我正在开发一款Android应用程序来处理该领域技术人员的工作人员
首先让我解释一下我的应用程序的布局：
该应用程序的主要部分包含3个选项卡
标签1 - 主页标签
- 包含当前打开的工作人员的摘要
选项卡2 - 指定的工作单选项卡
- 包含当前分配给登录用户的工作单列表
选项卡3 - 未分配的工作单选项卡
- 包含分配给用户工作人员的工作人员列表，但不包含给特定人员
我使用一个名为“Database”的类，它是一个Singleton类，它是Application上下文的一部分，因此可以在整个应用程序中访问它。我将在下面加入一些代码
以下是问题：
当用户单击列表中的特定工作订单时，将启动工作订单详细信息活动，显示有关工作订单的各种信息。如果工作订单是“未分配”工作订单，它还会显示“取得所有权”按钮，将“所有者”字段更改为当前用户，将其从未分配的列表中删除，然后将其添加到该用户的指定列表中。但是，一旦用户点击后退按钮关闭工作订单详细信息屏幕（活动），然后返回到选项卡视图，列表就不会更新，直到您以某种方式强制视图刷新（例如在列表上向下滚动，以便刚改变所有权的工作单是在屏幕外。
我试过了：
- 将自定义ListAdapter移动到Database（singleton）类中并通过那里访问它
- 在列表适配器上调用“notifyDataSetChanged（）”
有没有人有任何关于如何在每次选择标签时更新它的想法（或通过点击后退按钮解雇工作单细节屏幕）？我一直在寻找一个解决方案，并没有成功找到我找到的任何东西，所以我再次在这里发布，知道这里的大多数人都比我聪明！
提前感谢您的帮助！我在下面列出了相关代码：
数据库类：
public class Database extends Application {
private static Database instance = null;
private ArrayList<Workorder> assignedwolist;
private ArrayList<Workorder> unassignedwolist;
private Credentials creds;
private WOListAdapter assignedadapter;
private WOListAdapter unassignedadapter;
private static void checkInstance() {
if(instance==null) {
throw new IllegalStateException("Database class not created yet!");
}
}
@Override
public void onCreate() {
super.onCreate();
instance=this;
}
public Database() {
this.creds=null;
this.assignedwolist = getAssignedWorkorders();
this.unassignedwolist = getUnassignedWorkorders();
this.assignedadapter=new WOListAdapter(this,getAssignedWorkorders());
this.unassignedadapter=new WOListAdapter(this,getUnassignedWorkorders());
}
public ArrayList<String> getSummary() {
int numassigned = assignedwolist.size();
int assignedp1 = 0;
for(Workorder wo:assignedwolist) {
if(wo.getPriority().equalsIgnoreCase("1")) {
assignedp1++;
}
}
int numunassigned = unassignedwolist.size();
int unassignedp1 = 0;
for(Workorder wo:unassignedwolist) {
if(wo.getPriority().equalsIgnoreCase("1")) {
unassignedp1++;
}
}
ArrayList<String> summary = new ArrayList<String>();
summary.add(Integer.toString(numassigned));
summary.add(Integer.toString(assignedp1));
summary.add(Integer.toString(numunassigned));
summary.add(Integer.toString(unassignedp1));
return summary;
}
public Workorder getWO(String id) {
for(Workorder wo:assignedwolist) {
if(wo.getId().equalsIgnoreCase(id)) {
return wo;
}
}
for(Workorder wo:unassignedwolist) {
if(wo.getId().equalsIgnoreCase(id)) {
return wo;
}
}
return null;
}
public ArrayList<Workorder> getAssignedWorkorders() {
return assignedwolist;
}
public ArrayList<Workorder> getUnassignedWorkorders() {
return unassignedwolist;
}
public void setValidated(boolean validated) {
this.validated = validated;
}
public boolean isValidated() {
return validated;
}
public void takeOwnership(String wonum) {
Workorder wo;
for(int i=0;i<unassignedwolist.size();i++) {
if(unassignedwolist.get(i).getId().equalsIgnoreCase(wonum)) {
wo = unassignedwolist.remove(i);
wo.setOwner(creds.getUsername());
assignedwolist.add(wo);
Collections.sort(assignedwolist);
return;
}
}
this.assignedadapter.notifyDataSetChanged();
this.unassignedadapter.notifyDataSetChanged();
}
public WOListAdapter getAssignedAdapter() {
return assignedadapter;
}
public WOListAdapter getUnassignedAdapter() {
return unassignedadapter;
}
}
主应用程序（包含标签）：
public class MainApp extends TabActivity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.tab);
/*Tab host for tabs */
TabHost tabHost = (TabHost)findViewById(android.R.id.tabhost);// The activity TabHost
TabSpec hometabspec = tabHost.newTabSpec("Home");
TabSpec assignedtabspec = tabHost.newTabSpec("Assigned");
TabSpec unassignedtabspec = tabHost.newTabSpec("Unassigned");
hometabspec.setIndicator("Home",getResources().getDrawable(R.drawable.ic_tab_home)).setContent(new Intent(this,HomeActivity.class));
assignedtabspec.setIndicator("Assigned",getResources().getDrawable(R.drawable.ic_tab_assigned)).setContent(new Intent(this,AssignedActivity.class));
unassignedtabspec.setIndicator("Unassigned",getResources().getDrawable(R.drawable.ic_tab_unassigned)).setContent(new Intent(this,UnassignedActivity.class));
tabHost.addTab(hometabspec);
tabHost.addTab(assignedtabspec);
tabHost.addTab(unassignedtabspec);
tabHost.getTabWidget().setCurrentTab(0);
}
}
AssignedActivity：
public class AssignedActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Database db = (Database)getApplicationContext();
setContentView(R.layout.wolist);
ListView listview =(ListView)findViewById(R.id.wolistview);
listview.setTextFilterEnabled(false);
WOListAdapter wolistadapter = db.getAssignedAdapter();
listview.setAdapter(wolistadapter);
listview.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterview, View view, int position,
long arg3) {
Workorder wo = (Workorder)adapterview.getItemAtPosition(position);
Intent i = new Intent();
i.setClass(AssignedActivity.this,WorkorderDetailActivity.class);
i.putExtra("wonum",wo.getId());
startActivity(i);
}
});
}
}
UnassignedActivity：
public class UnassignedActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Database db = (Database)getApplicationContext();
setContentView(R.layout.wolist);
ListView listview =(ListView)findViewById(R.id.wolistview);
listview.setTextFilterEnabled(false);
WOListAdapter wolistadapter = db.getUnassignedAdapter();
listview.setAdapter(wolistadapter);
listview.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterview, View view, int position,
long arg3) {
Workorder wo = (Workorder)adapterview.getItemAtPosition(position);
Intent i = new Intent();
i.setClass(UnassignedActivity.this,WorkorderDetailActivity.class);
i.putExtra("wonum",wo.getId());
startActivity(i);
}
});
}
}
WorkorderDetailActivity：
public class WorkorderDetailActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Database db = (Database)getApplicationContext();
final Workorder wo;
Bundle extras = getIntent().getExtras();
if(extras!=null) {
//Set Fields
wo = db.getWO(extras.getString("wonum"));
setContentView(R.layout.wodetail);
TextView tv=(TextView)findViewById(R.id.wonumview);
tv.setTextSize(20);
tv.setText(wo.getId());
tv=(TextView)findViewById(R.id.wodescriptionview);
tv.setTextSize(18);
tv.setText(wo.getDescription());
tv=(TextView)findViewById(R.id.wolocationview);
tv.setTextSize(18);
tv.setText(wo.getLocation());
tv=(TextView)findViewById(R.id.wostatusview);
tv.setTextSize(18);
tv.setText(wo.getStatus());
tv=(TextView)findViewById(R.id.woreporteddateview);
tv.setTextSize(18);
tv.setText(wo.getReportdate().substring(0, 19));
tv=(TextView)findViewById(R.id.wotypeview);
tv.setTextSize(18);
tv.setText(wo.getType());
//Assigned or Unassigned adjustments
tv=(TextView)findViewById(R.id.woownerview);
Button b = (Button)findViewById(R.id.TakeOwnershipButton);
if(wo.getOwner().equalsIgnoreCase("none")) { //Display TakeOwnership button
b.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Database db = (Database)getApplicationContext();
db.takeOwnership(wo.getId());
Button b = (Button)findViewById(R.id.TakeOwnershipButton);
TextView tv=(TextView)findViewById(R.id.woownerview);
b.setVisibility(View.INVISIBLE);
tv.setVisibility(View.VISIBLE);
tv.setTextSize(18);
tv.setText(wo.getOwner());
}
});
b.setVisibility(View.VISIBLE);
tv.setVisibility(View.INVISIBLE);
} else { //Display owner
b.setVisibility(View.INVISIBLE);
tv.setVisibility(View.VISIBLE);
tv.setTextSize(18);
tv.setText(wo.getOwner());
}
//Icon color adjustment based on priority
ImageView icon = (ImageView)findViewById(R.id.woiconview);
switch(wo.getPriorityNum()) {
case 1: icon.setColorFilter(Color.RED); break;
case 2: icon.setColorFilter(Color.YELLOW); break;
case 3: icon.setColorFilter(Color.GREEN); break;
case 4: icon.setColorFilter(Color.BLUE); break;
default: icon.setColorFilter(Color.TRANSPARENT); break;
}
//Status change options
Spinner s = (Spinner)findViewById(R.id.wostatusselector);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, db.getValidStatuses(wo.getStatus()));
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
s.setAdapter(adapter);
} else { //No wonum was passed in!
TextView tv = new TextView(this);
tv.setText("Error Retrieving Workorder");
setContentView(tv);
}
}
}
答案 0 :(得分：2)
我使用setOnTabChanged（）更新Google Analytics并从AdMob请求新添加：
tabHost.setOnTabChangedListener(new OnTabChangeListener(){
public void onTabChanged(String tabId) {
tracker.dispatch();
adView.requestFreshAd();
}});