将数据存储到文件中

//布局文件
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="wrap_content"
    android:layout_height="match_parent">

    <EditText android:id="@+id/edit"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:hint="Type something here"/>
</LinearLayout>


//例子
    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 succeede",Toast.LENGTH_SHORT).show();
        }else{
            Log.d("123","FILE OPEN ERROR");
        }
    }
    protected void onDestroy(){
        super.onDestroy();
        String inputTest  = edit.getText().toString();
        save(inputTest);
        Log.d("123","FILE SAVE OK");
    }

    public void save(String inputTest) {
        FileOutputStream out = null;
        BufferedWriter writer = null;
        try{
            out = openFileOutput("caicai123.txt", Context.MODE_PRIVATE);
            //out.getFD(

            File filesDir = getFilesDir();
            Log.d("123", filesDir.toString());
            writer = new BufferedWriter(new OutputStreamWriter(out));
            writer.write(inputTest);

        }catch (IOException e){
            e.printStackTrace();
        }

        finally{
            try {
                if (writer != null) {
                    writer.close();
                }
            }catch(IOException e1){
                e1.printStackTrace();
            }
        }

    }


    public String load(){
        FileInputStream in = null;
        BufferedReader reader = null;
        StringBuilder content = new StringBuilder();
        try{
            in = openFileInput("caicai123.txt");
            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();
    }