android - Android：java.lang.RuntimeException：无法启动活动组件信息

Question

我对android还很陌生，所以如果这是一个完全的菜鸟问题，我深表歉意。我花了几个小时寻找类似的主题，但我找不到解决方案。

尝试运行应用程序时出现此错误：

> java.lang.RuntimeException: Unable to start activity
> ComponentInfo{com.avnsoft.runtracker/com.avnsoft.runtracker.RunActivity}:
> java.lang.NullPointerException

堆栈跟踪：

> AndroidRuntime(21828): FATAL EXCEPTION: main 06-07 00:35:24.792:
> E/AndroidRuntime(21828): java.lang.RuntimeException: Unable to start
> activity
> ComponentInfo{com.avnsoft.runtracker/com.avnsoft.runtracker.RunActivity}:
> java.lang.NullPointerException 06-07 00:35:24.792:
> E/AndroidRuntime(21828): at
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
> 06-07 00:35:24.792: E/AndroidRuntime(21828): at
> android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
> 06-07 00:35:24.792: E/AndroidRuntime(21828): at
> android.app.ActivityThread.access$600(ActivityThread.java:141) 06-07
> 00:35:24.792: E/AndroidRuntime(21828): at
> android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
> 06-07 00:35:24.792: E/AndroidRuntime(21828): at
> android.os.Handler.dispatchMessage(Handler.java:99) 06-07
> 00:35:24.792: E/AndroidRuntime(21828): at
> android.os.Looper.loop(Looper.java:137) 06-07 00:35:24.792:
> E/AndroidRuntime(21828): at
> android.app.ActivityThread.main(ActivityThread.java:5041) 06-07
> 00:35:24.792: E/AndroidRuntime(21828): at
> java.lang.reflect.Method.invokeNative(Native Method) 06-07
> 00:35:24.792: E/AndroidRuntime(21828): at
> java.lang.reflect.Method.invoke(Method.java:511) 06-07 00:35:24.792:
> E/AndroidRuntime(21828): at
> com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
> 06-07 00:35:24.792: E/AndroidRuntime(21828): at
> com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 06-07
> 00:35:24.792: E/AndroidRuntime(21828): at
> dalvik.system.NativeStart.main(Native Method) 06-07 00:35:24.792:
> E/AndroidRuntime(21828): Caused by: java.lang.NullPointerException
> 06-07 00:35:24.792: E/AndroidRuntime(21828): at
> android.view.ViewGroup.addViewInner(ViewGroup.java:3338) 06-07
> 00:35:24.792: E/AndroidRuntime(21828): at
> android.view.ViewGroup.addView(ViewGroup.java:3210) 06-07
> 00:35:24.792: E/AndroidRuntime(21828): at
> android.view.ViewGroup.addView(ViewGroup.java:3186) 06-07
> 00:35:24.792: E/AndroidRuntime(21828): at
> com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:289)
> 06-07 00:35:24.792: E/AndroidRuntime(21828): at
> com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:279)
> 06-07 00:35:24.792: E/AndroidRuntime(21828): at
> android.app.Activity.setContentView(Activity.java:1901) 06-07
> 00:35:24.792: E/AndroidRuntime(21828): at
> com.avnsoft.runtracker.SingleFragmentActivity.onCreate(SingleFragmentActivity.java:21)
> 06-07 00:35:24.792: E/AndroidRuntime(21828): at
> com.avnsoft.runtracker.RunActivity.onCreate(RunActivity.java:11) 06-07
> 00:35:24.792: E/AndroidRuntime(21828): at
> android.app.Activity.performCreate(Activity.java:5104) 06-07
> 00:35:24.792: E/AndroidRuntime(21828): at
> android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
> 06-07 00:35:24.792: E/AndroidRuntime(21828): at
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
> 06-07 00:35:24.792: E/AndroidRuntime(21828): ... 11 more

活动片段.xml：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/fragmentContainer"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  />

活动运行.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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".RunActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

</RelativeLayout>

片段运行.xml：

<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    >
    <TableRow>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="right"
            android:paddingRight="5sp"
            android:text="@string/started"
            />
        <TextView android:id="@+id/run_startedTextView"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            />
    </TableRow>
    <TableRow>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="right"
            android:paddingRight="5sp"
            android:text="@string/latitude"
            />
        <TextView android:id="@+id/run_latitudeTextView"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            />
    </TableRow>
    <TableRow>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="right"
            android:paddingRight="5sp"
            android:text="@string/longitude"
            />
        <TextView android:id="@+id/run_longitudeTextView"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            />
    </TableRow>
    <TableRow>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="right"
            android:paddingRight="5sp"
            android:text="@string/altitude"
            />
        <TextView android:id="@+id/run_altitudeTextView"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            />
    </TableRow>
    <TableRow>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="right"
            android:paddingRight="5sp"
            android:text="@string/elapsed_time"
            />
        <TextView android:id="@+id/run_durationTextView"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:textSize="25sp"
            />
    </TableRow>
    <LinearLayout
        android:orientation="horizontal"
        android:layout_height="wrap_content"
        >
        <Button android:id="@+id/run_startButton"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/start"
            />
        <Button android:id="@+id/run_stopButton"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/stop"
            />
    </LinearLayout>
</TableLayout>

SingleFragmentActivity.java：

package com.avnsoft.runtracker;


import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.widget.FrameLayout;

public abstract class SingleFragmentActivity extends FragmentActivity {
    protected static final String FRAGMENT_TAG = "SingleFragmentActivity.Fragment";

    protected abstract Fragment createFragment();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        FrameLayout fl = new FrameLayout(this);
        fl.setId(R.id.fragmentContainer);
        setContentView(fl);

        FragmentManager manager = getSupportFragmentManager();
        Fragment fragment = manager.findFragmentById(R.id.fragmentContainer);

        if (fragment == null) {
            fragment = createFragment();
            manager.beginTransaction()
                .add(R.id.fragmentContainer, fragment)
                .commit();
        }
    }
}

运行活动.java：

package com.avnsoft.runtracker;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.Menu;

public class RunActivity extends SingleFragmentActivity {

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

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

    @Override
    protected Fragment createFragment() {
        return new RunFragment();
    }

}

最后是 RunFragment.java：

package com.avnsoft.runtracker;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

public class RunFragment extends Fragment {

    private Button mStartButton, mStopButton;
    private TextView mStartedTextView,
    mLatitudeTextView,
    mLongitudeTextView,
    mAltitudetextView,
    mDurationTextView;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setRetainInstance(true);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
    //Create View   
    View view = inflater.inflate(R.layout.fragment_run, container, false);

    //Assign widgets
    mStartedTextView = (TextView)view.findViewById(R.id.run_startedTextView);
    mLatitudeTextView = (TextView)view.findViewById(R.id.run_latitudeTextView);
    mLongitudeTextView = (TextView)view.findViewById(R.id.run_longitudeTextView);
    mAltitudetextView = (TextView)view.findViewById(R.id.run_altitudeTextView);
    mDurationTextView = (TextView)view.findViewById(R.id.run_durationTextView);

    mStartButton = (Button)view.findViewById(R.id.run_startButton);
    mStopButton = (Button)view.findViewById(R.id.run_stopButton);

    return view;

    }

}

我为过多的代码道歉，但在花了 4 个小时试图找到问题后，我不知道它在哪里......有人可以帮忙吗？谢谢！

score 0 · Accepted Answer

我认为NPE是由这个引起的：

FrameLayout fl = new FrameLayout(this);

Android 期望一个 Context 的引用，你只能在调用 onCreate 之后获得它。

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_fragment);
    ...

android - Android：java.lang.RuntimeException：无法启动活动组件信息

1 回答 1

Related

Reference