在 ListView 中加载多个图像

Question

我正在学习 NewBoston 教程 (https://www.youtube.com/watch?v=nOdSARCVYic&list=PL6gx4Cwl9DGBsvRxJJOzG4r4k_zLKrnxl&index=48)

他展示了如何将图像放入列表中，但他从未展示过如何为每段文本分配不同的图像。

这是我的 MainActivity.

public class MainActivity extends Activity {

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


    String[] Jobsites = {"River Park Place", "Mayfair", "Jameson House"};
    ListAdapter jobsiteAdapter = new CustomAdapter(this, Jobsites);
    ListView jobsiteListView = (ListView) findViewById(R.id.jobsiteListView);
    jobsiteListView.setAdapter(jobsiteAdapter);

    jobsiteListView.setOnItemClickListener(
            new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                    String jobsite = String.valueOf(parent.getItemAtPosition(position));
                    //Toast.makeText(MainActivity.this, jobsite, Toast.LENGTH_LONG).show();
                    if (jobsite == "River Park Place"){
                        //Perform segue to the proper view where employess can sign in
                        //******************************************
                        System.out.println("*****************");
                        System.out.println("Attempting to segue");
                        System.out.println("*****************");



                        //******************************************
                    }else{
                        System.out.println("*****************");
                        System.out.println("These jobsites aren't avaliable yet!");
                        System.out.println("*****************");
                        Toast.makeText(MainActivity.this, "**These Sites aren't avaliable yet!**", Toast.LENGTH_LONG).show();
                    }
                }
            }
        );

    }
}

在视频中，我们制作了一个处理图像的自定义视图。这是代码。

class CustomAdapter extends ArrayAdapter<String> {


public CustomAdapter(Context context, String[] jobsites) {
    super(context,R.layout.custom_row ,jobsites);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater jobsiteInflater = LayoutInflater.from(getContext());
    View customView = jobsiteInflater.inflate(R.layout.custom_row, parent, false);

    String singleJobsiteItem = getItem(position);

    ImageView josbiteImage = (ImageView) customView.findViewById(R.id.josbiteImage);

    josbiteImage.setImageResource(R.drawable.riverparkplace);


    return customView;

    }
}

我还有另外两张图片要添加到列表底部的两项文本中。现在它只是为列表中的所有三行一遍又一遍地加载相同的图片。

Answer 1

You need to 由于图像的缘故实施基础适配器

Answer 2

让我逐步指导您完成此过程。在我们继续之前，您需要了解 ListView 的 ArrayAdapter 会使用您指定的数据填充每一行。换句话说，您希望像处理 Jobsites 字符串数组一样将图像传递给适配器。

定义一个 simple wrapper object，其中包含您的字符串 (Jobsites) 和您要分配给它的图像。

public class SimpleObject {

    private String jobSite;
    private int imageID; // your R.drawable.image

    public SimpleObject(String jobSite, int imageID) {
        this.jobSite = jobSite;
        this.imageID = imageID;
    }

    public String getJobSite() {
        return jobSite;
    }

    public int getImageID() {
        return imageID;
    }
}

初始化适配器要使用的 SimpleObject 数组。在主 activity 的 onCreate() 中，执行以下操作：

ArrayList<SimpleObject> objectList = new ArrayList<>();
objectList.add(new SimpleObject("River Park Place", R.drawable.image1);
objectList.add(new SimpleObject("Mayfair", R.drawable.image2);
// the list goes on....

现在，将 CustomAdapter 更改为按住 SimpleObject 而不是 String:

class CustomAdapter extends ArrayAdapter<SimpleObject> {


    public CustomAdapter(Context context, ArrayList<SimpleObject> objectList) {
        super(context,R.layout.custom_row ,objectList);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater jobsiteInflater = LayoutInflater.from(getContext());
        View customView = jobsiteInflater.inflate(R.layout.custom_row, parent, false);

        // Get the SimpleObject
        SimpleObject item = (SimpleObject) getItem(position);
        String singleJobsiteItem = item.getJobSite(); // get the String

        ImageView josbiteImage = (ImageView) customView.findViewById(R.id.josbiteImage);

        josbiteImage.setImageResource(item.getImageID()); // get the image ID and assign it to jobsiteImage :)


        return customView;

    }
}

现在确保使用新的 SimpleObject 列表初始化主 activity 中的适配器：
```
ListAdapter jobsiteAdapter = new CustomAdapter(this, objectList);
```

在 ListView 中加载多个图像

Load Multiple Images in ListView

java

android

listview

android-studio-2.0