[英]Checkbox geting unchecked after scrolling Custom listview…!
我創建自定義列表視圖,並在其中添加復選框。
首先,我選中所有復選框,然后向下滾動列表視圖,然后選中“未選中”復選框。
我該怎么辦?
CustomListItem.java
package com.example.customlistviewdemo;
import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
public class CustomListItem extends ArrayAdapter<String> {
private final Activity context;
private final String[] TitleArray;
private final String[] SubTitlearray;
private final String[] TimeArray;
private final Integer[] MainImageId;
public CustomListItem(Activity context, String[] TitleArray,
String[] SubTitlearray, String[] TimeArray, Integer[] MainImageId) {
super(context, R.layout.list_item, TitleArray);
this.context = context;
this.TitleArray = TitleArray;
this.SubTitlearray = SubTitlearray;
this.TimeArray = TimeArray;
this.MainImageId = MainImageId;
}
@Override
public View getView(int position, View view, ViewGroup parent) {
LayoutInflater inflater = context.getLayoutInflater();
View rowView = inflater.inflate(R.layout.list_item, null, true);
ImageView animal, car, environment, map1, warning1, map2, warning2, download, share, plant;
animal = (ImageView) rowView.findViewById(R.id.imgAnimal);
car = (ImageView) rowView.findViewById(R.id.imgCar);
environment = (ImageView) rowView.findViewById(R.id.imgEnvironment);
plant = (ImageView) rowView.findViewById(R.id.imgPlant);
map1 = (ImageView) rowView.findViewById(R.id.imgMap);
warning1 = (ImageView) rowView.findViewById(R.id.imgWarning);
map2 = (ImageView) rowView.findViewById(R.id.imgMap2);
warning2 = (ImageView) rowView.findViewById(R.id.imgWarining2);
download = (ImageView) rowView.findViewById(R.id.imgDownload);
CheckBox chk = (CheckBox) rowView.findViewById(R.id.checkbox);
share = (ImageView) rowView.findViewById(R.id.imgShare);
animal.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(getContext(), "Animal ImageView is Clicked",
5000).show();
// TODO Auto-generated method stub
}
});
car.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(getContext(), "Cars ImageView is Clicked", 5000)
.show();
// TODO Auto-generated method stub
}
});
environment.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(getContext(),
"environment ImageView is Clicked", 5000).show();
// TODO Auto-generated method stub
}
});
------------------------------------------------------------------
...........................SO on............................
..........................................................
TextView mainTitle = (TextView) rowView.findViewById(R.id.txtMainTitle);
ImageView mainImage = (ImageView) rowView
.findViewById(R.id.imgMainImage);
TextView SubText = (TextView) rowView.findViewById(R.id.txtSubTitle);
TextView TimeText = (TextView) rowView.findViewById(R.id.txtTimeTitle);
mainTitle.setText(TitleArray[position]);
SubText.setText(SubTitlearray[position]);
TimeText.setText(TimeArray[position]);
mainImage.setImageResource(MainImageId[position]);
return rowView;
}
}
ActivityMain.java
package com.example.customlistviewdemo;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;
public class MainActivity extends Activity {
ListView list;
String[] TitleArray = { "Testing Title1. This is MainTitle",
"Testing Title2. This is MainTitle",
"Testing Title3. This is MainTitle",
"Testing Title4. This is MainTitle",
"Testing Title5. This is MainTitle",
"Testing Title6. This is MainTitle" };
String[] SubTitleArray = { "Reported by Man 1", "Reported by Man 2",
"Reported by Man 3", "Reported by Man 4", "Reported by Man 5",
"Reported by Man 6" };
String[] TimeArray = { "about 1 hour ago", "about 2 hour ago",
"about 3 hour ago", "about 4 hour ago", "about 5 hour ago",
"about 6 hour ago" };
Integer[] MainImageId = { R.drawable.android1, R.drawable.android2,
R.drawable.android3, R.drawable.android4, R.drawable.android5,
R.drawable.android6 };
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CustomListItem adapter = new CustomListItem(MainActivity.this,
TitleArray, SubTitleArray, TimeArray, MainImageId);
list = (ListView) findViewById(R.id.listView1);
list.setAdapter(adapter);
}
}
list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#FFF"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="10dp" >
<TextView
android:id="@+id/txtMainTitle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="This is Sample Text"
android:textAppearance="?android:attr/textAppearanceLarge" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="130dp" >
<LinearLayout
android:layout_width="150dp"
android:layout_height="wrap_content"
android:paddingRight="15dp" >
<CheckBox
android:layout_width="wrap_content"
android:layout_height="fill_parent" />
<ImageView
android:id="@+id/imgMainImage"
android:layout_width="100dp"
android:layout_height="fill_parent" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/txtSubTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp"
android:text="This is Sample Text"
android:textAppearance="?android:attr/textAppearanceSmall"
android:textSize="16dp" />
<TextView
android:id="@+id/txtTimeTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="This is Sample Text"
android:textAppearance="?android:attr/textAppearanceSmall"
android:textSize="12dp" />
<HorizontalScrollView
android:id="@+id/scrollView1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:scrollbars="none" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginTop="8dp" >
<ImageView
android:id="@+id/imgAnimal"
android:layout_width="25dp"
android:layout_height="25dp"
android:layout_marginRight="10dp"
android:src="@drawable/channel_animal" />
<ImageView
android:id="@+id/imgCar"
android:layout_width="25dp"
android:layout_height="25dp"
android:layout_marginRight="10dp"
android:src="@drawable/channel_car" />
<ImageView
android:id="@+id/imgEnvironment"
android:layout_width="25dp"
android:layout_height="25dp"
android:layout_marginRight="10dp"
android:src="@drawable/channel_environment" />
<ImageView
android:id="@+id/imgPlant"
android:layout_width="25dp"
android:layout_height="25dp"
android:layout_marginRight="10dp"
android:src="@drawable/channel_plant" />
<ImageView
android:id="@+id/imgMap"
android:layout_width="25dp"
android:layout_height="25dp"
android:layout_marginRight="10dp"
android:src="@drawable/tab_icon_map" />
<ImageView
android:id="@+id/imgWarning"
android:layout_width="25dp"
android:layout_height="25dp"
android:layout_marginRight="10dp"
android:src="@drawable/warning_icon" />
</LinearLayout>
</HorizontalScrollView>
<HorizontalScrollView
android:id="@+id/scrollView2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:scrollbars="none" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<ImageView
android:id="@+id/imgMap2"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_marginRight="10dp"
android:src="@drawable/tab_icon_map" />
<ImageView
android:id="@+id/imgWarining2"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_marginRight="10dp"
android:src="@drawable/warning_icon" />
<ImageView
android:id="@+id/imgDownload"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_marginRight="10dp"
android:src="@drawable/download_icon" />
<ImageView
android:id="@+id/imgShare"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_marginRight="10dp"
android:src="@drawable/share_icon" />
</LinearLayout>
</HorizontalScrollView>
</LinearLayout>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<View
android:id="@+id/view"
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_toRightOf="@+id/text1"
android:background="#FF9900" />
</LinearLayout>
</LinearLayout>
我希望像這樣的體系結構那樣修改您的適配器類,我希望它能起作用:重要的幾行是設置標簽和獲取標簽。
public class MyAdapter extends ArrayAdapter<Model> {
private final List<Model> list;
private final Activity context;
boolean checkAll_flag = false;
boolean checkItem_flag = false;
public MyAdapter(Activity context, List<Model> list) {
super(context, R.layout.row, list);
this.context = context;
this.list = list;
}
static class ViewHolder {
protected TextView text;
protected CheckBox checkbox;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder = null;
if (convertView == null) {
LayoutInflater inflator = context.getLayoutInflater();
convertView = inflator.inflate(R.layout.row, null);
viewHolder = new ViewHolder();
viewHolder.text = (TextView) convertView.findViewById(R.id.label);
viewHolder.checkbox = (CheckBox) convertView
.findViewById(R.id.check);
viewHolder.checkbox
.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
int getPosition = (Integer) buttonView.getTag(); // Here
// we get the position that we have set for the checkbox using setTag.
list.get(getPosition).setSelected(
buttonView.isChecked()); // Set the value of
// checkbox to
// maintain its
// state.
}
});
convertView.setTag(viewHolder);
convertView.setTag(R.id.label, viewHolder.text);
convertView.setTag(R.id.check, viewHolder.checkbox);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.checkbox.setTag(position); // This line is important.
viewHolder.text.setText(list.get(position).getName());
viewHolder.checkbox.setChecked(list.get(position).isSelected());
return convertView;
}
}
當您在ListView
中使用CheckBox
時, ListView
存在一個問題,即Android
無法維護CheckBox
的Checked state
,因為當您Scroll ListView
,它將使用getView()
方法為每一行生成新的View
,並且Garbage Collector
將刪除所有上面的內容View
以騰出空間,以便CheckBox
狀態也將被Garbage Collector
破壞或Garbage Collector
。 您可以通過以下示例解決此問題:
main.xml中
<relativelayout
android:layout_height="match_parent"
android:layout_width="match_parent"
tools:context=".Main"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<listview
android:divider="#000"
android:dividerheight="0.8dp"
android:id="@+id/listView1"
android:layout_alignparentleft="true"
android:layout_alignparenttop="true"
android:layout_height="match_parent"
android:layout_width="match_parent">
</listview>
<button
android:id="@+id/button1"
android:layout_alignparenttop="true"
android:layout_centerhorizontal="true"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:text="Check Selected">
</button>
</relativelayout>
list_item.xml
<relativelayout
android:layout_height="match_parent"
android:layout_width="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<textview
android:id="@+id/textView1"
android:layout_alignparentleft="true"
android:layout_alignparenttop="true"
android:layout_height="wrap_content"
android:layout_marginbottom="10dp"
android:layout_margintop="10dp"
android:layout_width="wrap_content"
android:text="Medium Text"
android:textappearance="?android:attr/textAppearanceMedium">
</textview>
<checkbox
android:focusable="false"
android:focusableintouchmode="false"
android:id="@+id/checkBox1"
android:layout_alignbaseline="@+id/textView1"
android:layout_alignbottom="@+id/textView1"
android:layout_alignparentright="true"
android:layout_height="wrap_content"
android:layout_marginright="16dp"
android:layout_width="wrap_content">
</checkbox>
</relativelayout>
Main.java
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import android.app.Activity;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class Main extends Activity implements OnItemClickListener{
ListView apps;
PackageManager packageManager;
ArrayList <String> checkedValue;
Button bt1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
bt1 = (Button) findViewById(R.id.button1);
apps = (ListView) findViewById(R.id.listView1);
packageManager = getPackageManager();
final List <PackageInfo> packageList = packageManager
.getInstalledPackages(PackageManager.GET_META_DATA); // all apps in the phone
final List <PackageInfo> packageList1 = packageManager
.getInstalledPackages(0);
try {
packageList1.clear();
for (int n = 0; n < packageList.size(); n++)
{
PackageInfo PackInfo = packageList.get(n);
if (((PackInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) != true)
//check weather it is system app or user installed app
{
try
{
packageList1.add(packageList.get(n)); // add in 2nd list if it is user installed app
Collections.sort(packageList1,new Comparator <PackageInfo>()
// this will sort App list on the basis of app name
{
public int compare(PackageInfo o1,PackageInfo o2)
{
return o1.applicationInfo.loadLabel(getPackageManager()).toString()
.compareToIgnoreCase(o2.applicationInfo.loadLabel(getPackageManager())
.toString());// compare and return sorted packagelist.
}
});
} catch (NullPointerException e) {
e.printStackTrace();
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
Listadapter Adapter = new Listadapter(this,packageList1, packageManager);
apps.setAdapter(Adapter);
apps.setOnItemClickListener(this);
bt1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Toast.makeText(Main.this,"" + checkedValue,Toast.LENGTH_LONG).show();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public void onItemClick(AdapterView arg0, View v, int position, long arg3) {
// TODO Auto-generated method stub
CheckBox cb = (CheckBox) v.findViewById(R.id.checkBox1);
TextView tv = (TextView) v.findViewById(R.id.textView1);
cb.performClick();
if (cb.isChecked()) {
checkedValue.add(tv.getText().toString());
} else if (!cb.isChecked()) {
checkedValue.remove(tv.getText().toString());
}
}
}
Listadapter.java
import java.util.List;
import android.app.Activity;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.graphics.drawable.Drawable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.TextView;
public class Listadapter extends BaseAdapter{
List <PackageInfo> packageList;
Activity context;
PackageManager packageManager;
boolean[] itemChecked;
public Listadapter(Activity context, List <PackageInfo> packageList,
PackageManager packageManager) {
super();
this.context = context;
this.packageList = packageList;
this.packageManager = packageManager;
itemChecked = new boolean[packageList.size()];
}
private class ViewHolder {
TextView apkName;
CheckBox ck1;
}
public int getCount() {
return packageList.size();
}
public Object getItem(int position) {
return packageList.get(position);
}
public long getItemId(int position) {
return 0;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
final ViewHolder holder;
LayoutInflater inflater = context.getLayoutInflater();
if (convertView == null) {
convertView = inflater.inflate(R.layout.list_item, null);
holder = new ViewHolder();
holder.apkName = (TextView) convertView
.findViewById(R.id.textView1);
holder.ck1 = (CheckBox) convertView
.findViewById(R.id.checkBox1);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
PackageInfo packageInfo = (PackageInfo) getItem(position);
Drawable appIcon = packageManager
.getApplicationIcon(packageInfo.applicationInfo);
String appName = packageManager.getApplicationLabel(
packageInfo.applicationInfo).toString();
appIcon.setBounds(0, 0, 40, 40);
holder.apkName.setCompoundDrawables(appIcon, null, null, null);
holder.apkName.setCompoundDrawablePadding(15);
holder.apkName.setText(appName);
holder.ck1.setChecked(false);
if (itemChecked[position])
holder.ck1.setChecked(true);
else
holder.ck1.setChecked(false);
holder.ck1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (holder.ck1.isChecked())
itemChecked[position] = true;
else
itemChecked[position] = false;
}
});
return convertView;
}
}
為什么不使用setOnCheckedChangeListener()
來保持/保持每個頭寸項目的檢查狀態?
切記將setChecked()
setOnCheckedChangeListener()
,否則將觸發先前的ViewHolder對象的setOnCheckedChangeListener()
,從而導致上一項未選中的問題。
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