What are Android ANRs? How to avoid and solve ANR (important)

What are Android ANRs? How to avoid and solve ANR (important)

ANR (Application Not Responding) refers to the situation where an Android application cannot respond to user input or interact with the system when it performs time-consuming or blocking operations on the main thread (UI thread). When an ANR occurs, the application is considered unresponsive by the system and may cause the application to crash or be forced to close by the user.

In Android application development, common ANR (Application Not Responding) problems include:

• InputDispatchingTimeout: This type of ANR is raised by the system when the app fails to respond to user input events (such as clicks, touch events) within 5 seconds. This usually happens when a time-consuming or blocking operation is performed on the main thread, preventing user input events from being processed.

• BroadcastTimeout: When the broadcast receiver (BroadcastReceiver) fails to complete the broadcast processing within 10 seconds, the system will trigger this type of ANR. This could be due to time-consuming operations performed in the broadcast receiver, or operations on the main thread that take a long time to complete.

• ServiceTimeout: When the service (Service) fails to complete the operation or respond to the request from other components within 20 seconds, the system will raise this type of ANR. Similar to ANRs from broadcast receivers and the application's main thread, this can be caused by time-consuming or blocking operations performed in the service.

• ContentProviderTimeout: This type of ANR is triggered when a content provider (ContentProvider) fails to complete a request from another application within 10 seconds. This could be due to the content provider performing time-consuming database queries or operations that process large amounts of data.

• ANR in a third-party library or component: ANR problems can also be caused by improper use of third-party libraries or components. For example, if a time-consuming third-party library call is performed on the UI thread, it may also cause the application to become unresponsive.

These are common ANR problems in Android. When ANR occurs, the problem should be solved by optimizing the code, using asynchronous operations, setting a reasonable timeout period, etc., to ensure that the application can respond to user operations in a timely manner, and avoid application unresponsiveness or crash caused by ANR.

To avoid and resolve ANR issues, here are some suggestions:

• Use asynchronous operations: Ensure lightweight tasks are performed on the main thread, while moving time-consuming operations (such as network requests, database queries, etc.) to background threads. You can use threads, Handler, AsyncTask, Executor, etc. to handle asynchronous operations.

• Optimize code and algorithms: Make sure your code runs efficiently and avoid using complex algorithms or double calculations as much as possible. For time-consuming operations, try to use more efficient methods.

• Use multithreading: process time-consuming operations in separate threads to avoid blocking the main thread. Multithreaded operations can be managed using Java's threads or thread pools.

• Using Handler and Message Queue: Through the Handler and Message Queue mechanism, operations can be performed in a background thread and the UI can be updated in the main thread. This ensures that UI operations are performed in the main thread, avoiding ANR issues.

• Use AsyncTask or Loader: Android provides classes such as AsyncTask and Loader to simplify asynchronous operations. They provide convenience methods to perform tasks in the background and update the UI in the main thread.

• Avoid main thread blocking: Avoid performing time-consuming operations on the main thread, such as long network requests, complex calculations, or file operations. These operations should be done in background threads or asynchronous tasks.

• Reasonably set the timeout period: If the application needs to perform time-consuming operations, the timeout period should be set within a reasonable time. If the operation does not complete within the timeout period, you can choose to cancel the operation or perform appropriate error handling.

• Use HandlerThread or IntentService: If you need to perform long-running tasks in the background, you can use HandlerThread or IntentService to manage threads. They provide convenience methods to handle background tasks and communicate with the main thread.

• Use an asynchronous library or framework: Using an asynchronous processing library or framework like RxJava, Coroutines, etc. can simplify the management of asynchronous operations and provide better control and error handling mechanisms.

• Regularly check for ANR issues: During development, you should periodically check your app for ANR issues. You can monitor application response time, check the running status of the main thread, and use tools such as Systrace, Traceview, etc. to analyze application performance and troubleshoot potential problems.

In short, the key to avoiding and solving the ANR problem is to perform time-consuming operations in a background thread and ensure that the main thread can respond to user input and system interaction in a timely manner. Reasonable asynchronous processing, optimized code and algorithm, and proper thread management are the keys to effectively solve the ANR problem.