您好我正在尝试实施登录屏幕，显示进度对话框并允许手机旋转。
我想问一下最好的方法是什么（IntentService，AsyncTask，Service）并允许手机旋转？
我在AsyncTask等中使用空片段读了很多不同的答案。
答案 0 :(得分：1)
您可以在清单中执行类似的操作以允许轮换：
<application
android:allowBackup="true"
android:configChanges="orientation|keyboardHidden|screenSize"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme">
<activity
android:name=".activities.MainActivity"
android:configChanges="orientation|keyboardHidden|screenSize"
android:label="@string/app_name"/>
然后，您可以在活动中使用此snipet捕获旋转：
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
Log.v(this.getClass().getName(), "onConfigurationChanged()");
}
要使用进度对话框执行asynctask，这个snipet应该给你一个光线：
private ProgressDialog pDialog;
private class MyAsync extends AsyncTask<String, Void, String> {
Activity context;
public MyAsync (Activity context) {
this.context = context;
}
@Override
protected void onPreExecute(){
super.onPreExecute();
pdia = new ProgressDialog(context);
pdia.setMessage("Loading...");
pdia.show();
}
@Override
protected String doInBackground(String... urls) {
...
//do your login scheme
...
//context.methods()
return "ok";
}
@Override
protected void onPostExecute(String result) {
pDialog.dismiss();
if(result!=null && result.equals("ok")){
//login was successfully done
} else {
//login has failed
}
}
}
要使用此asynctask，你应该打电话：
new MyAsync(this).execute(null, null , null);
顺便说一下this是你的活动/片段。
答案 1 :(得分：0)
Try adding this attribute android:configChanges="orientation" to your Activity element in the AndroidManifest.xml file.
show a ProgressDialog in the onPreExecute method of an AsyncTask object and canceling the ProgressDialog in the onPostExecute method. doInBackground method is running When change the orientation.
答案 2 :(得分：0)
有关详细解答，请参阅http://www.androiddesignpatterns.com/2013/04/retaining-objects-across-config-changes.html。
基本上，您可以在LoginActivity中使用setRetainInstance设置为true的片段，以便在方向更改期间重新创建活动时不会破坏它。
示例代码：
public class AsyncFragment extends Fragment {
private LoginTask mTask;
private AsyncTaskListener mListener;
private static final String TAG = "AsyncFragment";
private boolean isTaskRunning = false;
private ProgressDialog mProgressDialog;
FrameLayout mLayout;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
mTask = new LoginTask();
mTask.execute();
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
mLayout = new FrameLayout(getActivity());
mLayout.setLayoutParams(new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
if(isTaskRunning) {
mProgressDialog = new ProgressDialog(getActivity());
mProgressDialog.show();
}
return mLayout;
}
@Override
public void onDestroyView() {
if(mProgressDialog != null && mProgressDialog.isShowing()) {
mProgressDialog.dismiss();
mProgressDialog = null;
}
super.onDestroyView();
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
try {
mListener = (AsyncTaskListener) context;
} catch (ClassCastException e) {
Log.d(TAG, "Class not instance of AsyncTaskListener");
}
}
@Override
public void onDetach() {
mListener = null;
super.onDetach();
}
private class LoginTask extends AsyncTask<Void,Integer,Void> {
@Override
protected Void doInBackground(Void... params) {
if(mListener != null) {
mListener.onBackground();
}
SystemClock.sleep(10000);
return null;
}
@Override
protected void onPreExecute() {
isTaskRunning = true;
mProgressDialog = new ProgressDialog(getActivity());
mProgressDialog.show();
if(mListener != null) {
mListener.onPreExecute();
}
super.onPreExecute();
}
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
if(mListener != null) {
mListener.onPostExecute();
}
isTaskRunning = false;
if(mProgressDialog != null && mProgressDialog.isShowing()) {
mProgressDialog.dismiss();
mProgressDialog = null;
}
}
@Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
if(mListener != null) {
mListener.onProgressUpdate(values[0]);
}
}
@Override
protected void onCancelled() {
super.onCancelled();
if(mListener != null) {
mListener.onCancelled();
}
}
}
//Listener to notify for async task callbacks
public interface AsyncTaskListener{
void onPreExecute();
void onPostExecute();
void onCancelled();
void onBackground();
void onProgressUpdate(int progress);
}
}
LoginActivity
public class MainActivity extends AppCompatActivity implements AsyncFragment.AsyncTaskListener{
private static final String FRAGMENT_TAG = "asyncFragment";
private static final String TAG = "MainActivity";
private AsyncFragment mAsyncFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
FragmentManager fm = getSupportFragmentManager();
mAsyncFragment = (AsyncFragment) fm.findFragmentByTag(FRAGMENT_TAG);
if (mAsyncFragment == null) { //fragment was retained during orientation change
mAsyncFragment = new AsyncFragment();
fm.beginTransaction().add(mAsyncFragment, FRAGMENT_TAG).commit();
}
}
@Override
public void onPreExecute() {
Log.d(TAG, "onPreExecute: ");
}
@Override
public void onPostExecute() {
Log.d(TAG, "onPostExecute: ");
}
@Override
public void onCancelled() {
Log.d(TAG, "onCancelled: ");
}
@Override
public void onBackground() {
Log.d(TAG, "onBackground: ");
}
@Override
public void onProgressUpdate(int progress) {
Log.d(TAG, "onProgressUpdate: ");
}
答案 3 :(得分：-1)
<activity
android:name=".MainActivity"
android:configChanges="orientation|screenSize">
</activity>
这样就不会重新创建活动。但您可以使用onConfigurationChanged()