问题
Actually, I am trying to make an app with free and paid flavors. When I use simple findViewById method to bind then it works fine. But when I trying to add butterKnife, I desperately stuck with butterKnife.
I am trying to bind content (such as AdMob OR Button) by butterknife bind in MainActivity.java file. but it shows Nullpointer exception error first it shows on AdMob object nullpointer exception. I run clean project then it shows on button.onClickListener Nullpointer exception.
Please help me...
Here is the Error: which shows AdMob nullpointerException:
09-08 19:04:30.860 19466-19466/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.santossingh.jokeapp.free, PID: 19466
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.santossingh.jokeapp.free/com.santossingh.jokeapp.free.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.ads.AdView.loadAd(com.google.android.gms.ads.AdRequest)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.ads.AdView.loadAd(com.google.android.gms.ads.AdRequest)' on a null object reference
at com.santossingh.jokeapp.free.MainActivity.onCreate(MainActivity.java:62)
at android.app.Activity.performCreate(Activity.java:6237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
09-08 19:04:35.652 837-2192/system_process E/Surface: getSlotFromBufferLocked: unknown buffer: 0xf2cf6c90
09-08 19:04:56.030 837-853/system_process E/BluetoothAdapter: Bluetooth binder is null
09-08 19:06:20.986 837-853/system_process E/BluetoothAdapter: Bluetooth binder is null
09-08 19:07:41.011 837-853/system_process E/BluetoothAdapter: Bluetooth binder is null
09-08 19:09:01.042 837-853/system_process E/BluetoothAdapter: Bluetooth binder is null
09-08 19:10:20.982 837-853/system_process E/BluetoothAdapter: Bluetooth binder is null
09-08 19:11:46.019 837-853/system_process E/BluetoothAdapter: Bluetooth binder is null
09-08 19:13:06.051 837-853/system_process E/BluetoothAdapter: Bluetooth binder is null
09-08 19:14:41.018 837-853/system_process E/BluetoothAdapter: Bluetooth binder is null
09-08 19:16:06.047 837-853/system_process E/BluetoothAdapter: Bluetooth binder is null
2-MainActivity.java
public class MainActivity extends AppCompatActivity implements AsyncResponse{
@BindView(R.id.avi) AVLoadingIndicatorView avLoadingIndicatorView;
@BindView(R.id.button_jokeTeller) Button button_JokeTeller;
@BindView(R.id.instruction_TextView)
TextView instruction;
@BindView(R.id.container) RelativeLayout relativeLayout;
@BindView(R.id.adView) AdView adView;
@BindView(R.id.progressBar) LinearLayout linearLayout;
private InterstitialAd mInterstitialAd;
EndpointsAsyncTask endpointsAsyncTask;
private static final String JOKE_TAG="joke";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ButterKnife.bind(this);
endpointsAsyncTask = new EndpointsAsyncTask(this);
AdRequest adRequestBanner = new AdRequest.Builder().build();
adView.loadAd(adRequestBanner);
mInterstitialAd = new InterstitialAd(this);
mInterstitialAd.setAdUnitId(getString(R.string.interstitial_ad_unit_id));
AdRequest adRequestInterstitial = new AdRequest.Builder().build();
mInterstitialAd.loadAd(adRequestInterstitial);
button_JokeTeller.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
showInterstitial();
}
});
mInterstitialAd.setAdListener(new AdListener() {
@Override
public void onAdClosed() {
showProgressbar(true);
showJoke();
}
@Override
public void onAdFailedToLoad(int errorCode) {
Toast.makeText(getApplicationContext(), "Ad failed to load! error code: " + errorCode, Toast.LENGTH_SHORT).show();
}
@Override
public void onAdLeftApplication() {
showProgressbar(true);
Toast.makeText(getApplicationContext(), "Ad left application!", Toast.LENGTH_SHORT).show();
}
@Override
public void onAdOpened() {
Toast.makeText(getApplicationContext(), "Ad is opened!", Toast.LENGTH_SHORT).show();
}
});
}
private void showInterstitial() {
if (mInterstitialAd.isLoaded()) {
mInterstitialAd.show();
}
}
public void showJoke(){
endpointsAsyncTask.execute(getString(R.string.keyword));
}
@Override
public void processFinish(String result) {
Intent intent = new Intent(this, JokeActivity
.class)
.putExtra(JOKE_TAG, result);
showProgressbar(false);
startActivity(intent);
}
public void showProgressbar(boolean a){
if(a==true){
relativeLayout.setVisibility(View.GONE);
linearLayout.setVisibility(View.VISIBLE);
}else{
linearLayout.setVisibility(View.GONE);
relativeLayout.setVisibility(View.VISIBLE);
}
}
}
3- activity_main.xml file
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
android:id="@+id/activity_main"
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:background="#0e73a6"
android:padding="10dp"
tools:context="com.santossingh.jokeapp.free.MainActivity"
xmlns:ads="http://schemas.android.com/apk/res-auto"
xmlns:app="http://schemas.android.com/apk/res-auto">
<LinearLayout
android:id="@+id/progressBar"
android:layout_width="match_parent"
android:gravity="center"
android:layout_height="match_parent">
<com.wang.avi.AVLoadingIndicatorView
android:id="@+id/avi"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="@style/AVLoadingIndicatorView"
android:visibility="visible"
app:indicatorName="BallPulseIndicator"
/>
</LinearLayout>
<RelativeLayout android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/container">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/instructions"
android:textColor="#fff"
android:id="@+id/instruction_TextView"
/>
<Button android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/button_jokeTeller"
android:layout_below="@+id/instruction_TextView"
android:text="@string/button_text"
/>
<!-- view for AdMob Banner Ad -->
<com.google.android.gms.ads.AdView
android:id="@+id/adView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
ads:adSize="BANNER"
ads:adUnitId="@string/banner_ad_unit_id"/>
</RelativeLayout>
</RelativeLayout>
4- manifest file
<manifest xmlns:android="http://schemas.android.com/apk/res/android">
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<application>
<activity android:name="com.santossingh.jokeapp.free.MainActivity"
>
<!-- This meta-data tag is required to use Google Play Services. -->
<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version"/>
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>
<activity
android:name="com.google.android.gms.ads.AdActivity"
android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize"
android:theme="@android:style/Theme.Translucent"/>
</manifest>
回答1:
you are missing
adView = (AdView)this.findViewById(R.id.adView);
Change code as below
AdRequest adRequestBanner = new AdRequest.Builder().build();
**adView = (AdView)this.findViewById(R.id.adView);**
adView.loadAd(adRequestBanner);
Update dependency for
dependencies { compile 'com.jakewharton:butterknife:8.0.1' apt 'com.jakewharton:butterknife-compiler:8.0.1' }
回答2:
make sure to add the three adMob lines only AFTER the setContentView command
otherwise - this command will return a null value :
mAdView = **findViewById(R.id.adView);**
Example for the correct command sequence:
setContentView(R.layout.activity_item_list); // <== make asure this comes **BEFORE** the Admob mAdView commands
mAdView = findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder().build();
mAdView.loadAd(adRequest);
回答3:
The Right answer for it is that I used gradle 2.2.0 or newer version. So thanks for JakeWarton github link [https://github.com/JakeWharton/butterknife]which clearly describe the integration of Butterknife with new version of gradle. As a result the implementation of butterKnife in newer version of gradle step by step as follows :
1- Firstly, Add classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8' dependencies:
dependencies {
....
classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'
}
2- Secondly, add in build.gradle app module butterKnife
dependencies {
....
compile 'com.jakewharton:butterknife:8.4.0'
annotationProcessor 'com.jakewharton:butterknife-compiler:8.4.0'
}
So over all conclusion is that when we used gradle 2.2.0 or newer version then we need to add above changes. That's it, so easy... :)
回答4:
I faced similar issue. When I checked closely in resource file There were two resource file for my activity:
\res\layout\activity_main_lauch.xml
\res\layout-v21\activity_main_lauch.xml
I was modifying single file, hence it was throwing error. When I apply the change in both files it started working.
回答5:
AdView adView = findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder().build();
adView.loadAd(adRequest);
set this code after a few lines of code, sometimes it takes time to load ads and Adview. So add this codes after a few lines of code to get result and try to run again.
来源：https://stackoverflow.com/questions/39401662/how-to-solve-nullpointerexception-void-com-google-android-gms-ads-adview-loadad