Android how to use adapter for listView without extending listActivity

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情书的邮戳
情书的邮戳 2020-12-19 08:34

I have an application with tabs. In one tab I need to put data (strings) in rows. To do so I chose tableLayout but when I wanted to use a contextmenu

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  • 2020-12-19 09:14

    main Activity class:

    import java.util.ArrayList;
    import android.app.Activity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.AdapterView.OnItemClickListener;
    import android.widget.Button;
    import android.widget.ListView;
    
    public class SelectedActivity extends Activity {
    
    private SelectedAdapter selectedAdapter;
    private ArrayList<String> list;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.selected_example);
    
        // populate the model - a simple a list
        list = new ArrayList<String>();
        list.add("Apple");
        list.add("Orange");
        list.add("Grape");
        list.add("Grape1");
        list.add("Grape2");
        list.add("Grape3");
        list.add("Grape4");
        list.add("Grape5");
        list.add("Grape6");
    
        // create our SelectedAdapter
        selectedAdapter = new SelectedAdapter(this,0,list);
        selectedAdapter.setNotifyOnChange(true);
    
        ListView listview = (ListView) findViewById(R.id.listExample);
        listview.setAdapter(selectedAdapter);
    
        listview.setOnItemClickListener(new OnItemClickListener() {
            //@Override
            public void onItemClick(AdapterView arg0, View view,
                                           int position, long id) {
                // user clicked a list item, make it "selected"
                selectedAdapter.setSelectedPosition(position);
            }
        });
    }
    

    Adapter class:

       import java.util.List;
        import android.content.Context;
        import android.graphics.Color;
        import android.view.LayoutInflater;
        import android.view.View;
        import android.view.ViewGroup;
        import android.widget.ArrayAdapter;
        import android.widget.Button;
        import android.widget.TextView;
    
        public class SelectedAdapter extends ArrayAdapter{
    
            // used to keep selected position in ListView
            private int selectedPos = -1;   // init value for not-selected
    
            public SelectedAdapter(Context context, int textViewResourceId,
                           List objects) {
                 super(context, textViewResourceId, objects);
            }
            public void setSelectedPosition(int pos){
            selectedPos = pos;
                 // inform the view of this change
                 notifyDataSetChanged();
            }
            public int getSelectedPosition(){
                 return selectedPos;
            }
            @Override
            public View getView(int position, View convertView, ViewGroup parent) {
                     View v = convertView;
                     // only inflate the view if it's null
                     // if (v == null) {
                            LayoutInflater vi =   (LayoutInflater)this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                            v = vi.inflate(R.layout.selected_row, null);
                     //  }
    
                     // get text view
                         TextView label = (TextView)v.findViewById(R.id.txtExample);
                         Button btn=(Button)v.findViewById(R.id.btn1);
    
                         // change the row color based on selected state
                         if(selectedPos == position){
                            label.setBackgroundColor(Color.CYAN);
                            btn.setBackgroundResource(R.drawable.next);
                         }
                         else{
                            label.setBackgroundColor(Color.WHITE);
                         }
    
                         label.setText(this.getItem(position).toString());       
                         return(v);
            }
    }
    
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  • 2020-12-19 09:37

    main.xml:

    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:background="@drawable/bg8"
        android:id="@+id/RootView"
        >
            <LinearLayout android:id="@+id/myLayout"
                android:layout_width="wrap_content"
                android:layout_height="fill_parent">
           </LinearLayout>
    
    </LinearLayout>
    

    You need to define an xml which will be used to hold data of each row:

    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" android:weightSum="1">
    
       <TableRow
           android:id="@+id/tableRow1"
           android:layout_width="793dp"
           android:layout_height="wrap_content"
           android:layout_weight="0.23" >
    
            <TextView android:id="@+id/col1"
                android:layout_height="fill_parent"
                android:layout_width="wrap_content"
                android:width="50dp"
               android:textSize="18sp"
    
            />
            <TextView android:id="@+id/col2"
                android:layout_height="fill_parent"
                android:layout_width="wrap_content"
                android:width="150dp"
                android:textSize="18sp"
            />
          <ImageView android:id="@+id/editimage"
                android:background="@drawable/edit"
                android:clickable="true"
                android:onClick="ClickHandlerForEditImage" 
                android:layout_width="35dp" 
             android:layout_height="35dp"/>  
    
        </TableRow>
    
    </LinearLayout>
    

    In the above xml i have also included the ImageView, it is not really required but this is just to update you that we can include the other controls also.

    & at the last you should have a function in your related class:

    private void LoadData()
    {
    
        DBAdapter db = new DBAdapter(this);
        db.open();
        Cursor cur = db.GetData();
        private ListView lv = (ListView)findViewById(R.id.myLayout);
        lv.setAdapter(null);
        if(cur.moveToFirst())
        {
                String[] from = new String[] {"_id","column1"};
                int[] to = new int[] {R.id.col1, R.id.col2};
                SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,R.layout.grid_item, cur, from, to);
                lv.setAdapter(adapter);  
    
         }
           db.close();
             }
    }
    
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  • 2020-12-19 09:39

    It appears that noone has answered you contextMenu question. To get a context menu to work with your list , after you call ListView yourList = getListView(); you must call registerForContextMenu(yourList);

    And to handle the menu creation you must implement the method

    @Override public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo){ 
    super.onCreateContextMenu(context, v,menuInfo);
    MenuInflater inflater = getMenuInflater();
    menu.setHeaderTitle("YOUR TITLE");
    menu.setHeaderIcon(R.drawable.YOUR DRAWABLE);
    inflater.inflate(R.menu.YOUR_MENU_RESOURCE, menu);
    }
    

    Then you can respond to clicks by implenting the method

    @Override public boolean onContextItemSelected(MenuItem item){
    switch(item.getItemId()){
    case R.id.YOUR_MENU_ITEM: // do stuff if the item is selected
     return true;
    case R.id.YOUR_MENU_ITEM: // do stuff if the item is selected
     return true;
    case R.id.YOUR_MENU_ITEM: // do stuff if the item is selected
     return true;
     }
     return false; // nothing selected
    }
    
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