如何在Android进入和退出时控制Android中的活动？

时间：2017-02-07 14:50:53

标签： android firebase firebase-realtime-database firebase-authentication

我正在尝试使用Firebase为Android中的血库制作一个Android应用程序。我的主页显示了一个城市捐赠者名单，联系号码。但问题是当用户登录然后返回主页时他/她可以看到该应用程序停止的donner列表。

为了更好地理解，我在这里给出了我的全班代码。谁能在这个过程中帮助我？提前谢谢。

package alik.com.pmscs;

import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import com.firebase.client.Firebase;
import com.firebase.ui.database.FirebaseListAdapter;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;

import java.util.ArrayList;

import alik.com.loader.Information;

public class HomePage extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {

Intent intent;
FirebaseAuth auth;
FirebaseAuth.AuthStateListener authStateListener;
ListView listView;
ArrayList <Information> informations;
Firebase firebase;
ImageView call;
//FirebaseUser user;
FirebaseAuth.AuthStateListener listener;
GoogleSignInOptions signInOptions;

DatabaseReference reference;
NavigationView navigationView;
com.firebase.ui.database.FirebaseListAdapter <Information> adapter;

SharedPreferences sharedPreferences;
SharedPreferences.Editor editor;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home_page);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    auth=FirebaseAuth.getInstance();
    listener=new FirebaseAuth.AuthStateListener() {
        @Override
        public void onAuthStateChanged(FirebaseAuth firebaseAuth) {
            FirebaseUser user=auth.getCurrentUser();
            if(user==null){
                Menu menu=navigationView.getMenu();
                menu.findItem(R.id.nav_signoutfrom).setVisible(false);
                menu.findItem(R.id.nav_profileon).setVisible(false);
                menu.findItem(R.id.nav_adddonnor).setVisible(false);
            }

        }
    };


    listView=(ListView)findViewById(R.id.listView);

    FirebaseDatabase.getInstance().setPersistenceEnabled(true);

    final FirebaseDatabase database=FirebaseDatabase.getInstance();
    reference=database.getReference();
    reference.keepSynced(true);
    adapter=new FirebaseListAdapter<Information>(
            this,
            Information.class,
            R.layout.donorlist,
            reference
    ) {
        @Override
        protected void populateView(View v, Information model, int position) {

            ((TextView)v.findViewById(R.id.donnor_blood)).setText(model.getBloodgroup());
            ((TextView)v.findViewById(R.id.donor_name)).setText(model.getName());
            ((TextView)v.findViewById(R.id.donor_contact)).setText(model.getContact());
            ((TextView)v.findViewById(R.id.donor_city)).setText(model.getCity()+", "+model.getCountry());

        }
    };
    listView.setAdapter(adapter);




    ColorDrawable colorDrawable=new ColorDrawable(Color.parseColor("#bc212b"));
    getSupportActionBar().setBackgroundDrawable(colorDrawable);



    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);
}

@Override
public void onBackPressed() {
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.home_page, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

//@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();

    if (id == R.id.nav_reg) {
        // Handle the camera action
        intent=new Intent(getApplicationContext(),RegisterAccount.class);
        startActivity(intent);
        //finish();

    } else if (id == R.id.nav_login) {
        intent=new Intent(getApplicationContext(),Login.class);
        startActivity(intent);
        //finish();

    }
    else if (id == R.id.nav_profileon) {

        if(listener!=null){

            Toast.makeText(getApplicationContext(),"This Feature is Comming Soon!!", Toast.LENGTH_LONG).show();


        }
        else {
            Toast.makeText(getApplicationContext(),"Please Login First", Toast.LENGTH_LONG).show();

        }
    }
    else if(id==R.id.nav_adddonnor){
        if(listener!=null){
            startActivity(new Intent(getApplicationContext(),DonnarRegistration.class));
            //finish();
        }
        else{
            Toast.makeText(getApplicationContext(),"Please Login First", Toast.LENGTH_LONG).show();

        }

    }
    else if (id == R.id.nav_signoutfrom) {

        if(listener!=null){
            FirebaseAuth.getInstance().signOut();
            Toast.makeText(getApplicationContext(), "Sign Out Successfully", Toast.LENGTH_LONG).show();


        }
        else{
            Toast.makeText(getApplicationContext(),"Please Login First", Toast.LENGTH_LONG).show();
        }


    }


    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}

@Override
protected void onStop() {
    super.onStop();
    if(listener!=null){
        auth.removeAuthStateListener(listener);
    }
}

@Override
protected void onStart() {
    super.onStart();
    auth.addAuthStateListener(listener);
}

@Override
protected void onPostResume() {
    super.onPostResume();

}
}

我的登录类代码在这里

package alik.com.pmscs;

import android.content.Intent;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.Toast;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
public class Login extends AppCompatActivity {

private EditText inputEmail, inputPassword;
private FirebaseAuth auth;
private ProgressBar progressBar;
private Button btnSignup, btnLogin;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);

    ColorDrawable colorDrawable=new ColorDrawable(Color.parseColor("#bc212b"));
    getSupportActionBar().setBackgroundDrawable(colorDrawable);
    getSupportActionBar().setTitle("Sign Up");

    auth = FirebaseAuth.getInstance();

    inputEmail = (EditText) findViewById(R.id.email);
    inputPassword = (EditText) findViewById(R.id.password);
    progressBar = (ProgressBar) findViewById(R.id.progressBar);
    btnSignup = (Button) findViewById(R.id.btn_signup);
    btnLogin = (Button) findViewById(R.id.btn_login);


    auth=FirebaseAuth.getInstance();

    btnSignup.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent=new Intent(getApplicationContext(), RegisterAccount.class);
            startActivity(intent);
            finish();

        }
    });
    btnLogin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String email = inputEmail.getText().toString();
            final String password = inputPassword.getText().toString();

            if (TextUtils.isEmpty(email)) {
                Toast.makeText(getApplicationContext(), "Enter email address!", Toast.LENGTH_SHORT).show();
                return;
            }

            if (TextUtils.isEmpty(password)) {
                Toast.makeText(getApplicationContext(), "Enter password!", Toast.LENGTH_SHORT).show();
                return;
            }
            progressBar.setVisibility(View.VISIBLE);
            auth.signInWithEmailAndPassword(email, password).addOnCompleteListener(Login.this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(Task<AuthResult> task) {
                    progressBar.setVisibility(View.GONE);
                    if (!task.isSuccessful()) {
                        // there was an error
                        Toast.makeText(getApplicationContext(),"There is an error",Toast.LENGTH_LONG).show();
                        if (password.length() < 6) {
                            inputPassword.setError(getString(R.string.minimum_password));
                        } else {
                            Toast.makeText(Login.this, getString(R.string.auth_failed), Toast.LENGTH_LONG).show();
                        }
                    } else {
                        Intent intent = new Intent(Login.this, HomePage.class);
                        startActivity(intent);
                        finish();
                    }

                }
            });
        }
    });
}


}

所以问题是当我登录然后尝试回到我的主页活动时它停止了。所以我需要专家的帮助来解决它。如果你帮我完成这项任务，那将是一种乐趣。

我的gradle文件：

dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.4.0'
compile 'com.android.support:design:23.4.0'
compile 'com.firebase:firebase-client-android:2.4.0'
compile 'com.google.firebase:firebase-auth:10.0.1'
compile 'com.google.firebase:firebase-core:10.0.1'
compile 'com.google.firebase:firebase-database:10.0.1'
compile 'com.google.firebase:firebase-storage:10.0.1'

compile 'com.firebaseui:firebase-ui-database:0.4.0'

}
apply plugin: 'com.google.gms.google-services'

1 个答案:

答案 0 :(得分：0)

您是否尝试按以下方式更改登录活动？在这里，我正在检查用户是否已登录Login活动，如果是，我正在调用HomePage活动。 

public class Login extends AppCompatActivity {

private EditText inputEmail, inputPassword;
private FirebaseAuth auth;
private ProgressBar progressBar;
private Button btnSignup, btnLogin;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    auth = FirebaseAuth.getInstance();

    if (auth.getCurrentUser() != null) {

        Intent intent = new Intent(Login.this, HomePage.class);
        startActivity(intent);
        finish();
    }

    setContentView(R.layout.activity_login);

    ColorDrawable colorDrawable=new ColorDrawable(Color.parseColor("#bc212b"));
    getSupportActionBar().setBackgroundDrawable(colorDrawable);
    getSupportActionBar().setTitle("Sign Up");

    inputEmail = (EditText) findViewById(R.id.email);
    inputPassword = (EditText) findViewById(R.id.password);
    progressBar = (ProgressBar) findViewById(R.id.progressBar);
    btnSignup = (Button) findViewById(R.id.btn_signup);
    btnLogin = (Button) findViewById(R.id.btn_login);

    btnSignup.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent=new Intent(getApplicationContext(), RegisterAccount.class);
            startActivity(intent);
            finish();

        }
    });
    btnLogin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String email = inputEmail.getText().toString();
            final String password = inputPassword.getText().toString();

            if (TextUtils.isEmpty(email)) {
                Toast.makeText(getApplicationContext(), "Enter email address!", Toast.LENGTH_SHORT).show();
                return;
            }

            if (TextUtils.isEmpty(password)) {
                Toast.makeText(getApplicationContext(), "Enter password!", Toast.LENGTH_SHORT).show();
                return;
            }
            progressBar.setVisibility(View.VISIBLE);
            auth.signInWithEmailAndPassword(email, password).addOnCompleteListener(Login.this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(Task<AuthResult> task) {
                    progressBar.setVisibility(View.GONE);
                    if (!task.isSuccessful()) {
                        // there was an error
                        Toast.makeText(getApplicationContext(),"There is an error",Toast.LENGTH_LONG).show();
                        if (password.length() < 6) {
                            inputPassword.setError(getString(R.string.minimum_password));
                        } else {
                            Toast.makeText(Login.this, getString(R.string.auth_failed), Toast.LENGTH_LONG).show();
                        }
                    } else {
                        Intent intent = new Intent(Login.this, HomePage.class);
                        startActivity(intent);
                        finish();
                    }

                }
            });
        }
    });
}

希望这可以满足您的要求

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