Android应用程序崩溃按钮单击

时间：2016-03-01 15:10:06

标签： java android xml button logcat

我正在构建一个应用程序，然后在按钮上单击应用程序崩溃。该应用程序在一周前完美运行，自上次测试以来，代码一直没有改变。现在，当我单击Login in按钮时，它会崩溃。这没有任何意义，因为它没有被编辑。源代码如下。

Login.java 

package com.example.martin.ivebeenthere;

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;

public class Login extends AppCompatActivity {

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

    public void onClickbtnFeed(View view)
    {
        startActivity(new Intent(Login.this, Feed.class));
    }

}

content_login.xml 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.example.martin.ivebeenthere.Login"
    tools:showIn="@layout/activity_login">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imageView"
        android:src="@drawable/logo"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginBottom="276dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:ems="10"
        android:hint="Username"
        android:id="@+id/editText"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPassword"
        android:ems="10"
        android:hint="Password"
        android:id="@+id/editText2"
        android:layout_below="@+id/editText"
        android:layout_centerHorizontal="true" />

    <Button
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:text="Login"
        android:id="@+id/button3"
        android:layout_below="@+id/editText2"
        android:layout_centerHorizontal="true"
        android:onClick="onClickbtnFeed"/>

    <Button
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:text="Login With Facebook"
        android:id="@+id/button4"
        android:background="#3b5998"
        android:textColor="#ffffff"
        android:layout_below="@+id/button3"
        android:layout_alignLeft="@+id/button3"
        android:layout_alignStart="@+id/button3"
        android:layout_marginTop="25dp" />

</RelativeLayout>

Feed.java（与按钮链接的页面） 

package com.example.martin.ivebeenthere;

import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
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.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

public class Feed extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

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

        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);

        String[] users = {"\nMartin Hoban\n\nVisited Dublin 2 Hours Ago\n","\nJack White\n\nVisited Mayo 10 Hours Ago\n","\nSarah Cox\n\nVisited Cork 1 Day Ago\n","\nMalcolm Holmes\n\nVisited Knock 2 Days Ago\n", "\nCraig Fisher\n\nVisited The Spire 2 Days Ago\n", "\nHannah Smith\n\nVisited Mayo 3 Days Ago\n"
        ,"\nLanelle Delaune\n\nVisited Limerick 1 Week Ago\n", "\nHanna Whitlow\n\nVisited Paris 1 Week Ago\n", "\nMoses Primm\n\nVisited Italy 3 Weeks Ago\n", "\nBerta Pedraza\n\nVisited The Aillwee Caves 1 Month Ago\n"};
        ArrayAdapter<String> itemsAdapter =
                new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, users);
        ListView listView = (ListView) findViewById(R.id.listView);
        listView.setAdapter(itemsAdapter);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {
                if (position == 4) {

                    Intent myIntent = new Intent(view.getContext(), CheckinInfo.class);
                    startActivityForResult(myIntent, 0);
                }
            }
        });
    }

    @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.feed, menu);
        return true;
    }

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

        if (id == R.id.nav_feed) {
            startActivity(new Intent(getApplicationContext(), Feed.class));
        } else if (id == R.id.nav_map) {
            startActivity(new Intent(getApplicationContext(), Map.class));
        } else if (id == R.id.nav_account) {
            startActivity(new Intent(getApplicationContext(), Account.class));
        } else if (id == R.id.nav_logout) {
            startActivity(new Intent(getApplicationContext(), Home.class));
            Toast.makeText(getApplicationContext(), "Logged Out",
                    Toast.LENGTH_LONG).show();
        }

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

logcat的 

Caused by: java.lang.NullPointerException
at com.example.martin.ivebeenthere.Feed.onCreate(Feed.java:38)
at android.app.Activity.performCreate(Activity.java:5047)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2056)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2117) 
at android.app.ActivityThread.access$700(ActivityThread.java:134) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1218) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:137) 
at android.app.ActivityThread.main(ActivityThread.java:4867) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:511) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774) 
at dalvik.system.NativeStart.main(Native Method)

activity_feed.xml 

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <include
        layout="@layout/app_bar_feed"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</android.support.v4.widget.DrawerLayout>

app_bar_feed.xml 

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.example.martin.ivebeenthere.Feed">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_feed" />

</android.support.design.widget.CoordinatorLayout>

在activity_feed.xml的设计视图中呈现问题 

java.lang.IllegalArgumentException: No drawer view found with gravity LEFT
    at android.support.v4.widget.DrawerLayout.openDrawer(DrawerLayout.java:1464)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at com.android.layoutlib.bridge.util.ReflectionUtils.invoke(ReflectionUtils.java:45)
    at com.android.layoutlib.bridge.android.support.DrawerLayoutUtil.openDrawer(DrawerLayoutUtil.java:56)
    at com.android.layoutlib.bridge.android.support.DrawerLayoutUtil.openDrawer(DrawerLayoutUtil.java:50)
    at android.view.BridgeInflater.postInflateProcess(BridgeInflater.java:361)
    at com.android.layoutlib.bridge.impl.RenderSessionImpl.postInflateProcess(RenderSessionImpl.java:968)
    at com.android.layoutlib.bridge.impl.RenderSessionImpl.postInflateProcess(RenderSessionImpl.java:973)
    at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:235)
    at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:426)
    at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:350)
    at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:510)
    at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:498)
    at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:888)
    at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:498)
    at com.android.tools.idea.rendering.RenderTask.access$600(RenderTask.java:72)
    at com.android.tools.idea.rendering.RenderTask$3.call(RenderTask.java:610)
    at com.android.tools.idea.rendering.RenderTask$3.call(RenderTask.java:607)
    at com.android.tools.idea.rendering.RenderService.runRenderAction(RenderService.java:362)
    at com.android.tools.idea.rendering.RenderTask.render(RenderTask.java:607)
    at com.android.tools.idea.rendering.RenderTask.render(RenderTask.java:629)
    at com.intellij.android.designer.designSurface.AndroidDesignerEditorPanel$6.run(AndroidDesignerEditorPanel.java:480)
    at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:320)
    at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:310)
    at com.intellij.util.ui.update.MergingUpdateQueue$2.run(MergingUpdateQueue.java:254)
    at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:269)
    at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:227)
    at com.intellij.util.ui.update.MergingUpdateQueue.run(MergingUpdateQueue.java:217)
    at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:238)
    at com.intellij.util.Alarm$Request$1.run(Alarm.java:351)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

2 个答案:

答案 0 :(得分：0)

我认为无法找到引用的维度资源。

原因可能是，您只为特定屏幕尺寸指定了尺寸。

your content.xml：

android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"

在values-820dp / dimens.xml中定义它们或在content.xml中定义它们 你也可以删除它们。

答案 1 :(得分：0)

局部变量navigationView为空。这意味着您的nav_view布局中没有ID为activity_feed的视图。请务必将findViewById() onCreate()中尝试查找的所有视图都包含在布局中。

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