我目前正在尝试为学习目的制作一个简单的任务杀手,我创建了一个列表视图,显示所有用户安装的应用程序带复选框,因此用户可以选择应用程序应该在屏幕关闭时被杀死。
但我仍然坚持如何保存复选框状态并获取已检查应用的程序包名称
我的搜索堆栈溢出很长时间但仍然不知道该怎么做,请帮帮我,谢谢
这是我的代码
AppAdapter.java
public class AppAdapter extends BaseAdapter {
private LayoutInflater layoutInflater;
private List<AppList> listStorage;
public AppAdapter(Context context, List<AppList> customizedListView) {
layoutInflater =(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
listStorage = customizedListView;
}
@Override
public int getCount() {
return listStorage.size();
}
@Override
public Object getItem(int position) {
return position;
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
final ViewHolder listViewHolder;
if(convertView == null){
listViewHolder = new ViewHolder();
convertView = layoutInflater.inflate(R.layout.installed_app_list, parent, false);
listViewHolder.textInListView = (TextView)convertView.findViewById(R.id.list_app_name);
listViewHolder.imageInListView = (ImageView)convertView.findViewById(R.id.app_icon);
listViewHolder.checkBox = (CheckBox)convertView.findViewById(R.id.checkBox);
convertView.setTag(listViewHolder);
listViewHolder.checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if(isChecked){
listViewHolder.checkBox.setSelected(listStorage.get(position).isSelected());
}
}
});
}else{
listViewHolder = (ViewHolder)convertView.getTag();
}
listViewHolder.textInListView.setText(listStorage.get(position).getName());
listViewHolder.imageInListView.setImageDrawable(listStorage.get(position).getIcon());
listViewHolder.checkBox.setChecked(listStorage.get(position).isSelected());
return convertView;
}
static class ViewHolder{
TextView textInListView;
ImageView imageInListView;
CheckBox checkBox;
}
}
Applist.java
public class AppList {
private String name;
Drawable icon;
private static final String PREFERENCES_NAMESPACE = "checkboxes_states";
boolean selected = false;
private SharedPreferences mSettings;
private SharedPreferences.Editor mEditor;
public AppList(Context context, String name, Drawable icon) {
this.name = name;
this.icon = icon;
mSettings = context.getSharedPreferences(PREFERENCES_NAMESPACE, 0);
mEditor = mSettings.edit();
setSelected(mSettings.getBoolean(name, selected));
}
public String getName() {
return name;
}
public Drawable getIcon() {
return icon;
}
public boolean isSelected() {
return selected;
}
public void setSelected(boolean selected) {
if(this.selected != selected) { // update if changed
mEditor.putBoolean(getName(), selected);
mEditor.apply();
this.selected = selected;
}
}
}
MainActivity.java
public class MainActivity extends Activity {
Context context;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
context = getApplicationContext();
ListView userInstalledApps = (ListView)findViewById(R.id.installed_app_list);
List<AppList> installedApps = getInstalledApps();
AppAdapter installedAppAdapter = new AppAdapter(MainActivity.this, installedApps);
userInstalledApps.setAdapter(installedAppAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
private List<AppList> getInstalledApps() {
List<AppList> res = new ArrayList<AppList>();
List<PackageInfo> packs = getPackageManager().getInstalledPackages(0);
for (int i = 0; i < packs.size(); i++) {
PackageInfo p = packs.get(i);
if ((isSystemPackage(p) == false)) {
String appName = p.applicationInfo.loadLabel(getPackageManager()).toString();
Drawable icon = p.applicationInfo.loadIcon(getPackageManager());
res.add(new AppList(context, appName, icon));
}
}
return res;
}
private boolean isSystemPackage(PackageInfo pkgInfo) {
return ((pkgInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) ? true : false;
}
}
提前致谢
答案 0 :(得分:1)
你从未调用过AppList.setSelected()。 调用listViewHolder onClickListener,然后probaby通知适配器有更改。 您可能还想调用setChecked而不是setSelected
listViewHolder.checkBox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
boolean isSelected = listStorage.get(position).isSelected();
listViewHolder.checkBox.setChecked(!isSelected);
listStorage.get(position).setSelected(!isSelected)
notifyDataSetChanged();
}
});
您可以通过设置checkChangedListener而不是onClickListener来进一步改进这一点,但首先要解决初始问题。
编辑:OP解决了最初的问题,现在正在评论改进。 将onClick替换为:
listViewHolder.checkBox.setOnCheckedChangeListener(new OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean isChecked) {
listStorage.get(position).setSelected(isChecked)
notifyDataSetChanged();
}
});
答案 1 :(得分:1)
创建界面:
public interface AppSelector {
void selectApp(String appName);
void removeApp(String appName);
boolean isSelected(String appName);
}
将其添加到AppAdapter:
public class AppAdapter extends BaseAdapter {
private AppSelector appSelector;
private List<AppList> listStorage;
public AppAdapter(AppSelector appSelector, List<AppList> customizedListView) {
this.appSelector = appSelector;
listStorage = customizedListView;
}
....
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
final ViewHolder listViewHolder;
if(convertView == null){
listViewHolder = new ViewHolder();
convertView = LayoutInflater.from(parent.getContext()).inflate(R.layout.installed_app_list, parent, false);
listViewHolder.textInListView = (TextView)convertView.findViewById(R.id.list_app_name);
listViewHolder.imageInListView = (ImageView)convertView.findViewById(R.id.app_icon);
listViewHolder.checkBox = (CheckBox)convertView.findViewById(R.id.checkBox);
convertView.setTag(listViewHolder);
listViewHolder.checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
appSelector.selectApp(listStorage.get(position).getName());
} else {
appSelector.removeApp(listStorage.get(position).getName());
}
}
});
} else {
listViewHolder = (ViewHolder)convertView.getTag();
}
listViewHolder.textInListView.setText(listStorage.get(position).getName());
listViewHolder.imageInListView.setImageDrawable(listStorage.get(position).getIcon());
listViewHolder.checkBox.setChecked(appSelector.isSelected(listStorage.get(position).getName()));
return convertView;
}
....
}
通过您的MainActivity实施:
class MainActivity extends AppCompatActivity implements AppSelector {
private static final String PREFERENCES_NAMESPACE = "checkboxes_states";
private SharedPreferences checkedAppsPreferences;
....
@Override
protected void onCreate(Bundle savedInstanceState) {
....
checkedAppsPreferences = getSharedPreferences(PREFERENCES_NAMESPACE, 0);
....
AppAdapter installedAppAdapter = new AppAdapter(this, installedApps);
....
}
@Override
public void selectApp(String appName) {
checkedAppsPreferences.edit()
.putBoolean(appName, true)
.apply();
}
@Override
public void removeApp(String appName) {
checkedAppsPreferences.edit()
.remove(appName)
.apply();
}
@Override
public boolean isSelected(String appName) {
return checkedAppsPreferences.contains(appName) && checkedAppsPreferences.getBoolean(appName, false);
}
....
}
您的AppList类不应包含对Context或SharedPreferences的任何引用以及“check”/“unchecking”的逻辑。它应该是简单的POJO。
使用界面,您可以轻松地将共享首选项替换为其他类型的存储库,如SQLite
已编辑:我更改了AppAdapter getView mwthod:
listViewHolder.checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
appSelector.selectApp(listStorage.get(position).getName());
} else {
appSelector.removeApp(listStorage.get(position).getName());
}
}
});
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