问题是 ListView 是不断重绘的视图之一，这意味着这很糟糕，因为重绘时它会丢失状态
if (statuses.getString(statuses.getColumnIndexOrThrow(Database.getAlarmStatus())).equals("ON")){
s.toggle();
}
首先创建报警项……你应该根据你的需要来制作。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;
}
}
现在我们需要一个自定义开关类因为这个：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, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, 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命名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 ->活动_main.xml
<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>
现在我们需要一个适配器来负责绘制项目及其处理。为班级命名报警适配器
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, View view, ViewGroup viewGroup) {
tmpItem = listOfAlarms.get(i);
if (view == null) {
LayoutInflater inflater = LayoutInflater.from(context);
tmpView = inflater.inflate(R.layout.alarm_list_item, null, 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;
}
}
}
现在终于主要活动
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, View view, int position, long id) {
AlarmItem item = adapter.getItem(position);
showToast("Alarm " + item.getAlarmName() + " clicked");
}
}
这是完整的android studio项目，如果您有任何问题：LINK
现在您需要做的就是将数据库中的结果转换为此列表或修改报警项和用户界面。该解决方案将起作用，并且您已经在适配器中拥有一些有用的方法。
快乐编码！
