Android 학습 노트 (13) Shared Preference 가 파악 해 야 할 기초

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical"
 6      >
 7 
 8     <EditText
 9         android:id="@+id/et_data"
10         android:layout_width="wrap_content"
11         android:layout_height="wrap_content"
12         android:ems="10" >
13 
14         <requestFocus />
15     </EditText>
16 
17     <Button
18         android:id="@+id/btn_read"
19         android:layout_width="wrap_content"
20         android:layout_height="wrap_content"
21         android:text="  " />
22     
23     <Button
24         android:id="@+id/btn_write"
25         android:layout_width="wrap_content"
26         android:layout_height="wrap_content"
27         android:text="  " />
28     
29     <Button
30         android:id="@+id/btn_clear"
31         android:layout_width="wrap_content"
32         android:layout_height="wrap_content"
33         android:text="  " />
34 
35 </LinearLayout>

 1 /**
 2  * MainActivity
 3  * 
 4  * @author liuwei
 5  * 
 6  */
 7 public class MainActivity extends Activity {
 8     private SharedPreferences preferences;
 9     private Editor editor;
10     EditText et_data;
11     Button btn_read;
12     Button btn_write;
13     Button btn_clear;
14 
15     @Override
16     protected void onCreate(Bundle savedInstanceState) {
17         super.onCreate(savedInstanceState);
18         setContentView(R.layout.activity_main);
19         et_data = (EditText) findViewById(R.id.et_data);
20         btn_read = (Button) findViewById(R.id.btn_read);
21         btn_write = (Button) findViewById(R.id.btn_write);
22         btn_clear = (Button) findViewById(R.id.btn_clear);
23         preferences = getPreferences(Activity.MODE_PRIVATE);
24         editor = preferences.edit();
25         btn_read.setOnClickListener(new OnClickListener() {
26 
27             @Override
28             public void onClick(View v) {
29                 String str = preferences.getString("key", "     ");
30                 Toast.makeText(getApplicationContext(), str, Toast.LENGTH_SHORT)
31                         .show();
32             }
33         });
34         btn_write.setOnClickListener(new OnClickListener() {
35 
36             @Override
37             public void onClick(View v) {
38                 editor.putString("key", et_data.getText().toString());
39                 if (editor.commit()) {
40                     Toast.makeText(getApplicationContext(), "    ",
41                             Toast.LENGTH_SHORT).show();
42                 }
43             }
44         });
45         btn_clear.setOnClickListener(new OnClickListener() {
46 
47             @Override
48             public void onClick(View v) {
49                 editor.clear();
50                 if (editor.commit()) {
51                     Toast.makeText(getApplicationContext(), "    ",
52                             Toast.LENGTH_SHORT).show();
53                 }
54 
55             }
56         });
57     }
58 }