Question

我需要下载才能启动按钮点击。按钮出现在列表视图的singleitemvew活动中。我看到下载文件的例子分配了一个像这样的网址

private static String file_url = " http:// some example url"

我使用解析来下载文件。如何将值分配给＆＃34; file_url＆＃34; 这是我的代码

singleitemvew.java

public class SingleItemView extends Activity

 {
ProgressDialog mProgressDialog;
String heading;
String subHeading;
String levelImg;
String apiImg;
String apiText;
String descImgOne;
String descImgTwo;
  String codeText;
ImageLoader imgloader = new ImageLoader(this);

String fileurl;



private ProgressDialog pDialog;
ImageView my_image;
// Progress dialog type (0 - for Horizontal progress bar)
public static final int progress_bar_type = 0;


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

    Intent i = getIntent();

    heading= i.getStringExtra("heading");
        subHeading = i.getStringExtra("subheading");
    levelImg = i.getStringExtra("levelimg");
        apiImg = i.getStringExtra("apiimg");
        apiText = i.getStringExtra("apitext");
        descImgOne = i.getStringExtra("descimgone");
    descImgTwo = i.getStringExtra("descimgtwo");
        codeText = i.getStringExtra("codetext");
    fileurl = i.getStringExtra("download");



    TextView headingtxt = (TextView)findViewById(R.id.singleitemheading);
    TextView subheadingtxt = (TextView)findViewById(R.id.singleitemsubheading);
    TextView apitxt = (TextView)findViewById(R.id.singleitemviewapitext);
    TextView codetxt = (TextView) findViewById(R.id.singleitemviewcodetext);

    ImageView level =(ImageView) findViewById(R.id.levelimg);
    ImageView api =(ImageView) findViewById(R.id.singleitemviewapiimg);
    ImageView descone =(ImageView) findViewById(R.id.descriptionimgone);
    ImageView desctwo =(ImageView) findViewById(R.id.descriptionimgtwo);



    Button downloadbtn = (Button) findViewById(R.id.singleitemviewButton);

    headingtxt.setText(heading);
    subheadingtxt.setText(subHeading);
    apitxt.setText(apiText);
    codetxt.setText(codeText);

    imgloader.DisplayImage(levelImg, level);
    imgloader.DisplayImage(apiImg, api);
    imgloader.DisplayImage(descImgOne, descone);
    imgloader.DisplayImage(descImgTwo, desctwo);



    downloadbtn.setOnClickListener(new OnClickListener(){
        @Override
        public void onClick(View v){

            new DownloadFileFromURL().execute(file_url);
        }
    });

}  

@Override
protected Dialog onCreateDialog(int id) {
    switch (id) {
        case progress_bar_type: // we set this to 0
            pDialog = new ProgressDialog(this);
            pDialog.setMessage("Downloading file. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setMax(100);
            pDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            pDialog.setCancelable(true);
            pDialog.show();
            return pDialog;
        default:
            return null;
    }
}

class DownloadFileFromURL extends AsyncTask<String, String, String> {

    /**
     * Before starting background thread
     * Show Progress Bar Dialog
     * */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        showDialog(progress_bar_type);
    }

    /**
     * Downloading file in background thread
     * */
    @Override
    protected String doInBackground(String... f_url) {
        int count;
        try{

         URL url = new URL(f_url[0]);

        URLConnection conection = url.openConnection();
        conection.connect();
        // this will be useful so that you can show a tipical 0-100% progress bar
        int lenghtOfFile = conection.getContentLength();

        // download the file
        InputStream input = new BufferedInputStream(url.openStream(), 8192);

        // Output stream
        OutputStream output = new FileOutputStream("/sdcard/download/downloadedfile.rar");

        byte data[] = new byte[1024];

        long total = 0;

        while ((count = input.read(data)) != -1) {
            total += count;
            // publishing the progress....
            // After this onProgressUpdate will be called
            publishProgress(""+(int)((total*100)/lenghtOfFile));

            // writing data to file
            output.write(data, 0, count);
        }

        // flushing output
        output.flush();

        // closing streams
        output.close();
        input.close();

    } catch (Exception e) {
        Log.e("Error: ", e.getMessage());
    }

    return null;
}

/**
 * Updating progress bar
 * */
protected void onProgressUpdate(String... progress) {
    // setting progress percentage
    pDialog.setProgress(Integer.parseInt(progress[0]));
}

/**
 * After completing background task
 * Dismiss the progress dialog
 * **/
@Override
protected void onPostExecute(String file_url) {
    // dismiss the dialog after the file was downloaded
    dismissDialog(progress_bar_type);


}

}
}

Answer 1

1.像这样编辑你的DownloadFileFromURL类。

class DownloadFileFromURL extends AsyncTask<String, Void String>
{
    String file_url;
    public DownloadFileFromURL(String file_url)
    {
        this.file_url = file_url;
    }
    //remove URL url = new URL(f_url[0]); from your doInBackground() method
}

2.更改SingleItemViewClass的调用对象

downloadbtn.setOnClickListener(new OnClickListener()
{
 @Override
    public void onClick(View v)
    {
        new DownloadFileFromURL(file_url).execute();
    }
});

如果有问题，请告诉我。

设置网址以从parse.com下载文件

1 个答案: