在从 AppWidgetProvider 调用的异步任务中将字符串分配给文本值

Question

我正在尝试通过异步任务在小部件中设置 textview 值。我创建了一个简单的小部件，其布局如下所示：

widget_test.xml

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

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:background="@drawable/widget_bg_normal"
    >


    <TextView
        android:id="@+id/widget_tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="testing 123"
        android:layout_gravity="center_horizontal|center"
        android:layout_marginTop="5dip"
        android:padding="10dip"
        android:textColor="@android:color/black"
        >
    </TextView>

</LinearLayout>

我的 AppWidgetProvider 代码是：

package com.example.beerportfoliopro;

import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.Context;

/**
 * Created by Mike on 12/26/13.
 */
public class HelloWidget extends AppWidgetProvider {

    @Override
    public void onEnabled(Context context){

        //build url for async task
        String url = "hiddenURL";

        //call async task
        new GetRandomBeer(context).execute(url);



    }

    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds){

        //todo: call update code, which should be the same as onEnabled


    }


}

上面的代码应该控制启用应用程序时发生的情况（也就是当用户将应用程序添加到他们的主屏幕时）以及应用程序在根据我的 hello_widget-provider.xml 中设置的时间进行自我更新时应该执行的操作。 ：

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

<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
    android:minWidth="146dip"
    android:minHeight="72dip"
    android:updatePeriodMillis="1000"
    android:initialLayout="@layout/widget_test"
    >

</appwidget-provider>

出于测试目的，我没有让我的异步任务解析任何 json，但我只是试图通过异步任务更改我的小部件上的文本值。这是我的异步任务的代码：

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 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.JSONArray;
import org.json.JSONObject;

import android.app.Activity;
import android.app.ProgressDialog;
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.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.beerportfolio.beerportfoliopro.R;

public class GetRandomBeer extends AsyncTask
        <String, Void, String> {

    Context c;

    public GetRandomBeer(Context context)
    {
        c = context;

    }

    @Override
    protected String doInBackground(String... arg0) {
        // TODO Auto-generated method stub
        return readJSONFeed(arg0[0]);
    }



    protected void onPostExecute(String result){
        Log.d("taste","Inside get taste");
        //decode json here
        try{

            //todo: get all beer data



            //todo: set text views with data
            TextView breweryTitle = (TextView) ((Activity) c).findViewById(R.widget_tv);




        }
        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();
    }

}

我现在的问题是我的 widget_tv 现在显示错误：

cannot resolve symbol widget_tv

Answer 1

您的 TextView ID 应该是：R.id.widget_tv 而不是 R.widget_tv

Answer 2

在执行异步任务之前，您是否在传递给异步任务的活动类中调用了 setContentView(view)？如果不是，你应该使用布局充气器来充气 textview

((Activity) c).getLayoutInflater().inflate(R.id.widget_tv, null);