Java 我的应用程序在单击任何活动后崩溃

Logcat

package com.digitalhuntapps.yogasan;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import androidx.appcompat.widget.Toolbar;
import android.view.MenuItem;
import android.widget.LinearLayout;

import com.facebook.ads.AdSize;
import com.facebook.ads.AdView;

public class neti extends AppCompatActivity {
private AdView adView;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.neti);
    adView = new AdView(this, getResources().getString(R.string.Banner), AdSize.BANNER_HEIGHT_50);

    // Find the Ad Container
    LinearLayout adContainer = (LinearLayout) findViewById(R.id.banner_container);

    // Add the ad view to your activity layout
    adContainer.addView(adView);

    // Request an ad
    adView.loadAd();
    setToolbar();
}
private void setToolbar() {
    Toolbar toolbar = findViewById(R.id.toolbar);
    toolbar.setTitle("Yogasan");
    setSupportActionBar(toolbar);
    androidx.appcompat.app.ActionBar actionbar = getSupportActionBar();
    actionbar.setDisplayHomeAsUpEnabled(true); }

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    onBackPressed();
    return true;
}
}

---

答案在日志中：

2020-06-19 12:02:21.792 27656-27750/com.digitalhuntapps.yogasan V/FA: Inactivity, disconnecting from the service
2020-06-19 12:02:42.371 27656-27656/com.digitalhuntapps.yogasan W/Settings: Setting device_provisioned has moved from android.provider.Settings.Secure to android.provider.Settings.Global.
2020-06-19 12:02:42.371 27656-27656/com.digitalhuntapps.yogasan V/HiTouch_HiTouchSensor: User setup is finished.
2020-06-19 12:02:42.498 27656-27656/com.digitalhuntapps.yogasan V/AudioManager: querySoundEffectsEnabled...
2020-06-19 12:02:42.502 27656-27656/com.digitalhuntapps.yogasan E/Value of ex: x= com.digitalhuntapps.yogasan.neti
2020-06-19 12:02:42.528 27656-27656/com.digitalhuntapps.yogasan I/FIAM.Headless: Removing display event listener
2020-06-19 12:02:42.531 27656-27750/com.digitalhuntapps.yogasan V/FA: Recording user engagement, ms: 25806
2020-06-19 12:02:42.533 27656-27750/com.digitalhuntapps.yogasan V/FA: Connecting to remote service
2020-06-19 12:02:42.541 27656-27656/com.digitalhuntapps.yogasan W/ActivityThread: handleWindowVisibility: no activity for token android.os.BinderProxy@4f86b08
2020-06-19 12:02:42.549 27656-27750/com.digitalhuntapps.yogasan V/FA: Activity paused, time: 1154190741
2020-06-19 12:02:42.550 27656-27656/com.digitalhuntapps.yogasan V/ActivityThread: callActivityOnCreate
2020-06-19 12:02:42.552 27656-27656/com.digitalhuntapps.yogasan V/FA: onActivityCreated
2020-06-19 12:02:42.568 27656-27750/com.digitalhuntapps.yogasan D/FA: Logging event (FE): user_engagement(_e), Bundle[{ga_event_origin(_o)=auto, engagement_time_msec(_et)=25806, ga_screen_class(_sc)=MainActivity, ga_screen_id(_si)=1695052977539026206}]
2020-06-19 12:02:42.588 27656-27750/com.digitalhuntapps.yogasan V/FA: Connection attempt already in progress
2020-06-19 12:02:42.657 27656-27656/com.digitalhuntapps.yogasan D/AndroidRuntime: Shutting down VM
2020-06-19 12:02:42.658 27656-27656/com.digitalhuntapps.yogasan I/QarthLog: [PatchStore] createDisableExceptionQarthFile
2020-06-19 12:02:42.658 27656-27656/com.digitalhuntapps.yogasan I/QarthLog: [PatchStore] create disable file for com.digitalhuntapps.yogasan uid is 10366
2020-06-19 12:02:42.660 27656-27656/com.digitalhuntapps.yogasan E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.digitalhuntapps.yogasan, PID: 27656
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.digitalhuntapps.yogasan/com.digitalhuntapps.yogasan.neti}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.LinearLayout.addView(android.view.View)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3782)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3961)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:91)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:149)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:103)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2386)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:213)
        at android.app.ActivityThread.main(ActivityThread.java:8178)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1101)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.LinearLayout.addView(android.view.View)' on a null object reference
        at com.digitalhuntapps.yogasan.neti.onCreate(:24)
        at android.app.Activity.performCreate(Activity.java:8086)
        at android.app.Activity.performCreate(Activity.java:8074)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1313)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3755)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3961) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:91) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:149) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:103) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2386) 
        at android.os.Handler.dispatchMessage(Handler.java:107) 
        at android.os.Looper.loop(Looper.java:213) 
        at android.app.ActivityThread.main(ActivityThread.java:8178) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1101) 
2020-06-19 12:02:42.678 27656-27656/com.digitalhuntapps.yogasan I/Process: Sending signal. PID: 27656 SIG: 9

---

findviewbyid返回null，这意味着它找不到您的横幅容器

包含此活动的设计

neti.xml

文件，以便我们可以看到问题所在。问题似乎出在

banner\u容器上

，它显然没有被充气

---

PS：请对类使用基于驼峰大小写的命名方案，例如，将该类从

neti

重命名为

neti

或

NetiActivity

（这更好）。

检查您的R.layout.neti文件中是否存在横幅容器。

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.digitalhuntapps.yogasan/com.digitalhuntapps.yogasan.neti}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.LinearLayout.addView(android.view.View)' on a null object reference