中的onBackPressed()方法,addToBackStack()方法無法正常工作下面是我編寫的MainActivity代碼。 我正在加載第一個屏幕中的片段列表。當用戶點擊任何列表項時,行星名稱將在我已經在單獨的類中定義的詳細片段中向用戶顯示。如果不覆蓋android
我將「Fragment Planet List」 - >「Fragment Planet Detail」的事務添加回棧中。所以我期望的是,當我按下行星細節片段的後退按鈕時,它應該在手機中加載行星列表。但這並不是這樣發生的。
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.FrameLayout;
import com.meditab.fragments.fragment.FragmentPlanetDetail;
import com.meditab.fragments.fragment.FragmentPlanetList;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends ActionBarActivity implements Callback {
private FrameLayout frmPlanetList;
private FrameLayout frmPlanetDetail;
private boolean isPhone;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
frmPlanetList = (FrameLayout) findViewById(R.id.frmPlanetList);
frmPlanetDetail = (FrameLayout) findViewById(R.id.frmPlanetDetail);
if (null != frmPlanetDetail) {
isPhone = false;
} else {
isPhone = true;
}
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.frmPlanetList, new FragmentPlanetList());
fragmentTransaction.commit();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onListItemClicked(int intPosition) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
List<String> lstPlanetArray = getPlanetArray();
String strPlanetName = lstPlanetArray.get(intPosition);
FragmentPlanetDetail fragmentPlanetDetail = FragmentPlanetDetail.newInstance(strPlanetName);
if (isPhone) {
fragmentTransaction.addToBackStack(null);
fragmentTransaction.replace(R.id.frmPlanetList, fragmentPlanetDetail);
} else {
fragmentTransaction.replace(R.id.frmPlanetDetail, fragmentPlanetDetail);
}
fragmentTransaction.commit();
}
private List<String> getPlanetArray() {
List<String> lstPlanets = new ArrayList<>(10);
lstPlanets.add("Mercury");
lstPlanets.add("Venus");
lstPlanets.add("Earth");
lstPlanets.add("Mars");
lstPlanets.add("Jupiter");
lstPlanets.add("Saturn");
lstPlanets.add("Uranus");
lstPlanets.add("Neptune");
lstPlanets.add("Saturn");
return lstPlanets;
}
}
但是,如果我重寫backPress方法並以編程方式彈出返回堆棧,它工作得很好。
@Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() != 0) {
getFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
我是否需要用這種方法重寫onBackPressed()方法,如果我想實現這種行爲? 沒有記錄您需要在此鏈接中重寫此方法。 Android Back Press Fragment Documentation
片段行星詳細類
import android.app.Fragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.meditab.fragments.R;
/**
* Created by BHARGAV on 25-Dec-14.
*/
public class FragmentPlanetDetail extends Fragment {
private String strPlanetName;
public FragmentPlanetDetail() {
}
public static FragmentPlanetDetail newInstance(String strPlanetName) {
FragmentPlanetDetail fragmentPlanetDetail = new FragmentPlanetDetail();
Bundle bundle = new Bundle();
bundle.putString("Planet_Name", strPlanetName);
fragmentPlanetDetail.setArguments(bundle);
return fragmentPlanetDetail;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle bundle = getArguments();
if (null != bundle) {
strPlanetName = bundle.getString("Planet_Name");
}
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.planet_name, container, false);
TextView txtPlanetName = (TextView) rootView.findViewById(R.id.txtPlanetName);
txtPlanetName.setText(strPlanetName);
return rootView;
}
}
片段行星列表類別:
import android.app.Activity;
import android.app.Fragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import com.meditab.fragments.Callback;
import com.meditab.fragments.R;
import java.util.ArrayList;
import java.util.List;
/**
* Created by BHARGAV on 25-Dec-14.
*/
public class FragmentPlanetList extends Fragment {
private ListView listView;
private ArrayAdapter<String> stringArrayAdapter;
private Callback callback;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final View rootView = inflater.inflate(R.layout.listview, container, false);
listView = (ListView) rootView.findViewById(R.id.listView);
stringArrayAdapter = new ArrayAdapter<>(getActivity(),
android.R.layout.simple_list_item_1, getPlanetArray());
listView.setAdapter(stringArrayAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
callback.onListItemClicked(position);
}
});
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
callback = (Callback) activity;
}
private List<String> getPlanetArray() {
List<String> lstPlanets = new ArrayList<>(5);
lstPlanets.add("Mercury");
lstPlanets.add("Venus");
lstPlanets.add("Earth");
lstPlanets.add("Mars");
lstPlanets.add("Jupiter");
lstPlanets.add("Saturn");
lstPlanets.add("Uranus");
lstPlanets.add("Neptune");
lstPlanets.add("Saturn");
return lstPlanets;
}
}
回調接口:
/**
* Created by BHARGAV on 26-Dec-14.
*/
public interface Callback {
public void onListItemClicked(int intPosition);
}
感謝。請讓我知道是否需要任何額外的細節或代碼。
您定位的是哪個版本的android? –
我針對運行ICS及以上版本的設備。 –
同樣的狀況,相同的問題。還沒有解決方案! :( 請讓我知道,如果你發現任何東西 – mt0s