如何将上下文从活动传递到不是活动的另一个类中的ArrayAdapter？

Question

I'm trying to use an array of movies and put them in a listview. After debugging, the only thing that makes the activity crash is using getContext(). I tried getApplicationContext() and that also crashed the app. I'm not sure what to do. Here's a method in one class.

private void displayMovies(List<Movie> movies) {
     ArrayAdapter adapter = new
     ArrayAdapter(DisplayMoviesActivity.getContext(),
         android.R.layout.simple_list_item_1, movies);
     ListView listView = DisplayMoviesActivity.getListView();
}

This is a different class.

public class DisplayMoviesActivity extends AppCompatActivity {

static ListView displayMoviesView;
static Context context;

public DisplayMoviesActivity(Context context) {
    this.context = context;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_display_movies);
    displayMoviesView = (ListView) findViewById(R.id.displayMoviesView);
    String searchText = (getIntent().getStringExtra("text"));
    RottenTomatoesJSON RTJSON = new RottenTomatoesJSON(this);
    RTJSON.searchMovieByName(searchText, 12);

}

public static Context getContext() {
    return context;
}

public static ListView getListView() {
    return displayMoviesView;
}
}

The app crashes whenever I try to start the activity. This is the class I use to start the activity.

public void searchMovies(View v){
    SearchView searchBar = (SearchView) findViewById(R.id.searchView);
    if (searchBar.isIconified() || searchBar.getQuery() == null || searchBar.getQuery() == "") {
        Context context = getApplicationContext();
        CharSequence text = "Please enter movie to search!";
        int duration = Toast.LENGTH_LONG;
        Toast toast = Toast.makeText(context, text, duration);
        toast.show();
    } else {
        String searchText = searchBar.getQuery().toString();
        Intent intent = new Intent(this, DisplayMoviesActivity.class);
        intent.putExtra("text",searchText);
        startActivity(intent);
        finish();
    }
}

I think this is the relevant logcat.

I/art: Background sticky concurrent mark sweep GC freed 2773(224KB)
  AllocSpace objects, 0(0B) LOS objects, 17% free, 931KB/1135KB, paused
 5.134ms total 40.550ms
 W/art: Suspending all threads took: 5.956ms
 D/OpenGLRenderer: Render dirty regions requested: true
 D/Atlas: Validating map...
 I/OpenGLRenderer: Initialized EGL, version 1.4
 D/OpenGLRenderer: Enabling debug mode 0
 W/EGL_emulation: eglSurfaceAttrib not implemented
 W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface   0xa638a320, error=EGL_SUCCESS

Answer 1

Remove the constructor with Context parameter.

public DisplayMoviesActivity(Context context) {
    this.context = context;
}

instead, pass the Context to your object of the displayMovies method. Please provide the code of your class.

NOTE

You code makes clear that person who wrote it lacks common android development knowledge.

END NOTE

Example:

Helper helper = new Helper(this);
helper.displayMovies(//);

Answer 2

A close look at the docs for Activity shows the following inheritance hierarchy:

java.lang.Object
   ↳    android.content.Context
       ↳    android.content.ContextWrapper
           ↳    android.view.ContextThemeWrapper
               ↳    android.app.Activity

Note that Context is an ancestor of Activity . This means that an Activity is a Context . There is no need for a constructor in an Activity sublcass which accepts a Context . (Besides, this constructor will never be called.)

If the code which needs a Context occurs in a method inside your Activity subclass, you can just use this to refer to the current Activity object (which is also a Context ):

ArrayAdapter adapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, movies);