package com.example.demo1; import java.util.EventListener; public interface MyAsyncTaskListener extends EventListener
{
public Object Task(Object... parameters);
public void TaskCompleted(Object result);
}
package com.example.demo1;
import android.os.AsyncTask;
public class MyAsyncTask extends AsyncTask<Object, Void, Object> {
private MyAsyncTaskListener myAsyncTaskListeners = null;
@Override
protected Object doInBackground(Object... params) {
if(myAsyncTaskListeners != null)
return myAsyncTaskListeners.Task(params);
else
return null;
}
@Override
protected void onPostExecute(Object result) {
if(myAsyncTaskListeners != null)
myAsyncTaskListeners.TaskCompleted(result);
}
public void setAsyncTaskListener(MyAsyncTaskListener listener)
{
myAsyncTaskListeners = listener;
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); StrictMode.setThreadPolicy(new
StrictMode.ThreadPolicy.Builder().detectDiskReads().detectDiskWrites().detectNetwork().penaltyLog().build());
StrictMode.setVmPolicy(
new StrictMode.VmPolicy.Builder().detectLeakedSqlLiteObjects().detectLeakedClosableObjects().penaltyLog().penaltyDeath().build()); getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN); final ImageView image = (ImageView)this.findViewById(R.id.image); MyAsyncTask task = new MyAsyncTask();
task.setAsyncTaskListener(new MyAsyncTaskListener() {
@Override
public Object Task(Object... parameters) {
try {
File file = downloadFile(parameters[0].toString());
TiffDecoder.nativeTiffOpen(file.getPath());
int[] pixels = TiffDecoder.nativeTiffGetBytes();
Bitmap mBitmap = Bitmap.createBitmap(pixels, TiffDecoder.nativeTiffGetWidth(), TiffDecoder.nativeTiffGetHeight(),Bitmap.Config.ARGB_8888);
TiffDecoder.nativeTiffClose();
return mBitmap;
} catch (IOException e) {
// TODO 自动生成的 catch 块
e.printStackTrace();
}
return null;
} @Override
public void TaskCompleted(Object result) {
if(result == null)
return; image.setImageBitmap((Bitmap)result);
}
}); task.execute("http://xibei1-image.jfdedu.com/00006009b4673bbc-ff2a-49bd-91fe-764c01b2acce01.tif");
} private File downloadFile(String strUrl) throws IOException
{
URL url = new URL(strUrl);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
urlConnection.connect(); File file = File.createTempFile("myfile", ".tif", this.getCacheDir());
if(file.exists())
file.delete();
file.createNewFile(); FileOutputStream fileOutput = new FileOutputStream(file);
InputStream inputStream = urlConnection.getInputStream();
byte[] buffer = new byte[1024];
int bufferLength = 0;
while ( (bufferLength = inputStream.read(buffer)) > 0 ) {
fileOutput.write(buffer, 0, bufferLength);
}
fileOutput.close();
return file;
}
上面的示例干扰代码比较多，其实这个类的使用方法是这样的：
MyAsyncTask task = new MyAsyncTask();
//定义了一个匿名类，这个匿名类继承了接口MyAsyncTaskListener，并且实例化了这个匿名类型的一个实例，传递给接口方法。
task.setAsyncTaskListener(new MyAsyncTaskListener() {
@Override
public Object Task(Object... parameters) {
//执行耗时操作并返回结果
} @Override
public void TaskCompleted(Object result) {
//接收并使用异步请求结果
}
}); //开始异步请求
task.execute("http://xibei1-image.jfdedu.com/00006009b4673bbc-ff2a-49bd-91fe-764c01b2acce01.tif");