在onPace、onStop和onDesty方法中调用超类方法的正确顺序是什么？为什么？
在onPace、onStop和onDesty方法中调用超类方法的正确顺序是什么？为什么？
提问于 2018-05-04 04:01:42
我刚刚浏览了Android开发者网站，在Activity Life周期中进行了刷新，并且在每个代码示例中，除了超类方法之外，还有一条评论说“总是首先调用超类方法”。
虽然这在创建半周期中是有意义的：onCreate，onStart和onResume，但我对于在销毁半循环中正确的过程是什么：onPause，onStop，onDestroy。
1.Google建议
@Override
protected void onStop() {
super.onStop(); // Always call the superclass method first
//my implementation here
}
2.另一种方式
@Override
protected void onStop() {
//my implementation here
super.onStop();
}
回答 2
Stack Overflow用户
发布于 2018-05-04 12:48:17
super.overridenMethod()：
if (!mCalled) {
throw new SuperNotCalledException(
"Activity " + mComponent.toShortString() +
" did not call through to super.onStop()");
}
查看Activity.onPause（）的方法体：
protected void onPause() {
if (DEBUG_LIFECYCLE) Slog.v(TAG, "onPause " + this);
// This is to invoke
// Application.ActivityLifecyleCallbacks.onActivityPaused(Activity)
getApplication().dispatchActivityPaused(this);
// The flag to enforce calling of this method
mCalled = true;
}
Activity.onStop（）有一个类似的方法体。看看Activity.onDestroy（）：
protected void onDestroy() {
if (DEBUG_LIFECYCLE) Slog.v(TAG, "onDestroy " + this);
mCalled = true;
// dismiss any dialogs we are managing.
if (mManagedDialogs != null) {
final int numDialogs = mManagedDialogs.size();
for (int i = 0; i < numDialogs; i++) {
final ManagedDialog md = mManagedDialogs.valueAt(i);
if (md.mDialog.isShowing()) {
md.mDialog.dismiss();
}
}
mManagedDialogs = null;
}
// close any cursors we are managing.
synchronized (mManagedCursors) {
int numCursors = mManagedCursors.size();
for (int i = 0; i < numCursors; i++) {
ManagedCursor c = mManagedCursors.get(i);
if (c != null) {
c.mCursor.close();
}
}
mManagedCursors.clear();
}
// Close any open search dialog
if (mSearchManager != null) {
mSearchManager.stopSearch();
}
getApplication().dispatchActivityDestroyed(this);
}
在此，排序可能很重要，具体取决于你的活动设置方式。
下面的代码来自android.app.ListActivity：
public class ListActivity extends Activity {
....
@Override
protected void onDestroy() {
mHandler.removeCallbacks(mRequestFocus);
super.onDestroy();
}
....
}
而且，从包含在android sdk中的LunarLander示例应用程序：
public class LunarLander extends Activity {
....
@Override
protected void onPause() {
mLunarView.getThread().pause(); // pause game when Activity pauses
super.onPause();
}
....
}
Stack Overflow用户
发布于 2018-05-04 13:38:56
这是一个很好的抽象类：
package mobi.sherif.base;
import android.app.Activity;
import android.os.Bundle;
public abstract class BaseActivity extends Activity {
protected abstract void doCreate(Bundle savedInstanceState);
protected abstract void doDestroy();
protected abstract void doResume();
protected abstract void doPause();
protected abstract void doStart();
protected abstract void doStop();
protected abstract void doSaveInstanceState(Bundle outState);
@Override
protected final void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
doCreate(savedInstanceState);
}
@Override
protected final void onDestroy() {
doDestroy();
super.onDestroy();
}
@Override
protected final void onResume() {
super.onResume();
doResume();
}
@Override
protected final void onPause() {
doPause();
super.onPause();
}
@Override
protected final void onStop() {
doStop();
super.onStop();
}
@Override
protected final void onStart() {
super.onStart();
doStart();
}
@Override
protected final void onSaveInstanceState(Bundle outState) {
doSaveInstanceState(outState);
super.onSaveInstanceState(outState);
}
}
这些函数中所做的任何事情对于Activity类来说都是私有的，并且不会与你的子类发生任何冲突。例如（onDestroy）
protected void onDestroy() {
if (DEBUG_LIFECYCLE) Slog.v(TAG, "onDestroy " + this);
mCalled = true;
// dismiss any dialogs we are managing.
if (mManagedDialogs != null) {
final int numDialogs = mManagedDialogs.size();
for (int i = 0; i < numDialogs; i++) {
final ManagedDialog md = mManagedDialogs.valueAt(i);
if (md.mDialog.isShowing()) {
md.mDialog.dismiss();
}
}
mManagedDialogs = null;
}
// close any cursors we are managing.
synchronized (mManagedCursors) {
int numCursors = mManagedCursors.size();
for (int i = 0; i < numCursors; i++) {
ManagedCursor c = mManagedCursors.get(i);
if (c != null) {
c.mCursor.close();
}
}
mManagedCursors.clear();
}
// Close any open search dialog
if (mSearchManager != null) {
mSearchManager.stopSearch();
}
getApplication().dispatchActivityDestroyed(this);
}
创建一个应用程序类来计算当前正在运行的活动的数量：
package mobi.shush;
import android.app.Activity;
import android.app.Application;
import android.app.Application.ActivityLifecycleCallbacks;
import android.os.Bundle;
public class SherifApplication extends Application implements ActivityLifecycleCallbacks {
@Override
public void onCreate() {
super.onCreate();
registerActivityLifecycleCallbacks(this);
}
public int getCount() {
return count;
}
int count = 0;
@Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
count++;
}
@Override
public void onActivityDestroyed(Activity activity) {
count--;
}
@Override
public void onActivityPaused(Activity activity) {}
@Override
public void onActivityResumed(Activity activity) {}
@Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {}
@Override
public void onActivityStarted(Activity activity) {}
@Override
public void onActivityStopped(Activity activity) {}
}
以下几点可能没有意义，或者不是一种好的做法，但它只是证明一个观点（人们可能会发现更真实的情况）。创建MainActivity，当完成时以及最后一次活动时，该活动将被视为GoodBye活动：
@Override
protected void onDestroy() {
super.onDestroy();
if(((SherifApplication) getApplication()).getCount() == 0) {
//i want to go to a certain activity when there are no other activities
startActivity(new Intent(this, GoodBye.class));
}
}
例如，performStop函数调用的函数依次调用onStop函数：
final void performStop() {
if (mLoadersStarted) {
mLoadersStarted = false;
if (mLoaderManager != null) {
if (!mChangingConfigurations) {
mLoaderManager.doStop();
} else {
mLoaderManager.doRetain();
}
}
}
if (!mStopped) {
if (mWindow != null) {
mWindow.closeAllPanels();
}
if (mToken != null && mParent == null) {
WindowManagerGlobal.getInstance().setStoppedState(mToken, true);
}
mFragments.dispatchStop();
mCalled = false;
mInstrumentation.callActivityOnStop(this);
if (!mCalled) {
throw new SuperNotCalledException(
"Activity " + mComponent.toShortString() +
" did not call through to super.onStop()");
}
synchronized (mManagedCursors) {
final int N = mManagedCursors.size();
for (int i=0; i<N; i++) {
ManagedCursor mc = mManagedCursors.get(i);
if (!mc.mReleased) {
mc.mCursor.deactivate();
mc.mReleased = true;
}
}
}
mStopped = true;
}
mResumed = false;
}
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/-100004479
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