ListView 从 EditText 更新

Question

我有一个自定义列表视图，它是从对话框中的EditText 组件更新的。我有自定义行、适配器类和自定义对话框都可以工作，但我似乎无法触发adatper 类中的代码，该代码会将文本从编辑文本控件添加到列表中。这是我的活动代码，如果您需要适配器代码，请告诉我。在我将自定义行和适配器添加到列表之前它工作了:(

问题症状：emailAdapter.notifyDataSetChanged(); 什么都不做

public class InvitePlayers_Activity extends Activity {
    ListViewAdapter emailAdapter = null;
    ImageView imgView_mail;
    ImageView imgView_confirm;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.requestWindowFeature(Window.FEATURE_NO_TITLE); //remove title bar
        setContentView(R.layout.activity_inviteplayers);

        //Generate list View from ArrayList
        displayListView();
    }

    private void displayListView() {
        //assign controls
        final ListView listView = (ListView) findViewById(R.id.listView_invitePlayers);
        imgView_mail = (ImageView)findViewById(R.id.imgView_mail);

        //Test data
        ArrayList<String> inviteNew = new ArrayList<String>();
        final ArrayList<ArrayList<String>> inviteList = new ArrayList<ArrayList<String>>();

        emailAdapter = new ListViewAdapter(this,inviteList);
        listView.setAdapter(emailAdapter);

        // Assign adapter to ListView
        listView.setTextFilterEnabled(true);

        //Edit listeners
        imgView_mail.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view)
            {
                        //variables
                        final String enteredMail = "testListViewEntry";
                        final ArrayList<ArrayList<String>> inviteList = new ArrayList<ArrayList<String>>();
                        ArrayList<String> invite = new ArrayList<String>();
                        invite.add(0, enteredMail);//add first email
                        invite.add(1,"icon_invitestatussent.png"); //add first status icon
                        inviteList.add(invite);
                        emailAdapter.notifyDataSetChanged();
                        listView.setAdapter(emailAdapter);
            }
        });
    }
}

请求的适配器代码

public class ListViewAdapter extends BaseAdapter {
    private Activity context;
    ArrayList<ArrayList<String>> inviteDetails = new ArrayList<ArrayList<String>>();
    public ListViewAdapter(Activity context, ArrayList<ArrayList<String>> inviteDetails ) {
        this.inviteDetails = inviteDetails;
        this.context = context;
    }

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

    @Override
    public Object getItem(int i) {
        return inviteDetails.get(i).get(0);
    }

    @Override
    public long getItemId(int i) {
        return i;
    }

    public View getView(int position, View view, ViewGroup parent){
        //Inflater
        LayoutInflater inflater = context.getLayoutInflater();

        //get row view
        if (view == null) {
            LayoutInflater mInflater = (LayoutInflater)
                    context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);

            view = mInflater.inflate(R.layout.list_item_email, null);
        }

        //assign controls
        final TextView textView_playerEmail = (TextView) view.findViewById(R.id.textView_playerEmail);
        ImageView imgView_inviteStatus = (ImageView) view.findViewById(R.id.imgView_inviteStatus);

        //Assign control values that are dynamic
        textView_playerEmail.setText(inviteDetails.get(position).get(0));
        imgView_inviteStatus.setImageResource(R.drawable.icon_invitestatussent);

        return view;
    }

    @Override
    public void notifyDataSetChanged() {
        super.notifyDataSetChanged();
    }
}

自定义行xml

<?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">

    <TextView xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:padding="10dp"
        android:textSize="16sp"
        android:id="@+id/textView_playerEmail"
        android:textColor="@color/white"
        android:text="item1">
    </TextView>

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imgView_inviteStatus" />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imgView_remove"
        android:src="@drawable/btn_cancel" />
</LinearLayout>

活动布局

        <LinearLayout
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="20"
            android:background="@color/yellow"
            android:layout_margin="20dp"
            android:padding="5dp">

            <LinearLayout
                android:orientation="horizontal"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:weightSum="1"
                android:gravity="left|center">


                <ImageView
                    android:layout_width="45dp"
                    android:layout_height="34dp"
                    android:id="@+id/imgView_mail"
                    android:src="@drawable/btn_mail"
                    android:layout_weight="0.22"
                    android:padding="3dp" />
            </LinearLayout>

            <ListView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/listView_invitePlayers"
                android:layout_gravity="center_horizontal" />
        </LinearLayout>

        <ImageView
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:id="@+id/btn_confirm"
            android:src="@drawable/btn_confirm"
            android:clickable="false"
            android:adjustViewBounds="true"
            android:layout_gravity="center_horizontal"
            android:padding="2dp"
            android:layout_weight="1" />
    </LinearLayout>

</FrameLayout>

Answer 1

嗯，对于我们讨论的内容，你想要这样的东西：

当你想自定义ListView时，你必须编写自己的适配器。在这种特殊情况下，我将继承 BaseAdapter 类。

此自定义适配器将占用我的数据模型，并将数据膨胀到我的 ListView 行。

首先，我将创建自定义行的 XML。你可以看下面的代码。

item_mail.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test text"
        android:id="@+id/tv_mail"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_centerVertical="true"/>

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/iv_icon"
        android:layout_alignParentTop="true"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true"
        android:src="@android:drawable/ic_menu_report_image" />
</RelativeLayout>

在这里，我创建了一个显示文本和图像的行。

现在，我将创建我的自定义适配器来处理这个 XML。如下所示。

MailAdapter.java

public class MailAdapter extends BaseAdapter {

    private static final String LOG_TAG = MailAdapter.class.getSimpleName();

    private Context context_;
    private ArrayList<ArrayList<String>> mailitems;

    public MailAdapter(Context context, ArrayList<ArrayList<String>> mailitems) {
        this.context_ = context;
        this.mailitems = mailitems;
    }

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

    @Override
    public Object getItem(int position) {
        return mailitems.get(position).get(0);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            LayoutInflater mInflater = (LayoutInflater)
                    context_.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);

            convertView = mInflater.inflate(R.layout.item_mail, null);
        }

        TextView tv_mail = (TextView) convertView.findViewById(R.id.tv_mail);
        ImageView iv_icon = (ImageView) convertView.findViewById(R.id.iv_icon);

        String mail = mailitems.get(position).get(0);
        String icon = mailitems.get(position).get(1);

        Log.d(LOG_TAG,"Mail: " + mail + " mail_icon: " + icon);

        tv_mail.setText(mail);
        // iv_icon.setImageURI(); Here you can do whatever logic you want to update your image, using URI's, ID's, or something else.

        return convertView;
    }
}

好的。现在我们拥有一切来完成这项工作。在您的 Activity 课程中，执行以下操作：

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <TextView
        android:text="@string/hello_world"
        android:id="@+id/tv_header"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@+id/tv_header">

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Add mail"
            android:id="@+id/button"
            android:layout_gravity="center" />

        <ListView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/listView" />
    </LinearLayout>

</RelativeLayout>

MainActivity.java

public class MainActivity extends ActionBarActivity {

    private int numMail = 1; // Dummy int to create my items with different numbers.

    private MailAdapter mailAdapter; // Your custom adapter.

    private ArrayList<ArrayList<String>> mailItems; // This is going to be your data structure, everytime you change it, call the notifyDataSetChanged() method.

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

        Button bt = (Button) findViewById(R.id.button);
        ListView lv_mail = (ListView) findViewById(R.id.listView);
        mailItems = new ArrayList<>();
        mailAdapter = new MailAdapter(this,mailItems);
        lv_mail.setAdapter(mailAdapter);

        bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addItem(); // The method I'm using to insert the item. Look for it below.
            }
        });
    }

    // Here I'm creating a new ArrayList, and appending it to my 'mailItems' Array. After that, I'm notifying the adapter that my data changed.
    private void addItem() {
        ArrayList<String> mail = new ArrayList<>();

        mail.add(0,"mail " + numMail++);
        mail.add(1,"path_to_image"); // Depending on what you want to do, put your path, URI, or whatever other way you want to store that image data.

        mailItems.add(mail); // Inserting the data on the ArrayList.
        mailAdapter.notifyDataSetChanged(); // Notifying the adapter that my ArrayList was modified.
    }
}

这应该可以解决问题。

我猜您的问题是您没有更新自定义适配器中的同一个 ArrayList。这就是为什么当你打电话给notifyDataSetChanged()什么都没发生时，我的意思是。您正在创建一个新的ArrayList，它与您的适配器中的不同。所以这就是我所做的……我将ArrayList 设为全局，然后在我的自定义适配器构造函数中使用它。之后，当用户触发我的按钮的onClick() 方法时，我将在我的全局数组中插入一些新数据，然后通知适配器数据已更改。

你可以阅读更多关于 here 的信息，我发现了一个类似的问题 here，你也可以阅读。

编辑：另一个related question，这可能是一个有趣的阅读。