Added restart password and back in application.

app/src/main/AndroidManifest.xml

@@ -5,6 +5,7 @@
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
 
     <application
+        android:requestLegacyExternalStorage="true"
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
@@ -16,7 +17,6 @@
         <activity android:name=".MainActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
-
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>

app/src/main/java/com/zadanie1/mw/FormPassword.java

@@ -1,17 +1,73 @@
 package com.zadanie1.mw;
 
+import android.content.Intent;
 import android.os.Bundle;
 import android.app.Activity;
+import android.view.View;
+import android.widget.Button;
+import android.widget.EditText;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.PrintWriter;
 
 public class FormPassword extends Activity {
-
+    private static final String FILE_NAME = "passwd.txt";
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_form_password);
 
+        final EditText newpassword;
+        final EditText renewpassword;
+        Button confirm;
 
+        newpassword = (EditText) findViewById(R.id.newpassword);
+        renewpassword = (EditText) findViewById(R.id.renewpassword);
+        confirm = (Button) findViewById(R.id.button);
 
+        confirm.setOnClickListener(new View.OnClickListener() {
+            public void onClick(View arg0) {
+                if (newpassword.getText().toString().equals(renewpassword.getText().toString())) {
 
+                    String text = newpassword.getText().toString();
+                    FileOutputStream fos = null;
+
+                    Toast toast = Toast.makeText(getApplicationContext(),
+                            "Password has been changed",
+                            Toast.LENGTH_SHORT);
+                    toast.show();
+
+                    try {
+                        fos = openFileOutput(FILE_NAME, MODE_PRIVATE);
+                        fos.write(text.getBytes());
+
+                    } catch (FileNotFoundException e) {
+                        e.printStackTrace();
+                    } catch (IOException e) {
+                        e.printStackTrace();
+                    } finally {
+                        if (fos != null) {
+                            try {
+                                fos.close();
+                            } catch (IOException e) {
+                                e.printStackTrace();
+                            }
+                        }
+                    }
+                    onBackPressed();
+                }
+                else
+                    {
+                        Toast toast = Toast.makeText(getApplicationContext(),
+                                "Password has NOT been changed",
+                                Toast.LENGTH_SHORT);
+                        toast.show();
+                    }
+            }
+        });
     }
 }

app/src/main/java/com/zadanie1/mw/MainActivity.java

@@ -10,6 +10,7 @@ import android.widget.Button;
 import android.view.View.OnClickListener;
 import android.widget.EditText;
 import android.widget.TextView;
+import android.widget.Toast;
 
 import java.io.File;
 import java.io.FileReader;
@@ -45,8 +46,6 @@ public class MainActivity extends AppCompatActivity {
     }
 
 
-
-
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -57,26 +56,50 @@ public class MainActivity extends AppCompatActivity {
         restartpassword = (Button) findViewById(R.id.restartpassword);
         textPassword = findViewById(R.id.editText);
 
+
         restartpassword.setOnClickListener(new OnClickListener() {
             public void onClick(View arg0) {
                 Intent myIntent = new Intent(MainActivity.this,
                         FormPassword.class);
                 startActivity(myIntent);
-                finish();
             }
         });
 
         button.setOnClickListener(new OnClickListener() {
             private final String filename =  getFilesDir() + "/passwd.txt";
+
+            private boolean isFileExists(File file) {
+                return file.exists() && !file.isDirectory();
+
+            }
+
             @Override
             public void onClick(View view) {
                 response.setText(textPassword.getText());
+
+                File file = new File(filename);
+
                  try {
+                     if (isFileExists(file)) {
                          if (textPassword.getText().toString().equals(readFile(filename).toString())) {
+                             Toast toast = Toast.makeText(getApplicationContext(),
+                                     "Password is correct!",
+                                     Toast.LENGTH_SHORT);
+                             toast.show();
                              Intent myIntent2 = new Intent(MainActivity.this,
                                      Noto.class);
                              startActivity(myIntent2);
-                        finish();
+
+                         }
+                     }  else if (textPassword.getText().toString().equals("FirstPassword!")) {
+                         Intent myIntent2 = new Intent(MainActivity.this,
+                                 Noto.class);
+                         startActivity(myIntent2);
+                     }  else {
+                         Toast toast = Toast.makeText(getApplicationContext(),
+                                 "Password is NOT correct",
+                                 Toast.LENGTH_SHORT);
+                         toast.show();
                      }
                      }  catch(IOException e){
                      e.printStackTrace();

app/src/main/java/com/zadanie1/mw/Noto.java

@@ -72,7 +72,7 @@ public class Noto extends AppCompatActivity {
             fos = openFileOutput(FILE_NAME, MODE_PRIVATE);
             fos.write(text.getBytes());
 
-            ChangeNote.getText().clear();
+            /*ChangeNote.getText().clear();*/
             Toast.makeText(this, "Saved to " + getFilesDir() + "/" + FILE_NAME, Toast.LENGTH_LONG).show();
 
         } catch (FileNotFoundException e) {

build.gradle

@@ -7,7 +7,7 @@ buildscript {
         
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath 'com.android.tools.build:gradle:3.5.1'
         
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files