使用FileInputStream和FileOutputStream的物件呼叫方法來建立

將資料寫入手機記憶體

public class HandFile {
    private Context context;
    public HandFile(Context context) {
        this.context = context;
}

    public void writeFileData(String filename,String message){
        try {
            FileOutputStream fileOutputStream =context
 
.openFileOutput(filename,context.MODE_PRIVATE);
            byte[] bytes=message.getBytes();
fileOutputStream.write(bytes);
fileOutputStream.close();
} catch (FileNotFoundException e) {
            e.printStackTrace();
} catch (IOException e) {
            e.printStackTrace();
}
    }

    public String readFileData
 
(String fileName){
        String result="";
FileInputStream fileInputStream = null;
        try {
            fileInputStream = context.openFileInput(fileName);
            int length=fileInputStream.available();
            byte[] bytes=new byte[length];
fileInputStream.read(bytes);
result=new String(bytes);
 
fileInputStream.close();
} catch (Exception e) {
            e.printStackTrace();
}

        return result;
}

}

public class MainActivity extends AppCompatActivity {
    private TextView mtv;
@Override
protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String message="emmmm……我就是傳說中的資料，嘻嘻嘻。我特麼學android好累啊，" +
                "可是又有什麼辦法呢，誰讓我大一大二兩年太放縱了呢，現在學點東西不至於找不到工作吧，" +
                "考研也很累啊，下雪了，我的書還能到嗎……";
HandFile handFile=new HandFile(this);
handFile.writeFileData("first",message);
String result=handFile.readFileData("first");
mtv= (TextView) findViewById(R.id.file);
mtv.setText(result);
}
}