请参阅下面的代码.
显示ListVIEw的方法是displayAlarmList().
我试图用来设置开关状态的方法是InitSwitches(),它在displayAlarmList()内部被调用.
在onCreate()方法中调用displayAlarmList().
public voID displayAlarmList(){ final String[] columns = {Database.getAlarmID(),Database.getAlarmTime(),Database.getAlarmname(),Database.getAlarmStatus(),Database.getAlarmRepeats()}; Cursor c = Database.selectAlarm(db,Database.gettablename(),columns,null,null); int[] to = new int[]{ R.ID.alarmID,R.ID.alarmTime,R.ID.alarmname,R.ID.alarmStatus,R.ID.alarmRepeats,}; SimpleCursorAdapter ca = new SimpleCursorAdapter(this,R.layout.alarm_info,c,to,0); lstAlarm.setAdapter(ca); InitSwitches(); lstAlarm.setonItemClickListener(new OnItemClickListener() { @OverrIDe public voID onItemClick(AdapterVIEw<?> ListVIEw,VIEw vIEw,int position,long ID) { Alarm alarm = new Alarm(); Cursor selectedCursor = (Cursor) ListVIEw.getItemAtposition(position); Switch s = (Switch) vIEw.findVIEwByID(R.ID.alarmSwitch); String whereArgs = Integer.toString(selectedCursor.getInt(selectedCursor.getColumnIndexOrThrow(Database.getAlarmID()))); Cursor data = Database.Rawquery(db,"SELECT * FROM " + Database.gettablename() + " WHERE " + Database.getAlarmID() + " = " + whereArgs); if (data.movetoFirst()) { alarm.setAlarmID(data.getString(data.getColumnIndexOrThrow(Database.getAlarmID()))); alarm.setAlarmname(data.getString(data.getColumnIndexOrThrow(Database.getAlarmname()))); alarm.setAlarmTime(data.getString(data.getColumnIndexOrThrow(Database.getAlarmTime()))); alarm.setAlarmSound(data.getString(data.getColumnIndexOrThrow(Database.getAlarmSound()))); alarm.setAlarmRepeats(data.getString(data.getColumnIndexOrThrow(Database.getAlarmRepeats()))); alarm.setAlarmStatus(data.getString(data.getColumnIndexOrThrow(Database.getAlarmStatus()))); } Intent i = new Intent(vIEw.getContext(),ScreenEdit.class); i.putExtra("editAlarm",new Gson().toJson(alarm)); startActivityForResult(i,EDIT_ALARM); } });}public voID InitSwitches(){ VIEw v; Switch s; int index = 0; String query = "Select " + Database.getAlarmID() + "," + Database.getAlarmStatus() + " FROM " + Database.gettablename(); Cursor statuses = Database.Rawquery(db,query); while (statuses.movetoNext()) { v = lstAlarm.getAdapter().getVIEw(index++,null); s = (Switch) v.findVIEwByID(R.ID.alarmSwitch); if (statuses.getString(statuses.getColumnIndexOrThrow(Database.getAlarmStatus())).equals("ON")){ s.toggle(); } else{ } }} ScreenShot of app
从屏幕截图中可以看出,第二行中的开关应该是ON,但事实并非如此.我也尝试了InvilIDateVIEw(),但没有工作.请帮忙.
解决方法 问题是ListVIEw是不断重绘的那些视图之一,这意味着这很糟糕,因为它会在重绘时失去状态if (statuses.getString(statuses.getColumnIndexOrThrow(Database.getAlarmStatus())).equals("ON")){ s.toggle();} 首先创建AlarmItem ……你应该根据自己的需要制作它.这是我的
public class AlarmItem { private String alarmname; private String alarmDescption; private boolean state; private long ID; public AlarmItem(String alarmname,String alarmDescption,long ID,boolean state) { this.alarmname = alarmname; this.alarmDescption = alarmDescption; this.ID = ID; this.state = state; } public long getID() { return ID; } public voID setID(long ID) { this.ID = ID; } public String getAlarmname() { return alarmname; } public voID setAlarmname(String alarmname) { this.alarmname = alarmname; } public String getAlarmDescption() { return alarmDescption; } public voID setAlarmDescption(String alarmDescption) { this.alarmDescption = alarmDescption; } public boolean getState() { return state; } public voID setState(boolean state) { this.state = state; }} 现在我们需要一个CustomSwitch类,因为：LINK
import androID.content.Context;import androID.util.AttributeSet;import androID.Widget.Switch;public class CustomSwitch extends Switch { private OnCheckedchangelistener mListener; public CustomSwitch(Context context) { super(context); } public CustomSwitch(Context context,AttributeSet attrs) { super(context,attrs); } public CustomSwitch(Context context,AttributeSet attrs,int defStyleAttr) { super(context,attrs,defStyleAttr); } public CustomSwitch(Context context,int defStyleAttr,int defStyleRes) { super(context,defStyleAttr,defStyleRes); } @OverrIDe public voID setonCheckedchangelistener(OnCheckedchangelistener Listener) { // Do not call supper method mListener = Listener; } @OverrIDe public voID setChecked(boolean checked) { super.setChecked(checked); if (mListener != null) { mListener.onCheckedChanged(this,checked); } } public voID setCheckedProgrammatically(boolean checked) { // You can call super method,it doesn't have a Listener... he he :) super.setChecked(checked); }} 创建一个布局文件并将其命名为alarm_List_item.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="50dp" androID:orIEntation="vertical"> <com.example.alarm.List.CustomSwitch androID:ID="@+ID/alarmSwitch" androID:layout_wIDth="wrap_content" androID:layout_height="wrap_content" androID:layout_alignParentRight="true" androID:layout_centerVertical="true" androID:layout_marginRight="10dp"/> <linearLayout androID:layout_wIDth="match_parent" androID:layout_height="wrap_content" androID:layout_marginleft="5dp" androID:layout_toleftOf="@ID/alarmSwitch" androID:orIEntation="vertical"> <TextVIEw androID:ID="@+ID/tvAlarmname" androID:layout_wIDth="match_parent" androID:layout_height="wrap_content" androID:layout_margintop="5dp" androID:text="Alarm name" androID:textSize="18sp"/> <TextVIEw androID:ID="@+ID/tvAlarmDesc" androID:layout_wIDth="match_parent" androID:layout_height="wrap_content" androID:layout_margintop="5dp" androID:text="Alarm description" androID:textSize="15sp"/> </linearLayout></relativeLayout>
现在主要布局 – > activity_main.xml中
<linearLayout xmlns:androID="http://schemas.androID.com/apk/res/androID" androID:layout_wIDth="match_parent" androID:layout_height="match_parent" androID:orIEntation="vertical"> <ListVIEw androID:ID="@+ID/lvAlarms" androID:layout_wIDth="match_parent" androID:layout_height="match_parent"/></linearLayout>
现在我们需要一个负责绘制项目及其处理的适配器.将类命名为AlarmAdapter
import androID.content.Context;import androID.vIEw.LayoutInflater;import androID.vIEw.VIEw;import androID.vIEw.VIEwGroup;import androID.Widget.BaseAdapter;import androID.Widget.Compoundbutton;import androID.Widget.TextVIEw;import java.util.List;public class AlarmAdapter extends BaseAdapter { private List<AlarmItem> listofAlarms; private Context context; private OnAlarmCheckedchangelistener mCallback; // avoID constant allocation private VIEw tmpVIEw; private AlarmItemVIEwHolder mHolder; private AlarmItem tmpItem; public AlarmAdapter(List<AlarmItem> listofAlarms,Context context,OnAlarmCheckedchangelistener callBack) { this.listofAlarms = listofAlarms; this.context = context; mCallback = callBack; } @OverrIDe public int getCount() { return listofAlarms == null ? 0 : listofAlarms.size(); } @OverrIDe public AlarmItem getItem(int i) { return listofAlarms == null ? null : listofAlarms.get(i); } @OverrIDe public long getItemID(int i) { return 0; } @OverrIDe public VIEw getVIEw(final int i,VIEwGroup vIEwGroup) { tmpItem = listofAlarms.get(i); if (vIEw == null) { LayoutInflater inflater = LayoutInflater.from(context); tmpVIEw = inflater.inflate(R.layout.alarm_List_item,false); mHolder = new AlarmItemVIEwHolder(tmpVIEw); tmpVIEw.setTag(mHolder); } else { tmpVIEw = vIEw; mHolder = (AlarmItemVIEwHolder) vIEw.getTag(); } mHolder.getAlarmnameTextVIEw().setText(tmpItem.getAlarmname()); mHolder.getAlarmDescriptionTextVIEw().setText(tmpItem.getAlarmDescption()); mHolder.getSwitch().setCheckedProgrammatically(tmpItem.getState()); mHolder.getSwitch().setonCheckedchangelistener(new Compoundbutton.OnCheckedchangelistener() { @OverrIDe public voID onCheckedChanged(Compoundbutton compoundbutton,boolean b) { listofAlarms.get(i).setState(b); mCallback.onAlarmStateChanged(listofAlarms.get(i),i); } }); return tmpVIEw; } public voID clear() { listofAlarms.clear(); notifyDataSetChanged(); } public voID refill(List<AlarmItem> listofAlarms) { this.listofAlarms = listofAlarms; notifyDataSetChanged(); } public voID toggleAllSwitches() { for (AlarmItem item : listofAlarms) { item.setState(!item.getState()); } notifyDataSetChanged(); } public interface OnAlarmCheckedchangelistener { public voID onAlarmStateChanged(AlarmItem item,int postionInList); } private class AlarmItemVIEwHolder { VIEw base; CustomSwitch mSwitch; TextVIEw mAlarmname; TextVIEw mAlarmDescription; public AlarmItemVIEwHolder(VIEw base) { this.base = base; } public CustomSwitch getSwitch() { if (mSwitch == null) { mSwitch = (CustomSwitch) base.findVIEwByID(R.ID.alarmSwitch); } return mSwitch; } public TextVIEw getAlarmnameTextVIEw() { if (mAlarmname == null) { mAlarmname = (TextVIEw) base.findVIEwByID(R.ID.tvAlarmname); } return mAlarmname; } public TextVIEw getAlarmDescriptionTextVIEw() { if (mAlarmDescription == null) { mAlarmDescription = (TextVIEw) base.findVIEwByID(R.ID.tvAlarmDesc); } return mAlarmDescription; } }} 现在终于进入了MainActivity
import androID.app.Actionbar;import androID.os.Bundle;import androID.os.Handler;import androID.os.Looper;import androID.support.v7.app.ActionBaractivity;import androID.vIEw.VIEw;import androID.Widget.AdapterVIEw;import androID.Widget.ListVIEw;import androID.Widget.Toast;import java.util.ArrayList;import java.util.List;public class MainActivity extends ActionBaractivity implements AdapterVIEw.OnItemClickListener,AlarmAdapter.OnAlarmCheckedchangelistener { private ListVIEw ListVIEw; private AlarmAdapter adapter; private Toast toast; private Handler handler; private Runnable handlerRunnable; @OverrIDe protected voID onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentVIEw(R.layout.activity_main); // Make a nice actionbar Title Actionbar ab = getActionbar(); if (ab != null) { ab.setTitle("Alarm List"); } ListVIEw = (ListVIEw) findVIEwByID(R.ID.lvAlarms); // Simulating alarms from database. You need to convert your items to these List<AlarmItem> alarmsFromDb = new ArrayList<>(); alarmsFromDb.add(new AlarmItem("Alarm 1","Lalalala",1,true)); alarmsFromDb.add(new AlarmItem("Alarm 2","something",2,false)); alarmsFromDb.add(new AlarmItem("Alarm 3","gfdgdf",3,true)); alarmsFromDb.add(new AlarmItem("Alarm 4","sda",4,true)); alarmsFromDb.add(new AlarmItem("Alarm 5","yxcxyc",5,false)); alarmsFromDb.add(new AlarmItem("Alarm 6","dsfsd",6,false)); adapter = new AlarmAdapter(alarmsFromDb,this,this); ListVIEw.setAdapter(adapter); ListVIEw.setonItemClickListener(this); // Toggle all switches after 5s... this is what you need,right? handlerRunnable = new Runnable() { @OverrIDe public voID run() { adapter.toggleAllSwitches(); showToast("All switches toggeled :)"); } }; handler = new Handler(Looper.getMainLooper()); handler.postDelayed(handlerRunnable,5 * 1000); } @OverrIDe protected voID onDestroy() { super.onDestroy(); if (handler != null) { handler.removeCallbacks(handlerRunnable); handler = null; handlerRunnable = null; } } private voID showToast(String str) { if (toast != null) { toast.cancel(); } toast = Toast.makeText(this,str,Toast.LENGTH_SHORT); toast.show(); } @OverrIDe public voID onAlarmStateChanged(AlarmItem item,int postionInList) { String onOff = item.getState() ? "ON" : "OFF"; showToast("Alarm " + item.getAlarmname() + " is: " + onOff); } @OverrIDe public voID onItemClick(AdapterVIEw<?> parent,long ID) { AlarmItem item = adapter.getItem(position); showToast("Alarm " + item.getAlarmname() + " clicked"); }} 如果您有任何问题,这是完整的androID工作室项目：LINK
现在,您只需将数据库中的结果转换为此列表或修改AlarmItem和UI.此解决方案将起作用,您已在适配器中使用了一些有用的方法.
快乐的编码！
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