我正在尝试创建自己的 android 小部件。我希望它包含一个列表视图，该列表视图从在线数据库的异步任务中获取数据。
到目前为止，我有我的 res/xml.stat_widget.xml
<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider
xmlns:android="http://schemas.android.com/apk/res/android"
android:minWidth="220dp"
android:minHeight="72dp"
android:updatePeriodMillis="86400000"
android:initialLayout="@layout/widget_stat_view">
</appwidget-provider>
和布局widget_stat_view：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/statisticsTitle"
android:gravity="center"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:ems="10"
android:text="Your Statistics"
android:textSize="20sp"
android:textStyle = "bold"
android:padding="5dip"
>
</TextView>
<View
android:layout_width="1dp"
android:layout_height="30dp">
</View>
<ListView
android:id="@+id/yourStats"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:dividerHeight="0px"
android:divider="@null"
>
</ListView>
</LinearLayout>
我现在正在尝试编写调用异步任务的小部件提供程序。我按照我在正常应用程序活动中使用的异步任务对我的异步任务进行了建模。它尚未设置为更改小部件中的数据，但我在从我的提供者调用它时遇到问题：
package com.example.beerportfoliopro;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.Context;
import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.util.Log;
import android.widget.RemoteViews;
import com.beerportfolio.beerportfoliopro.R;
/**
* Created by Mike on 9/12/13.
*/
public class StatWidgetProvider extends AppWidgetProvider {
@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager,
int[] appWidgetIds) {
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
String userName = prefs.getString("userName", null);
String userID = prefs.getString("userID", null);
String url = "myURL";
new GetJSONStatWidget(this).execute(url);
}
public static void updateWidgetContent(Context context,
AppWidgetManager appWidgetManager) {
RemoteViews remoteView = new RemoteViews(context.getPackageName(),
R.layout.widget_stat_view);
remoteView.setTextViewText(R.id.title, strLatestTitle);
Intent launchAppIntent = new Intent(context, TutListActivity.class);
PendingIntent launchAppPendingIntent = PendingIntent.getActivity(context,
0, launchAppIntent, PendingIntent.FLAG_UPDATE_CURRENT);
remoteView.setOnClickPendingIntent(R.id.full_widget, launchAppPendingIntent);
ComponentName tutListWidget = new ComponentName(context,
TutWidgetProvider.class);
appWidgetManager.updateAppWidget(tutListWidget, remoteView);
}
}
我在上面的代码中遇到的第一个错误：
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
错误是：
getDefaultSharedPreferences
(android.content.Context)
in PreferenceManager cannot be applied
to
(com.example.beerportfoliopro.StatWidgetProvider)
我在这一行也遇到了错误：
new GetJSONStatWidget(this).execute(url);
我的异步任务代码是这样的：
package com.example.beerportfoliopro;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.zip.Inflater;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONObject;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.preference.PreferenceManager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RatingBar;
import android.widget.RatingBar.OnRatingBarChangeListener;
import android.widget.TextView;
import android.widget.Toast;
import com.beerportfolio.beerportfoliopro.R;
public class GetJSONStatWidget extends AsyncTask
<String, Void, String> {
Context c;
String b;
public GetJSONStatWidget(Context context)
{
c = context;
}
@Override
protected String doInBackground(String... arg0) {
// TODO Auto-generated method stub
return readJSONFeed(arg0[0]);
}
protected void onPostExecute(String result){
//decode json here
try{
JSONObject json = new JSONObject(result);
String beerCount = json.getString("beerCount");
String breweryCount = json.getString("breweryCount");
String styleCount = json.getString("styleCount");
String highABV = json.getString("highABV");
String highIBU = json.getString("highIBU");
//todo: everything below is for the listview
//make array list for stats
final List<BasicStat> basicStatList = new ArrayList<BasicStat>();
//create object
BasicStat stat1 = new BasicStat("Beer Count: ", beerCount);
basicStatList.add(stat1);
BasicStat stat2 = new BasicStat("Brewery Count: ", breweryCount);
basicStatList.add(stat2);
BasicStat stat3 = new BasicStat("Style Count: ", styleCount);
basicStatList.add(stat3);
BasicStat stat4 = new BasicStat("High ABV: ", highABV);
basicStatList.add(stat4);
BasicStat stat5 = new BasicStat("High IBU: ", highIBU);
basicStatList.add(stat5);
//acces listview
ListView lv = (ListView) ((Activity) c).findViewById(R.id.yourStats);
//add items to listview
StatInfoAdapter adapter1 = new StatInfoAdapter(c ,R.layout.stat_list_item, basicStatList);
lv.setAdapter(adapter1);
}
catch(Exception e){
}
}
public String readJSONFeed(String URL) {
StringBuilder stringBuilder = new StringBuilder();
HttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(URL);
try {
HttpResponse response = httpClient.execute(httpGet);
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
if (statusCode == 200) {
HttpEntity entity = response.getEntity();
InputStream inputStream = entity.getContent();
BufferedReader reader = new BufferedReader(
new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
stringBuilder.append(line);
}
inputStream.close();
} else {
Log.d("JSON", "Failed to download file");
}
} catch (Exception e) {
Log.d("readJSONFeed", e.getLocalizedMessage());
}
return stringBuilder.toString();
}
}