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1 使ç¨SharedPreferencesåå¨æ°æ®
2 æ件åå¨æ°æ®
3 SQLiteæ°æ®åºåå¨æ°æ®
4 使ç¨ContentProvideråå¨æ°æ®
5 ç½ç»åå¨æ°æ®
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第ä¸ç§ï¼ 使ç¨SharedPreferencesåå¨æ°æ®
SharedPreferencesæ¯Androidå¹³å°ä¸ä¸ä¸ªè½»é级çåå¨ç±»ï¼ä¸»è¦æ¯ä¿åä¸äºå¸¸ç¨çé
ç½®æ¯å¦çªå£ç¶æï¼ä¸è¬å¨Activityä¸ éè½½çªå£ç¶æonSaveInstanceStateä¿åä¸è¬ä½¿ç¨SharedPreferenceså®æï¼å®æä¾äºAndroidå¹³å°å¸¸è§çLongé¿ æ´å½¢ãIntæ´å½¢ãStringå符串åçä¿åã
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public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//è·åSharedPreferences对象
Context ctx = MainActivity.this;
SharedPreferences sp = ctx.getSharedPreferences("SP", MODE_PRIVATE);
//åå
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Editor editor = sp.edit();
editor.putString("STRING_KEY", "string");
editor.putInt("INT_KEY", 0);
editor.putBoolean("BOOLEAN_KEY", true);
editor.commit();
//è¿åSTRING_KEYçå¼
Log.d("SP", sp.getString("STRING_KEY", "none"));
//å¦æNOT_EXISTä¸åå¨ï¼å
è¿åå¼ä¸º"none"
Log.d("SP", sp.getString("NOT_EXIST", "none"));
}
}
第äºç§ï¼ æ件åå¨æ°æ®
å
³äºæ件åå¨ï¼Activityæä¾äºopenFileOutput()æ¹æ³å¯ä»¥ç¨äºææ°æ®è¾åºå°æ件ä¸ï¼å
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代ç 示ä¾ï¼
public void save(){
try {
FileOutputStream outStream=this.openFileOutput("a.txt",Context.MODE_WORLD_READABLE);
outStream.write(text.getText().toString().getBytes());
outStream.close();
Toast.makeText(MyActivity.this,"Saved",Toast.LENGTH_LONG).show();
} catch (FileNotFoundException e) {
return;
}
catch (IOException e){
return ;
}
}
第ä¸ç§ï¼ SQLiteæ°æ®åºåå¨æ°æ®
SQLiteæ¯è½»é级åµå
¥å¼æ°æ®åºå¼æï¼å®æ¯æ SQL è¯è¨ï¼å¹¶ä¸åªå©ç¨å¾å°çå
åå°±æå¾å¥½çæ§è½ãæ¤å¤å®è¿æ¯å¼æºçï¼ä»»ä½äººé½å¯ä»¥ä½¿ç¨å®ã许å¤å¼æºé¡¹ç®ï¼(Mozilla, PHP, Pythonï¼é½ä½¿ç¨äº SQLiteã
SQLite ç±ä»¥ä¸å 个ç»ä»¶ç»æï¼SQL
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æ ¸ãå端以åé件ã
SQLite éè¿å©ç¨
èææºåèææ°æ®åºå¼æï¼VDBEï¼ï¼ä½¿è°è¯ãä¿®æ¹åæ©å± SQLite çå
æ ¸åå¾æ´å æ¹ä¾¿ã
读åæ件示ä¾ï¼
public void load(){
try {
FileInputStream inStream=this.openFileInput("a.txt");
ByteArrayOutputStream stream=new ByteArrayOutputStream();
byte[] buffer=new byte[1024];
int length=-1;
while((length=inStream.read(buffer))!=-1) {
stream.write(buffer,0,length);
}
stream.close();
inStream.close();
text.setText(stream.toString());
Toast.makeText(MyActivity.this,"Loaded",Toast.LENGTH_LONG).show();
} catch (FileNotFoundException e) {
e.printStackTrace();
}
catch (IOException e){
return ;
}
}
第åç§ ä½¿ç¨ContentProvideråå¨æ°æ® ContentProviderå
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