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      1 /*
      2  * Copyright (C) 2010 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.apis.app;
     18 
     19 import com.example.android.apis.R;
     20 
     21 import android.app.Activity;
     22 import android.app.Fragment;
     23 import android.app.FragmentTransaction;
     24 import android.os.Bundle;
     25 import android.view.LayoutInflater;
     26 import android.view.View;
     27 import android.view.ViewGroup;
     28 import android.view.View.OnClickListener;
     29 import android.widget.Button;
     30 import android.widget.TextView;
     31 
     32 public class FragmentStack extends Activity {
     33     int mStackLevel = 1;
     34 
     35     @Override
     36     protected void onCreate(Bundle savedInstanceState) {
     37         super.onCreate(savedInstanceState);
     38         setContentView(R.layout.fragment_stack);
     39 
     40         // Watch for button clicks.
     41         Button button = (Button)findViewById(R.id.new_fragment);
     42         button.setOnClickListener(new OnClickListener() {
     43             public void onClick(View v) {
     44                 addFragmentToStack();
     45             }
     46         });
     47         button = (Button)findViewById(R.id.delete_fragment);
     48         button.setOnClickListener(new OnClickListener() {
     49             public void onClick(View v) {
     50                 getFragmentManager().popBackStack();
     51             }
     52         });
     53 
     54         if (savedInstanceState == null) {
     55             // Do first time initialization -- add initial fragment.
     56             Fragment newFragment = CountingFragment.newInstance(mStackLevel);
     57             FragmentTransaction ft = getFragmentManager().beginTransaction();
     58             ft.add(R.id.simple_fragment, newFragment).commit();
     59         } else {
     60             mStackLevel = savedInstanceState.getInt("level");
     61         }
     62     }
     63 
     64     @Override
     65     public void onSaveInstanceState(Bundle outState) {
     66         super.onSaveInstanceState(outState);
     67         outState.putInt("level", mStackLevel);
     68     }
     69 
     70 //BEGIN_INCLUDE(add_stack)
     71     void addFragmentToStack() {
     72         mStackLevel++;
     73 
     74         // Instantiate a new fragment.
     75         Fragment newFragment = CountingFragment.newInstance(mStackLevel);
     76 
     77         // Add the fragment to the activity, pushing this transaction
     78         // on to the back stack.
     79         FragmentTransaction ft = getFragmentManager().beginTransaction();
     80         ft.replace(R.id.simple_fragment, newFragment);
     81         ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
     82         ft.addToBackStack(null);
     83         ft.commit();
     84     }
     85 //END_INCLUDE(add_stack)
     86 
     87 //BEGIN_INCLUDE(fragment)
     88     public static class CountingFragment extends Fragment {
     89         int mNum;
     90 
     91         /**
     92          * Create a new instance of CountingFragment, providing "num"
     93          * as an argument.
     94          */
     95         static CountingFragment newInstance(int num) {
     96             CountingFragment f = new CountingFragment();
     97 
     98             // Supply num input as an argument.
     99             Bundle args = new Bundle();
    100             args.putInt("num", num);
    101             f.setArguments(args);
    102 
    103             return f;
    104         }
    105 
    106         /**
    107          * When creating, retrieve this instance's number from its arguments.
    108          */
    109         @Override
    110         public void onCreate(Bundle savedInstanceState) {
    111             super.onCreate(savedInstanceState);
    112             mNum = getArguments() != null ? getArguments().getInt("num") : 1;
    113         }
    114 
    115         /**
    116          * The Fragment's UI is just a simple text view showing its
    117          * instance number.
    118          */
    119         @Override
    120         public View onCreateView(LayoutInflater inflater, ViewGroup container,
    121                 Bundle savedInstanceState) {
    122             View v = inflater.inflate(R.layout.hello_world, container, false);
    123             View tv = v.findViewById(R.id.text);
    124             ((TextView)tv).setText("Fragment #" + mNum);
    125             tv.setBackgroundDrawable(getResources().getDrawable(android.R.drawable.gallery_thumb));
    126             return v;
    127         }
    128     }
    129 //END_INCLUDE(fragment)
    130 }
    131