ListView - 将项目从 1 行更改为 2 行

Question

如何修改下面的代码，使每个项目有两行而不是一行？我希望 mSample 部分中的代码与我发布的布局相同，因此请不要不恰当地修改它，除非有必要。下面是一张图片，用一行描述了列表的外观。

我知道点击事件和列表适配器代码需要更改，但我不知道该怎么做。

我还有一个名为 list_item_entry.xml 的 xml，它在线性布局中包含两个文本视图（一个比另一个大），但我不确定是否需要使用它。 p>

package com.example.android.animationsdemo;

import android.app.Activity;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;

/**
 * The launchpad activity for this sample project. This activity launches other activities that
 * demonstrate implementations of common animations.
 */
public class MainActivity extends ListActivity {
    /**
     * This class describes an individual sample (the sample title, and the activity class that
     * demonstrates this sample).
     */
    private class Sample {
        private CharSequence title;
        private Class<? extends Activity> activityClass;

        public Sample(int titleResId, Class<? extends Activity> activityClass) {
            this.activityClass = activityClass;
            this.title = getResources().getString(titleResId);
        }

        @Override
        public String toString() {
            return title.toString();
        }
    }

    /**
     * The collection of all samples in the app. This gets instantiated in {@link
     * #onCreate(android.os.Bundle)} because the {@link Sample} constructor needs access to {@link
     * android.content.res.Resources}.
     */
    private static Sample[] mSamples;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Instantiate the list of samples.
        mSamples = new Sample[]{
                new Sample(R.string.title_crossfade, CrossfadeActivity.class),
                new Sample(R.string.title_card_flip, CardFlipActivity.class),
                new Sample(R.string.title_screen_slide, ScreenSlideActivity.class),
                new Sample(R.string.title_zoom, ZoomActivity.class),
                new Sample(R.string.title_layout_changes, LayoutChangesActivity.class),
        };

        setListAdapter(new ArrayAdapter<Sample>(this,
                android.R.layout.simple_list_item_1,
                android.R.id.text1,
                mSamples));
    }

    @Override
    protected void onListItemClick(ListView listView, View view, int position, long id) {
        // Launch the sample associated with this list position.
        startActivity(new Intent(MainActivity.this, mSamples[position].activityClass));
    }

}

list_item_entry.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:minHeight="?android:attr/listPreferredItemHeight"
    android:gravity="center_vertical"
    android:paddingRight="?android:attr/scrollbarSize"
    android:baselineAligned="false">

    <RelativeLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dip"
        android:layout_marginRight="6dip"
        android:layout_marginTop="6dip"
        android:layout_marginBottom="6dip"
        android:layout_weight="1">

        <TextView android:id="@+id/list_item_entry_title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:singleLine="true"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:ellipsize="marquee"
            android:fadingEdge="horizontal"
            />

        <TextView android:id="@+id/list_item_entry_summary"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/list_item_entry_title"
            android:layout_alignLeft="@id/list_item_entry_title"
            android:textAppearance="?android:attr/textAppearanceSmall"
            android:singleLine="true"
            android:textColor="?android:attr/textColorSecondary"
            />

    </RelativeLayout>

</LinearLayout>

类错误

package com.example.android.animationsdemo;

import android.app.Activity;
import android.app.ListActivity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;

/**
 * The launchpad activity for this sample project. This activity launches other activities that
 * demonstrate implementations of common animations.
 */
public class MainActivity extends ListActivity {
    /**
     * This class describes an individual sample (the sample title, and the activity class that
     * demonstrates this sample).
     */
    private class Sample {
        private CharSequence title;
        private CharSequence summary;
        private Class<? extends Activity> activityClass;

        public Sample(int titleResId, int summaryResId, Class<? extends Activity> activityClass) {
            this.activityClass = activityClass;
            this.title = getResources().getString(titleResId);
            this.summary = getResources().getString(summaryResId);

        }

        @Override
        public String toString() { return title.toString(); return summary.toString(); }
    }

    /**
     * The collection of all samples in the app. This gets instantiated in {@link
     * #onCreate(android.os.Bundle)} because the {@link Sample} constructor needs access to {@link
     * android.content.res.Resources}.
     */
    private static Sample[] mSamples;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Instantiate the list of samples.
        mSamples = new Sample[]{
                new Sample(R.string.title_crossfade, R.string.summary_crossfade, CrossfadeActivity.class),
                new Sample(R.string.title_card_flip, R.string.summary_card_flip, CardFlipActivity.class),
                new Sample(R.string.title_screen_slide, R.string.summary_screen_slide, ScreenSlideActivity.class),
                new Sample(R.string.title_zoom, R.string.summary_zoom, ZoomActivity.class),
                new Sample(R.string.title_layout_changes, R.string.summary_layout_changes, LayoutChangesActivity.class),
        };
    }

    @Override
    protected void onListItemClick(ListView listView, View view, int position, long id) {
        // Launch the sample associated with this list position.
        startActivity(new Intent(MainActivity.this, mSamples[position].activityClass));
    }

    static class MyAdapter extends BaseAdapter {

        static class ViewHolder {
            TextView title;
            TextView summary;
        }

        LayoutInflater inflater;
        Sample[] mSamples;

        public MyAdapter(Context contexts, Sample[] samples) {
            this.mSamples = samples;
            inflater = LayoutInflater.from(contexts);

        }

        @Override
        public int getCount() {
            return mSamples.length;
        }

        @Override
        public Object getItem(int position) {
            return mSamples[position];
        }

        @Override
        public long getItemId(int position) {
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder viewHolder;
            if (convertView == null) {
                convertView = inflater.inflate(R.layout.entry, null);
                viewHolder = new ViewHolder();

                viewHolder.title = (TextView) convertView.findViewById(R.id.list_item_entry_title);
                viewHolder.summary = (TextView) convertView.findViewById(R.id.list_item_entry_summary);
                convertView.setTag(viewHolder);
            } else {
                viewHolder = (ViewHolder) convertView.getTag();
            }
            viewHolder.title.setText(mSamples[position].title);
            viewHolder.summary.setText(mSamples[position].summary);
            return convertView;
        }
    }
}

Answer 1

也许对你有帮助

public class MainActivity extends ListActivity {

   /*
     current code
   */

    public void onCreate(Bundle savedInstanceState) {
     //
     //

       setListAdapter(new SampleAdapter(this,
            android.R.layout.simple_list_item_1,
            mSamples));
    }

    @Override
    protected void onListItemClick(ListView listView, View view, int position, long id) {
        // Launch the sample associated with this list position.
        startActivity(new Intent(MainActivity.this, mSamples[position].activityClass));
    }

    public static class SampleAdapter extends ArrayAdapter<Sample>{

            SampleAdapter(Context context, int resource, Sample[] objects) {
                super(context, resource, objects);
            }

            @Override
            public View getView(int position, View convertView, ViewGroup parent) {
                View rootView = super.getView(position, convertView, parent);
                TextView firstLine = rootView.findViewById(R.id.list_item_entry_title);
                TextView secondLine = rootView.findViewById(R.id.list_item_entry_summary);
                firstLine.setText(getItem(position)./*Sample class field*/);
                secondLine.setText(getItem(position)./*Sample class field*/);
                return rootView;
            }
        }
}

Answer 2

如果您想自定义包含多个TextView 的行，那么您应该实现自己的适配器。您发布的 xml 没有用，因为您使用的是 android.R.layout.simple_list_item_1 和 android.R.id.text1。要实现您想做的事情，请尝试以下操作：

public class MyAdapter extends BaseAdapter {

    static class ViewHolder {
        TextView title;
        TextView summary;
    }

    LayoutInflater inflater;
    Sample[] mSamples;

    public MyAdapter(Context contexts, Sample[] samples) {
        this.mSamples = samples;
        inflater = LayoutInflater.from(contexts);

    }

    @Override
    public int getCount() {
        return mSamples.length;
    }

    @Override
    public Object getItem(int position) {
        return mSamples[position];
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder;
        if (convertView == null) {
            convertView = inflater.inflate(R.layout.entry, null);
            viewHolder = new ViewHolder();

            viewHolder.title = (TextView) convertView.findViewById(R.id.list_item_entry_title);
            viewHolder.summary = (TextView) convertView.findViewById(R.id.list_item_entry_summary);
            convertView.setTag(viewHolder);
        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }
        viewHolder.title.setText(mSamples[position].title);
        viewHolder.summary.setText(mSamples[position].summary);
        return convertView;
    }
}

你可以这样使用它：

list.setAdapter(new MyAdapter(this, samples));