Activity 基础 管理器 生命周期
目录
目录
Activity 基础 管理器 生命周期
应用进入前后台判断
getApplication().registerActivityLifecycleCallbacks(new SampleActivityLifecycleCallbacks() {
private int mFinalCount;
@Override
public void onActivityStarted(Activity activity) {
super.onActivityStarted(activity);
mFinalCount++;
if (mFinalCount == 1){
//如果mFinalCount ==1，说明是从后台到前台
}
}
@Override
public void onActivityStopped(Activity activity) {
super.onActivityStopped(activity);
mFinalCount--;
if (mFinalCount == 0){
//如果mFinalCount ==0，说明是前台到后台
}
}
}
获取自己App中的所有Activity
try {
PackageInfo packageInfo = getPackageManager().getPackageInfo(getPackageName(), PackageManager.GET_ACTIVITIES);
for (ActivityInfo activity : packageInfo.activities) {
Log.i("bqt", activity.name); //com.bqt.test.MainActivity
}
} catch (PackageManager.NameNotFoundException e) {
e.printStackTrace();
}
获取栈顶和栈底的Activity
ActivityManager manager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningTaskInfo> list = manager.getRunningTasks(Integer.MAX_VALUE);
for (ActivityManager.RunningTaskInfo info : list) {
Log.i("bqt", info.topActivity.getClassName() + "---" + info.baseActivity.getClassName());
}
Activity管理器
ActivityStackManager
定义一个集合（Stack）保存所有还未销毁的 Activity
public class ActivityStackManager {
private Stack<ActivityInfo> activityStack;
private static ActivityStackManager instance = new ActivityStackManager();
private ActivityStackManager() {//构造方法私有
}
public static ActivityStackManager getInstance() {
return instance;
}
//入栈
public void push(Activity activity) {
if (activityStack == null) activityStack = new Stack<>();
for (int i = 0; i < activityStack.size(); i++) {
if (activity == activityStack.get(i).activity) return;
}
activityStack.add(ActivityInfo.newBuilder()
.activity(activity)
.startTime(System.currentTimeMillis())
.build());
}
//出栈
public void pop(Activity activity) {
if (activityStack != null && activityStack.size() > 0 && activity != null) {
activity.finish();
activityStack.remove(new ActivityInfo(activity));
}
}
//第一种方式
public ActivityInfo getActivityInfo(Activity activity) {
ActivityInfo activityInfo = null;
if (activityStack != null && activityStack.size() > 0) {
for (ActivityInfo info : activityStack) {
if (info.activity == activity) {
activityInfo = info;
break;
}
}
}
return activityInfo;
}
//第二种方式，不建议采用这种方式，因为在使用中发现可能会报数组越界异常
//原因可能是当我通过search查找到之后和通过get获取之前这段时间，某个Activity被移除掉了，所以导致数组大小改变，取值时就可能越界了
public ActivityInfo getActivityInfo2(Activity activity) {
ActivityInfo activityInfo = null;
if (activityStack != null && activityStack.size() > 0) {
int index = activityStack.search(new ActivityInfo(activity));
if (index >= 0) {
activityInfo = activityStack.get(index);
}
}
return activityInfo;
}
public long getStartTime(Activity activity) {
ActivityInfo activityInfo = getActivityInfo(activity);
return activityInfo != null ? activityInfo.startTime : 0;
}
}
registerActivityLifecycleCallbacks
注册 Activity 生命周期回调
registerActivityLifecycleCallbacks(new ActivityLifecycleCallbacks() {
@Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
ActivityStackManager.getInstance().push(activity);
}
@Override
public void onActivityDestroyed(Activity activity) {
long time = ActivityStackManager.getInstance().getStartTime(activity);
String date = new SimpleDateFormat("yyyy.MM.dd HH:mm:ss SSS", Locale.getDefault()).format(new Date(time));
Log.i("bqt", "【" + activity.getClass().getSimpleName() + "启动时间】" + date);
ActivityStackManager.getInstance().pop(activity);//必须放在获取消息后面，否则一经清空了就获取不到了
}
@Override
public void onActivityStarted(Activity activity) {
}
@Override
public void onActivityResumed(Activity activity) {
Log.i("bqt", "当前Activity" + "(" + activity.getClass().getSimpleName()+".java" + ":" +30 + ")");
}
@Override
public void onActivityPaused(Activity activity) {
}
@Override
public void onActivityStopped(Activity activity) {
}
@Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
}
});
ActivityInfo
保存与Activity相关的一些信息
//用于保存Activity示例以及与Activity相关的一些信息，比如Activity启动时间等
public class ActivityInfo {
public Activity activity;
public long startTime;
public ActivityInfo(Activity activity) {
this.activity = activity;
}
@Override
public boolean equals(Object obj) {//必须重写equals方法
return obj instanceof ActivityInfo && ((ActivityInfo) obj).activity.equals(activity);
}
//省略Builder代码
}
一个通用的AppManager
/**
* activity堆栈式管理
*/
public class AppManager {
private static Stack<Activity> activityStack;
private static AppManager instance;
private AppManager() {
}
public static AppManager getAppManager() {
if (instance == null) {
instance = new AppManager();
}
return instance;
}
/**
* 添加Activity到堆栈
*/
public void addActivity(Activity activity) {
if (activityStack == null) {
activityStack = new Stack<>();
}
activityStack.add(activity);
}
/**
* 获取当前Activity（堆栈中最后一个压入的）
*/
public Activity currentActivity() {
return activityStack.lastElement();
}
/**
* 结束当前Activity（堆栈中最后一个压入的）
*/
public void finishActivity() {
Activity activity = activityStack.lastElement();
finishActivity(activity);
}
/**
* 结束指定的Activity
*/
public void finishActivity(Activity activity) {
if (activity != null && !activity.isFinishing()) {
activityStack.remove(activity);
activity.finish();
activity = null;
}
}
/**
* 结束指定类名的Activity
*/
public void finishActivity(Class<?> cls) {
for (Activity activity : activityStack) {
if (activity.getClass().equals(cls)) {
finishActivity(activity);
break;
}
}
}
/**
* 结束所有Activity
*/
public void finishAllActivity() {
for (int i = 0, size = activityStack.size(); i < size; i++) {
if (null != activityStack.get(i)) {
finishActivity(activityStack.get(i));
break;
}
}
activityStack.clear();
}
/**
* 获取指定的Activity
*/
public static Activity getActivity(Class<?> cls) {
if (activityStack != null)
for (Activity activity : activityStack) {
if (activity.getClass().equals(cls)) {
return activity;
}
}
return null;
}
public static Stack<Activity> getActivitys() {
return activityStack;
}
/**
* 退出应用程序
*/
public void AppExit(Context context) {
try {
finishAllActivity();
android.os.Process.killProcess(android.os.Process.myPid());// 杀死该应用进程
System.exit(0);
} catch (Exception ignored) {
}
}
/**
* 返回当前Activity栈中Activity的数量
*/
public int getActivityCount() {
int count = activityStack.size();
return count;
}
/**
* 堆栈中移除Activity
*/
public void removeActivity(Activity activity) {
if (activityStack == null) {
return;
} else if (activityStack.contains(activity)) {
activityStack.remove(activity);
}
if (activity != null && !activity.isFinishing()) {
activity.finish();
activity = null;
}
}
}
零碎知识点
启动Activit
public static void launche(Context ctx) {
Intent intent = new Intent(ctx, TestActivity.class);
intent.putExtra("", "");
ctx.startActivity(intent);
}
启动并返回数据
public static void launche(Activity ctx, int requestCode) {
Intent intent = new Intent(ctx,TestActivity.class);
intent.putExtra("", "");
ctx.startActivityForResult(intent, requestCode);
}
@Override
public void finish() {
Intent intent = new Intent();
intent.putExtra("", "");
setResult(RESULT_OK, intent);
super.finish();
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK && requestCode == 123 && data != null) {
aaa = data.getParcelableArrayListExtra("aaa");
}
}
启动其他应用的Activity
Intent intent = new Intent();
intent.setComponent(new ComponentName(packageName, "com.bqt.test.MainActivity"));//需要提供包名和Activity完整类名
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
//intent.setAction("android.intent.action.MAIN");
context.startActivity(intent);
同时启动多个Activity
Intent second = new Intent(this,SecondActivity.class); //先启动SecondActivity
Intent third = new Intent(this,ThirdActivity.class); //再启动ThirdActivity
startActivities(new Intent[]{second,third});
等价于
startActivity(new Intent(this, SecondActivity.class)); //先启动SecondActivity
startActivity(new Intent(this, ThirdActivity.class)); //再启动ThirdActivity
我们先启动的是SecondActivity，然后启动ThirdActivity
但是实际上用户只看到启动了ThirdActivity，ThirdActivity返回时用户会看的SecondActivity
重新启动一个Activity
第一种方式，调用 recreate() 方法，会自动走一遍Activity的生命周期
第二种方式，先调用 Activity 的 finish() 方法，再启动【startActivity(activity.getIntent())】
按返回键让Frag回退到上一个网页
Activity
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && fragment != null) {
return fragment.goBack() || super.onKeyDown(keyCode, event);
}
return super.onKeyDown(keyCode, event);
}
Fragment
private String preUrl;//防止网页挂掉时一直返回不了的问题
public boolean goBack() {
if (mWebView.canGoBack() && !mWebView.getUrl().equals(preUrl)) {//防止网页挂掉时一直返回不了的问题
preUrl = mWebView.getUrl();
mWebView.goBack();
return true;
}
return false;
}
再按一次返回键退出
private long currentBackPressedTime = 0;
/**
* 退出间隔
*/
public static final int BACK_PRESSED_INTERVAL = 2000;
@Override
public void onBackPressed() {
if (System.currentTimeMillis() - currentBackPressedTime > BACK_PRESSED_INTERVAL) {
currentBackPressedTime = System.currentTimeMillis();
Toast.makeText(this, "再按一次返回键退出", Toast.LENGTH_SHORT).show();
} else {
finish();
}
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) { //onKeyDown的优先级比onBackPressed高
onBackPressed();
return true;//消耗掉此事件
} else {
return super.onKeyDown(keyCode, event);
}
}
防止短时间内按钮被快速点击
方式一，放在BaseActivity中统一处理：
private long lastClickTime;
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (ev.getAction() == MotionEvent.ACTION_DOWN) {
if (isFastDoubleClick()) {
return true;//消耗掉 ACTION_DOWN 事件
}
}
return super.dispatchTouchEvent(ev);
}
public boolean isFastDoubleClick() {
long timeD = System.currentTimeMillis() - lastClickTime;
lastClickTime = System.currentTimeMillis();
return timeD <= 500;
}
方式二，工具类判断：
public class FastClickUtils {
private static final int MIN_DELAY_TIME = 1000; // 两次点击间隔不能少于1000ms
private static long lastClickTime;
public static boolean isFastClick() {
return isFastClick(MIN_DELAY_TIME);
}
public static boolean isFastClick(long delayTime) {
boolean flag = true;
long currentClickTime = System.currentTimeMillis();
if (currentClickTime - lastClickTime >= delayTime) {
flag = false;
}
lastClickTime = currentClickTime;
return flag;
}
}
ListActivity模板代码
public class MainActivity extends ListActivity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
String[] array = {"",
"",
"",
"",};
setListAdapter(new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, array));
array[0] = getListView().getParent().getClass().getName(); //FrameLayout，所以不要在Parent中addView
ImageView imageView = new ImageView(this);
imageView.setImageResource(R.drawable.icon);
getListView().addFooterView(imageView);
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
switch (position) {
case 0:
break;
case 1:
break;
case 2:
break;
}
}
}
2018-5-30
本文来自博客园，作者：白乾涛，转载请注明原文链接：https://www.cnblogs.com/baiqiantao/p/9112611.html
