Question

我有一个ListView只显示一个项而不是两个。这就是我的主要活动：

public class MainActivity extends Activity {
ImageView Add;
ImageView Shadow;
ProgressBar PB;

ListView listView;
String[] valuesUp = { "Lorem ipsum dolor sit amet, consectetur adipiscing elit",
        "Sed non justo eros. Praesent a nisl dui" };
String[] valuesDown = { "Quisque ut ante eu arcu sagittis porta eu a dolor...",
        "In orci augue facilisis eget fermentum consequat ac..." };
int[] imgValues = {R.drawable.mobileapp_16, R.drawable.mobileapp_19};

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    ArrayAdapter<String> adapter = new MyAdapter(this, valuesUp, valuesDown, imgValues);
    listView = (ListView) findViewById(R.id.listView1);
    listView.setAdapter(adapter);
}

那就是我的适配器：

public class MyAdapter extends ArrayAdapter<String> {
private final Context context;
private final String[] valuesUp;
private final String[] valuesDown;
private final int[] ImageValue;
private TextView textViewUp;
private TextView textViewDown;
private ImageView image;

public MyAdapter(Context context, String[] valuesUP, String[] valuesDown, int[] imageValue) {
    super(context, R.layout.rowlayout, valuesUP);
    this.context = context;
    this.valuesUp = valuesUP;
    this.valuesDown = valuesDown;
    this.ImageValue = imageValue;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View rowView;

    rowView = inflater.inflate(R.layout.rowlayout, parent, false);
    textViewUp = (TextView) rowView.findViewById(R.id.row_text_view_up);
    textViewDown = (TextView) rowView.findViewById(R.id.row_text_view_down);
    image = (ImageView) rowView.findViewById(R.id.image);
    textViewUp.setText(valuesUp[position]);
    textViewDown.setText(valuesDown[position]);
    image.setImageDrawable(context.getResources().getDrawable(ImageValue[position]));

    return rowView;
}}

当我调试时，我发现getView被调用了很多次（大约12次）并且所有的时间“位置”都是0.为什么这样？谢谢！

我现在发现了我的问题！有点奇怪。列表的高度表现得很奇怪。当我在做“wrap_content或match_parent时，它给了我一个项目，但是当我把400dp放到它的确定时。为什么会这样？” 那是我的XML：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/progress"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#000000"
android:orientation="vertical" >

<ImageView
    android:id="@+id/imageView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentTop="true"
    android:background="@drawable/topbar_bg" />

<ImageView
    android:id="@+id/imageView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/imageView1"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:src="@drawable/topbar_leftcircle" />

<ImageView
    android:id="@+id/imageView3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/imageView1"
    android:layout_alignParentTop="true"
    android:layout_marginLeft="5dp"
    android:layout_toRightOf="@+id/imageView2"
    android:src="@drawable/topbar_logo" />

<ImageView
    android:id="@+id/imageView4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/imageView1"
    android:layout_alignParentRight="true"
    android:layout_alignParentTop="true"
    android:layout_marginRight="5dp"
    android:scaleType="fitStart"
    android:src="@drawable/topbar_menu" />

<ImageView
    android:id="@+id/imageView5"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/imageView1"
    android:layout_alignParentTop="true"
    android:layout_marginRight="5dp"
    android:layout_toLeftOf="@+id/imageView4"
    android:src="@drawable/topbar_key" />

<ScrollView
    android:id="@+id/scrollView2"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentBottom="true"
    android:layout_below="@+id/imageView1"
    android:layout_centerHorizontal="true" >

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

        <ImageButton
            android:id="@+id/imageButton1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/imageView1"
            android:layout_centerHorizontal="true"
            android:background="#00000000"
            android:src="@drawable/mobileapp_14" />

        <ImageView
            android:id="@+id/imageView6"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignBottom="@+id/imageButton1"
            android:layout_centerHorizontal="true"
            android:scaleType="fitXY"
            android:src="@drawable/transparent_bg" />

        <TextView
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentRight="true"
            android:layout_alignTop="@+id/imageView6"
            android:layout_marginBottom="5dp"
            android:layout_marginLeft="10dp"
            android:layout_marginRight="10dp"
            android:layout_marginTop="10dp"
            android:maxLines="2"
            android:text="Sed at vestibulum elit. Nunc quam erat, gravida ac consequat"
            android:textColor="@color/RedText"
            android:textSize="15dp" />

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignBottom="@+id/imageButton1"
            android:layout_alignParentLeft="true"
            android:layout_alignParentRight="true"
            android:layout_below="@+id/textView1"
            android:layout_marginLeft="10dp"
            android:layout_marginRight="10dp"
            android:maxLines="2"
            android:text="Nullam sed erat erat, ut faucibus nunc. Etiam et mi di ante lacinia suscipit. Mauris gravida turpis eget lectus ullam..."
            android:textColor="@color/WhiteText"
            android:textSize="12dp" />

        <ImageView
            android:id="@+id/imageView7"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/imageButton1"
            android:layout_centerHorizontal="true"
            android:background="#00000000"
            android:scaleType="centerCrop"
            android:src="@drawable/mobileapp_15" />

        <ListView
            android:id="@+id/listView1"
            android:layout_width="match_parent"
            android:layout_height="600dp"
            android:layout_below="@id/imageView7" >

        </ListView>

    </RelativeLayout>
</ScrollView>

Answer 1

@roiberg 你的代码在我的模拟器中工作正常。检查您的XML代码

Answer 2

我找到了你的问题。

您的问题是XML格式。

从xml中删除 ScrollView 。问题将解决。

Answer 3

你不应该将listView的高度保持为wrap_content，因为这非常昂贵。将它作为fill_parent / match_parent给出并尝试一下。

给予wrap_content将使系统执行大量操作来计算listView的高度。这将给位置0处的项目多次调用。

您不应该在scrollView中提供ListView。这永远不会奏效！

Answer 4

像这样改变你的活动

公共类MainActivity扩展Activity { ImageView添加; ImageView Shadow; ProgressBar PB;

ListView listView;
String[] valuesUp = { "Lorem ipsum dolor sit amet, consectetur adipiscing elit",
"Sed non justo eros. Praesent a nisl dui" };
String[] valuesDown = { "Quisque ut ante eu arcu sagittis porta eu a dolor...",
"In orci augue facilisis eget fermentum consequat ac..." };
int[] imgValues = {R.drawable.mobileapp_16, R.drawable.mobileapp_19};

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    listView = (ListView) findViewById(R.id.listView1);
    listView.setAdapter(new MyAdapter(this,valuesUp,valuesDown,imgValues));
}

像这样更改适配器

public class MyAdapter extends BaseAdapter {
private final Context context;
private final String[] valuesUp;
private final String[] valuesDown;
private final int[] ImageValue;
private TextView textViewUp;
private TextView textViewDown;
private ImageView image;

public MyAdapter(Context context, String[] valuesUP, String[] valuesDown, int[] imageValue) {
    super(context, R.layout.rowlayout, valuesUP);
    this.context = context;
    this.valuesUp = valuesUP;
    this.valuesDown = valuesDown;
    this.ImageValue = imageValue;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View rowView;

    rowView = inflater.inflate(R.layout.rowlayout, parent, false);
    textViewUp = (TextView) rowView.findViewById(R.id.row_text_view_up);
    textViewDown = (TextView) rowView.findViewById(R.id.row_text_view_down);
    image = (ImageView) rowView.findViewById(R.id.image);
    textViewUp.setText(valuesUp[position]);
    textViewDown.setText(valuesDown[position]);
    image.setImageDrawable(context.getResources().getDrawable(ImageValue[position]));

    return rowView;
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    return valuesUp.length;
}

@Override
public Object getItem(int arg0) {
    // TODO Auto-generated method stub
    return valuesUp[arg0];
}

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

Answer 5

我找到了解决方法。我将第一批图像放在一个独立的布局中，并使这个布局成为列表中的第一个单元格。所以，现在我将图像和列表本身作为一个大的可滚动列表。如果有人看到任何大问题，我想听听。

Answer 6

在我的情况下问题是因为我使用 NestedScrollView 所以解决方案是将 android：fillViewport =“true”添加到我的NestedScrollView

这是我的代码：

    <android.support.v4.widget.NestedScrollView
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fillViewport="true"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">
    </android.support.v4.widget.NestedScrollView>

ListView只有一个项目

6 个答案: