK) {
InputStream is = conn.getInputStream();
// 这里获取数据直接放在XmlPullParser里面解析
contacts = xmlParser(is);
return contacts;
} else {
return null;
}
}
// 这里并没有下载图片下来，而是把图片的地址保存下来了
private List<Contact> xmlParser(InputStream is) throws Exception {
List<Contact> contacts = null;
Contact contact = null;
XmlPullParser parser = Xml.newPullParser();
parser.setInput(is, "UTF-8");
int eventType = parser.getEventType();
while ((eventType = parser.next()) != XmlPullParser.END_DOCUMENT) {
switch (eventType) {
case XmlPullParser.START_TAG:
if (parser.getName().equals("contacts")) {
contacts = new ArrayList<Contact>();
} else if (parser.getName().equals("contact")) {
contact = new Contact();
contact.setId(Integer.valueOf(parser.getAttributeValue(0)));
} else if (parser.getName().equals("name")) {
contact.setName(parser.nextText());
} else if (parser.getName().equals("image")) {
contact.setImage(parser.getAttributeValue(0));
}
break;
case XmlPullParser.END_TAG:
if (parser.getName().equals("contact")) {
contacts.add(contact);
}
break;
}
}
return contacts;
}
/*
* 从网络上获取图片，如果图片在本地存在的话就直接拿，如果不存在再去服务器上下载图片
* 这里的path是图片的地址
*/
public
Uri getImageURI(String path, File cache)
throws
Exception {
String name = MD5.getMD5(path) + path.substring(path.lastIndexOf(
"."
));
File file =
new
File(cache, name);
// 如果图片存在本地缓存目录，则不去服务器下载
if
(file.exists()) {
return
Uri.fromFile(file);
//Uri.fromFile(path)这个方法能得到文件的URI
}
else
{
// 从网络上获取图片
URL url =
new
URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(
5000
);
conn.setRequestMethod(
"GET"
);
conn.setDoInput(
true
);
if
(conn.getResponseCode() ==
200
) {
InputStream is = conn.getInputStream();
FileOutputStream fos =
new
FileOutputStream(file);
byte
[] buffer =
new
byte
[
1024
];
int
len =
0
;
while
((len = is.read(buffer)) != -
1
) {
fos.write(buffer,
0
, len);
}
is.close();
fos.close();
// 返回一个URI对象
return
Uri.fromFile(file);
}
}
return
null
;
}
}
|
自定义Adapter
|
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
|
public
class
ImageAdapter
extends
BaseAdapter {
protected
static
final
int
SUCCESS_GET_IMAGE =
0
;
private
Context context;
private
List<Contact> contacts;
private
File cache;
private
LayoutInflater mInflater;
// 自己定义的构造函数
public
ImageAdapter(Context context, List<Contact> contacts, File cache) {
this
.context = context;
this
.contacts = contacts;
this
.cache = cache;
mInflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public
int
getCount() {
return
contacts.size();
}
@Override
public
Object getItem(
int
position) {
return
contacts.get(position);
}
@Override
public
long
getItemId(
int
position) {
return
position;
}
@Override
public
View getView(
int
position, View convertView, ViewGroup parent) {
// 1获取item,再得到控件
// 2 获取数据
// 3绑定数据到item
View view =
null
;
if
(convertView !=
null
) {
view = convertView;
}
else
{
view = mInflater.inflate(R.layout.item,
null
);
}
ImageView iv_header = (ImageView) view.findViewById(R.id.imageView);
TextView tv_name = (TextView) view.findViewById(R.id.textView);
Contact contact = contacts.get(position);
// 异步的加载图片 (线程池 + Handler ) ---> AsyncTask
asyncloadImage(iv_header, contact.image);
tv_name.setText(contact.name);
return
view;
}
private
void
asyncloadImage(ImageView iv_header, String path) {
ContactService service =
new
ContactService();
AsyncImageTask task =
new
AsyncImageTask(service, iv_header);
task.execute(path);
}
private
final
class
AsyncImageTask
extends
AsyncTask<String, Integer, Uri> {
private
ContactService service;
private
ImageView iv_header;
public
AsyncImageTask(ContactService service, ImageView iv_header) {
this
.service = service;
this
.iv_header = iv_header;
}
// 后台运行的子线程子线程
@Override
protected
Uri doInBackground(String... params) {
try
{
return
service.getImageURI(params[
0
], cache);
}
catch
(Exception e) {
e.printStackTrace();
}
return
null
;
}
// 这个放在在ui线程中执行
@Override
protected
void
onPostExecute(Uri result) {
super
.onPostExecute(result);
// 完成图片的绑定
if
(iv_header !=
null
&& result !=
null
) {
iv_header.setImageURI(result);
}
}
}
}
|
|
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
public
class
MainActivity
extends
Activity {
protected
static
final
int
SUCCESS_GET_CONTACT =
0
;
private
ListView mListView;
private
ImageAdapter mAdapter;
private
File cache;
@Override
public
void
onCreate(Bundle savedInstanceState) {
super
.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mListView = (ListView) findViewById(R.id.listView);
//创建缓存目录，系统一运行就得创建缓存目录的，
cache =
new
File(Environment.getExternalStorageDirectory(),
"cache"
);
if
(!cache.exists()){
cache.mkdirs();
}
//获取数据，主UI线程是不能做耗时操作的，所以启动子线程来做
new
Thread(){
public
void
run() {
ContactService service =
new
ContactService();
List<Contact> contacts =
null
;
try
{
contacts = service.getContactAll();
}
catch
(Exception e) {
e.printStackTrace();
}
//子线程通过Message对象封装信息，并且用初始化好的，
//Handler对象的sendMessage()方法把数据发送到主线程中，从而达到更新UI主线程的目的
Message msg =
new
Message();
msg.what = SUCCESS_GET_CONTACT;
msg.obj = contacts;
mHandler.sendMessage(msg);
};
}.start();
}
private
Handler mHandler =
new
Handler(){
public
void
handleMessage(android.os.Message msg) {
if
(msg.what == SUCCESS_GET_CONTACT){
List<Contact> contacts = (List<Contact>) msg.obj;
mAdapter =
new
ImageAdapter(getApplicationContext(),contacts,cache);
mListView.setAdapter(mAdapter);
}
};
};
@Override
protected
void
onDestroy() {
super
.onDestroy();
//清空缓存
File[] files = cache.listFiles();
for
(File file :files){
file.delete();
}
cache.delete();
}
}
|
务器xml文件
|
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
<?xml version=
"1.0"
encoding=
"UTF-8"
?>
<contacts>
<contact id=
"1"
>
<name>图标
1
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/1.png"
/>
</contact>
<contact id=
"2"
>
<name>图标
2
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/2.png"
/>
</contact>
<contact id=
"3"
>
<name>图标
3
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/3.png"
/>
</contact>
<contact id=
"4"
>
<name>图标
4
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/4.png"
/>
</contact>
<contact id=
"5"
>
<name>图标
5
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/5.png"
/>
</contact>
<contact id=
"6"
>
<name>图标
6
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/6.png"
/>
</contact>
<contact id=
"7"
>
<name>图标
7
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/7.png"
/>
</contact>
<contact id=
"8"
>
<name>图标
8
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/8.png"
/>
</contact>
<contact id=
"9"
>
<name>图标
9
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/9.png"
/>
</contact>
<contact id=
"10"
>
<name>图标
10
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/10.png"
/>
</contact>
<contact id=
"11"
>
<name>图标
11
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/11.png"
/>
</contact>
<contact id=
"12"
>
<name>图标
12
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/12.png"
/>
</contact>
<contact id=
"13"
>
<name>图标
13
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/13.png"
/>
</contact>
<contact id=
"14"
>
<name>图标
14
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/14.png"
/>
</contact>
<contact id=
"15"
>
<name>图标
15
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/15.png"
/>
</contact>
<contact id=
"16"
>
<name>图标
16
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/16.png"
/>
</contact>
<contact id=
"17"
>
<name>图标
17
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/17.png"
/>
</contact>
<contact id=
"18"
>
<name>图标
18
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/18.png"
/>
</contact>
<contact id=
"19"
>
<name>图标
19
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/19.png"
/>
</contact>
<contact id=
"20"
>
<name>图标
20
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/20.png"
/>
</contact>
<contact id=
"21"
>
<name>图标
21
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/1.png"
/>
</contact>
<contact id=
"22"
>
<name>图标
22
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/2.png"
/>
</contact>
<contact id=
"23"
>
<name>图标
23
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/3.png"
/>
</contact>
<contact id=
"24"
>
<name>图标
24
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/4.png"
/>
</contact>
<contact id=
"25"
>
<name>图标
25
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/5.png"
/>
</contact>
<contact id=
"26"
>
<name>图标
26
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/6.png"
/>
</contact>
<contact id=
"27"
>
<name>图标
27
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/7.png"
/>
</contact>
<contact id=
"28"
>
<name>图标
28
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/8.png"
/>
</contact>
<contact id=
"29"
>
<name>图标
29
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/9.png"
/>
</contact>
<contact id=
"30"
>
<name>图标
30
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/10.png"
/>
</contact>
<contact id=
"31"
>
<name>图标
31
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/11.png"
/>
</contact>
<contact id=
"32"
>
<name>图标
32
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/12.png"
/>
</contact>
<contact id=
"33"
>
<name>图标
33
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/13.png"
/>
</contact>
<contact id=
"34"
>
<name>图标
34
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/14.png"
/>
</contact>
<contact id=
"35"
>
<name>图标
35
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/15.png"
/>
</contact>
<contact id=
"36"
>
<name>图标
36
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/16.png"
/>
</contact>
<contact id=
"37"
>
<name>图标
37
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/17.png"
/>
</contact>
<contact id=
"38"
>
<name>图标
38
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/18.png"
/>
</contact>
<contact id=
"39"
>
<name>图标
39
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/19.png"
/>
</contact>
<contact id=
"40"
>
<name>图标
40
</name>
<image src=
"http://192.168.34.20:8080/AsyncTaskTest/image/20.png"
/>
</contact>
</contacts>
|