android 简单存取资料

java io

public class MainActivity extends AppCompatActivity {    private EditText edit;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);      edit = (EditText) findViewById(R.id.edit);       String inputText = load();        if (!TextUtils.isEmpty(inputText)) {           edit.setText(inputText);           edit.setSelection(inputText.length());       Toast.makeText(this, "Restoring succeeded", Toast.LENGTH_SHORT).show();      }          @Override    protected void onDestroy() {        super.onDestroy();        String inputText = edit.getText().toString();        save(inputText);    }    public void save(String inputText) {        FileOutputStream out = null;        BufferedWriter writer = null;        try {            out = openFileOutput("data", Context.MODE_PRIVATE);            writer = new BufferedWriter(new OutputStreamWriter(out));            writer.write(inputText);        } catch (IOException e) {            e.printStackTrace();        } finally {            try {                if (writer != null) {                    writer.close();                }            } catch (IOException e) {                e.printStackTrace();            }        }    }    public String load() {        FileInputStream in = null;        BufferedReader reader = null;        StringBuilder content = new StringBuilder();        try {            in = openFileInput("data");            reader = new BufferedReader(new InputStreamReader(in));            String line = "";            while ((line = reader.readLine()) != null) {                content.append(line);            }        } catch (IOException e) {            e.printStackTrace();        } finally {            if (reader != null) {                try {                    reader.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }        return content.toString();    }}

sharedpreferences
context class > getSharedPreferences(文件名,MODE_PRIVATE); 没这文建会自己创一个
Activity class>getPreferences(MODE_PRIVATE); 文件名会拿你activity命名

  Button saveData= (Button) findViewById(R.id.save);        Button getData=(Button) findViewById(R.id.get);        saveData.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                SharedPreferences.Editor editor=                        getSharedPreferences("datat",MODE_PRIVATE).edit();                //指定名称 并调用对象添加数据                editor.putString("name","tom");                editor.apply();//提交            }        });        getData.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                SharedPreferences preferences=getSharedPreferences("datat",MODE_PRIVATE);                String name = preferences.getString("name","");                Log.d("Mainactivity", "onClick: "+name);            }        });    }