我有一个程序，屏幕上有大约 50 个按钮，它看起来相当难看。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，并保存更改后的 URL 和文件名。我希望能够从使用按钮更改为使用一个微调器，希望只需一个异步下载任务，并且微调器作为选择下载 URL 和另存为的文件名的方式进行操作。这可能吗？在阅读了一些有关它的文档后，我感到很困惑。谢谢您的帮助。
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();
}
}
}
}
这对于我想要实现的目标是否正确？
最佳答案
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) {
}
}
}
这是一个满足您要求的示例类。我没有运行它，如果有一些错误，很抱歉，但基本思想在这里。
关于java - 安卓- "A spinner does not support item click events. Calling this method will raise an exception."，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/10458618/