安卓 - "A spinner does not support item click events. Calling this method will raise an exception."

Question

我有一个程序，屏幕大约有 50 个按钮，看起来相当丑陋。 每个按钮都有一个异步下载，它只是从一个按钮复制到另一个按钮，并将URL和文件名保存为更改。 我希望能够从使用按钮更改为使用一个微调器，希望只有一个异步下载任务，并且微调器作为选择下载 URL 和要另存为的文件名的方式运行。 这可能吗？ 在阅读了一些关于它的文档后，我感到困惑。 感谢您的帮助。

更新：

使用下面建议的代码，我创建了这个：

public class SpinnerActivity extends Activity{

public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
private Button startBtn;
private ProgressDialog mProgressDialog;
Spinner spDownloadFrom;
private ArrayAdapter<CharSequence> spinnerArrayAdapter;
String url[]= {"www.abc.com/download/a.txt",
    "www.abc.com/download/a.txt",
    "www.abc.com/download/a.txt",
    "www.abc.com/download/a.txt",
    "www.abc.com/download/a.txt",
    "www.abc.com/download/a.txt",
    "www.abc.com/download/a.txt"
    };
String links[]= {"Server 1",
    "Server 2",
    "Server 3",
    "Server 4",
    "Server 5",
    "Server 6",
    "Server 7",
    };
public void onCreate(Bundle savedInstanceState )
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mProgressDialog = new ProgressDialog(SpinnerActivity.this);
mProgressDialog.setMessage("Please be patient, file downloading...");
mProgressDialog.setIndeterminate(false);
mProgressDialog.setMax(100);
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

spDownloadFrom=(Spinner)findViewById(R.id.Spinner01);
spinnerArrayAdapter = new ArrayAdapter<CharSequence>(this, android.R.layout.simple_spinner_item, links);
spinnerArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spDownloadFrom.setAdapter(spinnerArrayAdapter);
spDownloadFrom.setOnItemSelectedListener(new SpinnerListener(spDownloadFrom));
}
public class SpinnerListener implements OnItemSelectedListener
{
Spinner sp;
public SpinnerListener(View v)
{
    sp=(Spinner)findViewById(v.getId());
}
@Override
public void onItemSelected(AdapterView<?> arg0, View v, int arg2,
        long arg3) {
    //Call to download class
        new DownloadFile().equals(url[arg2].toString());

}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
    // TODO Auto-generated method stub
}
}
class DownloadFile extends AsyncTask<String, Integer, String> { //put your download code
@Override
protected void onPreExecute() {
    super.onPreExecute();
    mProgressDialog.show();
}
@Override
protected void onProgressUpdate(Integer... progress) {
    super.onProgressUpdate(progress);
    mProgressDialog.setProgress(progress[0]);
}

@Override
protected String doInBackground(String... aurl) {
    try {
        URL url = new URL(aurl[0]);
        URLConnection connection = url.openConnection();
        connection.connect();
        int fileLength = connection.getContentLength();
        int tickSize = 2 * fileLength / 100;
        int nextProgress = tickSize;
        Log.d(
        "ANDRO_ASYNC", "Lenght of file: " + fileLength);
        InputStream input = new BufferedInputStream(url.openStream());
        String path = Environment.getExternalStorageDirectory()
                + "/Android/Data/"
                + getApplicationContext().getPackageName() + "/files";
        File file = new File(path);
        file.mkdirs();
        File outputFile = new File(file, "test1.pdf");
        OutputStream output = new FileOutputStream(outputFile);
        byte data[] = new byte[1024 * 1024];
        long total = 0;
        int count;
        while ((count = input.read(data)) != -1) {
            total += count;
            if (total >= nextProgress) {
                nextProgress = (int) ((total / tickSize + 1) * tickSize);
                this.publishProgress((int) (total * 100 / fileLength));
            }
            output.write(data, 0, count);
        }
        output.flush();
        output.close();
        input.close();
        mProgressDialog.dismiss();
    } catch (Exception e) {
    }
    return null;
}
protected void onProgressUpdate(String... progress) {
     Log.d("Downloading",progress[0]);
}
@Override
protected void onPostExecute(String unused) {
    File file = new File(Environment.getExternalStorageDirectory()
            + "/Android/Data/" + getApplicationContext().getPackageName()
            + "/files/test1.pdf");
    Intent testIntent = new Intent(Intent.ACTION_VIEW);
    testIntent.setType("application/pdf");
    Intent intent = new Intent();
    intent.setAction(Intent.ACTION_VIEW);
    Uri uri = Uri.fromFile(file);
    intent.setDataAndType(uri, "application/pdf");
    try {
        startActivity(intent);
    } catch (ActivityNotFoundException e) {
        Toast.makeText(SpinnerActivity .this,
                "No Application Available to View PDF", Toast.LENGTH_LONG).show();
    }
}
}
 }

这对于我想要完成的事情是正确的吗？

Answer 1

public class Example extends Activity{
Spinner spDownloadFrom;
private ArrayAdapter<CharSequence> spinnerArrayAdapter;
String url[]= {"www.abc.com/download/a.txt",
        "www.abc.com/download/a.txt",
        "www.abc.com/download/a.txt",
        "www.abc.com/download/a.txt",
        "www.abc.com/download/a.txt",
        "www.abc.com/download/a.txt",
        "www.abc.com/download/a.txt"
        };
String links[]= {"Server 1",
        "Server 2",
        "Server 3",
        "Server 4",
        "Server 5",
        "Server 6",
        "Server 7",
        };
public void onCreate(Bundle savedInstanceState )
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    spDownloadFrom=(Spinner)findViewById(R.id.addQuotation_spinnerProduct);
    spinnerArrayAdapter = new ArrayAdapter<CharSequence>(this, android.R.layout.simple_spinner_item, links);
    spinnerArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spDownloadFrom.setAdapter(spinnerArrayAdapter);
    spDownloadFrom.setOnItemSelectedListener(new SpinnerListener(spDownloadFrom));
}
public class SpinnerListener implements OnItemSelectedListener
{
    Spinner sp;
    public SpinnerListener(View v)
    {
        sp=(Spinner)findViewById(v.getId());
    }
    @Override
    public void onItemSelected(AdapterView<?> arg0, View v, int arg2,
            long arg3) {
        //Call to download class
            new DownloadFile().equals(url[arg2].toString());

    }
    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub
    }
}
class DownloadFile extends AsyncTask<String, String, String> { //put your download code
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }
    @Override
    protected String doInBackground(String... aurl) {

        return null;
    }
    protected void onProgressUpdate(String... progress) {
         Log.d("Downloading",progress[0]);
    }
    @Override
    protected void onPostExecute(String unused) {
    }
}
 }

这是一个示例类，可以满足您的要求。我没有运行它，如果有一些错误，我很抱歉，但基本的想法在这里。

Answer 2

很有可能。 将数据设置为数组并创建微调器。 虽然微调器确实不支持单击事件，但它确实会进行选择，因此在创建微调器后，您将拥有如下代码：

yourSpinner.setOnItemSelectedListener(new OnItemSelectedListener() {
    @Override
    public void onNothingSelected(AdapterView<?> parent) {
        // Nothing to do here
    }
    @Override
    public void onItemSelected(AdapterView<?> parent, View view,int pos, long id) {
        // Your code to get the URL and filename here
    }
});

您可以通过将所有必要的代码放在onItemSelected中来在选择后立即触发它，或者只是在那里设置一些变量，然后在布局中（微调器外部）有一个按钮来获取您设置的变量并开始在线活动。 第二个选项允许用户改变主意，而无需开始不需要的在线活动。

希望这有帮助。