前提：
如果有动画，最好把activity 设置成透明，不然会有黑屏！
<style name="Trancelust" parent="AppTheme"><item name="android:windowIsTranslucent">true</item></style>
方法一：代码里面设置
getActivity().startActivity(intent,bundle);getActivity().overridePendingTransition( R.anim.push_left_in,0);
@Overridepublic void finish() {super.finish();overridePendingTransition(0, R.anim.push_right_out);}
注意：overridePendingTransition一定要在startActivity 或者finish 之后调用，否则没有效果！而且可能会有各种其他问题！
具体原因得看源码。我们可以先看下overridePendingTransition 的注释：
/*** Call immediately after one of the flavors of {@link #startActivity(Intent)}* or {@link #finish} to specify an explicit transition animation to* perform next.** <p>As of {@link android.os.Build.VERSION_CODES#JELLY_BEAN} an alternative* to using this with starting activities is to supply the desired animation* information through a {@link ActivityOptions} bundle to* {@link #startActivity(Intent, Bundle) or a related function. This allows* you to specify a custom animation even when starting an activity from* outside the context of the current top activity.** @param enterAnim A resource ID of the animation resource to use for* the incoming activity. Use 0 for no animation.* @param exitAnim A resource ID of the animation resource to use for* the outgoing activity. Use 0 for no animation.*/public void overridePendingTransition(int enterAnim, int exitAnim) {
方法二：给activity 设置theme
<activity android:name="com.example.activity.AnimationActivity"android:theme="@style/AnimationActivityTheme"><style name="AnimationActivityTheme" parent="AppTheme"><item name="android:windowAnimationStyle">@style/left_in_right_out</item><item name="android:windowIsTranslucent">true</item></style><style name="left_in_right_out" mce_bogus="1" parent="AppTheme"><item name="android:activityOpenEnterAnimation">@anim/push_left_in</item><item name="android:activityOpenExitAnimation">@anim/push_right_out</item><item name="android:activityCloseEnterAnimation">@anim/push_left_in</item><item name="android:activityCloseExitAnimation">@anim/push_right_out</item></style>
left_in xml
<?xml version="1.0" encoding="utf-8"?><set xmlns:android="/apk/res/android"><translateandroid:duration="@android:integer/config_mediumAnimTime"android:fromXDelta="100%p"android:interpolator="@android:anim/accelerate_decelerate_interpolator"android:toXDelta="0" /></set>
right_out xml
<?xml version="1.0" encoding="utf-8"?><set xmlns:android="/apk/res/android"><translateandroid:duration="@android:integer/config_mediumAnimTime"android:fromXDelta="0"android:interpolator="@android:anim/accelerate_decelerate_interpolator"android:toXDelta="100%p" /></set>
总结：
1.使用theme 的方式在有些手机上有问题，可能动画不是你设置的，但是代码的没有问题。
2.有些手机room 自己修改了动画的方向，所以，不一定是你的代码生效了，而是默认就是这种动画。
比如小米手机启动activity ，不设置就是左进右出。
3.代码代用顺序问题。顺序不对，动画不生效，而且还会产生问题。
一定要先startActivity，或者 先finish，再调用overridePendingTransition
为什么一定要先startActivity，或者 先finish？
可以跟一下源码
Activity 的overridePendingTransition
public void overridePendingTransition(int enterAnim, int exitAnim) {try {ActivityManager.getService().overridePendingTransition(mToken, getPackageName(), enterAnim, exitAnim);} catch (RemoteException e) {}}
可以看到会调用 ActivityManager.getService().overridePendingTransition，也就是ActivityManagerService的overridePendingTransition
@Overridepublic void overridePendingTransition(IBinder token, String packageName,int enterAnim, int exitAnim) {synchronized(this) {ActivityRecord self = ActivityRecord.isInStackLocked(token);if (self == null) {return;}final long origId = Binder.clearCallingIdentity();if (self.state == ActivityState.RESUMED|| self.state == ActivityState.PAUSING) {mWindowManager.overridePendingAppTransition(packageName,enterAnim, exitAnim, null);}Binder.restoreCallingIdentity(origId);}}
又会调用mWindowManager （WindowManagerService） 的overridePendingAppTransition
@Overridepublic void overridePendingAppTransition(String packageName,int enterAnim, int exitAnim, IRemoteCallback startedCallback) {synchronized(mWindowMap) {mAppTransition.overridePendingAppTransition(packageName, enterAnim, exitAnim,startedCallback);}}
最终调用 mAppTransition.overridePendingAppTransition。也就是AppTransition 这个类。
void overridePendingAppTransition(String packageName, int enterAnim, int exitAnim,IRemoteCallback startedCallback) {if (isTransitionSet()) {clear();mNextAppTransitionType = NEXT_TRANSIT_TYPE_CUSTOM;mNextAppTransitionPackage = packageName;mNextAppTransitionEnter = enterAnim;mNextAppTransitionExit = exitAnim;postAnimationCallback();mNextAppTransitionCallback = startedCallback;} else {postAnimationCallback();}}boolean isTransitionSet() {return mNextAppTransition != TRANSIT_UNSET;}
可以看到这里面有一个isTransitionSet() 方法，默认是TRANSIT_UNSET，只有startActivity 或者finish 之后，这个mNextAppTransition 才不是TRANSIT_UNSET。所以需要先startActivity 或者finish，然后overridePendingTransition才会有作用。每次动画结束，这个值又会被值为TRANSIT_UNSET。
