Android 最基础生命周期及旋转屏幕问题
1 public class MainActivity extends Activity { 2 3 private static final String TAG ="MainActivity"; 4 5 @Override 6 protected void onCreate(Bundle savedInstanceState) { 7 8 super.onCreate(savedInstanceState); 9 setContentView(R.layout.activity_main); 10 Log.d(TAG, "onCreate"); 11 } 12 13 @Override 14 protected void onStart() { 15 16 super.onStart(); 17 Log.d(TAG, "onStart"); 18 } 19 20 @Override 21 protected void onRestart() { 22 23 super.onRestart(); 24 Log.d(TAG, "onRestart"); 25 } 26 27 @Override 28 protected void onResume() { 29 30 super.onResume(); 31 Log.d(TAG, "onResume"); 32 } 33 34 @Override 35 protected void onPause() { 36 37 super.onPause(); 38 Log.d(TAG, "onPause"); 39 } 40 41 @Override 42 protected void onStop() { 43 44 super.onStop(); 45 Log.d(TAG, "onStop"); 46 } 47 48 @Override 49 protected void onDestroy() { 50 51 super.onDestroy(); 52 Log.d(TAG, "onDestroy"); 53 } 54 55 @Override 56 public void onConfigurationChanged(Configuration newConfig) { 57 58 super.onConfigurationChanged(newConfig); 59 Log.d(TAG, "onConfigurationChanged"); 60 }
Activity各个生命周期
启动：
按返回键：
按home键
按home键后再次从图标启动
竖屏切横屏：
横屏切竖屏：
在AndroidManifest.xml 添加
android:configChanges="orientation"
切屏时和不加一样
根据Android SDK描述，在API13及以上还要加上screenSize。因为横竖屏变化，屏幕横竖尺寸也变化
android:configChanges="orientation|keyboardHidden|screenSize"
"orientation" The screen orientation has changed — the user has rotated the device. Note: If your application targets API level 13 or higher
(as declared by the minSdkVersion and targetSdkVersion attributes),
then you should also declare the "screenSize" configuration,
because it also changes when a device switches between portrait and landscape orientations.
然后再Activity中添加方法：
@Override
public void onConfigurationChanged(Configuration newConfig) {
Log.d(TAG, "onConfigurationChanged");
super.onConfigurationChanged(newConfig);
}
那么再旋转屏幕时，就会执行onConfigurationChanged方法
改变Activity的配置可能会使Activity重启动（默认情况下会重启），如果不想重新启动就需要配置configChanges属性，它可以配置多个用“|”分格。
当 在activity加上android:configChanges="keyboardHidden|orientation"属性,就不会重启 activity.而只是调用onConfigurationChanged(Configuration newConfig).这样就可以在这个方法里调整显示方式.
在xml文件里面可以进行配置configChanges也可以在代码中动态配置
android:configChanges=["mcc", "mnc", "locale",
"touchscreen", "keyboard", "keyboardHidden",
"navigation", "screenLayout", "fontScale",
"uiMode", "orientation", "screenSize",
"smallestScreenSize"]
还有屏幕旋转的相关配置：android:screenOrientation 这个属性是控制Activity启动时候的方向
android:screenOrientation=["unspecified" | "behind" |
"landscape" | "portrait" |
"reverseLandscape" | "reversePortrait" |
"sensorLandscape" | "sensorPortrait" |
"userLandscape" | "userPortrait" |
"sensor" | "fullSensor" | "nosensor" |
"user" | "fullUser" | "locked"]
android:screenOrientation="landscape"---控制Acitvity为横屏显示。
android:screenOrientation="portrait"---控制Activity为竖屏显示
unspecified--系统默认显示
user---用户当前的首选方向
behind---与当前堆栈下面的Activity同向
sensor---根据传感器定（常用）
nosensor---忽略传感器；系统根据unspecified显示
