1 /*
2  * Copyright (C) 2011 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.example.android.supportv4.app;
18 
19 import android.os.Bundle;
20 import android.view.LayoutInflater;
21 import android.view.View;
22 import android.view.View.OnClickListener;
23 import android.view.ViewGroup;
24 import android.widget.Button;
25 import android.widget.TextView;
26 
27 import androidx.core.content.ContextCompat;
28 import androidx.core.view.ViewCompat;
29 import androidx.fragment.app.Fragment;
30 import androidx.fragment.app.FragmentActivity;
31 import androidx.fragment.app.FragmentManager;
32 import androidx.fragment.app.FragmentTransaction;
33 
34 import com.example.android.supportv4.R;
35 
36 public class FragmentStackSupport extends FragmentActivity {
37     int mStackLevel = 1;
38 
39     @Override
onCreate(Bundle savedInstanceState)40     protected void onCreate(Bundle savedInstanceState) {
41         super.onCreate(savedInstanceState);
42         setContentView(R.layout.fragment_stack);
43 
44         // Watch for button clicks.
45         Button button = findViewById(R.id.new_fragment);
46         button.setOnClickListener(new OnClickListener() {
47             @Override
48             public void onClick(View v) {
49                 addFragmentToStack();
50             }
51         });
52         button = findViewById(R.id.home);
53         button.setOnClickListener(new OnClickListener() {
54             @Override
55             public void onClick(View v) {
56                 // If there is a back stack, pop it all.
57                 FragmentManager fm = getSupportFragmentManager();
58                 if (fm.getBackStackEntryCount() > 0) {
59                     fm.popBackStack(fm.getBackStackEntryAt(0).getId(),
60                             FragmentManager.POP_BACK_STACK_INCLUSIVE);
61                 }
62             }
63         });
64 
65         if (savedInstanceState == null) {
66             // Do first time initialization -- add initial fragment.
67             Fragment newFragment = CountingFragment.newInstance(mStackLevel);
68             FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
69             ft.add(R.id.simple_fragment, newFragment).commit();
70         } else {
71             mStackLevel = savedInstanceState.getInt("level");
72         }
73     }
74 
75     @Override
onSaveInstanceState(Bundle outState)76     public void onSaveInstanceState(Bundle outState) {
77         super.onSaveInstanceState(outState);
78         outState.putInt("level", mStackLevel);
79     }
80 
81 //BEGIN_INCLUDE(add_stack)
addFragmentToStack()82     void addFragmentToStack() {
83         mStackLevel++;
84 
85         // Instantiate a new fragment.
86         Fragment newFragment = CountingFragment.newInstance(mStackLevel);
87 
88         // Add the fragment to the activity, pushing this transaction
89         // on to the back stack.
90         FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
91         ft.replace(R.id.simple_fragment, newFragment);
92         ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
93         ft.addToBackStack(null);
94         ft.commit();
95     }
96 //END_INCLUDE(add_stack)
97 
98 //BEGIN_INCLUDE(fragment)
99     public static class CountingFragment extends Fragment {
100         int mNum;
101 
102         /**
103          * Create a new instance of CountingFragment, providing "num"
104          * as an argument.
105          */
newInstance(int num)106         static CountingFragment newInstance(int num) {
107             CountingFragment f = new CountingFragment();
108 
109             // Supply num input as an argument.
110             Bundle args = new Bundle();
111             args.putInt("num", num);
112             f.setArguments(args);
113 
114             return f;
115         }
116 
117         /**
118          * When creating, retrieve this instance's number from its arguments.
119          */
120         @Override
onCreate(Bundle savedInstanceState)121         public void onCreate(Bundle savedInstanceState) {
122             super.onCreate(savedInstanceState);
123             mNum = getArguments() != null ? getArguments().getInt("num") : 1;
124         }
125 
126         /**
127          * The Fragment's UI is just a simple text view showing its
128          * instance number.
129          */
130         @Override
onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)131         public View onCreateView(LayoutInflater inflater, ViewGroup container,
132                 Bundle savedInstanceState) {
133             View v = inflater.inflate(R.layout.hello_world, container, false);
134             View tv = v.findViewById(R.id.text);
135             ((TextView) tv).setText("Fragment #" + mNum);
136             ViewCompat.setBackground(tv,
137                     ContextCompat.getDrawable(getContext(), android.R.drawable.gallery_thumb));
138             return v;
139         }
140     }
141 //END_INCLUDE(fragment)
142 }
143