Android Sqlite数据库执行插入查询更新删除的操作对比

下面是在Android4.0上，利用Sqlite数据库的insert，query，update，delete函数以及execSql，rawQuery函数执行插入，查询，更新，删除操作花费时间的对比结果。

是在执行相同的动作，记录条数也一样的情况下的对比，多次验证的结果是：

（1）如果批量执行的记录数在1000条，则Android SqliteDatabase提供的insert，query，update，delete函数和直接写SQL文的execSql，rawQuery的效率差不多，几乎一样。所以使用哪种放到都可以，不会影响到执行效率。

（2）如果批量执行的记录数在10万条，则会存在差别。在某台手机上SqliteDatabase提供的insert执行插入操作耗时45秒，要比execSql插入35秒慢10秒左右。

可见在数据库大的情况下，还是有差别的。execSql省去了拼接sql语句的步骤，要比SqliteDatabase提供的insert，query，update，delete等函数效率高。当数据库越大，差别也越大。

• public class MainActivity extends Activity {  
•     private static final String TAG = "MainActivity";  
•       
•     private DBHelper mDbHelper = null;  
•     private static TextView mTvInfo;  
•     private static ProgressDialog mDialog = null;  
•       
•     private static Handler mHandler = new Handler() {  
•         @Override  
•         public void handleMessage(Message msg) {  
•             // TODO Auto-generated method stub  
•             if(mDialog != null) {  
•                 mDialog.dismiss();  
•                 mDialog = null;  
•             }  
•             if (msg.what == 0) {  
•                 Bundle b = msg.getData();  
•                 int seconds = b.getInt("seconds");  
•                 int ms = b.getInt("ms");  
•                 StringBuilder builder = new StringBuilder("insert插入1000条记录花费时间：");  
•                 if (seconds > 0) {  
•                     builder.append(seconds).append("s ");  
•                 }  
•                 builder.append(ms).append("ms");  
•                 String strLines[] = mTvInfo.getText().toString().split(" ");  
•                 // 最多显示8条信息  
•                 for (int i = 0; i < strLines.length; i++) {  
•                     builder.append(' ').append(strLines[i]);  
•                     if (i == 6) {  
•                         break; // 加上原来最多7条信息，共显示8条信息  
•                     }  
•                 }  
•                 mTvInfo.setText(builder.toString());  
•             } else if (msg.what == 1) {  
•                 Bundle b = msg.getData();  
•                 int seconds = b.getInt("seconds");  
•                 int ms = b.getInt("ms");  
•                 StringBuilder builder = new StringBuilder("execSql插入1000条记录花费时间：");  
•                 if (seconds > 0) {  
•                     builder.append(seconds).append("s ");  
•                 }  
•                 builder.append(ms).append("ms");  
•                   
•                 String strLines[] = mTvInfo.getText().toString().split(" ");  
•                 // 最多显示8条信息  
•                 for (int i = 0; i < strLines.length; i++) {  
•                     builder.append(' ').append(strLines[i]);  
•                     if (i == 6) {  
•                         break; // 加上原来最多7条信息，共显示8条信息  
•                     }  
•                 }  
•                 mTvInfo.setText(builder.toString());  
•             } else if (msg.what == 10) {  
•                 Bundle b = msg.getData();  
•                 int count = b.getInt("count");  
•                 int seconds = b.getInt("seconds");  
•                 int ms = b.getInt("ms");  
•                 StringBuilder builder = new StringBuilder("query查询");  
•                 builder.append(count).append("条记录花费时间：");  
•                 if (seconds > 0) {  
•                     builder.append(seconds).append("s ");  
•                 }  
•                 builder.append(ms).append("ms");  
•                   
•                 String strLines[] = mTvInfo.getText().toString().split(" ");  
•                 // 最多显示8条信息  
•                 for (int i = 0; i < strLines.length; i++) {  
•                     builder.append(' ').append(strLines[i]);  
•                     if (i == 6) {  
•                         break; // 加上原来最多7条信息，共显示8条信息  
•                     }  
•                 }  
•                 mTvInfo.setText(builder.toString());  
•             } else if (msg.what == 11) {  
•                 Bundle b = msg.getData();  
•                 int count = b.getInt("count");  
•                 int seconds = b.getInt("seconds");  
•                 int ms = b.getInt("ms");  
•                 StringBuilder builder = new StringBuilder("rawQuery查询");  
•                 builder.append(count).append("条记录花费时间：");  
•                 if (seconds > 0) {  
•                     builder.append(seconds).append("s ");  
•                 }  
•                 builder.append(ms).append("ms");  
•                   
•                 String strLines[] = mTvInfo.getText().toString().split(" ");  
•                 // 最多显示8条信息  
•                 for (int i = 0; i < strLines.length; i++) {  
•                     builder.append(' ').append(strLines[i]);  
•                     if (i == 6) {  
•                         break; // 加上原来最多7条信息，共显示8条信息  
•                     }  
•                 }  
•                 mTvInfo.setText(builder.toString());  
•             } else if (msg.what == 20) {  
•                 Bundle b = msg.getData();  
•                 int count = b.getInt("count");  
•                 int seconds = b.getInt("seconds");  
•                 int ms = b.getInt("ms");  
•                 StringBuilder builder = new StringBuilder("update更新");  
•                 builder.append(count).append("条记录花费时间：");  
•                 if (seconds > 0) {  
•                     builder.append(seconds).append("s ");  
•                 }  
•                 builder.append(ms).append("ms");  
•                   
•                 String strLines[] = mTvInfo.getText().toString().split(" ");  
•                 // 最多显示8条信息  
•                 for (int i = 0; i < strLines.length; i++) {  
•                     builder.append(' ').append(strLines[i]);  
•                     if (i == 6) {  
•                         break; // 加上原来最多7条信息，共显示8条信息  
•                     }  
•                 }  
•                 mTvInfo.setText(builder.toString());  
•             } else if (msg.what == 21) {  
•                 Bundle b = msg.getData();  
•                 int seconds = b.getInt("seconds");  
•                 int ms = b.getInt("ms");  
•                 StringBuilder builder = new StringBuilder("execSql更新1000条记录花费时间：");  
•                 if (seconds > 0) {  
•                     builder.append(seconds).append("s ");  
•                 }  
•                 builder.append(ms).append("ms");  
•                   
•                 String strLines[] = mTvInfo.getText().toString().split(" ");  
•                 // 最多显示8条信息  
•                 for (int i = 0; i < strLines.length; i++) {  
•                     builder.append(' ').append(strLines[i]);  
•                     if (i == 6) {  
•                         break; // 加上原来最多7条信息，共显示8条信息  
•                     }  
•                 }  
•                 mTvInfo.setText(builder.toString());  
•             } else if (msg.what == 30) {  
•                 Bundle b = msg.getData();  
•                 int count = b.getInt("count");  
•                 int seconds = b.getInt("seconds");  
•                 int ms = b.getInt("ms");  
•                 StringBuilder builder = new StringBuilder("delete删除");  
•                 builder.append(count).append("条记录花费时间：");  
•                 if (seconds > 0) {  
•                     builder.append(seconds).append("s ");  
•                 }  
•                 builder.append(ms).append("ms");  
•                   
•                 String strLines[] = mTvInfo.getText().toString().split(" ");  
•                 // 最多显示8条信息  
•                 for (int i = 0; i < strLines.length; i++) {  
•                     builder.append(' ').append(strLines[i]);  
•                     if (i == 6) {  
•                         break; // 加上原来最多7条信息，共显示8条信息  
•                     }  
•                 }  
•                 mTvInfo.setText(builder.toString());  
•             } else if (msg.what == 31) {  
•                 Bundle b = msg.getData();  
•                 int seconds = b.getInt("seconds");  
•                 int ms = b.getInt("ms");  
•                 StringBuilder builder = new StringBuilder("execSql删除1000条记录花费时间：");  
•                 if (seconds > 0) {  
•                     builder.append(seconds).append("s ");  
•                 }  
•                 builder.append(ms).append("ms");  
•                   
•                 String strLines[] = mTvInfo.getText().toString().split(" ");  
•                 // 最多显示8条信息  
•                 for (int i = 0; i < strLines.length; i++) {  
•                     builder.append(' ').append(strLines[i]);  
•                     if (i == 6) {  
•                         break; // 加上原来最多7条信息，共显示8条信息  
•                     }  
•                 }  
•                 mTvInfo.setText(builder.toString());  
•             }  
•               
•               
•         }  
•     };  
•           
•     @Override  
•     public void onCreate(Bundle savedInstanceState) {  
•         super.onCreate(savedInstanceState);  
•         setContentView(R.layout.activity_main);  
•           
•         Button btnCreateDb = (Button)findViewById(R.id.btnCreateDb);  
•         btnCreateDb.setOnClickListener(new OnClickListener() {  
•               
•             @Override  
•             public void onClick(View arg0) {  
•                 // TODO Auto-generated method stub  
•                 mDbHelper = new DBHelper(MainActivity.this, "test", null, 1);  
•             }  
•               
•         });  
•           
•         // insert插入  
•         Button btnInsert = (Button)findViewById(R.id.btnInsert);  
•         btnInsert.setOnClickListener(new OnClickListener() {  
•               
•             @Override  
•             public void onClick(View arg0) {  
•                 // TODO Auto-generated method stub  
•                 if (mDbHelper != null) {  
•                     mDialog = ProgressDialog.show(MainActivity.this, "insert插入", "正在插入1000条记录，请稍等……", true);  
•                     new Thread() { // 开启线程执行防止阻塞  
•                         @Override  
•                         public void run() {  
•                             SQLiteDatabase db = mDbHelper.getWritableDatabase();  
•                             try {  
•                                 // 利用事物批量插入数据以提高效率  
•                                 ContentValues values = new ContentValues();  
•                                 long startms = System.currentTimeMillis();  
•                                 db.beginTransaction();  
•                                 for (int i = 0; i < 1000; i++) {  
•                                     values.put("name", new String("张三") + i);  
•                                     values.put("birthday", "2012-12-08");  
•                                     values.put("gender", i%2);  
•                                     db.insert("student", null, values);  
•                                 }  
•                                 db.setTransactionSuccessful();  
•                                 db.endTransaction();  
•                                 long endms = System.currentTimeMillis();  
•                                 int seconds = (int)((endms - startms)/1000);  
•                                 int ms = (int)((endms - startms)%1000);  
•                                   
•                                 Message msg = new Message();  
•                                 msg.what = 0;  
•                                 // 使用bundle对象来传递数据  
•                                 Bundle b = new Bundle();  
•                                 if(seconds > 0) {  
•                                     b.putInt("seconds", seconds);  
•                                 }  
•                                 b.putInt("ms", ms);  
•                                 msg.setData(b);  
•                                 mHandler.sendMessage(msg);  
•                             } catch(Exception e) {  
•                                 e.printStackTrace();  
•                             } finally {  
•                                 db.close(); // 关闭数据库  
•                             }  
•                         }  
•                     }.start();  
•                 } else {  
•                     Toast.makeText(MainActivity.this, "请先创建数据库！", Toast.LENGTH_SHORT).show();  
•                 }  
•             }  
•         });  
•           
•         // execSQL插入  
•         Button btnExecSqlInsert = (Button)findViewById(R.id.btnExecSqlInsert);  
•         btnExecSqlInsert.setOnClickListener(new OnClickListener() {  
•   
•             @Override  
•             public void onClick(View arg0) {  
•                 // TODO Auto-generated method stub  
•                 if (mDbHelper != null) {  
•                     mDialog = ProgressDialog.show(MainActivity.this, "execSQL插入", "正在插入1000条记录，请稍等……", true);  
•                     new Thread() { // 开启线程执行防止阻塞  
•                         @Override  
•                         public void run() {  
•                             SQLiteDatabase db = mDbHelper.getWritableDatabase();  
•                             try {  
•                                 // 利用事物批量插入数据以提高效率  
•                                 long startms = System.currentTimeMillis();  
•                                 db.beginTransaction();  
•                                 for (int i = 0; i < 1000; i++) {  
•                                     db.execSQL("INSERT INTO student(name, birthday, gender) values(?, ?, ?)" ,  
•                                             new Object[]{new String("李四" + i), "2012-12-08", i%2});  
•                                 }  
•                                 db.setTransactionSuccessful();  
•                                 db.endTransaction();  
•                                 long endms = System.currentTimeMillis();  
•                                 int seconds = (int)((endms - startms)/1000);  
•                                 int ms = (int)((endms - startms)%1000);  
•                                   
•                                 Message msg = new Message();  
•                                 msg.what = 1;  
•                                 // 使用bundle对象来传递数据  
•                                 Bundle b = new Bundle();  
•                                 if(seconds > 0) {  
•                                     b.putInt("seconds", seconds);  
•                                 }  
•                                 b.putInt("ms", ms);  
•                                 msg.setData(b);  
•                                 mHandler.sendMessage(msg);  
•                             } catch(Exception e) {  
•                                 e.printStackTrace();  
•                             } finally {  
•                                 db.close(); // 关闭数据库  
•                             }  
•                         }  
•                     }.start();  
•                 }else {  
•                     Toast.makeText(MainActivity.this, "请先创建数据库！", Toast.LENGTH_SHORT).show();  
•                 }  
•             }  
•               
•         });  
•           
•         // query查询  
•         Button btnQuery = (Button)findViewById(R.id.btnQuery);  
•         btnQuery.setOnClickListener(new OnClickListener() {  
•               
•             @Override  
•             public void onClick(View arg0) {  
•                 // TODO Auto-generated method stub  
•                 if (mDbHelper != null) {  
•                     mDialog = ProgressDialog.show(MainActivity.this, "query查询", "正在查询记录，请稍等……", true);  
•                     new Thread() { // 开启线程执行防止阻塞  
•                         @Override  
•                         public void run() {  
•                             SQLiteDatabase db = mDbHelper.getWritableDatabase();  
•                               
•                             try {  
•                                 Log.d(TAG, "query Start：" + getDate());  
•                                 long startms = System.currentTimeMillis();  
•                                 // 查询所有记录  
•                                 Cursor c = db.query("student", null, null, null, null, null, new String("id ASC LIMIT 0,1000"));  
•                                 Log.d(TAG, "query End：" + getDate());  
•                                 long endms = System.currentTimeMillis();  
•                                 int seconds = (int)((endms - startms)/1000);  
•                                 int ms = (int)((endms - startms)%1000);  
•                                 if (c != null) {  
•                                     Message msg = new Message();  
•                                     msg.what = 10;  
•                                     // 使用bundle对象来传递数据  
•                                     Bundle b = new Bundle();  
•                                     b.putInt("count", c.getCount());  
•                                     if(seconds > 0) {  
•                                         b.putInt("seconds", seconds);  
•                                     }  
•                                     b.putInt("ms", ms);  
•                                     msg.setData(b);  
•                                     mHandler.sendMessage(msg);  
•                                     c.close();  
•                                 }  
•                             } catch(Exception e) {  
•                                 e.printStackTrace();  
•                             } finally {  
•                                 db.close(); // 关闭数据库  
•                             }  
•                         }  
•                     }.start();  
•                 }else {  
•                     Toast.makeText(MainActivity.this, "请先创建数据库！", Toast.LENGTH_SHORT).show();  
•                 }  
•             }  
•               
•         });  
•           
•         // rawQuery查询  
•         Button btnRawQuery = (Button)findViewById(R.id.btnRawQuery);  
•         btnRawQuery.setOnClickListener(new OnClickListener() {  
•   
•             @Override  
•             public void onClick(View arg0) {  
•                 // TODO Auto-generated method stub  
•                 if (mDbHelper != null) {  
•                     mDialog = ProgressDialog.show(MainActivity.this, "rawQuery查询", "正在查询记录，请稍等……", true);  
•                     new Thread() { // 开启线程执行防止阻塞  
•                         @Override  
•                         public void run() {  
•                             SQLiteDatabase db = mDbHelper.getWritableDatabase();  
•                               
•                             try {  
•                                 Log.d(TAG, "rawQuery Start：" + getDate());  
•                                 long startms = System.currentTimeMillis();  
•                                 // 查询所有记录  
•                                 Cursor c = db.rawQuery("SELECT * FROM student ORDER BY id ASC LIMIT 0,1000", null);  
•                                 Log.d(TAG, "rawQuery End：" + getDate());  
•                                 long endms = System.currentTimeMillis();  
•                                 int seconds = (int)((endms - startms)/1000);  
•                                 int ms = (int)((endms - startms)%1000);  
•                                 if (c != null) {  
•                                     Message msg = new Message();  
•                                     msg.what = 11;  
•                                     // 使用bundle对象来传递数据  
•                                     Bundle b = new Bundle();  
•                                     b.putInt("count", c.getCount());  
•                                     if(seconds > 0) {  
•                                         b.putInt("seconds", seconds);  
•                                     }  
•                                     b.putInt("ms", ms);  
•                                     msg.setData(b);  
•                                     mHandler.sendMessage(msg);  
•                                     c.close();  
•                                 }  
•                             } catch(Exception e) {  
•                                 e.printStackTrace();  
•                             } finally {  
•                                 db.close(); // 关闭数据库  
•                             }  
•                         }  
•                     }.start();  
•                 } else {  
•                     Toast.makeText(MainActivity.this, "请先创建数据库！", Toast.LENGTH_SHORT).show();  
•                 }  
•             }  
•               
•         });  
•           
•         // update更新  
•         Button btnUpdate = (Button)findViewById(R.id.btnUpdate);  
•         btnUpdate.setOnClickListener(new OnClickListener() {  
•               
•             @Override  
•             public void onClick(View arg0) {  
•                 // TODO Auto-generated method stub  
•                 if (mDbHelper != null) {  
•                     mDialog = ProgressDialog.show(MainActivity.this, "update更新", "正在更新1000条记录，请稍等……", true);  
•                     new Thread() { // 开启线程执行防止阻塞  
•                         @Override  
•                         public void run() {  
•                             SQLiteDatabase db = mDbHelper.getWritableDatabase();  
•                             try {  
•                                 ContentValues values = new ContentValues();  
•                                 long startms = System.currentTimeMillis();  
•                                 values.put("name", new String("王五"));  
•                                 values.put("birthday", "2012-12-09");  
•                                 values.put("gender", 0);  
•                                 int count = db.update("student", values, new String("id IN (SELECT id FROM student ORDER BY id ASC LIMIT 0,1000)"), null);  
•                                 long endms = System.currentTimeMillis();  
•                                 int seconds = (int)((endms - startms)/1000);  
•                                 int ms = (int)((endms - startms)%1000);  
•                                   
•                                 Message msg = new Message();  
•                                 msg.what = 20;  
•                                 // 使用bundle对象来传递数据  
•                                 Bundle b = new Bundle();  
•                                 b.putInt("count", count);  
•                                 if(seconds > 0) {  
•                                     b.putInt("seconds", seconds);  
•                                 }  
•                                 b.putInt("ms", ms);  
•                                 msg.setData(b);  
•                                 mHandler.sendMessage(msg);  
•                             } catch(Exception e) {  
•                                 e.printStackTrace();  
•                             } finally {  
•                                 db.close(); // 关闭数据库  
•                             }  
•                         }  
•                     }.start();  
•                 } else {  
•                     Toast.makeText(MainActivity.this, "请先创建数据库！", Toast.LENGTH_SHORT).show();  
•                 }  
•             }  
•         });  
•           
•         // execSQL更新  
•         Button btnExecSqlUpdate = (Button)findViewById(R.id.btnExecSqlUpdate);  
•         btnExecSqlUpdate.setOnClickListener(new OnClickListener() {  
•   
•             @Override  
•             public void onClick(View arg0) {  
•                 // TODO Auto-generated method stub  
•                 if (mDbHelper != null) {  
•                     mDialog = ProgressDialog.show(MainActivity.this, "execSQL更新", "正在更新1000条记录，请稍等……", true);  
•                     new Thread() { // 开启线程执行防止阻塞  
•                         @Override  
•                         public void run() {  
•                             SQLiteDatabase db = mDbHelper.getWritableDatabase();  
•                             try {  
•                                 long startms = System.currentTimeMillis();  
•                                 db.execSQL("UPDATE student SET name = ?, birthday = ?, gender = ? WHERE id IN (SELECT id FROM student ORDER BY id ASC LIMIT 0,1000)" ,  
•                                         new Object[]{new String("马六"), "2012-12-10", 1});  
•                                 long endms = System.currentTimeMillis();  
•                                 int seconds = (int)((endms - startms)/1000);  
•                                 int ms = (int)((endms - startms)%1000);  
•                                   
•                                 Message msg = new Message();  
•                                 msg.what = 21;  
•                                 // 使用bundle对象来传递数据  
•                                 Bundle b = new Bundle();  
•                                 if(seconds > 0) {  
•                                     b.putInt("seconds", seconds);  
•                                 }  
•                                 b.putInt("ms", ms);  
•                                 msg.setData(b);  
•                                 mHandler.sendMessage(msg);  
•                             } catch(Exception e) {  
•                                 e.printStackTrace();  
•                             } finally {  
•                                 db.close(); // 关闭数据库  
•                             }  
•                         }  
•                     }.start();  
•                 }else {  
•                     Toast.makeText(MainActivity.this, "请先创建数据库！", Toast.LENGTH_SHORT).show();  
•                 }  
•             }  
•               
•         });  
•           
•         // delete删除  
•         Button btnDelete = (Button)findViewById(R.id.btnDelete);  
•         btnDelete.setOnClickListener(new OnClickListener() {  
•               
•             @Override  
•             public void onClick(View arg0) {  
•                 // TODO Auto-generated method stub  
•                 if (mDbHelper != null) {  
•                     mDialog = ProgressDialog.show(MainActivity.this, "delete删除", "正在删除1000条记录，请稍等……", true);  
•                     new Thread() { // 开启线程执行防止阻塞  
•                         @Override  
•                         public void run() {  
•                             SQLiteDatabase db = mDbHelper.getWritableDatabase();  
•                             try {  
•                                 long startms = System.currentTimeMillis();  
•                                 int count = db.delete("student", new String("id IN (SELECT id FROM student ORDER BY id ASC LIMIT 0,1000)"), null);  
•                                 long endms = System.currentTimeMillis();  
•                                 int seconds = (int)((endms - startms)/1000);  
•                                 int ms = (int)((endms - startms)%1000);  
•                                   
•                                 Message msg = new Message();  
•                                 msg.what = 30;  
•                                 // 使用bundle对象来传递数据  
•                                 Bundle b = new Bundle();  
•                                 b.putInt("count", count);  
•                                 if(seconds > 0) {  
•                                     b.putInt("seconds", seconds);  
•                                 }  
•                                 b.putInt("ms", ms);  
•                                 msg.setData(b);  
•                                 mHandler.sendMessage(msg);  
•                             } catch(Exception e) {  
•                                 e.printStackTrace();  
•                             } finally {  
•                                 db.close(); // 关闭数据库  
•                             }  
•                         }  
•                     }.start();  
•                 } else {  
•                     Toast.makeText(MainActivity.this, "请先创建数据库！", Toast.LENGTH_SHORT).show();  
•                 }  
•             }  
•         });  
•           
•         // execSQL删除  
•         Button btnExecSqlDelete = (Button)findViewById(R.id.btnExecSqlDelete);  
•         btnExecSqlDelete.setOnClickListener(new OnClickListener() {  
•   
•             @Override  
•             public void onClick(View arg0) {  
•                 // TODO Auto-generated method stub  
•                 if (mDbHelper != null) {  
•                     mDialog = ProgressDialog.show(MainActivity.this, "execSQL删除", "正在删除1000条记录，请稍等……", true);  
•                     new Thread() { // 开启线程执行防止阻塞  
•                         @Override  
•                         public void run() {  
•                             SQLiteDatabase db = mDbHelper.getWritableDatabase();  
•                             try {  
•                                 long startms = System.currentTimeMillis();  
•                                 db.execSQL("DELETE FROM student WHERE id IN (SELECT id FROM student ORDER BY id ASC LIMIT 0,1000)");  
•                                 long endms = System.currentTimeMillis();  
•                                 int seconds = (int)((endms - startms)/1000);  
•                                 int ms = (int)((endms - startms)%1000);  
•                                   
•                                 Message msg = new Message();  
•                                 msg.what = 31;  
•                                 // 使用bundle对象来传递数据  
•                                 Bundle b = new Bundle();  
•                                 if(seconds > 0) {  
•                                     b.putInt("seconds", seconds);  
•                                 }  
•                                 b.putInt("ms", ms);  
•                                 msg.setData(b);  
•                                 mHandler.sendMessage(msg);  
•                             } catch(Exception e) {  
•                                 e.printStackTrace();  
•                             } finally {  
•                                 db.close(); // 关闭数据库  
•                             }  
•                         }  
•                     }.start();  
•                 }else {  
•                     Toast.makeText(MainActivity.this, "请先创建数据库！", Toast.LENGTH_SHORT).show();  
•                 }  
•             }  
•               
•         });  
•           
•         mTvInfo = (TextView)findViewById(R.id.tvInfo);  
•     }  
•   
•     @Override  
•     public boolean onCreateOptionsMenu(Menu menu) {  
•         getMenuInflater().inflate(R.menu.activity_main, menu);  
•         return true;  
•     }  
•       
•     /**   
•      * 获取系统时间   
•      * @return   
•      */    
•     public static String getDate(){  
•         Calendar ca = Calendar.getInstance();     
•         int year = ca.get(Calendar.YEAR);           // 获取年份     
•         int month = ca.get(Calendar.MONTH);         // 获取月份      
•         int day = ca.get(Calendar.DATE);            // 获取日     
•         int minute = ca.get(Calendar.MINUTE);       // 分      
•         int hour = ca.get(Calendar.HOUR);           // 小时      
•         int second = ca.get(Calendar.SECOND);       // 秒     
•         int millisecond = ca.get(Calendar.MILLISECOND); // 毫秒  
•        
•         String date = year + "/" + (month + 1 )+ "/" + day + " "+ hour + ":" + minute + ":" + second + ":" + millisecond;     
•     
•         return date;           
•     }  
• }