android - 图像图标未显示在 Listview Android 中？

Question

我有一个 ListView ，其中的项目来自数据库。我试图将 listview 项目的图像图标放在 xml 中。但是，它没有显示图标。我尝试了很多方法，但似乎没有任何效果？

这是我的 ListView :

public class TypeMenu extends AppCompatActivity {

    private String TAG = TypeMenu.class.getSimpleName();
    String bid;

    private ProgressDialog pDialog;
    private ListView lv;
    private static final String TAG_BID = "bid";

    // URL to get contacts JSON
    private static String url = "http://cloud....com/brtemp/index.php";

    ArrayList<HashMap<String, String>> contactList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_type_menu);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);




        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        contactList = new ArrayList<>();

        lv = (ListView) findViewById(R.id.list);

        new GetContacts().execute();


        // on seleting single product
        // launching Edit Product Screen
        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {

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

                // getting values from selected ListItem

                HashMap<String, String> selected = contactList.get(position);
                String selectedId= selected.get("id");
                Intent in = new Intent(getApplicationContext(), SubMenu.class);
                //  sending pid to next activity
                in.putExtra("id",selectedId);
                startActivityForResult(in, 100);
                Toast.makeText(getApplicationContext(),"Toast" +selectedId ,Toast.LENGTH_SHORT).show();
            }
        });
    }

    /**
     * Async task class to get json by making HTTP call
     */
    private class GetContacts extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Showing progress dialog
            pDialog = new ProgressDialog(TypeMenu.this);
            pDialog.setMessage("Please wait...");
            pDialog.setCancelable(false);
            pDialog.show();
           // Toast.makeText(getApplicationContext(),"Toast",Toast.LENGTH_LONG).show();

        }

        @Override
        protected Void doInBackground(Void... arg0) {
            HttpHandler sh = new HttpHandler();

            // Making a request to url and getting response
         String jsonStr = sh.makeServiceCall(url);

            Log.e(TAG, "Response from url: " + jsonStr);





            if (jsonStr != null) {
                try {
                    JSONArray jsonArry = new JSONArray(jsonStr);

                    for (int i = 0; i < jsonArry.length(); i++)
                    {

                        JSONObject c = jsonArry.getJSONObject(i);
                        String id = c.getString("id");
                        String type = c.getString("type");
                        HashMap<String, String> contact = new HashMap<>();

                       contact.put("id", id);
                        contact.put("type", type);
                        contactList.add(contact);


                    }
                } catch (final JSONException e) {
                    Log.e(TAG, "Json parsing error: " + e.getMessage());
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(getApplicationContext(),
                                    "Json parsing error: " + e.getMessage(),
                                    Toast.LENGTH_LONG)
                                    .show();
                        }
                    });

                }
            } else {
                Log.e(TAG, "Couldn't get json from server.");
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(getApplicationContext(),
                                "Couldn't get json from server. Check LogCat for possible errors!",
                                Toast.LENGTH_LONG)
                                .show();
                    }
                });

            }

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            // Dismiss the progress dialog
            if (pDialog.isShowing())
                pDialog.dismiss();
            /**
             * Updating parsed JSON data into ListView
             * */
            ListAdapter adapter = new SimpleAdapter(
                    TypeMenu.this, contactList,
                    R.layout.list_item, new String[]{ "type","id"},
                    new int[]{
                    R.id.type,R.id.arrow1});

            lv.setAdapter(adapter);
        }

}
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                onBackPressed();
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }
        }

如果我在上面的代码中输入“R.id.Type, R.id.arrow1”，则列表不会打开并出现错误。

这是我的 Listview.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    >

    <!-- Product id (pid) - will be DDEN - used to pass to other activity -->



        <TextView
            android:id="@+id/id"
            android:layout_width="30dp"
            android:layout_height="30dp"/>

        <TextView
            android:id="@+id/type"
            android:textSize="20dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>


    <ImageView
        android:id="@+id/arrow1"
        android:layout_width="match_parent"
        android:layout_height="15dp"
        android:layout_gravity="center"
        android:layout_weight="3"
        android:src="@drawable/dropdown" />

    </LinearLayout>

这是我的日志:

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.zeba.broccoli, PID: 1231
                  android.content.res.Resources$NotFoundException: Resource ID #0x1
                      at android.content.res.Resources.getValue(Resources.java:2452)
                      at android.support.v7.widget.AppCompatDrawableManager.loadDrawableFromDelegates(AppCompatDrawableManager.java:330)
                      at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:195)
                      at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:188)
                      at android.support.v7.content.res.AppCompatResources.getDrawable(AppCompatResources.java:100)
                      at android.support.v7.widget.AppCompatImageHelper.setImageResource(AppCompatImageHelper.java:73)
                      at android.support.v7.widget.AppCompatImageView.setImageResource(AppCompatImageView.java:81)
                      at android.widget.SimpleAdapter.setViewImage(SimpleAdapter.java:262)
                      at android.widget.SimpleAdapter.bindView(SimpleAdapter.java:192)
                      at android.widget.SimpleAdapter.createViewFromResource(SimpleAdapter.java:126)
                      at android.widget.SimpleAdapter.getView(SimpleAdapter.java:114)
                      at android.widget.AbsListView.obtainView(AbsListView.java:2828)
                      at android.widget.ListView.measureHeightOfChildren(ListView.java:1292)
                      at android.widget.ListView.onMeasure(ListView.java:1204)
                      at android.view.View.measure(View.java:18870)
                      at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728)
                      at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:464)
                      at android.view.View.measure(View.java:18870)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5908)
                      at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:703)
                      at android.support.design.widget.HeaderScrollingViewBehavior.onMeasureChild(HeaderScrollingViewBehavior.java:90)
                      at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1367)
                      at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:768)
                      at android.view.View.measure(View.java:18870)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5908)
                      at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
                      at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139)
                      at android.view.View.measure(View.java:18870)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5908)
                      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1435)
                      at android.widget.LinearLayout.measureVertical(LinearLayout.java:721)
                      at android.widget.LinearLayout.onMeasure(LinearLayout.java:612)
                      at android.view.View.measure(View.java:18870)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5908)
                      at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
                      at android.view.View.measure(View.java:18870)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5908)
                      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1435)
                      at android.widget.LinearLayout.measureVertical(LinearLayout.java:721)
                      at android.widget.LinearLayout.onMeasure(LinearLayout.java:612)
                      at android.view.View.measure(View.java:18870)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5908)
                      at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
                      at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:3076)
                      at android.view.View.measure(View.java:18870)
                      at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2392)
                      at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1416)
                      at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1661)
                      at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1301)
                      at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7016)
                      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:777)
                      at android.view.Choreographer.doCallbacks(Choreographer.java:590)
                      at android.view.Choreographer.doFrame(Choreographer.java:560)
                    at android.view.Choreographer$FrameDisplayEventRec
I/Process: Sending signal. PID: 1231 SIG: 9
Application terminated.

Answer 1

@z.al 我理解你的情况，但为了让你确定，SimpleAdapter 只是帮助将字符串类型值填充到 ID 指定的 TextView 中。

但在您的情况下，您应该实现自定义 ArrayAdapter 并在 getView() 方法中将图像图标设置为 imageView。

以下是让您清楚的简单 fragment :

public class Person {

public HashMap<String, String> contact;
void Person(HashMap<String, String> contact) {
this.contact = contact;
}
}

public class MyListAdapter extends ArrayAdapter<Person> {

private Context context;
private ArrayList<Person> contactList;

private LayoutInflater mInflater;
private boolean mNotifyOnChange = true;

public MyListAdapter(Context context, ArrayList<Person> contactList) {
    super(context, R.layout.my_row_layout);
    this.context = context;
    this.contactList = new ArrayList<>(contactList);
    this.mInflater = LayoutInflater.from(context);
}

@Override
public int getCount() {
    return contactList.size();
}

@Override
public Person getItem(int position) {
    return contactList.get(position);
}

@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    final ViewHolder holder;
    if (convertView == null) {
        holder = new ViewHolder();
            convertView = mInflater.inflate(R.layout.my_row_layout,parent, false);
            holder.name = (TextView) convertView.findViewById(R.id.textview_name);
            holder.description = (TextView) convertView.findViewById(R.id.textview_description);
        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }

Person person = contactList.get(position);
    holder.name.setText(person.get("name"));
    holder.image.setImageResource(person.get("id"));
    holder.pos = position;
    return convertView;
}

//---------------static views for each row-----------//
     static class ViewHolder {

         TextView name;
         TextView description;
         ImageView image;
         int pos; //to store the position of the item within the list
     }
}