我正在从 Android 中的 URL 解析 Json 数据。执行时我没有收到任何错误。但什么都没有发生。
这是我的 MainActivity.Java 代码：
公共类 MainActivity 扩展 ListActivity {
/** Called when the activity is first created. */
@SuppressWarnings({ "rawtypes", "unchecked" })
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setListAdapter(new ArrayAdapter(this, android.R.layout.simple_list_item_1,
this.fetchTwitterPublicTimeline()));
}
public ArrayList<String> fetchTwitterPublicTimeline()
{
ArrayList<String> listItems = new ArrayList<String>();
try {
URL twitter = new URL(
"http://twitter.com/statuses/public_timeline.json");
URLConnection tc = twitter.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(
tc.getInputStream()));
String line;
while ((line = in.readLine()) != null) {
JSONArray ja = new JSONArray(line);
for (int i = 0; i < ja.length(); i++) {
JSONObject jo = (JSONObject) ja.get(i);
listItems.add(jo.getString("text"));
}
}
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return listItems;
}
}
这是我的 manifest.xml 内容：
package="com.example.harsh"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity android:name=".MainActivity"
android:label="Android List View">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
这是 R.java 文件：
package com.example.harsh;
public final class R {
public static final class attr {
}
public static final class dimen {
public static final int activity_horizontal_margin=0x7f040000;
public static final int activity_vertical_margin=0x7f040001;
}
public static final class drawable {
public static final int ic_launcher=0x7f020000;
}
public static final class id {
public static final int action_settings=0x7f080000;
}
public static final class layout {
public static final int activity_main=0x7f030000;
}
public static final class menu {
public static final int main=0x7f070000;
}
public static final class string {
public static final int action_settings=0x7f050001;
public static final int app_name=0x7f050000;
public static final int hello_world=0x7f050002;
}
public static final class style {public static final int
activity_horizontal_margin=0x7f040000;
public static final int activity_vertical_margin=0x7f040001;
}
public static final class drawable {
public static final int ic_launcher=0x7f020000;
}
public static final class id {
public static final int action_settings=0x7f080000;
}
public static final class layout {
public static final int activity_main=0x7f030000;
}
public static final class menu {
public static final int main=0x7f070000;
}
public static final class string {
public static final int action_settings=0x7f050001;
public static final int app_name=0x7f050000;
public static final int hello_world=0x7f050002;
}
public static final class style {
public static final int AppBaseTheme=0x7f060000;
public static final int AppTheme=0x7f060001;
}
}
在运行它之后，什么都没有出现：
[2013-10-15 23:37:39 - FirstApp] adb is running normally.
[2013-10-15 23:37:39 - FirstApp] Performing com.example.harsh.MainActivity activity launch
[2013-10-15 23:37:40 - FirstApp] Automatic Target Mode: using existing emulator 'emulator-5554' running compatible AVD 'abc'
[2013-10-15 23:37:40 - FirstApp] Uploading FirstApp.apk onto device 'emulator-5554'
[2013-10-15 23:37:46 - FirstApp] Installing FirstApp.apk...
[2013-10-15 23:38:26 - FirstApp] Success!
所以我无法弄清楚是什么问题。