Question

Synposis：我有3项活动（LoginActivity，MainActivity和EditProfileActivity）。 Facebook登录我的LoginActivity后，我会使用MainActivity。（直到这一点，应用程序正常工作，没有错误）。我的导航有一个NavigationDrawer，当我点击NavigationDrawer中的Edit Profile链接时，它会启动EditProfileActivity。

问题：当我点击顶部蓝色栏中的LeftArrow时，应用程序崩溃了。

请参阅图片：

MainActivity

导航抽屉

EditProfileActivity

单击左上箭头的应用程序崩溃

这是我的Manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.example">

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <meta-data
            android:name="com.facebook.sdk.ApplicationId"
            android:value="@string/facebook_app_id" />

        <activity
            android:name="com.facebook.FacebookActivity"
            android:configChanges="keyboard|keyboardHidden|screenLayout|screenSize|orientation"
            android:label="@string/app_name" />
        <activity
            android:name="com.facebook.CustomTabActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE" />

                <data android:scheme="@string/fb_login_protocol_scheme" />
            </intent-filter>
        </activity>
        <activity android:name=".LoginActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <provider
            android:name="com.facebook.FacebookContentProvider"
            android:authorities="com.facebook.app.FacebookContentProvider"
            android:exported="true" />

        <activity
            android:name=".MainActivity"
            android:label="@string/title_activity_main"
            android:theme="@style/AppTheme.NoActionBar">
        </activity>
        <activity android:name=".EditProfileActivity"
            android:parentActivityName=".MainActivity" >
            <!-- The meta-data tag is required if you support API level 15 and lower -->
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".MainActivity" />
        </activity>
    </application>

</manifest>

这是我的MainActivity.java

package com.example.example;

import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.util.Log;
import android.view.View;
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.widget.ImageView;
import android.widget.TextView;

import java.io.InputStream;

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

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

        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 = (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.main, menu);
        Bundle inBundle = getIntent().getExtras();
        String first_name = inBundle.get("first_name").toString();
        String last_name = inBundle.get("last_name").toString();
        String imageUrl = inBundle.get("imageUrl").toString();

        TextView nameView = (TextView)findViewById(R.id.nameView);
        nameView.setText("" + first_name + " " + last_name);
        new DownloadImage((ImageView)findViewById(R.id.imageView)).execute(imageUrl);
        return true;
    }
    public class DownloadImage extends AsyncTask<String, Void, Bitmap> {
        ImageView bmImage;

        public DownloadImage(ImageView bmImage) {
            this.bmImage = bmImage;
        }

        protected Bitmap doInBackground(String... urls) {
            String urldisplay = urls[0];
            Bitmap mIcon11 = null;
            try {
                InputStream in = new java.net.URL(urldisplay).openStream();
                mIcon11 = BitmapFactory.decodeStream(in);
            } catch (Exception e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            return mIcon11;
        }

        protected void onPostExecute(Bitmap result) {
            bmImage.setImageBitmap(result);
        }
    }
    @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_camera) {
            // Handle the camera action
        } else if (id == R.id.nav_gallery) {

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

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

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

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

        } else if(id == R.id.nav_user_edit){
            Intent intent = new Intent(this, EditProfileActivity.class);
            startActivity(intent);
        }

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

Answer 1

您必须在清单文件中定义您的活动parent，如此

<meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="fully qualified activity name" />

确保您的活动的元数据包含后退按钮。其他明智的就像你没有告诉你回按钮去哪里!!

您必须在MainActivity.java文件中添加以下两行：

getSupportActionBar().setHomeButtonEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);

在onOptionsItemSelected（MenuItem item）方法中添加：

if (id==android.R.id.home)
        {
            NavUtils.navigateUpFromSameTask(this);
        }

Answer 2

在您的toolbar.xml中设置一个imageview。我喜欢你的toolbar.xml

 <ImageView
    android:id="@+id/tv_header_title2"
    android:layout_width="25dp"
    android:layout_height="wrap_content"
    android:layout_gravity="left"
    android:src="@drawable/backbutton"
    android:layout_marginLeft="15dp"/>

在MainActivity中

 ImageView img= (ImageView) findViewById(R.id.tv_header_title2);



and 


  img.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            finish();
        }
    });

动作栏上的后退按钮崩溃app android

2 个答案: