java - Android Studio Activity 登录屏幕不显示密码字段并且不显示用户名字段文本

Question

当我在 Android 模拟器中构建应用程序时，登录屏幕不显示密码字段和用户名字段文本。我在 log cat 文件中没有看到任何错误。我已经检查并重新检查了我的 Activity_login.xml 布局文件并且

ActivityLogin.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:id="@+id/toolbar"
    tools:context="com.example.kanak.selfdistructtext.LoginActivity"
    android:background="@color/background_floating_material_light">





    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/UserNameField"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:text="@string/user_name_field"
        android:inputType="text" />

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textPassword"
        android:ems="10"
        android:id="@+id/PasswordField"
        android:layout_below="@+id/UserNameField"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:text="@string/password_field" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/log_in_button"
        android:id="@+id/Loginbutton"
        android:layout_below="@+id/PasswordField"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:text="@string/sing_up"
        android:id="@+id/Sign_up_link"
        android:layout_marginTop="74dp"
        android:layout_below="@+id/Loginbutton"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginLeft="151dp"
        android:layout_marginStart="151dp" />

</RelativeLayout>

MainActivity.Java

package com.example.kanak.selfdistructtext;

import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.app.ActionBar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import com.parse.Parse;
import com.parse.ParseAnalytics;
import com.parse.ParseObject;
import com.parse.ParseUser;


public class MainActivity extends AppCompatActivity{

    public static final String TAG = MainActivity.class.getSimpleName();


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.app_bar_main);
       //Parse.initialize(this, "1UG3pTBg184gaIDzKNAqfrZnAYiXcW4xn8SSdiJv", "uTZhgB0edmy06OOdpcbriho7DypKsGybPfGZSGL1");
        // Parase Analytice
        ParseAnalytics.trackAppOpenedInBackground(getIntent());
        ParseUser currentUser = ParseUser.getCurrentUser();
        if (currentUser == null) {
            navigateToLogin();
        } else {

            Log.i(TAG, currentUser.getUsername());
        }


        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);




        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
    }

    private void navigateToLogin() {
        Intent intent = new Intent(this, LoginActivity.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
        startActivity(intent);
    }

    @Override
        public boolean onCreateOptionsMenu(Menu menu){
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.menu_main, 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_logout) {
                ParseUser.logOut();
                navigateToLogin();

            }

            return super.onOptionsItemSelected(item);
        }
    }

LoginActivity.Java

[package com.example.kanak.selfdistructtext;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import com.parse.LogInCallback;
import com.parse.ParseException;
import com.parse.ParseUser;

public class LoginActivity extends AppCompatActivity {
    protected EditText mUsername;
    protected EditText mPassword;
    protected Button mLoginButton;
    protected TextView mSignUpTextView;


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

        mSignUpTextView = (TextView)findViewById(R.id.Sign_up_link);
        mSignUpTextView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent intent = new Intent(LoginActivity.this, SignUpActivity.class);
                startActivity(intent);


            }
        });

        mUsername = (EditText)findViewById(R.id.UserNameField);
        mPassword = (EditText)findViewById(R.id.PasswordField);
        mLoginButton = (Button)findViewById(R.id.Loginbutton);
        mLoginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String username = mUsername.getText().toString();
                String password = mPassword.getText().toString();


                username = username.trim();
                password = password.trim();


                if (username.isEmpty() || password.isEmpty()) {

                    AlertDialog.Builder builder = new AlertDialog.Builder(LoginActivity.this);
                    builder.setMessage(R.string.Login_Error_Message);
                    builder.setTitle(R.string.Login_Error_Title);
                    builder.setPositiveButton(android.R.string.ok, null);
                    AlertDialog dialog = builder.create();
                    dialog.show();

                } else {
                    // Log In User
                    ParseUser.logInInBackground(username, password, new LogInCallback() {
                        @Override
                        public void done(ParseUser parseUser, ParseException e) {

                            if (e == null) {

                                // success signing in
                                Intent intent = new Intent(LoginActivity.this, MainActivity.class);
                                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
                                startActivity(intent);
                            }
                            else {

                                AlertDialog.Builder builder = new AlertDialog.Builder(LoginActivity.this);
                                builder.setMessage(e.getMessage());
                                builder.setTitle(R.string.Login_Error_Title);
                                builder.setPositiveButton(android.R.string.ok, null);
                                AlertDialog dialog = builder.create();
                                dialog.show();
                            }

                        }
                    });

                }
            }
        });


        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);



        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });


        }



}][1]

Answer 1

您正在使用 MainActivity 的 xml 设置 LoginActivity 的主要内容。所以在LoginActivity中设置LoginActivity的xml。

替换

setContentView(R.layout.app_bar_main);

至

setContentView(R.layout.activity_login);

在LoginActivity.java

您需要对 v7 的工具栏使用以下代码。

<android.support.v7.widget.Toolbar
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:local="http://schemas.android.com/apk/res-auto"
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="?attr/actionBarSize"
    android:background="@mipmap/navbg"
    local:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
    local:popupTheme="@style/ThemeOverlay.AppCompat.Light"
    />