类不能转换为android.view.View $ OnClickListener
我在试图做G + Signin时遇到了一些问题。 我认为G +按钮不起作用。
我也试过清理这个项目。
IDE：Android Studio 1.1.0 Play服务：6.5.87
谢谢。
–
LoginActivity：
package com.nimbus.podchest; import android.os.Bundle; import android.support.v4.app.FragmentActivity; import android.view.View; import com.google.android.gms.common.ConnectionResult; import com.google.android.gms.common.SignInButton; import com.google.android.gms.common.api.GoogleApiClient; import com.google.android.gms.plus.Plus; public class LoginActivity extends FragmentActivity implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener { private GoogleApiClient mGoogleApiClient; private SignInButton SignInButton; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_login); // Create a GoogleApiClient instance mGoogleApiClient = new GoogleApiClient.Builder(this) .addApi(Plus.API) .addScope(Plus.SCOPE_PLUS_LOGIN) .addConnectionCallbacks(this) .addOnConnectionFailedListener(this) .build(); SignInButton = (SignInButton) findViewById(R.id.sign_in_button); SignInButton.setOnClickListener((android.view.View.OnClickListener) this); } public void onClick(View view) { if (view.getId() == R.id.sign_in_button) { mGoogleApiClient.connect(); } } @Override protected void onStart() { super.onStart(); mGoogleApiClient.connect(); } @Override protected void onStop() { mGoogleApiClient.disconnect(); super.onStop(); } @Override public void onConnected(Bundle connectionHint) { // Connected to Google Play services! // The good stuff goes here. } @Override public void onConnectionSuspended(int cause) { // The connection has been interrupted. // Disable any UI components that depend on Google APIs // until onConnected() is called. } @Override public void onConnectionFailed(ConnectionResult result) { // This callback is important for handling errors that // may occur while attempting to connect with Google. // // More about this in the next section. } } logcat的：
03-10 23:58:26.747 10123-10123/com.nimbus.podchest E/AndroidRuntime﹕ FATAL EXCEPTION: main Process: com.nimbus.podchest, PID: 10123 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.nimbus.podchest/com.nimbus.podchest.LoginActivity}: java.lang.ClassCastException: com.nimbus.podchest.LoginActivity cannot be cast to android.view.View$OnClickListener at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2314) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2388) at android.app.ActivityThread.access$800(ActivityThread.java:148) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5312) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:696) Caused by: java.lang.ClassCastException: com.nimbus.podchest.LoginActivity cannot be cast to android.view.View$OnClickListener at com.nimbus.podchest.LoginActivity.onCreate(LoginActivity.java:25) at android.app.Activity.performCreate(Activity.java:5953) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1128) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2267) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2388) at android.app.ActivityThread.access$800(ActivityThread.java:148) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5312) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:696) 03-11 00:00:13.565 11822-11822/com.nimbus.podchest E/AndroidRuntime﹕ FATAL EXCEPTION: main Process: com.nimbus.podchest, PID: 11822 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.nimbus.podchest/com.nimbus.podchest.LoginActivity}: java.lang.ClassCastException: com.nimbus.podchest.LoginActivity cannot be cast to android.view.View$OnClickListener at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2314) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2388) at android.app.ActivityThread.access$800(ActivityThread.java:148) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5312) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:696) Caused by: java.lang.ClassCastException: com.nimbus.podchest.LoginActivity cannot be cast to android.view.View$OnClickListener at com.nimbus.podchest.LoginActivity.onCreate(LoginActivity.java:35) at android.app.Activity.performCreate(Activity.java:5953) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1128) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2267) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2388) at android.app.ActivityThread.access$800(ActivityThread.java:148) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5312) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:696)
如果您阅读Logcat，您会发现此处有问题：
com.nimbus.podchest.LoginActivity.onCreate(LoginActivity.java:25)
因此，在onCreate函数的第25行，您正在尝试将您的活动（ LoginActivity ）转换为android.view.View$OnClickListener 。 你不能像这样投这个类，因为没有相关的。
您需要在LoginActivity类的定义上添加implements OnClickListener以使您的LoginActivity转换工作。
现在，您将能够将当前的Activity传递给注册者：
SignInButton.setOnClickListener(this);