the code I used to show data in the text view from the database is here I tried Shared prefrences too but the app crashes when I execute it. I want to export the data in txt file in the external storage. Which method do I have to use to complete this action.

public class Export2 extends AppCompatActivity {
ImageView back;
Button button;
TextView tv,tv2,tv3;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_export2);
    initview();
    initListener();

}

Defining the objects

public void initview(){
    tv = findViewById(R.id.details2);
    tv2 = findViewById(R.id.babydetails2);
    tv3 = findViewById(R.id.vac_result2);
    back = findViewById(R.id.back);
    button = findViewById(R.id.exportbtn);
}

public void initListener(){

    back.setOnClickListener(v -> Export2.super.onBackPressed());
}

details I added to the textview through String Builder.

public void details(){

    DBase dBase = new DBase(this);
    DbaseBaby dbaseBaby = new DbaseBaby(this);
    VaccineDB2 vaccineDB2 = new VaccineDB2(this);


    Cursor cursor = dBase.getData();

    StringBuilder sb = new StringBuilder();

    while(cursor.moveToNext()){
        sb.append("\nMobile Number :"  cursor.getString(1)   "\nEmail : "  cursor.getString(2)
                  "\nMother's name : "  cursor.getString(3)   "\nFather's name : "  cursor.getString(4));
    }
    tv.setText(sb);

    Cursor c = dbaseBaby.getData();

    StringBuilder sb2 = new StringBuilder();

    while(c.moveToNext()){
        sb2.append(" \nBaby name : "   c.getString(1)   " \nBirthdate : "  c.getString(2)
                  " \nGender : "   c.getString(3)   " \nAge group : "   c.getString(4));
    }
    tv2.setText(sb2);


    Cursor cu = vaccineDB2.getData();

    StringBuilder sBuilder = new StringBuilder();

    while (cu.moveToNext()){
        sBuilder.append("\nVaccine : " cu.getString(1)   "\nVaccine : " cu.getString(2)
                  "\nVaccine : " cu.getString(3)    "\nVaccine : " cu.getString(4)    "\nVaccine : " cu.getString(5)
                  "\nVaccine : " cu.getString(6)    "\nVaccine : " cu.getString(7)    "\nVaccine : " cu.getString(8)
                  "\nVaccine : " cu.getString(9)    "\nVaccine : " cu.getString(10));
    }
    tv3.setText(sBuilder);
}

}

CodePudding user response：

You can use this code:

public void saveInTxt() throws IOException {
    String txt1 = tv.getText().toString();
    String txt2 = tv2.getText().toString();
    String txt3 = tv3.getText().toString();
    File f = new File("YOUR PATH");
    FileWriter fw = new FileWriter(f);

    fw.write(txt1);
    fw.write("\n");
    fw.write(txt2);
    fw.write("\n");
    fw.write(txt3);
    fw.write("\n");
    fw.flush();
    fw.close();
}

Note: You will need to ask for write permission.