API DEMO APPWIGHT 学习

1: APP WIGHT的 AppWidget Provider 配置文件 appwight_provider.xml

新建xml文件->类型：AppWidget Provider->文件会新建在res/xml下

它包含了Widget在桌面的大小（74*单元格-2），

单位dip,Widget自动更新的周期（android:updatePeriodMillis）此方法1.5以后已经失效，默认30分钟更新一次，如要自定义可以通过service在定时器中实现，添加Widget时假如要先进入一个界面进行配置，

这个就指定了配置Activity是谁（android:configure="com.example.android.apis.appwidget.ExampleAppWidgetConfigure"）；

该文件是在Receiver的resource属性里被指定的。

initiaLayout指定界面布局文件

<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
    android:minWidth="60dp"
    android:minHeight="30dp"
    android:updatePeriodMillis="86400000"
    android:initialLayout="@layout/appwidget_provider"
    android:configure="com.example.android.apis.appwidget.ExampleAppWidgetConfigure"
    >
</appwidget-provider>

        <receiver android:name=".appwidget.ExampleAppWidgetProvider">
            <meta-data android:name="android.appwidget.provider"
                    android:resource="@xml/appwidget_provider" />
            <intent-filter>
                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
            </intent-filter>
        </receiver>

2： APP WIGHT的界面布局 appwidgt_provider res/layout/

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/appwidget_text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textColor="#ff000000"
/>

3: app widht 核心处理代码

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.android.apis.appwidget;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.SystemClock;
import android.util.Log;
import android.widget.RemoteViews;
import java.util.ArrayList;
// Need the following import to get access to the app resources, since this
// class is in a sub-package.
import com.example.android.apis.R;
/**
 * A widget provider.  We have a string that we pull from a preference in order to show
 * the configuration settings and the current time when the widget was updated.  We also
 * register a BroadcastReceiver for time-changed and timezone-changed broadcasts, and
 * update then too.
 *
 * <p>See also the following files:
 * <ul>
 *   <li>ExampleAppWidgetConfigure.java</li>
 *   <li>ExampleBroadcastReceiver.java</li>
 *   <li>res/layout/appwidget_configure.xml</li>
 *   <li>res/layout/appwidget_provider.xml</li>
 *   <li>res/xml/appwidget_provider.xml</li>
 * </ul>
 */
public class ExampleAppWidgetProvider extends AppWidgetProvider {
    // log tag
    private static final String TAG = "ExampleAppWidgetProvider";
    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        Log.d(TAG, "onUpdate");
        // For each widget that needs an update, get the text that we should display:
        //   - Create a RemoteViews object for it
        //   - Set the text in the RemoteViews object
        //   - Tell the AppWidgetManager to show that views object for the widget.
        final int N = appWidgetIds.length;
        for (int i=0; i<N; i++) {
            int appWidgetId = appWidgetIds[i];
            String titlePrefix = ExampleAppWidgetConfigure.loadTitlePref(context, appWidgetId);
            updateAppWidget(context, appWidgetManager, appWidgetId, titlePrefix);
        }
    }
    
    public void onDeleted(Context context, int[] appWidgetIds) {
        Log.d(TAG, "onDeleted");
        // When the user deletes the widget, delete the preference associated with it.
        final int N = appWidgetIds.length;
        for (int i=0; i<N; i++) {
            ExampleAppWidgetConfigure.deleteTitlePref(context, appWidgetIds[i]);
        }
    }
    public void onEnabled(Context context) {
        Log.d(TAG, "onEnabled");
        // When the first widget is created, register for the TIMEZONE_CHANGED and TIME_CHANGED
        // broadcasts.  We don't want to be listening for these if nobody has our widget active.
        // This setting is sticky across reboots, but that doesn't matter, because this will
        // be called after boot if there is a widget instance for this provider.
        PackageManager pm = context.getPackageManager();
        pm.setComponentEnabledSetting(
                new ComponentName("com.example.android.apis", ".appwidget.ExampleBroadcastReceiver"),
                PackageManager.COMPONENT_ENABLED_STATE_ENABLED,
                PackageManager.DONT_KILL_APP);
    }
    public void onDisabled(Context context) {
        // When the first widget is created, stop listening for the TIMEZONE_CHANGED and
        // TIME_CHANGED broadcasts.
        Log.d(TAG, "onDisabled");
        Class clazz = ExampleBroadcastReceiver.class;
        PackageManager pm = context.getPackageManager();
        pm.setComponentEnabledSetting(
                new ComponentName("com.example.android.apis", ".appwidget.ExampleBroadcastReceiver"),
                PackageManager.COMPONENT_ENABLED_STATE_ENABLED,
                PackageManager.DONT_KILL_APP);
    }
    static void updateAppWidget(Context context, AppWidgetManager appWidgetManager,
            int appWidgetId, String titlePrefix) {
        Log.d(TAG, "updateAppWidget appWidgetId=" + appWidgetId + " titlePrefix=" + titlePrefix);
        // Getting the string this way allows the string to be localized.  The format
        // string is filled in using java.util.Formatter-style format strings.
        CharSequence text = context.getString(R.string.appwidget_text_format,
                ExampleAppWidgetConfigure.loadTitlePref(context, appWidgetId),
                "0x" + Long.toHexString(SystemClock.elapsedRealtime()));
        // Construct the RemoteViews object.  It takes the package name (in our case, it's our
        // package, but it needs this because on the other side it's the widget host inflating
        // the layout from our package).
        RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.appwidget_provider);
        views.setTextViewText(R.id.appwidget_text, text);
        // Tell the widget manager
        appWidgetManager.updateAppWidget(appWidgetId, views);
    }
}

4 app widht 配置Activity处理代码

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.android.apis.appwidget;
import android.app.Activity;
import android.appwidget.AppWidgetManager;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import java.util.ArrayList;
// Need the following import to get access to the app resources, since this
// class is in a sub-package.
import com.example.android.apis.R;
/**
 * The configuration screen for the ExampleAppWidgetProvider widget sample.
 */
public class ExampleAppWidgetConfigure extends Activity {
    static final String TAG = "ExampleAppWidgetConfigure";
    private static final String PREFS_NAME
            = "com.example.android.apis.appwidget.ExampleAppWidgetProvider";
    private static final String PREF_PREFIX_KEY = "prefix_";
    int mAppWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID;
    EditText mAppWidgetPrefix;
    public ExampleAppWidgetConfigure() {
        super();
    }
    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        // Set the result to CANCELED.  This will cause the widget host to cancel
        // out of the widget placement if they press the back button.
        setResult(RESULT_CANCELED);
        // Set the view layout resource to use.
        setContentView(R.layout.appwidget_configure);
        // Find the EditText
        mAppWidgetPrefix = (EditText)findViewById(R.id.appwidget_prefix);
        // Bind the action for the save button.
        findViewById(R.id.save_button).setOnClickListener(mOnClickListener);
        // Find the widget id from the intent. 
        Intent intent = getIntent();
        Bundle extras = intent.getExtras();
        if (extras != null) {
            mAppWidgetId = extras.getInt(
                    AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
        }
        // If they gave us an intent without the widget id, just bail.
        if (mAppWidgetId == AppWidgetManager.INVALID_APPWIDGET_ID) {
            finish();
        }
        mAppWidgetPrefix.setText(loadTitlePref(ExampleAppWidgetConfigure.this, mAppWidgetId));
    }
    View.OnClickListener mOnClickListener = new View.OnClickListener() {
        public void onClick(View v) {
            final Context context = ExampleAppWidgetConfigure.this;
            // When the button is clicked, save the string in our prefs and return that they
            // clicked OK.
            String titlePrefix = mAppWidgetPrefix.getText().toString();
            saveTitlePref(context, mAppWidgetId, titlePrefix);
            // Push widget update to surface with newly set prefix
            AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
            ExampleAppWidgetProvider.updateAppWidget(context, appWidgetManager,
                    mAppWidgetId, titlePrefix);
            // Make sure we pass back the original appWidgetId
            Intent resultValue = new Intent();
            resultValue.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, mAppWidgetId);
            setResult(RESULT_OK, resultValue);
            finish();
        }
    };
    // Write the prefix to the SharedPreferences object for this widget
    static void saveTitlePref(Context context, int appWidgetId, String text) {
        SharedPreferences.Editor prefs = context.getSharedPreferences(PREFS_NAME, 0).edit();
        prefs.putString(PREF_PREFIX_KEY + appWidgetId, text);
        prefs.commit();
    }
    // Read the prefix from the SharedPreferences object for this widget.
    // If there is no preference saved, get the default from a resource
    static String loadTitlePref(Context context, int appWidgetId) {
        SharedPreferences prefs = context.getSharedPreferences(PREFS_NAME, 0);
        String prefix = prefs.getString(PREF_PREFIX_KEY + appWidgetId, null);
        if (prefix != null) {
            return prefix;
        } else {
            return context.getString(R.string.appwidget_prefix_default);
        }
    }
    static void deleteTitlePref(Context context, int appWidgetId) {
    }
    static void loadAllTitlePrefs(Context context, ArrayList<Integer> appWidgetIds,
            ArrayList<String> texts) {
    }
}

配置文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    >
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/appwidget_configure_instructions"
    />
    <EditText
        android:id="@+id/appwidget_prefix"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
    />
    <Button
        android:id="@+id/save_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@android:string/ok"
    />
</LinearLayout>