Question

我正在获取一些JSON数据并将其解析为我的对象。我想用它来获取我需要的所有字段。但是我在我的arraylist上得到一个null，我不知道为什么例如。

private List<MovieDetail> mMovieDetails;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_detail);
    setupActionBar();


    Intent intent = getIntent();
    MovieDetail movieDetail = (MovieDetail) intent.getSerializableExtra(POSTER_TRANSFER);
    Glide.with(this).load(movieDetail.getPoster()).into((ImageView) findViewById(R.id.main_backdrop));

    ProcessMovieSearchImdbIDString processMovieSearchImdbIDString = new ProcessMovieSearchImdbIDString(movieDetail.getImdbID());
    processMovieSearchImdbIDString.execute();


    CollapsingToolbarLayout collapsingToolbarLayout = (CollapsingToolbarLayout) findViewById(R.id.main_collapsing);
    collapsingToolbarLayout.setTitle(movieDetail.getTitle());

       //this returns null which it shouldn't
    if(mMovieDetails !=null){
        for (MovieDetail detail: mMovieDetails) {
            Log.d("Details", "movie actors: " + detail.getActors());
        }
    }


    ((TextView) findViewById(R.id.grid_title)).setText(movieDetail.getTitle());
    ((TextView) findViewById(R.id.grid_writers)).setText(movieDetail.getWriter());
    ((TextView) findViewById(R.id.grid_actors)).setText(movieDetail.getActors());
    ((TextView) findViewById(R.id.grid_director)).setText(movieDetail.getDirector());
    ((TextView) findViewById(R.id.grid_genre)).setText(movieDetail.getGenre());
    ((TextView) findViewById(R.id.grid_released)).setText(movieDetail.getReleased());
    ((TextView) findViewById(R.id.grid_plot)).setText(movieDetail.getPlot());
    ((TextView) findViewById(R.id.grid_runtime)).setText(movieDetail.getRuntime());


}

private void setupActionBar() {
    ActionBar actionBar = getSupportActionBar();
    if (actionBar != null) {
        // Show the Up button in the action bar.
        actionBar.setDisplayHomeAsUpEnabled(true);
    }
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == android.R.id.home) {
        startActivity(new Intent(this, MainActivity.class));
        return true;
    }
    return super.onOptionsItemSelected(item);
}



public class ProcessMovieSearchImdbIDString extends JsonParse {
    public ProcessMovieSearchImdbIDString(String id) {
        super(id);
    }

    public void execute() {
        //super.execute();
        ProcessData processData = new ProcessData();
        processData.execute();
    }
    public class ProcessData extends DownloadSearchMovieImdbidJsonData {

        protected void onPostExecute(String webData) {
            super.onPostExecute(webData);
             //this doesn't return null
            mMovieDetails=getMovies();
            for (MovieDetail detail : mMovieDetails) {
                Log.d("Details", "movie actors a: " + detail.getActors());
            }

        }
    }
}

我不确定为什么在onCreate方法中使用数组时返回null。如果有人可以提供帮助，那将非常感激。

Answer 1

解决问题的方法是将列表移动到@ M.WaqasPervez提到的onPostExecute

这是代码修复

    public class ProcessMovieSearchImdbIDString extends JsonParse {
    public ProcessMovieSearchImdbIDString(String id) {
        super(id);
    }

    public void execute() {
        //super.execute();
        ProcessData processData = new ProcessData();
        processData.execute();
    }
    public class ProcessData extends DownloadSearchMovieImdbidJsonData {

        protected void onPostExecute(String webData) {
            super.onPostExecute(webData);

            mMovieDetails=getMovies();
            for (MovieDetail detail : mMovieDetails) {
                ((TextView) findViewById(R.id.grid_title)).setText(detail.getTitle());
                ((TextView) findViewById(R.id.grid_writers)).setText(detail.getWriter());
                ((TextView) findViewById(R.id.grid_actors)).setText(detail.getActors());
                ((TextView) findViewById(R.id.grid_director)).setText(detail.getDirector());
                ((TextView) findViewById(R.id.grid_genre)).setText(detail.getGenre());
                ((TextView) findViewById(R.id.grid_released)).setText(detail.getReleased());
                ((TextView) findViewById(R.id.grid_plot)).setText(detail.getPlot());
                ((TextView) findViewById(R.id.grid_runtime)).setText(detail.getRuntime());
            }

        }
    }
}

全部谢谢

在onCreate中使用数组返回null

1 个答案: