Question

有一个包含图像和文本视图的列表。我想做一个任务，即当用户点击某个项目时，更大的图像将显示在列表的右侧。

<LinearLayout
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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:orientation="horizontal"
tools:context="com.example.harshitbatra.baseadapter.MainActivity">

<LinearLayout
    android:layout_width="0sp"
    android:layout_height="match_parent"
    android:layout_weight="1">
    <ListView
        android:id="@+id/family_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    </ListView>
</LinearLayout>

<LinearLayout android:layout_width="0sp" android:layout_height="match_parent" android:layout_weight="2">
    <FrameLayout android:layout_width="match_parent" android:layout_height="match_parent">
        <ImageView android:id="@+id/image"
                   android:src="@drawable/harshitbatra1"
                   android:layout_width="match_parent"
                   android:layout_height="150sp"/>
    </FrameLayout>
</LinearLayout>

单击列表视图中的项目时，通过Toast输出是正确的，但它没有更新图像。 fImages数组是一个全局数组。这可能不使用碎片吗？

public class MainActivity extends AppCompatActivity
{
String[] fNames = {};
int[] fImages = { R.drawable.ic_launcher, R.drawable.ic_launcher, R.drawable.ic_launcher,R.drawable.ic_launcher, R.drawable.ic_launcher, R.drawable.ic_launcher, R.drawable.ic_launcher};
ListView listView;
ImageView image;

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    listView = (ListView) findViewById(R.id.family_list);
    CustomAdapter myAdapter = new CustomAdapter(getApplicationContext(), fNames, fImages);
    listView.setAdapter(myAdapter);
    listView.setOnItemClickListener(clickListener);
}



private AdapterView.OnItemClickListener clickListener = new AdapterView.OnItemClickListener()
{
    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l)
    {

        LayoutInflater inflator = getLayoutInflater();
        view = inflator.inflate(R.layout.activity_main, null);
        image = (ImageView) view.findViewById(R.id.image);
        Log.d("Image = "+image+" i = "+i,"OnClickListener");
        //Toast.makeText(MainActivity.this, "Image = "+image+" i = "+i, Toast.LENGTH_SHORT).show();
        image.setImageResource(fImages[i]);
        Toast.makeText(MainActivity.this, "You Selected = "+fNames[i], Toast.LENGTH_SHORT).show();
    }
};



/* Custom Adapter Implementation */
private class CustomAdapter extends BaseAdapter
{

    String[] fNames;
    int[] fImages;
    LayoutInflater inflator;

    public CustomAdapter(Context c, String[] fNames, int[] fImages)
    {
        this.fNames = fNames;
        this.fImages = fImages;
        this.inflator = (LayoutInflater.from(c));
    }

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

    @Override
    public Object getItem(int i)
    {
        return null;
    }

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

    @Override
    public View getView(int i, View view, ViewGroup viewGroup)
    {
        if(i%2 == 0)
        {
            view = inflator.inflate(R.layout.list_item_view,null);
        }
        else
        {
            view = inflator.inflate(R.layout.list_item_view_2,null);
        }

        ImageView icon = (ImageView) view.findViewById(R.id.icon);
        TextView name = (TextView) view.findViewById(R.id.name);

 //                Log.d("Icon = "+icon,"getView");
 //
 //         Log.d("Image = "+fImages[i], "getView");
           icon.setImageResource(fImages[i]);
        name.setText(fNames[i]);
        return view;
    }
}

}

Answer 1

这里错了。 view是您选择的项目视图。不要使用activity_main对其进行充气，只需删除那些行。

LayoutInflater inflator = getLayoutInflater();
view = inflator.inflate(R.layout.activity_main, null);
image = (ImageView) view.findViewById(R.id.image);

每次点击项目视图时，您都无需启动image。在onCreate()

中创建一次

@Override
protected void onCreate(Bundle savedInstanceState)
{
     super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_main);
     listView = (ListView) findViewById(R.id.family_list);

     // init image here
     image = (ImageView) findViewById(R.id.image);

     CustomAdapter myAdapter = new CustomAdapter(getApplicationContext(), fNames, fImages);
     listView.setAdapter(myAdapter);
     listView.setOnItemClickListener(clickListener);
}

希望它有所帮助！

单击列表视图中的列表项时，图像在框架布局中不会更改

1 个答案: