应用程序按导航抽屉中片段内的后退按钮退出 [英] App exits on presing back button inside fragments within navigation drawer
问题描述
当我尝试从子片段移动到父片段时，我的应用程序退出(它不会崩溃).LandingActivity.java是主要活动，我在其中调用片段ChannelGrid.java，后者调用片段GridMain.java.在片段GridMain应用程序退出时按了移动设备的后退按钮，而不是移至ChannelGrid.java.我向片段添加了addToBackStack("tag")，还尝试使用onKey()..我也在不同设备上测试了我的应用程序.找出其他具有相同问题的解决方案，并进行了尝试，但无济于事.
Navigation Drawer-LandingActivity.java-ChaanelGrid.java(Fragment)-GridMain.java(Fragment)
LandingActivity.java
currentFragment = new ChaanelGrid();
currentFragment.setArguments(args);
frgManager = getFragmentManager();
frgManager.beginTransaction().add(R.id.content_frame, currentFragment).addToBackStack("tag")
.commit();
ChaanelGrid.java
Fragment currentFragment = new GridMain();
FragmentManager frgManager;
frgManager = getFragmentManager();
frgManager.beginTransaction().add(R.id.content_frame, currentFragment).addToBackStack("GridMain")
.commit()
GridMain.java(我也尝试过不使用onKey()方法，但是没有用)
rootView.setOnKeyListener(new View.OnKeyListener() {
@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK)
{
Fragment currentFragment = new ChaanelGrid();
FragmentManager frgManager;
frgManager = getFragmentManager();
frgManager.beginTransaction().replace(R.id.content_frame, currentFragment)
.commit();
return true;
}
logcat详细
10-31 21:46:57.954 24452-24452/D/ActivityThread﹕ ACT-AM_ON_PAUSE_CALLED ActivityRecord{41eb8b98 token=android.os.BinderProxy@41bb9828 {xyz/xyz..activity.LandingActivity_}}
10-31 21:46:57.971 24452-24452/ D/ActivityThread﹕ ACT-PAUSE_ACTIVITY_FINISHING handled : 0 / android.os.BinderProxy@41bb9828
10-31 21:46:58.007 24452-24452/ V/InputMethodManager﹕ focusOut: android.widget.GridView@41f06f40 mServedView=android.widget.GridView@41f06f40 winFocus=false
10-31 21:46:58.297 24452-24452/ I/SurfaceTextureClient﹕ [0x5143bc58] frames:44, duration:1.002000, fps:43.883736
10-31 21:46:58.350 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.432 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.753 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.754 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.755 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 2)
10-31 21:46:58.879 24452-24452/ D/ActivityThread﹕ ACT-DESTROY_ACTIVITY handled : 1 / android.os.BinderProxy@41bb9828
我尝试在LandingActivity.java中添加以下内容
@Override
public void onBackPressed() {
FragmentManager frgManager;
frgManager = getFragmentManager();
Fragment fragment = fragmentManager.findFragmentByTag("GridMain");
if (fragment != null) {
GridMain gridMain = (GridMain) fragment;
if (!gridMain.onBackPressed()) {
super.onBackPressed();
}
}
else {
super.onBackPressed();
}
}
并随后在GridMain.java中
protected boolean onBackPressed() {
FragmentManager frgManager;
frgManager = getFragmentManager();
frgManager.popBackStack();
return true;
}
使用日志，我检查了LandingActivity.java的onBackPressed()是否正在被调用，但输出仍然相同.
这是我通常处理后退"按钮的方式:
// "State Machine" variables: to indicate which is the active Fragment.
private static boolean isHelpShown = false;
protected static boolean isInfoShown = false;
protected static boolean isMainShown = false;
private static boolean isViewShown = false;
// Used to switch between Fragments.
private static enum Fragments
{
MAIN,
VIEW,
HELP,
INFO
}
@Override
public final void onBackPressed()
{
if (isMainShown)
{
// We're in the MAIN Fragment.
finish();
}
else
{
// We're somewhere else, reload the MAIN Fragment.
showFragment(Fragments.MAIN);
}
}
private final void showFragment(final Fragments FragmentType)
{
isViewShown = false;
isHelpShown = false;
isInfoShown = false;
isMainShown = false;
final FragmentTransaction ft =
getSupportFragmentManager().beginTransaction();
/*
Replace whatever is in the fragment_container view with this
fragment, and add the transaction to the back stack so the user can
navigate back.
*/
switch(FragmentType)
{
case HELP:
{
ft.replace(R.id.frgMaster, new FRG_Help());
isHelpShown = true;
break;
}
case INFO:
{
ft.replace(R.id.frgMaster, new FRG_Info());
isInfoShown = true;
break;
}
case VIEW:
{
ft.replace(R.id.frgMaster, new FRG_View());
isViewShown = true;
break;
}
case MAIN:
{
ft.replace(R.id.frgMaster, new FRG_Main());
isMainShown = true;
break;
}
}
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
// Finalize the transaction...
ft.commit();
getSupportFragmentManager().executePendingTransactions();
}
如您所见，出于我的需要，我只会在我们进入MAIN Fragment(我退出)时或不在(当我回到MAIN Fragment:回到另一个MAIN Fragment，然后退出时)处理.
您可以在onBackPressed方法中添加更多检查，以检查您是否在另一个Fragment中，并相应地加载另一个.
My app exits when i try to move from child fragment to parent fragment(it doesn't crashes).Here LandingActivity.java is main activity in which I am calling fragment ChannelGrid.java which calls fragment GridMain.java.When i presses back button of mobile in fragment GridMain app exits rather than moving to ChannelGrid.java.I have added addToBackStack("tag") to fragments and also tried using onKey()..I tested my app on different devices also..I checked out other solutions with same issue and tried them but nothing works..
Navigation Drawer-LandingActivity.java-ChaanelGrid.java(Fragment)-GridMain.java(Fragment)
LandingActivity.java
currentFragment = new ChaanelGrid();
currentFragment.setArguments(args);
frgManager = getFragmentManager();
frgManager.beginTransaction().add(R.id.content_frame, currentFragment).addToBackStack("tag")
.commit();
ChaanelGrid.java
Fragment currentFragment = new GridMain();
FragmentManager frgManager;
frgManager = getFragmentManager();
frgManager.beginTransaction().add(R.id.content_frame, currentFragment).addToBackStack("GridMain")
.commit()
GridMain.java(i tried without onKey() method also but didn't worked)
rootView.setOnKeyListener(new View.OnKeyListener() {
@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK)
{
Fragment currentFragment = new ChaanelGrid();
FragmentManager frgManager;
frgManager = getFragmentManager();
frgManager.beginTransaction().replace(R.id.content_frame, currentFragment)
.commit();
return true;
}
logcat verbose
10-31 21:46:57.954 24452-24452/D/ActivityThread﹕ ACT-AM_ON_PAUSE_CALLED ActivityRecord{41eb8b98 token=android.os.BinderProxy@41bb9828 {xyz/xyz..activity.LandingActivity_}}
10-31 21:46:57.971 24452-24452/ D/ActivityThread﹕ ACT-PAUSE_ACTIVITY_FINISHING handled : 0 / android.os.BinderProxy@41bb9828
10-31 21:46:58.007 24452-24452/ V/InputMethodManager﹕ focusOut: android.widget.GridView@41f06f40 mServedView=android.widget.GridView@41f06f40 winFocus=false
10-31 21:46:58.297 24452-24452/ I/SurfaceTextureClient﹕ [0x5143bc58] frames:44, duration:1.002000, fps:43.883736
10-31 21:46:58.350 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.432 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.753 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.754 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.755 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 2)
10-31 21:46:58.879 24452-24452/ D/ActivityThread﹕ ACT-DESTROY_ACTIVITY handled : 1 / android.os.BinderProxy@41bb9828
I tried adding following in LandingActivity.java
@Override
public void onBackPressed() {
FragmentManager frgManager;
frgManager = getFragmentManager();
Fragment fragment = fragmentManager.findFragmentByTag("GridMain");
if (fragment != null) {
GridMain gridMain = (GridMain) fragment;
if (!gridMain.onBackPressed()) {
super.onBackPressed();
}
}
else {
super.onBackPressed();
}
}
and following in GridMain.java
protected boolean onBackPressed() {
FragmentManager frgManager;
frgManager = getFragmentManager();
frgManager.popBackStack();
return true;
}
Using Log i checked tht onBackPressed() of LandingActivity.java is being called but still the same output..
This is how I normally handle the Back Button:
// "State Machine" variables: to indicate which is the active Fragment.
private static boolean isHelpShown = false;
protected static boolean isInfoShown = false;
protected static boolean isMainShown = false;
private static boolean isViewShown = false;
// Used to switch between Fragments.
private static enum Fragments
{
MAIN,
VIEW,
HELP,
INFO
}
@Override
public final void onBackPressed()
{
if (isMainShown)
{
// We're in the MAIN Fragment.
finish();
}
else
{
// We're somewhere else, reload the MAIN Fragment.
showFragment(Fragments.MAIN);
}
}
private final void showFragment(final Fragments FragmentType)
{
isViewShown = false;
isHelpShown = false;
isInfoShown = false;
isMainShown = false;
final FragmentTransaction ft =
getSupportFragmentManager().beginTransaction();
/*
Replace whatever is in the fragment_container view with this
fragment, and add the transaction to the back stack so the user can
navigate back.
*/
switch(FragmentType)
{
case HELP:
{
ft.replace(R.id.frgMaster, new FRG_Help());
isHelpShown = true;
break;
}
case INFO:
{
ft.replace(R.id.frgMaster, new FRG_Info());
isInfoShown = true;
break;
}
case VIEW:
{
ft.replace(R.id.frgMaster, new FRG_View());
isViewShown = true;
break;
}
case MAIN:
{
ft.replace(R.id.frgMaster, new FRG_Main());
isMainShown = true;
break;
}
}
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
// Finalize the transaction...
ft.commit();
getSupportFragmentManager().executePendingTransactions();
}
As you can see, for my needs I only handle when we're in the MAIN Fragment (I quit) or when we aren't (I go back to the MAIN Fragment: another Back press and it quits).
You can add more checks in the onBackPressed method to check if you are in another Fragment and load another one, accordingly.
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