横竖屏切换时Activity生命周期变化解析
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作为参考，我们先看下Fragment和Activity的生命周期流程图
Activity各种场景生命周期介绍
下面是Activity的源码：
package com.sharejoys.interviewdemo;
import android.content.Intent;
import android.content.res.Configuration;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import butterknife.ButterKnife;
import butterknife.OnClick;
public class OneActivity extends AppCompatActivity{
private static final String TAG = OneActivity.class.getSimpleName();
@OnClick({R.id.btn1})
public void onViewClicked(View view) {
switch (view.getId()) {
case R.id.btn1:
startActivity(new Intent(OneActivity.this, MainActivity.class));
break;
default:
break;
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_one);
Log.d(TAG, "onCreate");
getSupportActionBar().setTitle("One");
ButterKnife.bind(this);
if (savedInstanceState != null) {
Log.d(TAG, savedInstanceState.getString("key1"));
Log.d(TAG, savedInstanceState.getString("key2"));
}
}
@Override
protected void onStart() {
Log.d(TAG, "onStart");
super.onStart();
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
Log.d(TAG, "onSaveInstanceState");
outState.putString("key1", "value1");
outState.putString("key2", "value2");
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
Log.d(TAG, "onRestoreInstanceState");
if (savedInstanceState != null) {
Log.d(TAG, savedInstanceState.getString("key1"));
Log.d(TAG, savedInstanceState.getString("key2"));
}
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
Log.d(TAG, "onConfigurationChanged");
}
@Override
protected void onResume() {
Log.d(TAG, "onResume");
Configuration mConfiguration = this.getResources().getConfiguration(); //获取设置的配置信息
int ori = mConfiguration.orientation; //获取屏幕方向
if (ori == Configuration.ORIENTATION_LANDSCAPE) {
//横屏
Log.d(TAG, "当前为横屏");
// setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);//强制为竖屏
} else if (ori == Configuration.ORIENTATION_PORTRAIT) {
//竖屏
// setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);//强制为横屏
Log.d(TAG, "当前为竖屏");
}
super.onResume();
}
@Override
protected void onPause() {
Log.d(TAG, "onPause");
super.onPause();
}
@Override
protected void onStop() {
Log.d(TAG, "onStop");
super.onStop();
}
@Override
protected void onDestroy() {
Log.d(TAG, "onDestroy");
super.onDestroy();
}
}
下面是清单文件的配置：
点击运行，正常进入，打印如下信息：
02-28 15:43:16.216 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onCreate
02-28 15:43:16.218 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onStart
02-28 15:43:16.220 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onResume
02-28 15:43:16.220 10244-10244/com.sharejoys.interviewdemo D/OneActivity: 当前为竖屏锁屏打印信息如下：
02-28 15:47:12.897 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onPause
02-28 15:47:12.966 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onSaveInstanceState
02-28 15:47:12.968 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onStop解锁打印信息如下：
02-28 15:49:39.112 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onStart
02-28 15:49:39.113 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onResume
02-28 15:49:39.113 10244-10244/com.sharejoys.interviewdemo D/OneActivity: 当前为竖屏跳转新界面打印信息如下：
02-28 15:50:16.240 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onPause
02-28 15:50:16.629 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onSaveInstanceState
02-28 15:50:16.630 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onStop从新界面返回打印信息如下：
02-28 15:51:05.060 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onStart
02-28 15:51:05.060 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onResume
02-28 15:51:05.061 10244-10244/com.sharejoys.interviewdemo D/OneActivity: 当前为竖屏关闭当前界面打印信息如下：
02-28 15:51:38.904 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onPause
02-28 15:51:39.309 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onStop
02-28 15:51:39.310 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onDestroy横竖屏生命周期变化
Activity清单文件申明没有配置configChanges属性。
进入界面
02-28 15:56:19.791 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onCreate
02-28 15:56:19.793 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onStart
02-28 15:56:19.795 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onResume
02-28 15:56:19.795 10244-10244/com.sharejoys.interviewdemo D/OneActivity: 当前为竖屏手机切换到横屏
02-28 15:57:09.175 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onPause
02-28 15:57:09.176 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onSaveInstanceState
02-28 15:57:09.177 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onStop
02-28 15:57:09.178 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onDestroy
02-28 15:57:09.244 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onCreate
02-28 15:57:09.245 10244-10244/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 15:57:09.245 10244-10244/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 15:57:09.246 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onStart
02-28 15:57:09.246 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onRestoreInstanceState
02-28 15:57:09.246 10244-10244/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 15:57:09.246 10244-10244/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 15:57:09.248 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onResume
02-28 15:57:09.249 10244-10244/com.sharejoys.interviewdemo D/OneActivity: 当前为横屏备注：其中value1和value2是在onSaveInstanceState存储的信息
手机切换回竖屏
02-28 15:58:58.213 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onPause
02-28 15:58:58.213 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onSaveInstanceState
02-28 15:58:58.216 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onStop
02-28 15:58:58.217 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onDestroy
02-28 15:58:58.266 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onCreate
02-28 15:58:58.266 10244-10244/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 15:58:58.266 10244-10244/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 15:58:58.278 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onStart
02-28 15:58:58.279 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onRestoreInstanceState
02-28 15:58:58.279 10244-10244/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 15:58:58.279 10244-10244/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 15:58:58.282 10244-10244/com.sharejoys.interviewdemo D/OneActivity: onResume
02-28 15:58:58.282 10244-10244/com.sharejoys.interviewdemo D/OneActivity: 当前为竖屏从上可知，当清单中没有配置configChanges属性时，从竖屏切换到横屏或者从横屏切换到竖屏，各生命周期都会走一次。
Activity清单文件申明配置configChanges属性，且值设置为orientation。
手机竖屏切换到横屏：
02-28 16:03:21.855 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onPause
02-28 16:03:21.856 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onSaveInstanceState
02-28 16:03:21.857 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onStop
02-28 16:03:21.858 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onDestroy
02-28 16:03:21.911 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onCreate
02-28 16:03:21.912 11214-11214/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 16:03:21.912 11214-11214/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 16:03:21.914 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onStart
02-28 16:03:21.914 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onRestoreInstanceState
02-28 16:03:21.914 11214-11214/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 16:03:21.914 11214-11214/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 16:03:21.916 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onResume
02-28 16:03:21.916 11214-11214/com.sharejoys.interviewdemo D/OneActivity: 当前为横屏手机横屏切换到竖屏：
02-28 16:04:10.753 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onPause
02-28 16:04:10.754 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onSaveInstanceState
02-28 16:04:10.756 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onStop
02-28 16:04:10.756 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onDestroy
02-28 16:04:10.798 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onCreate
02-28 16:04:10.798 11214-11214/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 16:04:10.799 11214-11214/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 16:04:10.808 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onStart
02-28 16:04:10.808 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onRestoreInstanceState
02-28 16:04:10.809 11214-11214/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 16:04:10.809 11214-11214/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 16:04:10.811 11214-11214/com.sharejoys.interviewdemo D/OneActivity: onResume
02-28 16:04:10.811 11214-11214/com.sharejoys.interviewdemo D/OneActivity: 当前为竖屏从上可知，当我们将configChanges的属性设置为orientation，各生命周期也会周一次
Activity清单文件申明配置configChanges属性，且值设置为orientation|keyboardHidden。
手机竖屏切换到横屏
02-28 16:05:58.115 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onPause
02-28 16:05:58.115 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onSaveInstanceState
02-28 16:05:58.126 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onStop
02-28 16:05:58.127 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onDestroy
02-28 16:05:58.165 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onCreate
02-28 16:05:58.165 11793-11793/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 16:05:58.165 11793-11793/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 16:05:58.169 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onStart
02-28 16:05:58.170 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onRestoreInstanceState
02-28 16:05:58.170 11793-11793/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 16:05:58.170 11793-11793/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 16:05:58.172 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onResume
02-28 16:05:58.172 11793-11793/com.sharejoys.interviewdemo D/OneActivity: 当前为横屏手机横屏切换到竖屏：
02-28 16:06:51.952 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onPause
02-28 16:06:51.953 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onSaveInstanceState
02-28 16:06:51.954 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onStop
02-28 16:06:51.955 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onDestroy
02-28 16:06:52.009 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onCreate
02-28 16:06:52.010 11793-11793/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 16:06:52.010 11793-11793/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 16:06:52.013 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onStart
02-28 16:06:52.013 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onRestoreInstanceState
02-28 16:06:52.013 11793-11793/com.sharejoys.interviewdemo D/OneActivity: value1
02-28 16:06:52.013 11793-11793/com.sharejoys.interviewdemo D/OneActivity: value2
02-28 16:06:52.015 11793-11793/com.sharejoys.interviewdemo D/OneActivity: onResume
02-28 16:06:52.015 11793-11793/com.sharejoys.interviewdemo D/OneActivity: 当前为竖屏从上可知，从上可知，当我们将configChanges的属性设置为orientation|keyboardHidde，各生命周期同样也会走一次。
将configChanges的属性设置为orientation|screenSize时
手机竖屏切换到横屏：
02-28 16:10:41.822 12199-12199/com.sharejoys.interviewdemo D/OneActivity: onConfigurationChanged手机横屏切换到竖屏：
02-28 16:10:59.392 12199-12199/com.sharejoys.interviewdemo D/OneActivity: onConfigurationChanged从上可知，当我们将configChanges的属性设置为orientation|screenSize，只会走onConfigurationChange。
总结：
注：以上结果是在android 27（>android 13）上测试得到的结果。
大于Android 3.2（API Level 13）
- 不设置Activity的android:configChanges，或设置Activity的android:configChanges="orientation"时，或是设置android:configChanges="orientation|keyboardHidden，切屏会重新调用各个生命周期，且都只执行一次。
- 设置Activity的android:configChanges="orientation|screenSize"时，切屏不会重新调用各个生命周期，只会执行onConfigurationChanged方法。
小于等于Android 3.2（API Level 13）
- 不设置Activity的android:configChanges时，切屏会重新调用各个生命周期，切横屏时会执行一次，切竖屏时会执行两次。
- 设置Activity的android:configChanges="orientation"时，切屏还是会重新调用各个生命周期，切横、竖屏时只会执行一次。
- 设置Activity的android:configChanges="orientation|keyboardHidden"时，切屏不会重新调用各个生命周期，只会执行onConfigurationChanged方法。
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