意图崩溃。安卓工作室

Question

我只想问你，为什么使用 Intent 会导致我的应用崩溃？我以前使用过相同的代码并且它可以工作，现在当我再次使用它时它就不行了。你觉得这段代码有什么问题。我什么也没找到。

MainActivity JAVA

public class MainActivity extends ActionBarActivity {

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

public void okay(View view) {
    Intent i = new Intent(this, Login.class);
    startActivity(i);

登录 JAVA（如果我调用它的 id，我只想弹出这个活动）

public class Login extends ActionBarActivity {
ListView listView;
ArrayAdapter<String> adapter;
String[] grocery_categories = {"Beverages", "Bakery", "Canned Goods", "Condiments", "Dairy", "Snacks", "Frozen Foods",
                                "Meat", "Produce", "Cleaners", "Paper Goods", "Personal Care", "Others"};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);
    listView = (ListView) findViewById(R.id.list_view);
    adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, grocery_categories);
    listView.setAdapter(adapter);
    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> listView, View view, int position, long id) {
            String grocery = (String) listView.getAdapter().getItem(position);
            Intent intent = new Intent(listView.getContext(),Login.class);
            listView.getContext().startActivity(intent);
            //or create other intents here
        }
    });

}

MainActivity.XML

<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"  tools:context=".MainActivity"
android:id="@+id/rl_main_activity">

<ImageView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/mobile_grocery_bckgrnd"
    android:src="@drawable/mobile_grocery"
    android:scaleType="centerCrop"
    />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="MOBILE GROCERY"
    android:id="@+id/mobile_grocery_app"
    android:textSize="45dp"
    android:textColor="#000000"
    android:gravity="center"

    android:textStyle="bold|italic"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Application"
    android:id="@+id/application"
    android:textColor="#000000"
    android:textSize="25dp"
    android:layout_below="@+id/mobile_grocery_app"
    android:layout_centerHorizontal="true" />

<EditText
    android:layout_width="200dp"
    android:layout_height="wrap_content"
    android:id="@+id/username"
    android:layout_alignParentBottom="true"
    android:layout_alignRight="@+id/application"
    android:layout_alignEnd="@+id/application"
    android:layout_marginBottom="135dp"
    android:hint="Username"
    android:textColorHint="#000000"
    />

<EditText
    android:layout_width="200dp"
    android:layout_height="wrap_content"
    android:id="@+id/password"
    android:layout_alignTop="@+id/username"
    android:layout_alignRight="@+id/username"
    android:layout_alignEnd="@+id/username"
    android:layout_marginTop="52dp"
    android:hint="Password"
    android:textColorHint="#000000"
    android:password="true" />

<Button
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="OK"
    android:id="@+id/ok"
    android:layout_below="@+id/password"
    android:layout_alignLeft="@+id/application"
    android:layout_alignStart="@+id/application"
    android:onClick="okay" />

登录.XML

<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"
tools:context="com.example.admin.mobilegroceryapp.Login"
android:id="@+id/rl_login">

<ImageView
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/login_bckgrnd"
    android:src="@drawable/login_bckgrnd"
    android:scaleType="centerCrop"
    />

<ListView
    android:id="@+id/list_view"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">



</ListView>

清单

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".Login"
            android:label="@string/title_activity_login" >
        </activity>
    </application>

</manifest>

LOGCAT

9-29 02:17:52.595    2019-2074/? D/BatteryService﹕ level:34 scale:100 status:2 health:2 present:true voltage: 3918 temperature: 350 technology: Li-ion  

AC powered:false USB powered:true icon:17303267 invalid charger:0 online:1 charge type:0 current avg:1
09-29 02:17:52.610    2140-2140/? D/STATUSBAR-BatteryController﹕ onReceive() - ACTION_BATTERY_CHANGED
09-29 02:17:52.610    2140-2140/? D/STATUSBAR-BatteryController﹕ onReceive() - level:34
09-29 02:17:52.610    2140-2140/? D/STATUSBAR-BatteryController﹕ onReceive() - plugged:2
09-29 02:17:52.615    2140-2140/? D/STATUSBAR-BatteryController﹕ onReceive() - BATTERY_STATUS_CHARGING:
09-29 02:17:52.625    2019-2074/? D/BatteryService﹕ turn on LED for charging
09-29 02:17:52.635    2140-2140/? D/STATUSBAR-PhoneStatusBar﹕ ACTION_BATTERY_CHANGED
09-29 02:17:52.650    2140-2140/? D/STATUSBAR-PhoneStatusBar﹕ NORMAL_BATTERY
09-29 02:17:52.670    1381-1381/? E/MtpService﹕ In MTPAPP onReceive:android.intent.action.BATTERY_CHANGED
09-29 02:17:52.670    1381-1381/? E/MtpService﹕ battPlugged Type : 2
09-29 02:17:53.405    2019-2078/? V/AlarmManager﹕ waitForAlarm result :2
09-29 02:17:53.540    5709-5709/? D/InCarWidget:main﹕ VLG_updateAllWidgets false
09-29 02:17:53.540    5709-5709/? D/InCarWidget:main﹕ VLG_buildWidgetView enabled=false
09-29 02:17:53.555    2019-2031/? W/AlarmManager﹕ FACTORY_ON= 0
09-29 02:17:56.555    2019-2078/? V/AlarmManager﹕ waitForAlarm result :2
09-29 02:17:56.690    5709-5709/? D/InCarWidget:main﹕ VLG_updateAllWidgets false
09-29 02:17:56.690    5709-5709/? D/InCarWidget:main﹕ VLG_buildWidgetView enabled=false
09-29 02:17:56.695    2019-5434/? W/AlarmManager﹕ FACTORY_ON= 0
09-29 02:17:59.690    2019-2078/? V/AlarmManager﹕ waitForAlarm result :2
09-29 02:17:59.800    5709-5709/? D/InCarWidget:main﹕ VLG_updateAllWidgets false
09-29 02:17:59.800    5709-5709/? D/InCarWidget:main﹕ VLG_buildWidgetView enabled=false
09-29 02:17:59.805    2019-2019/? W/AlarmManager﹕ FACTORY_ON= 0
09-29 02:18:00.000    2019-2078/? V/AlarmManager﹕ waitForAlarm result :8
09-29 02:18:00.010    2019-2062/? V/AlarmManager﹕ ClockReceiver onReceive() ACTION_TIME_TICK
09-29 02:18:00.010    2019-2062/? W/AlarmManager﹕ FACTORY_ON= 0
09-29 02:18:00.055    2140-2140/? D/STATUSBAR-Clock﹕ onReceive() - ACTION_TIME_TICK
09-29 02:18:00.080    2140-2140/? D/STATUSBAR-Clock﹕ onReceive() - ACTION_TIME_TICK
09-29 02:18:00.100    2140-2140/? D/TextLayoutCache﹕ Cache value 0x5ea48dc0 deleted, size = 144
09-29 02:18:00.160  30579-30579/? D/Launcher﹕ onTrimMemory. Level: 80
09-29 02:18:00.160  30579-30579/? D/Launcher﹕ releaseShadows called
09-29 02:18:00.165  30579-30579/? W/ManagedEGLContext﹕ doTerminate failed: EGL count is 2 but managed count is 1
09-29 02:18:02.810    2019-2078/? V/AlarmManager﹕ waitForAlarm result :2
09-29 02:18:02.940    5709-5709/? D/InCarWidget:main﹕ VLG_updateAllWidgets false
09-29 02:18:02.945    5709-5709/? D/InCarWidget:main﹕ VLG_buildWidgetView enabled=false
09-29 02:18:02.955    2019-2031/? W/AlarmManager﹕ FACTORY_ON= 0
09-29 02:18:05.960    2019-2078/? V/AlarmManager﹕ waitForAlarm result :2
09-29 02:18:06.090    5709-5709/? D/InCarWidget:main﹕ VLG_updateAllWidgets false
09-29 02:18:06.090    5709-5709/? D/InCarWidget:main﹕ VLG_buildWidgetView enabled=false
09-29 02:18:06.095    2019-5434/? W/AlarmManager﹕ FACTORY_ON= 0
09-29 02:18:07.135    2019-2210/? E/Watchdog﹕ !@Sync 6737
09-29 02:18:09.095    2019-2078/? V/AlarmManager﹕ waitForAlarm result :2
09-29 02:18:09.200    5709-5709/? D/InCarWidget:main﹕ VLG_updateAllWidgets false
09-29 02:18:09.200    5709-5709/? D/InCarWidget:main﹕ VLG_buildWidgetView enabled=false
09-29 02:18:09.205    2019-2019/? W/AlarmManager﹕ FACTORY_ON= 0

希望有人可以帮助我

Answer 1

您提供的 Logcat 对查找确切的错误没有帮助。但是，将您的 okay 方法更改为此。

    public void okay(View view) {
    Intent i = new Intent(MainActivity.this, Login.class);
    startActivity(i);

this 指的是onClick，所以，改成MainActivity.this。

为什么要在 onClick 上再次启动相同的活动？

listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> listView, View view, int position, long id) {
            String grocery = (String) listView.getAdapter().getItem(position);
            Intent intent = new Intent(listView.getContext(),Login.class);
            listView.getContext().startActivity(intent);

        }
    });