使用 ListView 截取图像到另一个 activity: java.lang.RuntimeException: 无法启动 activity ComponentInfo: java.lang.NullPointerException

Question

一直在尝试将一些图像和文本从我的 Volley ListView 传递到另一个 activity，但图像出现了一些问题。当我只传递文本时，它显示没有问题，但是一旦我插入代码以提取图像，我就会在 logcat:

中收到以下错误

03-04 22:24:05.185      368-368/com.wlodsgn.bunbunup E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.wlodsgn.bunbunup, PID: 368
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.wlodsgn.bunbunup/com.wlodsgn.bunbunup.DetailsActivity}: java.lang.NullPointerException
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2202)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2252)
            at android.app.ActivityThread.access0(ActivityThread.java:139)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5103)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:606)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.NullPointerException
            at com.wlodsgn.bunbunup.DetailsActivity.onCreate(DetailsActivity.java:39)
            at android.app.Activity.performCreate(Activity.java:5275)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2166)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2252)
            at android.app.ActivityThread.access0(ActivityThread.java:139)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5103)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)

错误看起来像是依赖于我的 DetailsActivity.java 下的以下部分：

    ImageLoader imageLoader = AppController.getInstance().getImageLoader();
    String bitmap = i.getStringExtra("images");
    NetworkImageView thumbNail = (NetworkImageView) findViewById(R.id.thumbnail);
    thumbNail.setImageUrl(bitmap, imageLoader);`

我试过用这个看看能不能解决问题，但是没有成功。

这里我 post 我的完整 DetailsActivity.java 和 VeroxJeansActivity.java 如果需要的话。

如果需要，我会添加更多代码。感谢任何帮助

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.TextView;

import com.android.volley.toolbox.Volley;
import com.android.volley.toolbox.NetworkImageView;
import com.android.volley.toolbox.ImageLoader;
import com.wlodsgn.bunbunup.app.AppController;

/**
 * Created by WiLo on 3/4/2015.
 */
public class DetailsActivity extends ActionBarActivity {
    private static String Titulo="titulo";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_details);
        /**getSupportActionBar().hide();**/

        //Back button
        ActionBar actionBar = getSupportActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);

        Intent i=getIntent();
        String name = i.getStringExtra(Titulo);
        TextView lblName = (TextView) findViewById(R.id.titulo);
        lblName.setText(name);

        ImageLoader imageLoader = AppController.getInstance().getImageLoader();
        String bitmap = i.getStringExtra("images");
        NetworkImageView thumbNail = (NetworkImageView) findViewById(R.id.thumbnail);
        thumbNail.setImageUrl(bitmap, imageLoader);

    }


    public void onClickHandler(View v){
        switch(v.getId()){
            case R.id.thumbnail:
                startActivity(new Intent(this,VeroxJeansActivity.class));
        }

    }
}

---------------------------------------- --

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;

import com.wlodsgn.bunbunup.adapter.CustomListAdapter;
import com.wlodsgn.bunbunup.app.AppController;
import com.wlodsgn.bunbunup.model.VeroxJeans;

import java.util.ArrayList;
import java.util.List;

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

import android.app.ProgressDialog;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.TextView;

import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.JsonArrayRequest;

/**
 * Created by WiLo on 2/27/2015.
 */
public class VeroxJeansActivity extends ActionBarActivity {

    /**@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_veroxjeans);



    }**/

    // Log tag
    private static final String TAG = VeroxJeansActivity.class.getSimpleName();

    // Verox Jeans json url
    private static final String url = "http://wlodsgn.x10host.com/json/vrxjns.json";
    private ProgressDialog pDialog;
    private List<VeroxJeans> veroxJeansList = new ArrayList<VeroxJeans>();
    private ListView listView;
    private CustomListAdapter adapter;
    private static String Titulo="titulo";
    private static String bitmap="thumbnailUrl";

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

        //Back button
        ActionBar actionBar = getSupportActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);

        listView = (ListView) findViewById(R.id.list);
        adapter = new CustomListAdapter(this, veroxJeansList);
        listView.setAdapter(adapter);

        pDialog = new ProgressDialog(this);
        // Showing progress dialog before making http request
        pDialog.setMessage("Loading...");
        pDialog.show();

        // changing action bar color
        getSupportActionBar().setBackgroundDrawable(
                new ColorDrawable(Color.parseColor("#1b1b1b")));

        // Creating volley request obj
        JsonArrayRequest veroxJeansReq = new JsonArrayRequest(url,
                new Response.Listener<JSONArray>() {
                    @Override
                    public void onResponse(JSONArray response) {
                        Log.d(TAG, response.toString());
                        hidePDialog();

                        // Parsing json
                        for (int i = 0; i < response.length(); i++) {
                            try {

                                JSONObject obj = response.getJSONObject(i);
                                VeroxJeans veroxjeans = new VeroxJeans();
                                veroxjeans.setTitulo(obj.getString("titulo"));
                                veroxjeans.setThumbnailUrl(obj.getString("image"));
                                veroxjeans.setMarca(obj.getString("marca"));
                                veroxjeans.setColor(obj.getString("color"));
                                veroxjeans.setTipo(obj.getString("tipo"));
                                veroxjeans.setRef(obj.getInt("ref"));

                                // adding verox jeans to verox jeans array
                                veroxJeansList.add(veroxjeans);

                            } catch (JSONException e) {
                                e.printStackTrace();
                            }

                        }

                        // notifying list adapter about data changes
                        // so that it renders the list view with updated data
                        adapter.notifyDataSetChanged();
                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                VolleyLog.d(TAG, "Error: " + error.getMessage());
                hidePDialog();

            }
        });

        // Adding request to request queue
        /**AppController.getInstance().addToRequestQueue(veroxJeansReq);**/
        AppController.getInstance().addToRequestQueue(veroxJeansReq);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener(){

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {
                String nombre = ((TextView) view.findViewById(R.id.titulo))
                        .getText().toString();

                bitmap = ((VeroxJeans)veroxJeansList.get(position)).getThumbnailUrl();
                Intent intent = new Intent(VeroxJeansActivity.this, DetailsActivity.class);
                intent.putExtra(Titulo, nombre);
                intent.putExtra("images", bitmap);

                startActivity(intent);
            }
        });

    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        hidePDialog();
    }

    private void hidePDialog() {
        if (pDialog != null) {
            pDialog.dismiss();
            pDialog = null;
        }
    }

    /**@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;
    }**/

}

Answer 1

答案在我 post 的最后一条评论中 post。需要在我的 .xml 文件的 ID 中将 thumbNail 改回 thumbnail。

使用 ListView 截取图像到另一个 activity: java.lang.RuntimeException: 无法启动 activity ComponentInfo: java.lang.NullPointerException

Using ListView volley image to another activity: java.lang.RuntimeException: Unable to start activity ComponentInfo: java.lang.NullPointerException

android

nullpointerexception

android-listview

runtimeexception

android-volley