Android Widget例子解析

下面的代码分为3个文件可以清楚的看到整个框架，主要是AppWidgetProvider类中的onUpdate、onDeleted、onEnabled、onDisabled和updateAppWidget方法之间的状态改变，使用Logcat仔细分析一个widget的生命周期。
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;
import com.example.android.apis.R; 
涉及到的文件有

ExampleAppWidgetConfigure.java
ExampleBroadcastReceiver.java
res/layout/appwidget_configure.xml
res/layout/appwidget_provider.xml
res/xml/appwidget_provider.xml

public class ExampleAppWidgetProvider extends AppWidgetProvider {

private static final String TAG = "ExampleAppWidgetProvider"; //logcat调试信息 
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
Log.d(TAG, "onUpdate");

// - 创建一个RemoteViews 对象
// - 设置RemoteViews 对象的文本
// - 告诉AppWidgetManager 显示 views对象给widget. 
final int N = appWidgetIds.length;
for (int i=0; i public void onEnabled(Context context) {
Log.d(TAG, "onEnabled");
// 当widget创建时注册TIMEZONE_CHANGED和 TIME_CHANGED改变的广播获取这些时间和区域的改变事件

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) {

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);

CharSequence text = context.getString(R.string.appwidget_text_format,
ExampleAppWidgetConfigure.loadTitlePref(context, appWidgetId),
"0x" + Long.toHexString(SystemClock.elapsedRealtime())); 
RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.appwidget_provider);
views.setTextViewText(R.id.appwidget_text, text); 
appWidgetManager.updateAppWidget(appWidgetId, views);
}
} 

package com.example.android.apis.appwidget; 
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.os.SystemClock;
import android.util.Log;
import android.widget.RemoteViews; 
import java.util.ArrayList; 

import com.example.android.apis.R; 

public class ExampleBroadcastReceiver extends BroadcastReceiver { 
public void onReceive(Context context, Intent intent) {
Log.d("ExmampleBroadcastReceiver", "intent=" + intent); 
// For our example, we'll also update all of the widgets when the timezone
// changes, or the user or network sets the time.
String action = intent.getAction();
if (action.equals(Intent.ACTION_TIMEZONE_CHANGED)
|| action.equals(Intent.ACTION_TIME_CHANGED)) {
AppWidgetManager gm = AppWidgetManager.getInstance(context);
ArrayList appWidgetIds = new ArrayList();
ArrayList texts = new ArrayList(); 
ExampleAppWidgetConfigure.loadAllTitlePrefs(context, appWidgetIds, texts); 
final int N = appWidgetIds.size();
for (int i=0; i}

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; 

import com.example.android.apis.R; 

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); 
setResult(RESULT_CANCELED); 
setContentView(R.layout.appwidget_configure); 
mAppWidgetPrefix = (EditText)findViewById(R.id.appwidget_prefix); 
findViewById(R.id.save_button).setOnClickListener(mOnClickListener); 
Intent intent = getIntent();
Bundle extras = intent.getExtras();
if (extras != null) {
mAppWidgetId = extras.getInt(
AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
} 
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; 
String titlePrefix = mAppWidgetPrefix.getText().toString();
saveTitlePref(context, mAppWidgetId, titlePrefix); 
AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
ExampleAppWidgetProvider.updateAppWidget(context, appWidgetManager,
mAppWidgetId, titlePrefix); 
Intent resultValue = new Intent();
resultValue.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, mAppWidgetId);
setResult(RESULT_OK, resultValue);
finish();
}
}; 
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();
}