android使用AsyncTask实现多线程下载实例
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2021-01-20
10:09:29
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android使用使用AsyncTask实现多线程下载实例实现多线程下载实例
AsyncTask不仅方便我们在子线程中对UI进行更新操作，还可以借助其本身的线程池来实现多线程任务。下面是一个使用
AsyncTask来实现的多线程下载例子。
01 效果图
02 核心类 – DownloadTask.class
public class DownloadTask extends AsyncTask<String, Integer, Integer> {
public static final int TYPE_SUCCESS = 0;
public static final int TYPE_FAILURE = 1;
public static final int TYPE_PAUSE = 2;
public static final int TYPE_CANCEL = 3;
public int positionDownload;
private boolean isPaused = false;
private boolean isCancelled = false;
private DownloadListener downloadListener;
private int lastProgress;
public DownloadTask(DownloadListener downloadListener){
this.downloadListener = downloadListener;
}
public void setDownloadListener(DownloadListener downloadListener){
this.downloadListener = downloadListener;
}
@Override
protected Integer doInBackground(String... params) {
InputStream is = null;
RandomAccessFile savedFile = null;
File file = null;
long downloadLength = 0;
String downloadUrl = params[0];
positionDownload = Integer.parseInt(params[1]);
String fileName = downloadUrl.substring(downloadUrl.lastIndexOf("/"));
String directory = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getPath();
file = new File(directory + fileName);
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