Android development examples to implement Files file reading and parsing function

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public class MainActivity extends AppCompatActivity {
  EditText edt;
  Button btn;
  TextView tv;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    (savedInstanceState);
    setContentView(.activity_main);
    edt = (EditText) findViewById();
    btn = (Button) findViewById();
    tv = (TextView) findViewById();
    (new () {
      @Override
      public void onClick(View view) {
        WriteFiles(().toString());
        (readFiles());
      }
    });
  }
  //Save the file content  public void WriteFiles(String content){
    try {
      FileOutputStream fos = openFileOutput("",MODE_PRIVATE);
      (());
      ();
    } catch (FileNotFoundException e) {
      ();
    } catch (IOException e) {
      ();
    }
  }
  //Read the file  public String readFiles(){
    String content = null;
    try {
      FileInputStream fis = openFileInput("");
      ByteArrayOutputStream baos = new ByteArrayOutputStream();
      byte[]buffer = new byte[1024];
      int len = 0;
      while ((len = (buffer))!=-1)
      {
        (buffer,0,len);
      }
      content = ();
      ();;
      ();
    } catch (FileNotFoundException e) {
      ();
    } catch (IOException e) {
      ();
    }
    return content;
  }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:andro
  xmlns:tools="/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:paddingBottom="@dimen/activity_vertical_margin"
  android:paddingLeft="@dimen/activity_horizontal_margin"
  android:paddingRight="@dimen/activity_horizontal_margin"
  android:paddingTop="@dimen/activity_vertical_margin"
  tools:context="">
  <EditText
    android:layout_width="wrap_content"
    android:layout_height="200dp"
    android:
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true" />
  <Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="New Button"
    android:
    android:layout_below="@+id/editText"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="90dp" />
  <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="New Text"
    android:
    android:layout_below="@+id/button"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:layout_alignParentBottom="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />
</RelativeLayout>