java - 更新选项卡中的 ListView(Android 应用程序)

Question

我正在开发一款 Android 应用程序来处理现场技术人员的工单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
- 包含当前打开的工单的摘要

标签 2 - 分配的工单标签
- 包含当前分配给登录用户的工单列表

标签 3 - 未分配的工单标签
- 包含分配给用户工作人员但不分配给特定人员的工单列表

我使用一个名为“数据库”的类，它是一个单例类，是应用程序上下文的一部分，因此可以在整个应用程序中访问它。我将在下面包含一些代码

问题来了:
当用户单击列表中的特定工单时，将启动工单详细信息 Activity ，显示有关该工单的各种信息。如果工单是“未分配”的，它还会显示一个“取得所有权”按钮，将“所有者”字段更改为当前用户，将其从未分配列表中删除，并将其添加到该用户的已分配列表中。但是，一旦用户点击后退按钮关闭工作单详细信息屏幕( Activity )，并返回到选项卡 View ，列表不会更新，直到您以某种方式强制刷新 View (例如在列表上向下滚动，以便刚刚更改所有权的工单不在屏幕上)。

我试过:
- 将自定义 ListAdapter 移动到数据库(单例)类中并通过那里访问它- 在列表适配器上调用“notifyDataSetChanged()”

有没有人知道如何在每次选择选项卡时更新它(或者通过点击后退按钮关闭工作单详细信息屏幕)？我一直在网上搜索以寻找解决方案，但没有成功，所以我再次在这里发帖，我知道这里的大多数人都比我聪明!

在此先感谢您的帮助!我在下面包含了相关代码:

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(包含选项卡):

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);
    }
}

分配的 Activity :

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);
            }
        });
    } 
}

未分配的 Activity :

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);
            }
        });
    }
}

工单详情 Activity :

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);
        }
    }
}

Answer 1

我使用 setOnTabChanged() 来更新 Google Analytics 并从 AdMob 请求新添加:

tabHost.setOnTabChangedListener(new OnTabChangeListener(){
            public void onTabChanged(String tabId) {
                tracker.dispatch();
                adView.requestFreshAd();
            }});