OnSharedPreferenceChangeListener没有被触发

Question

在MainActivity我注册了OnSharedPreferenceChangeListener在onCreate和UnRegistering在onDestroy。即使我改变偏好设置，回拨也不会在MainActivity中被解雇。我关注了堆栈溢出和Android文档中的其他问题，但所有这些解决方案都不适合我。

其实，我想知道，如果我们可以调试，为什么我的回调是没有得到所谓的或任何其他解决方案可能会有所帮助。

public class MainActivity extends AppCompatActivity { 

ImageAdapter imageAdapter; 
ArrayList<String> posterPaths = new ArrayList<>(); 
private SharedPreferences.OnSharedPreferenceChangeListener preferenceChangeListener = 
     new SharedPreferences.OnSharedPreferenceChangeListener(){ 
      @Override 
      public void onSharedPreferenceChanged(SharedPreferences prefs, String key) { 
       if (key.equals(getString(R.string.pref_order_key))) { 
        fetchImagesIfOnline(); 
       } 
      } 
     }; 



@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    MenuInflater menuInflater = getMenuInflater(); 
    menuInflater.inflate(R.menu.main,menu); 
    return true; 
} 

@Override 
protected void onDestroy() { 
    super.onDestroy(); 
    SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this); 
    preferences.unregisterOnSharedPreferenceChangeListener(preferenceChangeListener); 
} 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    int id = item.getItemId(); 
    switch(id) { 
     case R.id.action_settings: 
      startActivity(new Intent(this, Settings.class)); 
      return true; 
    } 
    return super.onOptionsItemSelected(item); 
} 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    PreferenceManager.setDefaultValues(this, R.xml.preferences, false); 

    SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this); 
    preferences.registerOnSharedPreferenceChangeListener(preferenceChangeListener); 


    imageAdapter = new ImageAdapter(getApplicationContext(), posterPaths); 
    GridView gridview = (GridView) findViewById(R.id.movie_grid); 
    gridview.setAdapter(imageAdapter); 

    gridview.setOnItemClickListener(new AdapterView.OnItemClickListener() { 
     @Override 
     public void onItemClick(AdapterView<?> parent, View view, int position, long id) { 
      String image = (String) parent.getItemAtPosition(position); 
      Intent movieDetailsIntent = new Intent(getApplicationContext(), MovieDetails.class); 
      movieDetailsIntent.putExtra("image",(String) imageAdapter.getItem(position)); 
      startActivity(movieDetailsIntent); 
     } 
    }); 

    fetchImagesIfOnline(); 
} 
public boolean isOnline() { 
    ConnectivityManager cm = 
      (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); 
    NetworkInfo netInfo = cm.getActiveNetworkInfo(); 
    return netInfo != null && netInfo.isConnectedOrConnecting(); 
} 

public void fetchImagesIfOnline() { 
    if (isOnline()) 
    { 
     SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this); 
     String sortOrder = preferences.getString(getString(R.string.pref_order_key),getString(R.string.pref_order_toprated)); 
     Log.d("DEBUG","Sort order is " + sortOrder); 
     DownloadTask downloadTask; 
     downloadTask = new DownloadTask(imageAdapter,posterPaths); 
     downloadTask.execute(sortOrder); 
    } 
} 

@Override 
public View onCreateView(View parent, String name, Context context, AttributeSet attrs) { 
    return super.onCreateView(parent, name, context, attrs); 
} 

}

Answer 1

在onCreate您注册监听

prefs.registerOnSharedPreferenceChangeListener(listener); 

你可以注销它onDistry

，如果你不喜欢这样，这应该工作！

listener = new SharedPreferences.OnSharedPreferenceChangeListener() { 
     public void onSharedPreferenceChanged(SharedPreferences prefs, String key) { 
     // your code 
     } 
    }; 

    prefs.registerOnSharedPreferenceChangeListener(listener);