在GridView中设置EditText返回NullPointerException吗？

Question

Hello and happy holidays, everyone.

This is the problem I'm having: I set up a GridView using mrKlar's PagedDragDrop here: https://github.com/mrKlar/PagedDragDropGrid

I'm trying to make it so that instead of pre-determined text underneath each item, the user has the option to input text below it. To do this, my initial thought was to edit the Item.java file to make it so that it outputted an EditText instead of string. So this is what I ended up with (you can compare it to the original Item.java file in the github link above):

package com.example.startingeleven;

import android.widget.EditText;

public class Item {

    private long id;
    private EditText name;
    private int drawable;

    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    public String getName() {
        return name.getText().toString();
    }
    public void setName(EditText name) {
        this.name = name;
    }
    public int getDrawable() {
        return drawable;
    }
    public void setDrawable(int drawable) {
        this.drawable = drawable;
    }
    public Item(long id, EditText name, int drawable) {
        super();
        this.id = id;
        this.name = name;
        this.drawable = drawable;
    }
}

This is the area of code in the main ExamplePagedDragDropGridAdapter file that I think is relevant to this

public class ExamplePagedDragDropGridAdapter extends Activity implements PagedDragDropGridAdapter {

    private Context context;
    private PagedDragDropGrid gridview;

    List<Page> pages = new ArrayList<Page>();

    public ExamplePagedDragDropGridAdapter(Context context, PagedDragDropGrid gridview) {
        super();
        this.context = context;
        this.gridview = gridview;
        EditText striker1 = (EditText)findViewById(R.id.striker1);

        Page page1 = new Page();
        List<Item> items = new ArrayList<Item>();
        items.add(new Item(1, striker1, R.drawable.jersey));
        page1.setItems(items);
        pages.add(page1);
    }

This is the LogCat that displays the error:

12-23 23:55:10.315: E/AndroidRuntime(1622): FATAL EXCEPTION: main
12-23 23:55:10.315: E/AndroidRuntime(1622): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.startingeleven/com.example.startingeleven.FieldActivity}: java.lang.NullPointerException
12-23 23:55:10.315: E/AndroidRuntime(1622):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at android.os.Handler.dispatchMessage(Handler.java:99)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at android.os.Looper.loop(Looper.java:137)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at android.app.ActivityThread.main(ActivityThread.java:5103)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at java.lang.reflect.Method.invokeNative(Native Method)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at java.lang.reflect.Method.invoke(Method.java:525)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at dalvik.system.NativeStart.main(Native Method)
12-23 23:55:10.315: E/AndroidRuntime(1622): Caused by: java.lang.NullPointerException
12-23 23:55:10.315: E/AndroidRuntime(1622):     at android.app.Activity.findViewById(Activity.java:1853)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at com.example.startingeleven.ExamplePagedDragDropGridAdapter.<init>(ExamplePagedDragDropGridAdapter.java:63)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at com.example.startingeleven.FieldActivity.onCreate(FieldActivity.java:29)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at android.app.Activity.performCreate(Activity.java:5133)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
12-23 23:55:10.315: E/AndroidRuntime(1622):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
12-23 23:55:10.315: E/AndroidRuntime(1622):     ... 11 more
12-23 23:55:46.794: I/Process(1622): Sending signal. PID: 1622 SIG: 9

Am I on the right track editing the Item file to get an EditText to show up below the items? I have a feeling this might be a lot to ask for a solution for, but then again I'm not the most knowledgable in android programming lol. Either way, any fix to this problem is well appreciated, and please just ask if you require any more information.

Thanks.

Answer 1

 EditText striker1 = (EditText)findViewById(R.id.striker1);

You are not inflating a layout. findViewById looks for a view with the id in the current infalted layout. Since you do not inflate a layout and try to initialize edittext you get NullPointerException

Answer 2

You just need to first inflate the layout in which you defined your edittext ie striker1 and then from that layout you have to call findviewbyid and you will get the edittext instance..!

This is what you really need to do:--

 View layout = inflater.inflate(R.layout.your_xml_layout,
                        null);
 EditText striker1 = (EditText)layout.findViewById(R.id.striker1);

NOTE

here R.layout.your_xml_layout : is the layout file in which you defined your edittext with id ie striker1.

just try it..!