節約使用sharedpreferences

Question

我使用複選框以列表視圖複選框的/加載狀態。我想，當用戶點擊該按鈕B1，以便在他退出並重新啓動應用程序加載正確的配置，以拯救他們的狀態。

這裏是代碼：

Main.java：

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

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; 

    } 



    } 

我看到sharedpreferences可以解決我的問題，但我不知道如何用它。 謝謝你的幫助。

Answer 1

要使用SharedPreferences，請按照下列步驟操作：

SharedPreferences mSharedPreferences = PreferenceManager .getDefaultSharedPreferences(context); 

中獲取價值：

boolean mCheckBoxValue = mSharedPreferences .getBoolean("CheckBox_Value", false); 

保存價值

boolean value= true; 
Editor mEditor = mSharedPreferences .edit(); 
mEditor.putBoolean("CheckBox_Value", value); 
mEditor.commit(); 

閱讀穿心蓮內酯的詳細信息ID開發者頁面 Saving Key-Value Sets