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Question

我创建了一个简单的应用程序，它读取 json 数据并在我的 MainActivity.java

的列表视图中显示所有结果

package com.test.rajat.minivie;

import android.app.SearchManager;
import android.content.Context;
import android.content.Intent;
import android.graphics.Typeface;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.SearchView;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.TextView;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.HashMap;

public class MainActivity extends ActionBarActivity implements AdapterView.OnItemClickListener{
private ListView list_movies;
private MyAdapter adapter;
private SearchView searchView;
private DetailsActivity details;
TextView tv_title,tv_releaseYear;
Typeface face;
JSONParser parser;
ArrayList<HashMap<String,String>> movies_list;
private static String url="https://api.themoviedb.org/3/search/movie?api_key=<pastedkey>";
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    face = Typeface.createFromAsset(getAssets(), "fonts/Roboto-Thin.ttf");
    list_movies = (ListView) findViewById(R.id.list_movies);
    tv_title = (TextView) findViewById(R.id.tv_title);
    tv_releaseYear = (TextView) findViewById(R.id.tv_releaseYear);
    list_movies.setOnItemClickListener(this);
    handleIntent(getIntent());
    parser = new JSONParser();
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.menu_main, menu);
    SearchManager searchManager =
            (SearchManager) getSystemService(Context.SEARCH_SERVICE);
     searchView=
            (SearchView) menu.findItem(R.id.action_search).getActionView();
    searchView.setSearchableInfo(
            searchManager.getSearchableInfo(getComponentName()));
    searchView.setIconifiedByDefault(false);
    final SearchView.OnQueryTextListener queryTextListener = new SearchView.OnQueryTextListener() {
        @Override
        public boolean onQueryTextChange(String newText) {

            return true;
        }

        @Override
        public boolean onQueryTextSubmit(String query) {
//                TextView textView=(TextView)findViewById(R.id.tvb_title);
//                textView.setText(query);
            String newquery=url+query.replaceAll(" ","%20");
            new RetrieveJSON().execute(newquery);
            searchView.clearFocus();
            return true;
        }
    };
    searchView.setOnQueryTextListener(queryTextListener);
    return true;
}
private void handleIntent(Intent intent) {

    if (Intent.ACTION_SEARCH.equals(intent.getAction())) {
        String query = intent.getStringExtra(SearchManager.QUERY);
    }
}
@Override
protected void onNewIntent(Intent intent) {

    handleIntent(intent);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml
    int id = item.getItemId();
    switch(id)
    {
        case R.id.action_settings:
            return true;
        case R.id.action_search:
    }

    return super.onOptionsItemSelected(item);
}

@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    details=new DetailsActivity();

    HashMap<String,String> movie_details=movies_list.get(position);
    Intent i=new Intent(this,DetailsActivity.class);
    i.putExtra("movie_details", movie_details);
    startActivity(i);


}

class RetrieveJSON extends AsyncTask<String,String,String>
{
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        movies_list=new ArrayList<HashMap<String,String>>();
    }

    @Override
    protected String doInBackground(String... params) {

        String str_json= parser.getJSONFromUrl(params[0]);
        Log.d("URL",params[0]);
        try {
            JSONObject json=new JSONObject(str_json);
            JSONArray jsonArray=new JSONArray(json.getString("results"));
            Log.d("LEN",Integer.toString(jsonArray.length()));
            for(int i=0;i<jsonArray.length();i++)
            {
                JSONObject tmp=jsonArray.getJSONObject(i);
                String title=tmp.getString("title");
                String release_date=tmp.getString("release_date");
                String overview=tmp.getString("overview");
                String rating=tmp.getString("vote_average");
                String poster_path=tmp.getString("poster_path");
                String backdrop_path=tmp.getString("backdrop_path");
                String vote_average=tmp.getString("vote_average");
                HashMap<String,String> movie=new HashMap<>();
                movie.put("title",title);
                movie.put("release_date",release_date);
                movie.put("overview",overview);
                movie.put("rating",rating);
                movie.put("poster_path",poster_path);
                movie.put("backdrop_path",backdrop_path);
                movie.put("vote_average",vote_average);
                movies_list.add(movie);
            }

        }

        catch(JSONException e)
        {

        }
        return null;
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        adapter=new MyAdapter(MainActivity.this,R.layout.row,movies_list);
        list_movies.setAdapter(adapter);
    }
}
}

在 OnItemClick() 中，我开始另一个 activity 并向其中添加列表项数据。但是 DetailsActivity.java 没有生成我放在 onCreate() 中的吐司。有帮助吗？

DetailsActivity.java

package com.test.rajat.minivie;

import android.content.Intent;
import android.os.Bundle;
import android.os.PersistableBundle;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.Menu;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.squareup.picasso.Picasso;

import java.util.HashMap;

/**
 * Created by Rajat on 7/16/2015.
 */
public class DetailsActivity extends ActionBarActivity {
    private HashMap<String,String> movie_details;
    private ImageView iv_poster_b;
    private TextView tv_title_b;
    @Override
    public void onCreate(Bundle savedInstanceState, PersistableBundle persistentState) {
        super.onCreate(savedInstanceState, persistentState);
        setContentView(R.layout.activity_movie_details);
        Intent intent=getIntent();
        movie_details=(HashMap<String,String>) intent.getSerializableExtra("movie_details");
        iv_poster_b=(ImageView) findViewById(R.id.iv_poster_b);
        tv_title_b=(TextView) findViewById(R.id.tv_title_b);
        Log.d("TAG","Created");
        // This toast and function is not getting called  //
        Toast.makeText(this, "title", Toast.LENGTH_SHORT).show();
        setDetails();

    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    private void setDetails(){
        tv_title_b.setText(movie_details.get("title"));
        Picasso.with(this).load("http://image.tmdb.org/t/p/w500"+movie_details.get("poster_path")).into(iv_poster_b);

    }
}

Answer 1

您将逻辑放在 DetailsActivity 中 API 21 of Android

中添加的方法中

@Override
public void onCreate(Bundle savedInstanceState, PersistableBundle persistentState) {

}

根据docs

Same as onCreate(android.os.Bundle) but called for those activities created with the attribute persistableMode set to persistAcrossReboots.

改为：

@Override
protected void onCreate(Bundle savedInstanceState) {

}

现在应该可以了

Answer 2

我认为您重写了错误的 onCreate() 方法，将其更改为

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

请尝试改变

Toast.makeText(this, "title", Toast.LENGTH_SHORT).show();

与

Toast.makeText(DetailsActivity.this, "title", Toast.LENGTH_SHORT).show();

Answer 3

只需重写正确的 onCreate() 方法，那就是

 @Override
 protected void onCreate(Bundle savedInstanceState){
 }

不是

public void onCreate (Bundle savedInstanceState, PersistableBundle persistentState)

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