Android Fragment栈机制探索

港控/mmm° 2022-12-18 06:59 148阅读 0赞

# 图解 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0NfQ3JlYXRvcg_size_16_color_FFFFFF_t_70_pic_center]

# 代码 #

import androidx.fragment.app.Fragment;
    import androidx.fragment.app.FragmentActivity;
    import androidx.fragment.app.FragmentManager;
    import androidx.fragment.app.FragmentTransaction;
    
    
    public class FragmentHelper { 
        static public void clearFragmentStack(FragmentActivity activity) { 
            FragmentManager fm = activity.getSupportFragmentManager();
            for(int i = 0; i < fm.getBackStackEntryCount(); ++i) { 
                fm.popBackStack();
            }
        }
    
        static public void clearFragmentStack(FragmentActivity activity, String name) { 
            FragmentManager fm = activity.getSupportFragmentManager();
            fm.popBackStack(name, FragmentManager.POP_BACK_STACK_INCLUSIVE);
        }
    
        static public void startFragmentInStack(FragmentActivity activity, int id, Fragment fragment, String name) { 
            FragmentTransaction fragmentTransaction = activity.getSupportFragmentManager().beginTransaction();
            fragmentTransaction.addToBackStack(name);
            fragmentTransaction.replace(id, fragment).commit();
        }
    
        static public void startFragment(FragmentActivity activity, int id, Fragment fragment) { 
            FragmentTransaction fragmentTransaction = activity.getSupportFragmentManager().beginTransaction();
            fragmentTransaction.replace(id, fragment).commit();
        }
    
        static public void restartFragmentInStack(FragmentActivity activity, int id, Fragment fragment, String name) { 
            clearFragmentStack(activity, name);
            startFragmentInStack(activity, id, fragment, name);
        }
    
        static public void restartFragment(FragmentActivity activity, int id, Fragment fragment) { 
            clearFragmentStack(activity);
            startFragment(activity, id, fragment);
        }
    
        static public void restartFragmentInStack(FragmentActivity activity, int id, Fragment fragment) { 
            clearFragmentStack(activity);
            startFragmentInStack(activity, id, fragment, null);
        }
    
        static public void startFragmentInStack(FragmentActivity activity, int id, Fragment fragment) { 
            startFragmentInStack(activity, id, fragment, null);
        }
    
    
    }

# 总结 #

如果fragment需要跳转，则第一次replace需要addToBackStack  
如果不需要跳转，则replace之前，最好清空FragmentStack栈中的所有Fragment再replace

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