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      1 /*
      2  * Copyright (C) 2007 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.skeletonapp;
     18 
     19 import android.app.Activity;
     20 import android.os.Bundle;
     21 import android.view.KeyEvent;
     22 import android.view.Menu;
     23 import android.view.MenuItem;
     24 import android.view.View;
     25 import android.view.View.OnClickListener;
     26 import android.widget.Button;
     27 import android.widget.EditText;
     28 
     29 /**
     30  * This class provides a basic demonstration of how to write an Android
     31  * activity. Inside of its window, it places a single view: an EditText that
     32  * displays and edits some internal text.
     33  */
     34 public class SkeletonActivity extends Activity {
     35 
     36     static final private int BACK_ID = Menu.FIRST;
     37     static final private int CLEAR_ID = Menu.FIRST + 1;
     38 
     39     private EditText mEditor;
     40 
     41     public SkeletonActivity() {
     42     }
     43 
     44     /** Called with the activity is first created. */
     45     @Override
     46     public void onCreate(Bundle savedInstanceState) {
     47         super.onCreate(savedInstanceState);
     48 
     49         // Inflate our UI from its XML layout description.
     50         setContentView(R.layout.skeleton_activity);
     51 
     52         // Find the text editor view inside the layout, because we
     53         // want to do various programmatic things with it.
     54         mEditor = (EditText) findViewById(R.id.editor);
     55 
     56         // Hook up button presses to the appropriate event handler.
     57         ((Button) findViewById(R.id.back)).setOnClickListener(mBackListener);
     58         ((Button) findViewById(R.id.clear)).setOnClickListener(mClearListener);
     59 
     60         mEditor.setText(getText(R.string.main_label));
     61     }
     62 
     63     /**
     64      * Called when the activity is about to start interacting with the user.
     65      */
     66     @Override
     67     protected void onResume() {
     68         super.onResume();
     69     }
     70 
     71     /**
     72      * Called when your activity's options menu needs to be created.
     73      */
     74     @Override
     75     public boolean onCreateOptionsMenu(Menu menu) {
     76         super.onCreateOptionsMenu(menu);
     77 
     78         // We are going to create two menus. Note that we assign them
     79         // unique integer IDs, labels from our string resources, and
     80         // given them shortcuts.
     81         menu.add(0, BACK_ID, 0, R.string.back).setShortcut('0', 'b');
     82         menu.add(0, CLEAR_ID, 0, R.string.clear).setShortcut('1', 'c');
     83 
     84         return true;
     85     }
     86 
     87     /**
     88      * Called right before your activity's option menu is displayed.
     89      */
     90     @Override
     91     public boolean onPrepareOptionsMenu(Menu menu) {
     92         super.onPrepareOptionsMenu(menu);
     93 
     94         // Before showing the menu, we need to decide whether the clear
     95         // item is enabled depending on whether there is text to clear.
     96         menu.findItem(CLEAR_ID).setVisible(mEditor.getText().length() > 0);
     97 
     98         return true;
     99     }
    100 
    101     /**
    102      * Called when a menu item is selected.
    103      */
    104     @Override
    105     public boolean onOptionsItemSelected(MenuItem item) {
    106         switch (item.getItemId()) {
    107         case BACK_ID:
    108             finish();
    109             return true;
    110         case CLEAR_ID:
    111             mEditor.setText("");
    112             return true;
    113         }
    114 
    115         return super.onOptionsItemSelected(item);
    116     }
    117 
    118     /**
    119      * A call-back for when the user presses the back button.
    120      */
    121     OnClickListener mBackListener = new OnClickListener() {
    122         public void onClick(View v) {
    123             finish();
    124         }
    125     };
    126 
    127     /**
    128      * A call-back for when the user presses the clear button.
    129      */
    130     OnClickListener mClearListener = new OnClickListener() {
    131         public void onClick(View v) {
    132             mEditor.setText("");
    133         }
    134     };
    135 }
    136