【发布时间】：2016-11-17 12:46:21
【问题描述】：
我想用ListView 实现小部件，当用户调整小部件的大小时，我想在列表中添加一个标题。我想实现这样的目标：
这是布局的代码：
这是行项目的布局 (list_row.xml)：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:background="@android:color/black" >
<TextView
android:id="@+id/heading"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:layout_alignParentLeft="true"
android:textColor="@color/white"
android:singleLine="true"
android:textSize="14sp"
android:textStyle="bold"
android:text="Heading"/>
<TextView
android:id="@+id/content"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:layout_alignParentLeft="true"
android:layout_below="@id/heading"
android:layout_marginTop="5dip"
android:textSize="14sp"
android:text="Content"/>
</RelativeLayout>
这是小部件初始布局的代码：
<?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"
android:background="@android:color/black" >
<ListView
android:id="@+id/listViewWidget"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
这是表头布局的代码：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/lay2">
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:text="Header List View"
android:textColor="@color/pink"
android:textAppearance="?android:attr/textAppearanceLarge"
/>
</RelativeLayout>
这是小部件元数据的代码：
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
android:initialLayout="@layout/widget_layout"
android:minHeight="40dip"
android:minWidth="40dip"
android:resizeMode="vertical|horizontal"
android:updatePeriodMillis="1800000"
>
</appwidget-provider>
这里是小部件提供者的代码：
public class WidgetProvider extends AppWidgetProvider {
@Override
public void onAppWidgetOptionsChanged(Context context, AppWidgetManager appWidgetManager, int appWidgetId, Bundle newOptions) {
//super.onAppWidgetOptionsChanged(context, appWidgetManager, appWidgetId, newOptions);
// See the dimensions and
Bundle options = appWidgetManager.getAppWidgetOptions(appWidgetId);
// Get min width and height.
int minWidth = options.getInt(AppWidgetManager.OPTION_APPWIDGET_MIN_WIDTH);
int minHeight = options.getInt(AppWidgetManager.OPTION_APPWIDGET_MIN_HEIGHT);
// Obtain appropriate widget and update it.
appWidgetManager.updateAppWidget(appWidgetId, getRemoteViews(context, minWidth, minHeight));
super.onAppWidgetOptionsChanged(context, appWidgetManager, appWidgetId, newOptions);
}
private RemoteViews getRemoteViews(Context context, int minWidth, int minHeight) {
// First find out rows and columns based on width provided.
int rows = getCellsForSize(minHeight);
int columns = getCellsForSize(minWidth);
// Now you changing layout base on you column count
// In this code from 1 column to 4
// you can make code for more columns on your own.
switch (rows) {
case 1: return new RemoteViews(context.getPackageName(), R.layout.widget_layout);
case 2:
//return new RemoteViews(context.getPackageName(), R.layout.activity_layout_widget_4column);
RemoteViews update2 = new RemoteViews(context.getPackageName(), R.layout.text_view_layout);
//for(int i = 0; i < 3; i++) {
RemoteViews textView = new RemoteViews(context.getPackageName(), R.layout.widget_layout);
//textView.setTextViewText(R.id.textView1, "TextView number " + String.valueOf(i));
update2.addView(R.id.lay2, textView);
//}
return update2;
case 3:
//return new RemoteViews(context.getPackageName(), R.layout.activity_layout_widget_4column);
RemoteViews update3 = new RemoteViews(context.getPackageName(), R.layout.text_view_layout);
//for(int i = 0; i < 3; i++) {
RemoteViews textView1 = new RemoteViews(context.getPackageName(), R.layout.widget_layout);
//textView.setTextViewText(R.id.textView1, "TextView number " + String.valueOf(i));
update3.addView(R.id.lay2, textView1);
//}
return update3;
case 4:
//return new RemoteViews(context.getPackageName(), R.layout.activity_layout_widget_4column);
RemoteViews update4 = new RemoteViews(context.getPackageName(), R.layout.text_view_layout);
//for(int i = 0; i < 3; i++) {
RemoteViews textView3 = new RemoteViews(context.getPackageName(), R.layout.widget_layout);
//textView.setTextViewText(R.id.textView1, "TextView number " + String.valueOf(i));
update4.addView(R.id.lay2, textView3);
//}
return update4;
default: return null;
}
}
private static int getCellsForSize(int size) {
int n = 2;
while (70 * n - 30 < size) {
++n;
}
return n - 1;
}
@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
final int N = appWidgetIds.length;
for (int i = 0; i < N; ++i) {
RemoteViews remoteViews = updateWidgetListView(context,
appWidgetIds[i]);
appWidgetManager.updateAppWidget(appWidgetIds[i],
remoteViews);
}
super.onUpdate(context, appWidgetManager, appWidgetIds);
}
private RemoteViews updateWidgetListView(Context context,
int appWidgetId) {
//which layout to show on widget
RemoteViews remoteViews = new RemoteViews(
context.getPackageName(),R.layout.widget_layout);
//RemoteViews Service needed to provide adapter for ListView
Intent svcIntent = new Intent(context, WidgetService.class);
//passing app widget id to that RemoteViews Service
svcIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
//setting a unique Uri to the intent
//don't know its purpose to me right now
svcIntent.setData(Uri.parse(
svcIntent.toUri(Intent.URI_INTENT_SCHEME)));
//setting adapter to listview of the widget
remoteViews.setRemoteAdapter(appWidgetId, R.id.listViewWidget,
svcIntent);
return remoteViews;
}
}
这是WidgetService的代码：
public class WidgetService extends RemoteViewsService{
@Override
public RemoteViewsFactory onGetViewFactory(Intent intent) {
int appWidgetId = intent.getIntExtra(
AppWidgetManager.EXTRA_APPWIDGET_ID,
AppWidgetManager.INVALID_APPWIDGET_ID);
return (new ListProvider(this.getApplicationContext(), intent));
}
}
这是ListProvider的代码：
public class ListProvider implements RemoteViewsService.RemoteViewsFactory{
private ArrayList listItemList = new ArrayList();
private Context context = null;
private int appWidgetId;
public ListProvider(Context context, Intent intent) {
this.context = context;
appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,
AppWidgetManager.INVALID_APPWIDGET_ID);
populateListItem();
}
private void populateListItem() {
for (int i = 0; i < 6; i++) {
ListItem listItem = new ListItem();
listItem.heading = "Heading" + i;
listItem.content = i + " This is the content of the app widget listview.Nice content though";
listItemList.add(listItem);
}
}
@Override
public int getCount() {
return listItemList.size();
}
@Override
public void onCreate() {
}
@Override
public void onDataSetChanged() {
}
@Override
public void onDestroy() {
}
@Override
public RemoteViews getLoadingView() {
return null;
}
@Override
public int getViewTypeCount() {
return 1;
}
@Override
public boolean hasStableIds() {
return false;
}
@Override
public long getItemId(int position) {
return position;
}
/*
*Similar to getView of Adapter where instead of View
*we return RemoteViews
*
*/
@Override
public RemoteViews getViewAt(int position) {
final RemoteViews remoteView = new RemoteViews(
context.getPackageName(), R.layout.list_row);
ListItem listItem = (ListItem)listItemList.get(position);
remoteView.setTextViewText(R.id.heading, listItem.heading);
remoteView.setTextViewText(R.id.content, listItem.content);
return remoteView;
}
}
这是ListItem的代码：
public class ListItem {
public String heading,content;
}
但是在调整大小时我得到了这个结果：
ListView 不见了。有人知道为什么吗？
【问题讨论】：
标签： android android-layout listview android-widget