实例_在文件中保留上次输入的类容

  1 public class MainActivity extends Activity
  2 {
  3     private EditText et;
  4 
  5     //
  6     //创建活动时读取是否有上次保存的内容
  7     //
  8     @Override
  9     protected void onCreate(Bundle savedInstanceState)
 10     {
 11         super.onCreate(savedInstanceState);
 12         setContentView(R.layout.activity_main);
 13         et = (EditText) findViewById(R.id.et);
 14         
 15         String inputText = load();
 16         //
 17         //if(!(inputText == null || inputText.length() == 0))
 18         //android.text.TextUtils
 19         //
 20         if(!TextUtils.isEmpty(inputText))//empty  空的 adj
 21         {
 22             et.setText(inputText);
 23             et.setSelection(inputText.length());
 24             Toast.makeText(this, "Restoring succeeded", Toast.LENGTH_SHORT).show();
 25         }
 26 
 27     }
 28 
 29     //
 30     //销毁活动时在文件中保存内容
 31     //
 32     @Override
 33     protected void onDestroy()
 34     {
 35         super.onDestroy();
 36         String inputText = et.getText().toString();
 37 
 38         save(inputText);
 39     }
 40 
 41     //
 42     //保存
 43     //
 44     private void save(String inputText)
 45     {
 46         BufferedWriter bWriter = null;
 47 
 48         try
 49         {
 50             bWriter = new BufferedWriter(new OutputStreamWriter(openFileOutput("data", Context.MODE_PRIVATE)));
 51             bWriter.write(inputText);
 52         } catch (IOException e)
 53         {
 54             e.printStackTrace();
 55         } finally
 56         {
 57             if (bWriter != null)
 58             {
 59                 try
 60                 {
 61                     bWriter.close();
 62                 } catch (IOException e)
 63                 {
 64                     e.printStackTrace();
 65                 }
 66             }
 67         }
 68     }
 69 
 70     //
 71     //读取
 72     //
 73     private String load()
 74     {
 75         StringBuffer content = new StringBuffer();
 76         BufferedReader bReader = null;
 77         try
 78         {
 79             bReader = new BufferedReader(new InputStreamReader(openFileInput("data")));
 80             String line = "";
 81             while ((line = bReader.readLine()) != null)
 82             {
 83                 content.append(line);
 84             }
 85         } catch (IOException e)
 86         {
 87             e.printStackTrace();
 88         } finally
 89         {    
 90             if(bReader != null)
 91             {
 92                 try
 93                 {
 94                     bReader.close();
 95                 } catch (IOException e)
 96                 {
 97                     // TODO Auto-generated catch block
 98                     e.printStackTrace();
 99                 }
100             }
101         }
102         
103         return content.toString();
104     }
105 }