我目前正在使用API Facebook，我尝试将一个美味的应用程序部分添加到我的应用程序中。
美味的部分：
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import android.content.Intent;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.Signature;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.util.Base64;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import com.facebook.AppEventsLogger;
import com.facebook.Session;
import com.facebook.SessionState;
import com.facebook.UiLifecycleHelper;
import com.google.android.gms.maps.SupportMapFragment;
public class MainActivity2 extends FragmentActivity {
private static final String USER_SKIPPED_LOGIN_KEY = "user_skipped_login";
private static final int SPLASH = 0;
private static final int SELECTION = 1;
private static final int SETTINGS = 2;
private static final int FRAGMENT_COUNT = SETTINGS +1;
private Fragment[] fragments = new Fragment[FRAGMENT_COUNT];
private MenuItem settings;
private boolean isResumed = false;
private boolean userSkippedLogin = false;
private UiLifecycleHelper uiHelper;
private Session.StatusCallback callback = new Session.StatusCallback() {
@Override
public void call(Session session, SessionState state, Exception exception) {
onSessionStateChange(session, state, exception);
}
};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try {
PackageInfo info = getPackageManager().getPackageInfo(
"info.androidhive.tabsswipe",
PackageManager.GET_SIGNATURES);
for (Signature signature : info.signatures) {
MessageDigest md = MessageDigest.getInstance("SHA");
md.update(signature.toByteArray());
Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT));
}
} catch (NameNotFoundException e) {
} catch (NoSuchAlgorithmException e) {
}
if (savedInstanceState != null) {
userSkippedLogin = savedInstanceState.getBoolean(USER_SKIPPED_LOGIN_KEY);
}
uiHelper = new UiLifecycleHelper(this, callback);
uiHelper.onCreate(savedInstanceState);
setContentView(R.layout.main);
FragmentManager fm = getSupportFragmentManager();
SplashFragment splashFragment = (SplashFragment) fm.findFragmentById(R.id.splashFragment);
fragments[SPLASH] = splashFragment;
fragments[SETTINGS] = fm.findFragmentById(R.id.userSettingsFragment);
SupportMapFragment test = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.mainActivity2);
fragments[SELECTION] = test;
FragmentTransaction transaction = fm.beginTransaction();
for(int i = 0; i < fragments.length; i++) {
transaction.hide(fragments[i]);
}
transaction.commit();
splashFragment.setSkipLoginCallback(new SplashFragment.SkipLoginCallback() {
@Override
public void onSkipLoginPressed() {
userSkippedLogin = true;
showFragment(SELECTION, false);
}
});
}
@Override
public void onResume() {
super.onResume();
uiHelper.onResume();
isResumed = true;
// Call the 'activateApp' method to log an app event for use in analytics and advertising reporting. Do so in
// the onResume methods of the primary Activities that an app may be launched into.
AppEventsLogger.activateApp(this);
}
@Override
public void onPause() {
super.onPause();
uiHelper.onPause();
isResumed = false;
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
uiHelper.onActivityResult(requestCode, resultCode, data);
}
@Override
public void onDestroy() {
super.onDestroy();
uiHelper.onDestroy();
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
uiHelper.onSaveInstanceState(outState);
outState.putBoolean(USER_SKIPPED_LOGIN_KEY, userSkippedLogin);
}
@Override
protected void onResumeFragments() {
super.onResumeFragments();
Session session = Session.getActiveSession();
if (session != null && session.isOpened()) {
// if the session is already open, try to show the selection fragment
showFragment(SELECTION, false);
userSkippedLogin = false;
} else if (userSkippedLogin) {
showFragment(SELECTION, false);
} else {
// otherwise present the splash screen and ask the user to login, unless the user explicitly skipped.
showFragment(SPLASH, false);
}
}
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// only add the menu when the selection fragment is showing
if (fragments[SELECTION].isVisible()) {
if (menu.size() == 0) {
settings = menu.add(R.string.settings);
}
return true;
} else {
menu.clear();
settings = null;
}
return false;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.equals(settings)) {
showSettingsFragment();
return true;
}
return false;
}
public void showSettingsFragment() {
showFragment(SETTINGS, true);
}
private void onSessionStateChange(Session session, SessionState state, Exception exception) {
if (isResumed) {
FragmentManager manager = getSupportFragmentManager();
int backStackSize = manager.getBackStackEntryCount();
for (int i = 0; i < backStackSize; i++) {
manager.popBackStack();
}
// check for the OPENED state instead of session.isOpened() since for the
// OPENED_TOKEN_UPDATED state, the selection fragment should already be showing.
if (state.equals(SessionState.OPENED)) {
showFragment(SELECTION, false);
} else if (state.isClosed()) {
showFragment(SPLASH, false);
}
}
}
private void showFragment(int fragmentIndex, boolean addToBackStack) {
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction transaction = fm.beginTransaction();
for (int i = 0; i < fragments.length; i++) {
if (i == fragmentIndex) {
transaction.show(fragments[i]);
} else {
transaction.hide(fragments[i]);
}
}
if (addToBackStack) {
transaction.addToBackStack(null);
}
transaction.commit();
}
}
导致问题的类＆＃34;是＆＃34;：
public class MainActivity extends FragmentActivity implements
ActionBar.TabListener {
这是XML：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<fragment
class="info.androidhive.tabsswipe.MainActivity"
android:id="@+id/mainActivity2"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<fragment android:name="info.androidhive.tabsswipe.SplashFragment"
android:id="@+id/splashFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<fragment android:name="com.facebook.widget.UserSettingsFragment"
android:id="@+id/userSettingsFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
我尝试过使用＆＃34; class =＆＃34;，＆＃34; android：name =＆＃34;和＆＃34; tag =＆＃34;。
我正在使用这两个类扩展android.support.v4.app.FragmentActivity。
这是日志！
04-02 20:16:33.880: D/KeyHash:(8899): ooZ4+XVqPy+UAL2Sk1NrWojLcIU=
04-02 20:16:33.997: D/AndroidRuntime(8899): Shutting down VM
04-02 20:16:33.997: W/dalvikvm(8899): threadid=1: thread exiting with uncaught exception (group=0x41aaf930)
04-02 20:16:34.028: E/AndroidRuntime(8899): FATAL EXCEPTION: main
04-02 20:16:34.028: E/AndroidRuntime(8899): java.lang.RuntimeException: Unable to start activity ComponentInfo{info.androidhive.tabsswipe/info.androidhive.tabsswipe.MainActivity2}: android.view.InflateException: Binary XML file line #24: Error inflating class fragment
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.os.Handler.dispatchMessage(Handler.java:99)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.os.Looper.loop(Looper.java:137)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.ActivityThread.main(ActivityThread.java:5039)
04-02 20:16:34.028: E/AndroidRuntime(8899): at java.lang.reflect.Method.invokeNative(Native Method)
04-02 20:16:34.028: E/AndroidRuntime(8899): at java.lang.reflect.Method.invoke(Method.java:511)
04-02 20:16:34.028: E/AndroidRuntime(8899): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-02 20:16:34.028: E/AndroidRuntime(8899): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-02 20:16:34.028: E/AndroidRuntime(8899): at dalvik.system.NativeStart.main(Native Method)
04-02 20:16:34.028: E/AndroidRuntime(8899): Caused by: android.view.InflateException: Binary XML file line #24: Error inflating class fragment
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
04-02 20:16:34.028: E/AndroidRuntime(8899): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:270)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.Activity.setContentView(Activity.java:1881)
04-02 20:16:34.028: E/AndroidRuntime(8899): at info.androidhive.tabsswipe.MainActivity2.onCreate(MainActivity2.java:91)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.Activity.performCreate(Activity.java:5104)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-02 20:16:34.028: E/AndroidRuntime(8899): ... 11 more
04-02 20:16:34.028: E/AndroidRuntime(8899): Caused by: java.lang.ClassCastException: info.androidhive.tabsswipe.MainActivity cannot be cast to android.app.Fragment
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.Fragment.instantiate(Fragment.java:585)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.Fragment.instantiate(Fragment.java:560)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.app.Activity.onCreateView(Activity.java:4709)
04-02 20:16:34.028: E/AndroidRuntime(8899): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:680)
04-02 20:16:34.028: E/AndroidRuntime(8899): ... 21 more
04-02 20:16:34.052: D/dalvikvm(8899): GC_CONCURRENT freed 194K, 3% free 9117K/9340K, paused 3ms+2ms, total 30ms
知道导致这个问题的原因是什么？ 提前谢谢你们！
答案 0 :(得分：2)
ClassCastException表示您尝试投放两个不同的内容（例如int和String ..）。在您的情况下，您尝试在布局中使用FragmentActivity类作为片段，但不是，MainActivity是 FragmentActivity 和不是< / strong> a Fragment。
根据你的 LogCat ，这一行：
java.lang.ClassCastException: info.androidhive.tabsswipe.MainActivity cannot be cast to android.app.Fragment
你的问题在这里：
<fragment
class="info.androidhive.tabsswipe.MainActivity"
android:id="@+id/mainActivity2"
android:layout_width="match_parent"
android:layout_height="match_parent" />
info.androidhive.tabsswipe.MainActivity不是Fragment，不能在布局中使用。
<强>更新
在评论中，我建议您重新设计自己的应用。您应首先创建Activity以显示您的登录FB，然后拨打Intent以FragmentActivity显示Tabs并显示您的面板。
你也可以尝试另外一件事：
FragmentActivity，其布局包含FrameLayout（例如id容器），位于Tabs和其他视图中。 FragmentTransaction并在FrameLayout（容器）内显示一个显示登录FB的片段。 remove此片段让用户看到＆＃34;背景＆＃34; 与您的Tabs并显示您的面板内。 希望这有帮助。