代码如下:
public class AsyncTaskTestActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_async);
}
private File apkFile;
private ProgressDialog dialog;
public void downloadApk(View v) {
//启动异步任务处理
new AsyncTask<Void, Integer, Void>() {
//1. 主线程, 显示提示视图
protected void onPreExecute() {
dialog = new ProgressDialog(AsyncTaskTestActivity.this);
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
dialog.show();
//准备用于保存APK文件的File对象 : /storage/sdcard/Android/package_name/files/xxx.apk
apkFile = new File(getExternalFilesDir(null), "update.apk");
}
//2. 分线程, 联网请求
@Override
protected Void doInBackground(Void... params) {
try {
//1. 得到连接对象
String path = "http://172.16.12.8:8080/Web_Server/App10_animation.apk";
URL url = new URL(path);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
//2. 设置
//connection.setRequestMethod("GET");
connection.setConnectTimeout(5000);
connection.setReadTimeout(10000);
//3. 连接
connection.connect();
//4. 请求并得到响应码200
int responseCode = connection.getResponseCode();
if(responseCode==200) {
//设置dialog的最大进度
dialog.setMax(connection.getContentLength());
//5. 得到包含APK文件数据的InputStream
InputStream is = connection.getInputStream();
//6. 创建指向apkFile的FileOutputStream
FileOutputStream fos = new FileOutputStream(apkFile);
//7. 边读边写
byte[] buffer = new byte[1024];
int len = -1;
while((len=is.read(buffer))!=-1) {
fos.write(buffer, 0, len);
//8. 显示下载进度
//dialog.incrementProgressBy(len);
//在分线程中, 发布当前进度
publishProgress(len);
//休息一会(模拟网速慢)
//Thread.sleep(50);
SystemClock.sleep(50);
}
fos.close();
is.close();
}
//9. 下载完成, 关闭, 进入3)
connection.disconnect();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
//3. 主线程, 更新界面
protected void onPostExecute(Void result) {
dialog.dismiss();
installAPK();
}
//在主线程中更新进度(在publishProgress()之后)
protected void onProgressUpdate(Integer[] values) {
dialog.incrementProgressBy(values[0]);
}
}.execute();
//int Integer float Float void Void
}
/**
* 启动安装APK
*/
private void installAPK() {
Intent intent = new Intent("android.intent.action.INSTALL_PACKAGE");
intent.setDataAndType(Uri.fromFile(apkFile), "application/vnd.android.package-archive");
startActivity(intent);
}
}