如何从android中的后台服务填充进度条百分比。我有一个可扩展的列表视图，每个子项目都有一个下载图标。点击该图标，我需要下载与该项目相关的媒体。如果用户点击下载图标并立即关闭应用程序，那么我们仍然需要下载资源并在下载后显示通知。但我无法弄清楚如何从后台服务填充进度条。请帮帮我。
以下是代码：
服务
public class MyService extends Service {
public MyService() {
}
static int i =0;
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
//TODO do something useful
System.out.println("Intent values .... "+intent.getStringExtra("KEY1"));
new DownloadResource().execute();
return Service.START_STICKY;
}
@Override
public IBinder onBind(Intent intent) {
// TODO: Return the communication channel to the service.
throw new UnsupportedOperationException("Not yet implemented");
}
@Override
public void onDestroy(){
super.onDestroy();
}
public class DownloadResource extends AsyncTask<String, Integer, String> {
@Override
protected String doInBackground(String... strings) {
//download the file here
return null;
}
protected void onPostExecute(String result) {
Notification.InboxStyle inboxStyle = new Notification.InboxStyle();
NotificationManager nManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
final Notification.Builder builder = new Notification.Builder(getBaseContext());
builder.setContentTitle("Lanes");
builder.setContentText("Starting ...");
builder.setSmallIcon(R.mipmap.ic_launcher);
builder.setAutoCancel(true);
inboxStyle.setBigContentTitle("Enter Content Text");
inboxStyle.addLine("hi events "+i);
builder.setStyle(inboxStyle);
nManager.notify("App Name",1000,builder.build());
}
@Override
protected void onProgressUpdate(Integer... values) {
//need to fill progres update here
super.onProgressUpdate(values);
}
}
}
我的活动代码：
public class MainActivity2 extends AppCompatActivity {
ExpandableListView expandableListView;
ExpandableListAdapter expandableListAdapter;
List<String> expandableListTitle;
HashMap<String, List<String>> expandableListDetail;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.android_listview);
expandableListView = (ExpandableListView) findViewById(R.id.expandableListView);
expandableListDetail = ExpandableListDataPump.getData();
expandableListTitle = new ArrayList<String>(expandableListDetail.keySet());
expandableListAdapter = new CustomExpandableListAdapter(this, expandableListTitle, expandableListDetail);
expandableListView.setAdapter(expandableListAdapter);
expandableListView.setOnGroupExpandListener(new ExpandableListView.OnGroupExpandListener() {
@Override
public void onGroupExpand(int groupPosition) {
Toast.makeText(getApplicationContext(),
expandableListTitle.get(groupPosition) + " List Expanded.",
Toast.LENGTH_SHORT).show();
}
});
expandableListView.setOnGroupCollapseListener(new ExpandableListView.OnGroupCollapseListener() {
@Override
public void onGroupCollapse(int groupPosition) {
Toast.makeText(getApplicationContext(),
expandableListTitle.get(groupPosition) + " List Collapsed.",
Toast.LENGTH_SHORT).show();
}
});
expandableListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView parent, View v,
int groupPosition, int childPosition, long id) {
Toast.makeText(
getApplicationContext(),
expandableListTitle.get(groupPosition)
+ " -> "
+ expandableListDetail.get(
expandableListTitle.get(groupPosition)).get(
childPosition), Toast.LENGTH_SHORT
).show();
return false;
}
});
}
}
活动xml文件：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ExpandableListView
android:id="@+id/expandableListView"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:indicatorLeft="?android:attr/expandableListPreferredItemIndicatorLeft"
android:divider="@android:color/darker_gray"
android:dividerHeight="0.5dp" />
</LinearLayout>
适配器：
public class CustomExpandableListAdapter extends BaseExpandableListAdapter {
private Context context;
private List<String> expandableListTitle;
private HashMap<String, List<String>> expandableListDetail;
public CustomExpandableListAdapter(Context context, List<String> expandableListTitle,
HashMap<String, List<String>> expandableListDetail) {
this.context = context;
this.expandableListTitle = expandableListTitle;
this.expandableListDetail = expandableListDetail;
}
@Override
public Object getChild(int listPosition, int expandedListPosition) {
return this.expandableListDetail.get(this.expandableListTitle.get(listPosition))
.get(expandedListPosition);
}
@Override
public long getChildId(int listPosition, int expandedListPosition) {
return expandedListPosition;
}
@Override
public View getChildView(int listPosition, final int expandedListPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
final String expandedListText = (String) getChild(listPosition, expandedListPosition);
if (convertView == null) {
LayoutInflater layoutInflater = (LayoutInflater) this.context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = layoutInflater.inflate(R.layout.list_item, null);
}
final TextView expandedListTextView = (TextView) convertView
.findViewById(R.id.expandedListItem);
ImageView imageView =(ImageView) convertView.findViewById(R.id.download);
final ProgressBar progressBar = (ProgressBar) convertView.findViewById(R.id.progressBar_cyclic);
imageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
progressBar.setVisibility(View.VISIBLE);
Intent i =new Intent(context,MyService.class);
i.putExtra("KEY1",expandedListTextView.getText().toString());
context.startService(i);
}
});
expandedListTextView.setText(expandedListText);
return convertView;
}
@Override
public int getChildrenCount(int listPosition) {
return this.expandableListDetail.get(this.expandableListTitle.get(listPosition))
.size();
}
@Override
public Object getGroup(int listPosition) {
return this.expandableListTitle.get(listPosition);
}
@Override
public int getGroupCount() {
return this.expandableListTitle.size();
}
@Override
public long getGroupId(int listPosition) {
return listPosition;
}
@Override
public View getGroupView(int listPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
String listTitle = (String) getGroup(listPosition);
if (convertView == null) {
LayoutInflater layoutInflater = (LayoutInflater) this.context.
getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = layoutInflater.inflate(R.layout.list_group, null);
}
TextView listTitleTextView = (TextView) convertView
.findViewById(R.id.listTitle);
listTitleTextView.setTypeface(null, Typeface.BOLD);
listTitleTextView.setText(listTitle);
return convertView;
}
@Override
public boolean hasStableIds() {
return false;
}
@Override
public boolean isChildSelectable(int listPosition, int expandedListPosition) {
return true;
}
}
适配器组xml文件：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/listTitle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="?android:attr/expandableListPreferredItemPaddingLeft"
android:textColor="@android:color/black"
android:paddingTop="10dp"
android:paddingBottom="10dp" />
</LinearLayout>
Adapter child xml：
<?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="wrap_content"
android:padding="20dp"
>
<TextView
android:id="@+id/expandedListItem"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="?android:attr/expandableListPreferredChildPaddingLeft"
android:text="hdhdh"
/>
<ImageView
android:layout_width="24dp"
android:layout_height="24dp"
android:id="@+id/download"
android:layout_alignParentRight="true"
android:layout_marginTop="13dp"
android:layout_marginRight="13dp"
android:src="@mipmap/ic_cloud_download_black_24dp"
/>
<ProgressBar
android:id="@+id/progressBar_cyclic"
android:layout_width="50dp"
android:layout_height="50dp"
android:minHeight="50dp"
android:minWidth="50dp"
android:layout_alignParentRight="true"
android:visibility="gone"
/>
</RelativeLayout>
答案 0 :(得分：0)
您应该找到并使用一个用于在系统中的组件之间进行通信的工具。 Android提供LocalBroadcastManager。有些人更喜欢使用活动总线库。您将必须学习如何使用这些工具之一，并连接组件，以便可以发布状态更新，另一个可以接收它们。