Shulou(Shulou.com)06/02 Report--

It is believed that many inexperienced people don't know what to do about how to achieve a friendly and broken interface in Android. Therefore, this article summarizes the causes and solutions of the problem. Through this article, I hope you can solve this problem.

The default crash mechanism of Android is APP flashback, and then displays a dialog box or Toast that "xxx has stopped running". The details of the crash can only be seen by developers in Logcat. Users must be confused when they see this happening. Indeed, this default exception handling is very unfriendly and easy to cause user loss. What we need to do now is that when an exception occurs in the program, a new Activity is created to apologize to the user, output the detailed exception information, and provide the function to submit the exception information to the developer.

First, encapsulate the method in BaseActivity:

/ * BaseActivity: this abstract class defines properties common to all activities. * all active objects in this APP inherit this class. * / public abstract class BaseActivity extends AppCompatActivity {private static final AppManager MANAGER = AppManager.get (); / * onCreate (): override the onCreate () method of the parent class to add this activity to the application manager. * / @ Override protected void onCreate (Bundle savedInstanceState) {super.onCreate (savedInstanceState); MANAGER.addActivity (this);} / / onCreate () / * onDestroy (): override the onDestroy () method of the parent class to remove this activity from the application manager. * / @ Override protected void onDestroy () {super.onDestroy (); MANAGER.removeActivity (this);} / / onDestroy () / * crash (): force the program to crash after catching an unexpected exception. * * @ param e passes in the exception object that caused the crash. * / protected void crash (Exception e) {Intent i; String dump; PrintWriter pw; StringWriter sw; sw = new StringWriter (); pw = new PrintWriter (sw); e.printStackTrace (pw); pw.flush (); dump = sw.toString (); I = new Intent (this, CrashActivity.class); i.putExtra ("dump", dump) StartActivity (I); MANAGER.finishAllExcept (CrashActivity.class);} / / crash () / * getCrashDump (): CrashActivity calls only. * get the incoming dump information. * * @ return the dump information passed in. * / String getCrashDump () {return getIntent () .getStringExtra ("dump");} / / getCrashDump ()} / / BaseActivity Abstract Class / / E.O.F

Two custom classes, AppManager and CrashActivity, are used in BaseActivity. Make sure the next two classes are in the same package as BaseActivity.

Add the AppManager class:

/ * AppManager: used to manage activities. This module can only be used within the base package. * this module is a single instance. You need to call AppManager.get () to obtain the instance and then call the method. *

* to ensure that the application manager works properly, create an abstract class BaseActivity that inherits Activity, and * override the onCreate () and onDestroy () methods of the BaseActivity class. * add the following code to the onCreate () method of the BaseActivity class: * AppManager.get (). AddActivity (this); * add the following code to the onDestroy () method of the BaseActivity class: * AppManager.get (). RemoveActivity (this); * finally, make sure that all active classes in this APP inherit from the BaseActivity class. * / class AppManager {private static final AppManager MANAGER = new AppManager (); private Stack mStack; private AppManager () {/ / set the scope keyword to private to hide the constructor of this class. MStack = new Stack ();} / / AppManager () (Class Constructor) / * get (): get the singleton of the AppManager class. The singleton MANAGER of the * * @ return class. * / static AppManager get () {return MANAGER;} / / get () / * addActivity (): add an active object to the stack. * * @ param activity the active object to add. * / void addActivity (BaseActivity activity) {mStack.add (activity); Log.i ("AppManager", "[+] Created:" + activity.getClass (). GetName ());} / / addActivity () / * removeActivity (): removes an active object from the stack. * * @ param activity the active object to remove. * / void removeActivity (BaseActivity activity) {mStack.remove (activity); Log.i ("AppManager", "Removed:" + activity.getClass (). GetName ());} / / removeActivity () / * finishAllExcept (): ends all activities in the stack except one specific activity. * the onDestroy () method of the BaseActivity class is triggered at the end of the activity, and the active objects in the stack are removed synchronously. * * @ param cls the class name of the activity to keep (xxxActivity.class) * / void finishAllExcept (Class cls) {int I, len; BaseActivity [] activities / / the onDestroy () method of the activity is called at the end of the activity, and the contents of the stack will be changed in real time / / to avoid reference errors caused by this, copy the contents of the stack to a temporary array activities = mStack.toArray (new BaseActivity [0]); len = activities.length; for (I = 0; I < len) + + I) {if (cls [I] .getClass ()! = cls) {/ / reference the active object from the array and end it. Changes in the stack contents do not affect the array definitions [I] .getClass ();} / / if [I] .getClass ()! = cls)} / / for (I = 0; I < len) + + I)} / / finishAllExcept () / * finishAllActivities (): ends all activities in the stack. * the onDestroy () method of the BaseActivity class is triggered at the end of the activity, and the active objects in the stack are removed synchronously. * / void finishAllActivities () {int I, len; BaseActivity [] activities; / / the active onDestroy () method is called when the activity ends, and the contents of the stack will be changed in real time / / to avoid reference errors caused by this, first copy the contents of the stack to a temporary array activities = mStack.toArray (new BaseActivity [0]); len = activities.length For (I = 0; I < len; + + I) {/ / references the active object from the array and ends. The change in the stack content does not affect the array values [I] .arrays ();} / / for (I = 0; I < len; + + I)} / / finishAllActivities ()} / / AppManager Class / / E.O.F

Create a new CrashActivity activity.

Active layout file activity_crash.xml

Add to the string resource strings.xml

An unexpected error occurred in the program\ nWe are very sorry for the inconvenience\ nThe following are the error details.

CrashActivity.java Code:

/ * CrashActivity: this activity is activated by any activity calling the crash () method. Outputs the exception information thrown. * / public class CrashActivity extends BaseActivity {/ / Note here is inheriting BaseActivity / * onCreate (): triggered when the activity is created. * / @ Override protected void onCreate (Bundle savedInstanceState) {String dump; TextView lblDetail; super.onCreate (savedInstanceState); setContentView (R.layout.activity_crash); dump = getCrashDump (); lblDetail = findViewById (R.id.lblCrashDetail); lblDetail.setText (dump); lblDetail.setMovementMethod (ScrollingMovementMethod.getInstance ()) } / / onCreate () / * onKeyDown (): triggered when the back key is pressed. * exit the program directly. * / @ Override public boolean onKeyDown (int keyCode, KeyEvent event) {if (keyCode = = KeyEvent.KEYCODE_BACK) {AppManager.get () .finishAllActivities (); return true;} / / if (keyCode = = KeyEvent.KEYCODE_BACK) else {return super.onKeyDown (keyCode, event) } / / else} / / onKeyDown () / * onUserLeaveHint (): triggered when you press the HOME key to return to the desktop. Just exit the program. * / @ Override protected void onUserLeaveHint () {AppManager.get () .finishAllActivities ();} / / onUserLeaveHint ()} / / CrashActivity Class / / E.O.F

What we need to do next is to catch the exception when the program throws it and bring the exception content into the CrashActivity. To do this, we need to add try/catch statement blocks to all the public and protected methods in Activity. (the private method does not need to be added, because the private method must also be called by a public or protected method, and the public/protected method that calls it is already catching exceptions.)

Let's add a button to MainActivity. The activity_main.xml layout code is as follows:

Add to strings.xml:

Crash test

MainActivity.java Code:

Public class MainActivity extends BaseActivity {/ / Note here inherits BaseActivity @ Override protected void onCreate (Bundle savedInstanceState) {/ / protected method must be wrapped in try/catch to add crash (e); statement to achieve friendly crash try {super.onCreate (savedInstanceState); setContentView (R.layout.activity_main) } / / try catch (Exception e) {crash (e);} / / catch (Exception e)} / / onCreate () public void onBtnCrashTestTapped (View v) {int [] arr; / / public method must be wrapped in try/catch / / add crash (e) to catch Statement to achieve a friendly crash try {arr = new int [4]; crashTest (arr);} / / try catch (Exception e) {crash (e) } / / catch (Exception e)} / / onBtnCrashTestTapped () private void crashTest (int [] arr) {/ / private method is not wrapped in try/catch / / unless a method with the throws keyword is called to force an exception arr [4] = 4 / / because the length of the arr array passed in is 4, an array out of bounds exception} / / crashTest ()} / / MainActivity Class / / E.O.F will be thrown here.

Install it on the phone and test it.

Click the [crash Test] button

The demo program here does not add the ability to submit error reports to developers, but of course the focus is on implementing a friendly crash interface.

After reading the above, have you mastered how Android can achieve a friendly crash interface? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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