如何在片段中實(shí)現(xiàn)onBackPared()？我們有沒有辦法onBackPressed()在Android片段中，類似于我們?cè)贏ndroid活動(dòng)中實(shí)現(xiàn)的方式？因?yàn)槠紊芷跊]有onBackPressed()..有什么其他方法可以替代騎嗎？onBackPressed()在Android 3.0片段中？
3 回答
ABOUTYOU
TA貢獻(xiàn)1812條經(jīng)驗(yàn) 獲得超5個(gè)贊
onBackPressedFragmentTransactionaddToBackStack
@Overridepublic void onBackPressed() {
int count = getSupportFragmentManager().getBackStackEntryCount();
if (count == 0) {
super.onBackPressed();
//additional code
} else {
getSupportFragmentManager().popBackStack();
}}
尚方寶劍之說
TA貢獻(xiàn)1788條經(jīng)驗(yàn) 獲得超4個(gè)贊
Java解決方案
public interface IOnBackPressed {
/**
* If you return true the back press will not be taken into account, otherwise the activity will act naturally
* @return true if your processing has priority if not false
*/
boolean onBackPressed();}public class MyActivity extends Activity {
@Override public void onBackPressed() {
Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.main_container);
if (!(fragment instanceof IOnBackPressed) || !((IOnBackPressed) fragment).onBackPressed()) {
super.onBackPressed();
}
} ...}public class MyFragment extends Fragment implements IOnBackPressed{
@Override
public boolean onBackPressed() {
if (myCondition) {
//action not popBackStack
return true;
} else {
return false;
}
}}Kotlin解
1-創(chuàng)建接口
interface IOnBackPressed {
fun onBackPressed(): Boolean}2-準(zhǔn)備你的活動(dòng)
class MyActivity : AppCompatActivity() {
override fun onBackPressed() {
val fragment =
this.supportFragmentManager.findFragmentById(R.id.main_container)
(fragment as? IOnBackPressed)?.onBackPressed()?.not()?.let {
super.onBackPressed()
}
}}3-在目標(biāo)片段中實(shí)現(xiàn)
class MyFragment : Fragment(), IOnBackPressed {
override fun onBackPressed(): Boolean {
return if (myCondition) {
//action not popBackStack
true
} else {
false
}
}}
www說
TA貢獻(xiàn)1775條經(jīng)驗(yàn) 獲得超8個(gè)贊
BaseActivity
創(chuàng)建類接口 OnBackPressedListenerpublic interface OnBackPressedListener { public void doBack();}創(chuàng)建實(shí)現(xiàn)以下技能的類： OnBackPressedListenerpublic class BaseBackPressedListener implements OnBackPressedListener { private final FragmentActivity activity; public BaseBackPressedListener(FragmentActivity activity) { this.activity = activity; } @Override public void doBack() { activity.getSupportFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE); }}從現(xiàn)在開始，我們將編寫我們的代碼。 BaseActivity及其碎片 在類的頂部創(chuàng)建私有偵聽器 BaseActivityprotected OnBackPressedListener onBackPressedListener;
創(chuàng)建方法來設(shè)置偵聽器 BaseActivitypublic void setOnBackPressedListener(OnBackPressedListener onBackPressedListener) { this.onBackPressedListener = onBackPressedListener;}在覆蓋 onBackPressed實(shí)現(xiàn)這樣的東西 @Overridepublic void onBackPressed() { if (onBackPressedListener != null) onBackPressedListener.doBack(); else super.onBackPressed();在你的碎片里 onCreateView您應(yīng)該添加我們的偵聽器 @Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { activity = getActivity(); ((BaseActivity)activity).setOnBackPressedListener(new BaseBackPressedListener(activity)); View view = ... ;//stuff with view return view;}
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