android随笔

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今天刚学习了android的三大数据存储的一个例子
public class MainActivity extends Activity {    private SharedPreferences preferences;    private SharedPreferences.Editor editor;    private Button read;    private Button write;    private EditText text;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        preferences = getSharedPreferences("Crazyit", MODE_PRIVATE);        editor = preferences.edit();        read = (Button) findViewById(R.id.button2);        write = (Button) findViewById(R.id.button);        text = (EditText) findViewById(R.id.editText);        read.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                String time = preferences.getString("time", null);                String string = preferences.getString("string", "");                int randNum = preferences.getInt("random", 0);                String result = time == null ? "暂时没有写入数据" : "写入时间为：" + time + "\n上次生成的随机数为：" + randNum;                Toast.makeText(MainActivity.this, result, Toast.LENGTH_SHORT).show();                text.setText(string);                Map<String, ?> map = preferences.getAll();                Log.d("@p", map.toString());            }        });        write.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                SimpleDateFormat sfd = new SimpleDateFormat("yyyy-MM-dd HH-mm-ss");                editor.putString("time", sfd.format(new Date()));                editor.putInt("random", (int) (Math.random() * 100));                editor.putString("string", text.getText().toString());                editor.commit();                Log.d("@p", preferences.getAll().toString());                Toast.makeText(MainActivity.this, "Ok!", Toast.LENGTH_SHORT).show();            }        });    }}
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